Monday, August 15, 2011

Can nasty dewpoints be useful?

Have you ever sat around when its 95 over 82, with 6000 J/kg of CAPE laughing at you, frustrated why you can't buy a cumulus cloud, much less a thunderstorm? Well, I have. And since we had quite a few of those days this summer, I did a bit of thinking. Two questions:

1. Why do you never see temperatures well above 100 with dewpoints of ~78F+? Note that all the extremely hot days in the southern plains usual see 100F+ temperatures with dewpoints 70F or lower.
2. In the summer, why is it that you can get very high dewpoints without even a cloud, while other areas with lower dewpoints see storms?

To answer both of these, I'll use a simple equation that explains dewpoint tendency within the boundary layer:


Now let's butcher this equation...

The first term is the dewpoint tendency, because we're talking about those nasty days where the dewpoint stayed at 81 or whatever all day, term (1) is 0. Also, many of those days were fairly calm, so the horizontal advection of dewpoint, term 2, is negligible. In fact, if we're trying to explain 80+ dewpoints, then this term can only be detrimental to us, because dewpoints all around are likely equal or lower than ours, so this can only be a sink term. Thus, all this simplifies down to 2 things, upward motion and plant breathing. Plants consistently add moisture to the air, so term (3) turns out to be the most efficient way to lower the dewpoint on a calm summer day...

Finally, this brings me to the conclusion: the reason why we don't see thunderstorms with 80+ dewpoints is because of the dewpoints themselves! They are telling us that the cap is incredibly strong so there's hardly any mixing going on with the free atmosphere (even though the boundary layer itself is growing in height). This may also explain why it's hard to get 100+ temperatures with 80+ dewpoints. In order to get 100+, there almost has to be mixing down of the high-theta air that resides within the cap...

Anyways, that's two cents for the day.

Dima

Thursday, July 14, 2011

Heat Wave - Martha and the Vandellas Style

Well hey there!

Since no one is posting or chasing because the dog days of summer are about to set in, I decided to post an 850 hPa map from GFS 1200 UTC 14 July 2011 to show the world how much fun everyone is going to have during this heat wave! This is a plot for 120 hr ahead (0000 UTC Fri):



Thank you eastern US ridge!!! Time to drive up the a/c utility costs!

Helicity

Tuesday, June 21, 2011

UW Storm Chasing - Alumni Edition

What up team UW-Madison,

While chasing today in the US is most likely going to involve chasing some sort of QLCS or MCS or something, we will be sending out a chase car to see if we can bag a tornado during the middle afternoon hours before everything goes to H-E-double hockey sticks. I describe some advantages and disadvantages below, and note that this discussion is brief and very casual, so if you want to comment more on it go for it, that's what this blog is all about baby:

Chasing Advantages:

Wisconsin located in the warm sector, near the triple point of the deep low pressure system. An occlusion will develop, with the warm sector branching from the twin cities clockwise to Madison and into Illinois. Warm, moist air will be advected from the Gulf of Mexico region into the upper Midwest, and this along with daytime heating will allow for the breaking up of a very weak (if at all even one) EML and morning cap over eastern Iowa and into south-central Wisconsin and destabilize the atmosphere this afternoon. SBCAPE values will reach 1500-2000 J/kg this afternoon. In terms of shear, the region exhibiting maximum helicity (both 0-1 km and 0-3 km) occurs near the warm front, which will push northward into eastern MN and central WI by 1800-1900 UTC. This, along with strong upper level forcing associated with the approaching upper level trough will allow for development of some respectable convection, and hopefully some discrete cells will fire between the triple point and near the warm front starting ~4 pm local time (2100 UTC).

Also, we'll be in Wisconsin, so the home crowd is on our side (that means wear the red AOS "home" jerseys and khaki shorts or else...)

Chasing Disadvantages:

Well, the shear profile is not the best in terms of chasing tornadoes today. Wind speeds remain southerly throughout the lower and middle troposphere east of the cold front (Illinois, southern Wisconsin, southeastern Iowa, south from Illinois towards the Gulf of Mexico), and bulk shear and helicity values (according to the 1200 UTC NAM and HRRR) are not favorable except near the warm front by I90/I94 during the afternoon hours. Since CAPE values are favorable east of the cold front and within the warm sector near the triple point, my guess is that any storms that fire will become linear and form some sort of squall line (with respect to the upper Midwest). Hence, chances of chasing tornadoes safely and accurately are not too high, except for near the warm front and triple point.

OUR GO ZONE: Tomah, WI. It will be just south of the warm front and south-east of the triple point, and is also near the I90/I94 interchange. If we get there by 1830 UTC (1:30 pm CDT), this will give us plenty of time to check out cumulus fields via satellite data (and our eyeballs) and see where to go from there. HRRR is showing lots of scattered convection and cells starting around 2100 UTC. I'm not trusting the HRRR completely, since it overestimated the strength of this morning's MCS and made the one in central Illinois look more epic than it really was. While are chances at seeing a tornado are very small, this will give us a chance to catch any supercells early on before they either die off or possibly congeal and kill our chasing chances for the evening.

Peace out,

Helicity and friends

P.S. Don't hate, use KolourPaint:

Sunday, June 19, 2011

Area Forecast discussion...for Monday June 20

I don't post much...but I thought since I took the time to do this
that it should go on the Tommy HRRRRR page...I really wanted to drop
the phrase "go zone"...but didn't want to sound like I was favoring
severe weather...death...and destruction...

A WEAKENING MCS IS EXPECTED TO BE ONGOING BY 12Z TOMORROW MORNING.
THE EXACT PLACEMENT OF THIS MCS...AND THE OUTFLOW BOUNDARIES IT LEAVES
BEHIND WILL HAVE A LARGE IMPACT THE TIMING AND PLACEMENT OF CONVECTIVE
INITIATION MONDAY AFTERNOON. GUIDANCE SHOWS A SHORTWAVE MOVING ACROSS
THE IA/SD/NE BORDER EARLY MONDAY MORNING...WITH THE BEST H850 THETA_E
ADVECTION ACROSS THE IA/MN BORDER. THESE LINGERING THUNDERSTORMS SHOULD
BE ELEVATED...WITH MINIMAL THREAT FOR SEVERE WEATHER...ALTHOUGH A STRAY
WIND OR HAIL REPORT IS POSSIBLE. HAVE HIGHEST POPS ACROSS THE NORTH
TO REFLECT THE NORTHERN TRACK SUPPORTED IN BY THE QPF PLACEMENT IN
THE 19.12Z GFS..ECMWF..AND NAM. HOWEVER...EXPANDED POPS ACROSS THE
ENTIRE CWA TO ACCOUNT FOR THE CONVECTION THAT IS EXPECTED TO BREAK
OUT ACROSS NEBRASKA SUNDAY EVENING...AND MAY STILL BE AROUND BY THE
START OF THE PERIOD.
THROUGHOUT THE REST OF THE MORNING HOURS AND INTO EARLY MONDAY
AFTERNOON...THE UPPER LEVEL PV ANOMALY ACROSS THE TX/OK PANHANDLES
SHOULD CONGEAL AN TAKE ON A NEGATIVE TILT AS THE JET STREAK ROUNDS
THE BASE OF THE TROUGH. ANY RESIDUAL CLOUD COVER FROM THE OVERNIGHT
CONVECTION SHOULD QUICKLY DISSIPATE...AND WARM AIR ADVECTION WITH
H700 TEMPS OF 14-16C WILL ESTABLISH A CAP ACROSS CWA. AN ELEVATED
MIXED LAYER FROM 700-500MB...COMBINED WITH AFTERNOON CLEARING SHOULD
ALLOW THE BOUNDARY LAYER TO RAPIDLY DESTABILIZE WITH SBCAPES OF
3000-4000J/KG IN PLACE BY LATE AFTERNOON. THIS CONDITIONAL INSTABILITY
WILL LIKELY BE REALIZED BY LATE AFTERNOON/EARLY EVENING AS THE STRONG
SYNOPTIC FORCING WITH THE HEIGHT FALLS AHEAD OF THE PV ANOMALY WILL
DYNAMICALLY DESTABILIZE THE MID LEVELS AND ERODE THE CAP. GIVEN THE
FAVORABLE THERMODYNAMIC ENVIRONMENT IN PLACE...ATTENTION THEN TURNS
TO THE WIND PROFILE TO DIAGNOSE THE CONVECTIVE MODE. BY MONDAY AFTERNOON
THE AFOREMENTIONED JET STREAK WILL BE SURGING NORTHWARD ACROSS CENTRAL
KS...EASTERN NE. DEEP LAYER SHEAR VALUES OF 50-60KTS WILL SUPPORT
SUPERCELLS. MEANWHILE 6HR PRESSURE FALLS OVER EASTERN NE/SD WILL
RESULT IN SOUTH SOUTHEASTERLY SURFACE WINDS. SOUNDINGS SHOWS VEERING
WIND PROFILE IN THE LOWER LEVELS FAVORABLE FOR TORNADOES GIVEN THAT
THE STORMS WILL BE SURFACE BASED. THE HIGHEST SHR VALUES WILL BE
ALONG THE WARM FRONT...WHICH SHOULD BE LOCATED ACROSS THE NORTHERN
HALF OF IOWA BY LATE AFTERNOON.
CURRENTLY ENVISION THE SCENARIO UNFOLDING WITH THE WARM FRONT LIFTING
ACROSS THE I80 CORRIDOR BY 18Z...HWY20 BY 21Z...AND TOWARD HWY18 BY 24Z.
GIVEN THE MODEL TRENDS WHICH HAVE INTENSIFIED THE SYSTEM SLIGHTLY AND
SLOWED IT DOWN...DONT SEE THE WARM FRONT SURGING NORTHWARD INTO
MINNESOTA. ALONG THAT SAME LINE OF THOUGHT...FEEL THAT THE CAP WILL
MOST LIKELY HOLD UNTIL AT LEAST 21Z...WITH CONVECTION BREAKING OUT IN
THE AREA OF ENHANCED CONVERGENCE ALONG THE WARM FRONT. THESE STORMS
ARE EXPECTED TO BE SUPERCELLULAR AND COULD QUICKLY TURN SEVERE. MEANWHILE
ANOTHER ROUND OF STORMS SHOULD DEVELOP CLOSER TO THE UPPER LEVEL DYNAMICS
ALONG THE DRY LINE IN EASTERN NE/KS...AND MOVE THROUGH CENTRAL IOWA
OVERNIGHT. THESE STORMS WILL INITIATE AS DISCRETE SUPERCELLS...AND
LIKELY GROW UPSCALE INTO A LINEAR COMPLEX WITH EMBEDDED HP SUPERCELLS.
THE SEVERE THREAT MAY LAST THROUGH THE EARLY MORNING HOURS OF TUESDAY.

- Hailstone...

Thursday, June 16, 2011

Few Clips of Chase video from 455

Here is a sneak peak of footage from our chase class, dates and locations are included in the videos...a more comprehensive webpage will be completed in the coming days. 

Watch in 720p!



Sunday, June 12, 2011

Blame Arizona

I just wanted to warn chasers about swarms of dust floating around from the enormous Arizona wildfires. These swarms have been known to murder developing, tornado-ambitious cumulus clouds in cold vein.

On a side note, the UW storm chasing class team will begin processing footage and pictures this week and we'll have them posted by the end of the week, hopefully.

OCD

Sunday, June 5, 2011

Montana here we come!!!

All,

One chase vehicle will be leaving tonight as we head west to chase the Northern Plains...Feel free to add your thoughts and analysis. With one week left in the chase class, we figure this could be our last decent shot at tors (hope not though).

Convergence

Friday, June 3, 2011

Storm Chasing on our Home Turf

Afternoon All,

We are nearly at Eau Claire where we plan to under go an epic exchange, severely increasing the amount of helicity in and around our chase vehicles. From there we plan to hang with the eventual cu field and bag a tor...er...thats the plan for now at least. Looks like two plays for the day, one is way up in NW WI and the other, which I stated above, is to hang with the southern stuff, which is in favorable chase terrain/road network.

Convergence

Saturday, May 28, 2011

LP Supercell NW Texas


Hey chasers!

Here is a link to the first video (albeit hastily made) from our chase near Mabelle, TX on Monday this past week, 720p HD available. Keith and I sat on this bad boy for at least 3 hours. A few times, it had a nasty hook on it, but LCL's were too high (temps in mid 90s). Still all in all a great storm to get the lawn chairs out and just enjoy. As always, thanks to Dan and Croix for helping us out. I think we chose the right storm that day... enjoy!


Also, here are a few pictures from that day that are stills in the video. This thing seriously looked like a volcanic ash cloud a few times once it went beast mode. Awesome.



Wednesday, May 25, 2011

Brief Recap of May 24 Outbreak.

The top image is from initiation and the bottom is from the morning. 

Couple of keys to the setup. First, the morning convection cluster limited the warm fronts progression north. Second it left a broad area of subsidence as highlighted by the red X. Also, due to this subsidence there was no development of shallow cumulus, which lead to afternoon highs in the region from the upper 80s to low 90s. This left dew point depressions of in excess of 30F where the yellow X is located. Why was it so favorable south? No subsidence, shallow cu field limiting day time heating (circled in yellow) and the further south than expected warm front/triple point which increased helicity in central Ok. The top image shows initiation, which, with a bulging dryline seems to change the low level shear, ie surface winds to have more of an easterly component, which only increases the lowest few km directional shear. 

Really think this is the reason why central Ok was hit hard and north along the KS/OK border was spared for the most part. 

Convergence

Tuesday, May 24, 2011

chasing update aos 455

Current location: Wichita, KS (12:08 PM)

Current destination: KS/OK border in less than 30 min or so

Reasoning: shortwave off rockies heading for KS/OK border. Things should start getting interesting when this moves east into a region full of CAPE and shear (especially near warm front as expected)

Over/under on tornadoes: my guess is 55 reports, 20 tornadoes

OCD says 62 reports, 8 tors

Helicity

Monday, May 23, 2011

AOS 455 chasing day 1 briefing

What up team,

I am typing this from my phone, so it will be short and sweet. Today the one and only aos 455 storm chasing van (including blog co authors OCD and Helicity) are on our way to Wichita, KS to do some dryline chasing in the south tomorrow. Along the way, and for fun, we will be checking out both the MCS and any cells that develop in front of it in southern IL. Our goal is more aimed at getting cool pics rather than tornadoes, as any cells that do develop may be too far east by the time we get to southern IL. We will keep you posted. The good news is that the shear is visible in the sky, and we like our chances albeit small.

Peace out,

Hel-to the-icity

Today's Chase Update

Hello Chasers,

We have decided to make our play for this afternoon, and opted for the southern most area (highlighted per our prevoius post). Reasons for this:

1) models under-estimated the amount of instability in the area along the dryline - mixed layer capes around 4-5k everywhere up and down the dryline.

2) Convective mode - seems to be less-discrete cell oriented towards the northern Go Zone, probably due to the enhanced stationary-frontal forcing in that vicinity.

3) If it blows up into a squall-line of rotating supercells, we want to be on the southern-most bit of convection.

We plan to cross the Red River ~18z (near Wichita Falls) and hang out around the vicinity of Vernon, Texas. Should be there by 19z... in time for initiation.

Update to follow this evening, post-chase. Happy chasing!

-Triple Point

Sunday, May 22, 2011

Tornadoes from this afternoon in West Central Missouri

Hey Chasers,

Today has been a ridiculous severe weather day with tornadoes being reported from The Twin Cities all the way south to the dryline in West Texas. I was able to get out this afternoon and head east 35miles on I-70 and caught three quick tornadoes on a line of cells that just kept reforming to the southwest and tracking over my general location. It was the perfect setup to get some quick touchdowns in a short period of time. which was the Waverly-Concordia-Higginsville, MO area. Here are the three tornado videos:










Fresh off the presses, ENJOY

Dan aka Squall Line

Videos from Chase 5-21-2011 Supercell NE of Topeka

Hey Chasers,

Just wanted to share the video I got from that insane storm yesterday in Northeast Kansas. Croix was my base support (Thanks as always). I got on a Supercell that formed sw of Topeka and then tracked it (Supercell went into Beast Mode) as it moved ene up through the Perry Lake area and eventually in Oskaloosa, KS and the long video finishes with a nighttime time lapse just outside of Levanworth, KS. This cell put down several shorter lived tornadoes, which you can see in the reports.

Video Compilation:


Shorter HD video:


Time to get out there and do it again today!!! :)

Enjoy,

Dan aka Squall Line

Saturday, May 21, 2011

Dryline (monster) Chasing - Monday / Tuesday


Hello blog posters and followers!

First off - sorry for the non-professional mspaint-edited photos...

Here's the DL - myself and Keith are flying into Tulsa, OK on Sunday night, and plan on dryline chasing on Monday and Tuesday in the Oklahoma / Texas / Kansas region. After taking a look at 12z and 00z models for today, here's what we have found...

Monday:

Upper level dynamics - not looking like a 'hell yes' situation, but good enough for supporting surface based convection in the western oklahoma region, or northwest texas. Skipping through all the traditional in-depth analysis, which we all know everyone on this blog is capable of... here is the EHI map for Monday evening (00z) in that region:
We highlight two dryline bulges right off the bat - one in northwest Oklahoma, and one in northwest Tay-has. To accompany this - here's a forecast sounding for the southern-most bulge (21z) ...
Aside from the super-adiabatic lapse rates at the surface, this southern most area is what we are leaning towards right now for our day on Monday. Of course, that could all change, but at this time it looks like about equally good upper level support for the entire region on Monday evening, but much better moisture return in the Wichita Falls vicinity, reaching slightly higher instability and just as good lower level directional shear profiles. Either way, we could end up in both of those highlight areas on Monday pending further model analysis. Should support supercell storms easily, with chaseable storm vectors.

Tuesday:

Dryline advances East. The actual dryline becomes 'muddy' overnight and into the early morning on Tuesday due to the forecast surface circulation, which wraps the moisture around the backside of the feature. However, during the afternoon the dryline looks to become more distinct as the developing surface low pulls dry air in behind it and acts to punch the dryline / dryslot in the northeast direction. Here, we focus on one location - near Enid, OK. The low level helicity is enhanced by the surface low, warm front, and advancing dryline. This looks like a non-traditional dryline bulge, but indeed is in the triple point area of the entire system for Tuesday.

Pictured: 18z sfc dewpoints.
Which evolves to this by 00z Wednesday:

Along with this, here's a forecast sounding for 00z just southwest of Enid, OK. Right in the middle of the highlighted circle on the above image...


To summarize: Go-Zones... Monday - either Northwest Oklahoma, or Northwest Texas (definitely leaning towards Texas play as of right now). Tuesday - Central Oklahoma.

Haha... Of course, if we sound like fools... please, somebody, anybody... say something!

But in all seriousness, if anyone has other thoughts on these two days, let me know. Hope to see other people out there as well... 608-448-1766 if you're looking to reach us either day. Hooray for chase-cations! As always, I appreciated both Dan and Croix's opinions on this preliminary forecast yesterday while we were deciding on booking our flights ;)



Wednesday, May 18, 2011

Big uncertainty and potential

Greetings chasers,

I wanted to quickly bring attention to the forecast for severe weather over the next few days & next week. We are currently beginning to setup a hefty Rex block with a strong cut-off upper-level anticyclone sprawling over Canada and a trough positioned off the Front Range. This kind of pattern is sure to provide fun forecasting as well as the occasional bust. There's a cut-off low that's slowly trekking E / NE giving the potential of severe weather and that will continue in the next few days. My hunch is that all the severe weather target maps for the next few days will be transitioned westward to account for the unanticipated "stronger than anticipated" ridge...

For next week, I wanted to point out why the models have difficulty in high amplitude, stationary regimes (such as the Rex block). The following shows the mean 500mb height contours of today's 12Z GFS ensembles valid next Monday (or maybe Tuesday). The shading represents the spread (or standard deviation) from the mean state, which is just the average of all the ensembles. Note that the spreads among the ensembles are fairly low west of the Miss. River (< 40m, on par or slightly higher than your typical day to day noise).


Now let's fast forward just 24 hours later and look at the same plot of 500mb heights.


Wham! Clearly there's action off the west coast! The spread among the ensembles is now > 100m, just west of the west coast. But, if we look closely, we can see why ... this is the typical diffluence region of a Rex block, and the model must take the strong jet streak (and associated vorticity) either to the north "over top" of the ridge axis or to the south into the developing cut-off. Yesterday, the models were taking most of the dynamics northward. Today, they're split, which explains the bullseyes in spread. Some of the ensembles, like the operational GFS itself is taking quite a bit of action to the south, which in additional to the dryline's 4000 cape may make things fun next week.....

Dima

Tuesday, May 10, 2011

Severe Weather Southern Plains 5/11/2011:

Hey Chasers,

It's been a slow start to the month of May especially after that kind of April. Historically and statistcally May is the most active tornado month during the year and it looks like tomorrow will be this month's first shot at an outbreak. SPC has already issued a Moderate Risk for tomorrow and rightfully so. I actually agree to a large part with their forecast discussion and think they have done a very nice job highlighting the synoptic setup and mesoscale setup. If you're curious to read more you should head to www.spc.noaa.gov and click two-day outlook. So lets get right down to the point brief overview covering highlights and "The Go Zone"



Strong negatively tilted upper level trough exiting the four corners region. Broad area of strong upper level diffluence (250-500mb) across TX stove pipe, OK panhandle, western KS. Interesting subtropical jet feature ahead of main shortwave trough (upper level pattern looking similar to 4/14/11 though shifted 200 miles farther west, spc touches on this). Mid level flow from SW, advecting strong EML from Mexican Rockies over southern plains. At sfc, developing lee side heat low with attendant warm front/cP cold front. Surface flow is S/SE off the gulf and large area of > 60s Tds across Central/Southern Plains and Midwest. Very well defined dryline extending North from West Texas north/northeast through central KS. Moderate upper level forcing, teamed with developing sfc low, and dry line will set the stage for tomorrows action.

The Go Zone:
SPC has its highest probabilites in a zone from west of Wichita, KS south through West Central OK to around the Red River Valley for severe storms (depicted on map with blue and red zones). While I agree with this large area focused to the East of the dryline, I will elect to put my "Go Zone" for the northern (red portion) for tomorrow. 12 model guidance is suggesting elevated convection will begin early afternoon farther to the north in Central NE and NorthCentral KS closer to the warm front. As afternoon temperatures climb signifcantly farther south in KS/OK/TX. The dryline is expected to begin mixing out with moist BL to the east. SFC convection should occur later in the afternoon along/just ahead of the dryline bulge (sfc forcing). Here backed flow ahead of the sfc low and moderate 0-6km bulk shear will be maximized. Mixed layer cape should be around 2,000 J/kg and even greater as you head south towards central OK and into the Red River Valley. Veering profiles with height and backed sfc flow (above) should yield discrete rotating supercells capable of tornadoes. Main concerns with tomorrow are large dewpoint depressions (Temperatures ahead of dryline in warm sector look to reach 80s and 90s). Very strong downdrafts and wet bulb profiles are indicative of very large hail. Also, the strength of upper level forcing and mid level shear does not look as impressive as earlier systems. Storms will be slow movers (15-30kts) and could seem some classic LP dryline monsters.

Since it looks as though there will be a lull after tomorrow and wednsday, I'm thinking about heading out and trying to verify my forecast above. It's close and should be a good show!

Fearless Fantasy Forecast: o/u 18 tornado reports (probably only 4 actual tors, :]), 50 hail reports, 50 wind reports

Happy Hunting,

Dan aka Squall Line

Monday, May 9, 2011

Chase-cation

Hello Everyone,

I just wanted to post a heads-up for the end of this month... myself and a co-worker have a 5 day span of days dedicated to chasing. These dates are May 26-30th. If anyone is interested in joining us, please let me know. As of right now, we have just two people guaranteed (Croix may or may not join us pending the UW chase class's plans) and are looking for a one or two more to potentially split costs, etc for driving and hotels. We plan to go wherever is necessary, and leaving as early on the first day as we can. Of course, the schedule is tentative on severe weather that week. Let's hope the 'severe wx cock block' breaks down by then (which, if you buy into the long range GFS, it looks to break down around May 23 or 24th... ish).

Friday, May 6, 2011

Omega Block: The Proverbial Severe Weather "Cock Block"

Hey Chasers,

All is quiet severe weather wise for the next day or two. Following that there should be several intersting tough dryline forecast type chase days capped off with a decent upper level system that will affect the Central Plains late Wednsday (isolated tornado potential). Unfortunately after that, it seems all the rumors are true for an Omega block pattern to take shape across the Nations heartland. See the two images below





I did a quick outline to emphasize the "omega" shape that is clearly evident in the upper level pattern. What does this mean for severe weather? Read the title again to get the vulgar interpretation of this pattern. I agree with Dima that all should be pretty quite severe weather wise while this pattern holds (at least as far as large outbreaks are concerned). The two positives chase wise though are: 1.) This omega block pattern looks to break up around the last week in May (just in time for storm chasing class to begin) 2.) Despite the lack of favorable upper level support, there should be some really challenging but fun dryline forecasts with isolated tornado potential.

For those of you who aren't too familiar with dryline chasing stay tuned as I am going to try and do a few "Go Zone" forecasts dedicated only to the dryline. They are traditionally Low Risk/High Reward kind of days. Maybe I or someone else can do a quick dryline chasing tutorial beforehand highlighting the dryline (of course), dryline bulges, upslope flow, thermal heat lows, monster cape, low shear, weak upper level dynamics, meso-scale features that induce low level helicity, storm propagation tendancies, and the sexiest Supercell of them all: the LP Supercell.

These kinds of chase days have large bust potential but if storms do fire and you happen to catch one that produces a "tor" it's a real treat.

Sorry Dima, couldn't stand to look at that shameless promotion of an absolutely crappy excuse for a video game anymore, lol...

Let the Dryline Extravaganza Begin!!!

Dan aka Squall Line

Sunday, May 1, 2011

In case the omega block sets up

and there's no severe weather anywhere, fear not ... I just found that Sony made this video game a few years ago:

Friday, April 29, 2011

Brief recap of outbreak and glimpse into future

The tornadoes that occurred on Wednesday were very impressive due to both the amount of long-lived supercells as well as the viciousness of the tornadoes. My guess is that, synoptically, it was a once in a 15 to 20 year event based on tornado # / strength. However, what made it rarer, and the juice that feeds media in our country, is the death and destruction that it wreaked. If we looked at the number of deaths caused, it is more of a 1-in-40 year event (think back to 4/3/1974).

Another interesting note about the past event is to realize how impressive our technology has become ... For example, CIMMS Convective-initiation product (a real-time algorithm to sense for when boundary layer cumulus have reached the level of free convection) is now able to provide 15 to 20 minute lead times before a cell even shows up on radar.

Check it out here

Also, speaking of better technology, I've attached my 2 favorite images from Wednesday, and I'll admit that to get them, I actually took a picture of my TV as Greg Forbes was playing with his GRLevel 3 radar while I was eating dinner. Anyways, here they are: the first is the supercell that passed through Tuscaloosa and the second is a cross-section of that same cell that shows the core of the tornado as it extends well above the cloud base.



To finish up, I wanted to mention that we may be going into a prolonged lull for widespread severe weather. Even though I know long-range forecasts for severe weather are extremely risky business, ensembles have been showing the development of an Omega block with the axis of higher heights just east of the Rockies. The models have some skill at predicting blocks which is why I think we won't see a tornado west of the Mississippi river until ~May 15th or so ... Go ahead and start grilling me.

Here's an image from this morning's GFS ensembles. The contours show mean 500mb heights, the colors are the spread amongst the ensembles. Note that minimum in spread where many of the ensembles have a cut-off, blocking ridge, with two cutoff lows to the southeast and southwest.

Wednesday, April 27, 2011

April Tornadoes: Yes another plot!

Hey Chasers and Blog Followers,

As another follow up to Jake's and Dima's posts I saw that Greg Corbin (Warning Coordinating Meteoroligst for SPC) has put together a nice trend plot for April tornadoes. I figured I would add it to the page because he statistically shows what Dima was talking about and goes as far as to say, "More tornadoes are being reported, on average, than ever before and this appears to be due to secular/demographic changes in the reporting process." On this plot you can clearly see 1974, which was referenced by Dima, as the most signifcant Tornado April on record mainly due to several outbreaks that occured during that month.



Through yesterday (4/26/11) the April 2011 preliminary report total has swelled to 683 and again this number is sure to rise as more reports from yesterday are coming in as Storm Damage Surveys and radar studies are being conducted by the NWS offices. Today is also another HIGH Risk day with likely more potential than yesterday. I also wanted to throw out another couple of pretty impressive preliminary stats for this month: 16 of the 26 days thus far have had at least one documented tornado, 10 days with more than 20 tornado reports, 5 days with more than 50 reports, and 2 days with over 100 reports.

Dan aka Squall Line

Sunday, April 24, 2011

Follow up on storm reports

I am responding to Hailstone's previous post regarding tornado reports / records. First, let me state that April has been quite active. Do I think that it's the most active April on record? Sure, if you assume that reliable records started in say ~1990 when the nationwide radar system was upgraded. But, I think that 1974, due to the one outbreak on 4/3/1974 that had ~60 tornadoes F3 or stornger would've generated something like 500 reports in today's reporting system, so it's possible that on that one day alone, we could've overtaken the total for all of April 2011. Hailstone also mentioned the 4/1 report/ground truth ratio during the NC outbreak. It would be interesting to map out how this ratio changes for different parts of the country.

Here are a few other interesting things to consider ...

1. There has been 1 tornado report west of Oklahoma City all of this year. Hey, that must be another record! A record low, that is. What does that mean? All the other reports have been east of Oklahoma City, where the population density greatly increases. Even though the SPC's watches and NWS's warnings have been very impressive, people still died due to i) bad luck and ii) failure to heed the warnings.

2. One factor that affects reports is population density, the other may be the standards of the NWS in documenting tornadoes. I was on the NWS Milwaukee site reading about how the WI outbreak was also the most reports for April on record. When looking over the chart of path length, path width, etc., it seemed that the radar is of huge helping when picking out the short-lived tornadoes. I commend the NWS for becoming really, really good at documenting all the events that occurred, but with an increasing rigor to put every single event in the history books, it seems that the saying "records were meant to be broken" was never truer.

Friday, April 22, 2011

April SPC Reports

Hey fellas -
I can't let all this hooplah go on about the April tornado reports without saying anything... On April 16th there were 106 reports in North Carolina....and according to the Raleigh office there were 28 confirmed Tornadoes....Thats almost a 4/1 tornado report ratio

http://www.erh.noaa.gov/rah/news/content/20110416.tornado.gif

There are a lot more chasers (none better than us though) and overall better communication which accounts for the Report inflation.... I'm not saying that in the past there weren't multiple reports on 1 tornado, but I am saying that comparing this month to past months could be misleading.... In terms of Fantasy Football...its like comparing Jerry Rice's 22TD catches in 12 games during the 1987 season, to Randy Moss's 23 in 16 games for 2007......
~Hailstone

Thursday, April 21, 2011

Severe Weather Event #2 4/22/11:

Hey Chasers and Blog followers,

I had made a post back on 4/18/11 discussing the historical perspective on April '11 Severe weather and where it falls in the history books. Current updated April Tornado reports are at 491! Tuesday's outbreak across Missouri and Illinois definitely added to the total and there were a few nasty tornadoes to boot. In that Monday post I had mentioned 4 future severe weather events. I wanted to put a post up for tomorrows event for those curious and any one thinking of chasing. I unfortunately will not be able to chase tomorrow due to work and I have a marathon to run the next morning. So no pics/vids from my end. Besides, I am holding out for Monday (Severe Weather Event #3), but that post will come on Sunday. Seeing as tomorrow is a bit complicated and given I've been putting all this attention towards the potential breaking of the single monthly total for "tor" reports, I am just going to focus on tornado hot spots for tomorrow, so no in depth Synoptic and Mesoscale setup. Only the "Go Zone".



The Go Zone:
There looks to be two favored areas for tornadoes tomorrow. The first area is along the warm front, cold front, sfc low triple point across NC Missouri/SW Illinois. Here strongest upper level forcing will move over area of maximized CAPE, enhanced shear, and > mid 60s tds. Any elevated storms that go surface based near or along the warm front will be aided by backed flow with time and will undoubtedly be rotating as right movers will be favored. Closer to the cold front across east central missori, surface based convection in the warm sector will happen a little bit later and will be aided by 850mb-700mb confluence region across central Missouri. Convection should start out as discrete storms and ultimately grow upscale as boundary layer flow/properties are modified by down drafts/gust fronts. I'd favor SW Illinois as prime spot for tornadoes from discrete sfc based cells.

The second area, which is a little harder to make out in the model data appears to be across Southcentral/eastern OK into North Central Texas. The southwest portion of the Cold Front associated with larger system will stall out into a quasi stationary front. To the South of this frontal area dewpoints should reach the mid to upper 60s all the way South and West as the dryline in West Texas. This front will extend SW to Northcentral Texas where it will meet up with a secondary surface low. Here backed upslope flow at the surface from thermally induced heat low will aid in 0-1km and 0-3km enhanced helicity values. Surface based Storms that form along and south of the quasi stationary front will have sufficient CAPE > 3500 J/KG and enhanced low level shear to make up for lack of stronger mid level flow. Farther to the South along the Texas dryline a few supercells may be possible before/jsut after sunset. There a greater chance for Large Hail exists, but given backed flow at the surface and very large cape values, could see a "tor".

Should be an interesting day. I am extremely excited to see how it all shakes out. If a few things shift over the next 12hrs, these Go Zones could be total busts, lol. All in the fun though.

Fearless Fantasy Forecast: o/u 15.5 Tornado Reports

Dan aka Squall Line
P.S. It's been way too quiet on this blog recently, what gives??? I'm about ready to propose we rename this blog,"Where the Squall Line meets Convergence and Helicity"

Tuesday, April 19, 2011

TVS picked up in Sleet "Supercell?"

Yep, no joke. Here's the image from WeatherTap:


TVS marked as red storm track line east of Beloit, WI. This occurred ~2145 UTC (4/19/2011).
And a satellite image to compliment that cell...


How about this one, the "snake" squall-line? Squall-line, ever seen this feature before? Few bookend vorticies out there tonight, wouldn't be surprised to hear about some nighttime tors.

And to play with model data 6 days out, it looks promising for a chase within range for those of us at UW...I'll eat crow when future runs have it 250 miles south, but thats fine. 



Helicity & Convergence


Monday, April 18, 2011

Severe Weather Outlook for the next 10 days:

Hey Chasers and Blog followers,

UPDATE 4/20/11:
After yesterdays powerful system and some updates to previous days, the official April '11 tornado report count is 481!!! 63 more tornado reports this month will break the old record of 543 in May '03. Again this is freaking insane considering the average number from April is around 150 reports historically!!! Stay tuned for more.

What a record breaking weekend for severe weather across the much of the central and southern portions of the country! All statistics, overinflation, and validity of every report aside, This past weekends three day severe weather event (tornado outbreaks) will likely go down in the history books as one of the most if not the most significant 3 day tornado outbreaks in history (even with the inflation of reports)and it has already gone down as the most deadly 3 day outbreak in history with 45 recorded deaths thus far. A three day running total of 267 tornado reports across 15 states and that number is still climbing. Here is an updated map from SPC of where we sit this year so far with Tornadoes:



That 501 total is after multiplying by 0.85 to address over counting (SPC also stresses this is raw data, subject to change). Total number of reports in 2011 thus far is 589. It is still early with 12 days left, but we are on our way to the most active Tornado month on record. As of 4/17/11 the April tornado report count was 371. After looking through various references, May 2003 was single most active tornado month on record at 543 reports.

I bring this point up because I believe there is a very real chance of breking this record when looking at the 10 day long range model output and that. Starting tomorrow, I count 4 upper level disturbances that will make their way across the heart of the country: 4/19/11, 4/22/11, 4/25/11, 4/27/11 each with significant potential to add to the April tornado total.






What I find fascinating is that each one of these upper level systems is following a simliar track off the Southern Rockies and then pushing NE across the Central Plains into the Central Midwest. Each system's upper level trough goes negatively tilted and has attendant surface Lows, fronts, rich moisture advection. I'll leave the stats/details/model output for another post. I know this pattern starts to become the norm as we get into May, but the fact that we have had such an active April already, the notion of breaking this record is something worth watching.

We are all witnessing weather history.

Dan aka Squall Line

Sunday, April 17, 2011

GO Zone shoveling edition

To comment further on the previous post, Convergence forgot the most important thing about forecasting this unfortunate April snow event...the GO ZONE!!!!

Based on the SREF forecast, Convergence's info, and my strong pessimism today, here is my snowfall GO ZONE:


Over/under:

Snow events: 1
Snow Precipitation: 2 inches
Frustration of Spring in WI (on scale of 1-10, where 10 is most frustrated): 7

Helicity

Get your shovels ready!!!

I can't make this up, SREF, GFS and NAM all produce a swath of 2-4 inches over Madison between 7pm and 7am. Not sure how much will accumulate (Ground temperatures above 32F) on the ground but it certainly will snow for ~5hrs over night. At this point I am not even mad, just think it is hilarious, are we in late Feb or Mid April???

Here is the proof,

GFS 9z sounding from 12z run Sunday April 17th over Madison,
 NAM 9z sounding from 12z run Sunday April 17th


And the 3z run of the SREF Plumes...



The HRRR is not in range for the event and will be posted once its in.

Also, we should figure out the final name of the blog and organize the side bars a bit better. Welcome some suggestions.  I personally think just naming the blog, "Go Zone" would be great. That way there is no questioning who coined the term!

-Convergence

Wednesday, April 13, 2011

Severe Weather Southern Plains:4/14/11




Hey Chasers and blog Followers, Figured I would update everyone on the severe weathe situation forthcoming tomorrow afternoon/evening across the Central/Southern Plains. I realize that probably none of you will be able to chase this event tomorrow, but it does look like a quite favorable setup, even a classic type event.


**UPDATE 7:30am 4/14/11**
After looking at latest data and model guidance have shifted my target area to get to this afternoon a bit farther South and East. I will be working until 2:30pm CST and then plan to head out right after. Will be taking Rachel with me as she is a good luck charm, and can drive. This way I should be able to get better video and continue to analyze latest obs, radar, etc. Back up base support would still be great if anyone has some time in the 3pm-6pm time frame. Yesterday I had mentioned the Wichita, KS area and while I still think storms will initially fire in that area Surface dryline/encroaching coldfront will occlude with warm front faster to the West, will plan to target the Neodesha, KS/Coffeyville, KS, Nowata, OK area. Would like to get to > 60s Td and be South of the leading edge of warm front area. Will update again one more time this afternoon before I head out if things change. Can already here the Twister theme song playing in my head, :)





Synoptic Setup:
A potent 30omb negatively tilted trough will dig its way Southeast across the Central Rockies late this evening into tomorrow afternoon over the SW Great Plains region. Attendant riggourous 500mb shortwave will eject over the region between 18z-00z tomorrow afternoon/evening. GFS, ECMWF, and WRF are all pretty much in line with the upper level pattern yielding a broad area of synoptic ascent from exit region of 100kt 300mb jet leading the upper level trough axis. A very focalized area of upper level diffluence resultant of the negatively tilted trough should also aid in strong upper level forcing over the region in question (This is exactly what I look for at upper levels in a classic severe weather outbreak setup). At mid levels SW flow at 700-850mbs will advect a strong EML with > 8K/Km lapse rates out ahead of the system across the dryline region of the Southern Plains this afternoon/evening into tomorrow morning. At low levels a deepening sfc low will develop to the Lee of the Southern Rockies and trek across Southern CO/Northern NM later this evening into tomorrow morning. As this system strengthens strong southerlies out ahead of the sfc low will pull low level moisture up across the Red River valley into Central OK and Southern KS. A distinct warm front and dryline setup will be in place across the region by 12Z-18Z tomorrow with lagging cold front drapped back across eastern CO.

Mesoscale Setup and Severe Parameters:
This pattern will promote the classic Sfc Low, Dryline, Warm Front triple point severe weather setup. Sfc forcing associated with deepening low and warm frontal lift will aid in elevated convection developing in the early to late morning hours across Eastern CO, Western KS, and SW NE. Afternoon heating and subsequent mixing out of BL should cause afternoon bulging/advancing dryline to act as the initial focal point for surface based convection to form. Uppper level cooling and forcing will further help to destabilize warm sector by later afternoon. Forecast ML CAPES across the warm sector should be 1000-1500 J/kg over South Central KS to > 2,000 J/kg across central OK. 0-6km bulk shear values over 40kts across the area in question will promote the development of Supercells. Backed flow at the surface and veering profiles with height will promote right movers as storms split and move ne into very favorable conditions for rotating updrafts and potential tornadoes. Look at any progged sounding in the warm sector and you will easily see what I'm talking about.



The "GO ZONE":
Based on what I mentioned above, my game plan is to head down to the Wichita area to be on the dryline for initiation) and wait for surface based storms to develop and move into the more favored zone for tornadic development. I think there will be a pretty large area for severe weather extending South along the dryline and eventual cold front overtaking, but want to focus on storms along the OK/KS border that will move into my favored area in red above. My main concern with tomorrow is BL moisture. Given the lack of time for return flow from off the gulf, I think > mid 60's Tds will be very difficult to get all the way into Central KS. 12z Model guidance shows a narrow tongue extending up from Central OK into Extreme Southern KS by 00z. Hoping Td depressions will not be too large to get ground circulations. That being said though, steep lapse rates and adequate CAPE values will lead to large hail potential with most storms especially as you head south, but also will promote very strong downdrafts due to the EML. Thinking that may be enough to overcome moisture shortcomings and get some of these funnels to the ground.

Fearless Fantasy Forecast: o/u 12 tornado reports, 45 hail reports, 30 wind reports

Let the games begin and I'll do my best to keep the "tor" streak alive and get some great pictures/videos for the blog. I'd love to hear anyones thoughts on the setup for tomorrow and I'm pretty sure SPC is going with a MOD risk as well. It's always good when we can agree on potential.

Happy Hunting,

Dan aka Squall Line

Tuesday, April 12, 2011

April 10, 2011 West / Central WI Chase *Updated*

Update: I have the video now uploaded to youtube:


Keep in mind that I wanted to document the entire chase, so this starts from LaCrosse and ends in Coloma. Few times in the video it really looked like a few of the cells were going to produce, but I still call the chase a success given the terrain we had to deal with and very fast storm motions. Enjoy!


Hey everyone!

I'll be posting a link to the full video of our entire chase from LaCrosse to Coloma in the short term (tons of clips to edit together into a video... should be about 10 minutes long or better). In the meantime, enjoy some of the pictures and video that Keith Cavey was able to get.





Also, here's a link to a google map which depicts our exact chase route. http://bit.ly/fPos95

Link to unedited raw video from Keith's camera is on this page:
http://www.youtube.com/user/OUcaveman001?feature=mhum

Monday, April 11, 2011

Sweet Lightning Video - 4/10/2011 Storm Chase

Hey all,

Check out this sweet lightning video from the backside of the supercell that ripped through north-central and northeast Wisconsin (I think it was the one that dropped tornado warnings in Appleton, but it could be the Oshkosh one).

Sorry about my face in part of it, I was dedicating the video to the owner of the camera.


video

I'll post some storm chasing pics as well later.

Helicity

Sunday, April 10, 2011

4/9/2011 tornado pics and videos

Here are two videos showing the brief touchdowns near Onawa, Iowa along with gustnadoes and strong downdrafts. It then moves on to the multiple vorticies Mapleton tornado (as it was just starting out) and then as I travel get around the bluffs and make my way into the city. The second video is just the multiple vorticy touch down. Enjoy and maybe Ill get some of the other structure put together in some kind of video in the near future. Enjoy!







Dan aka Squall Line

Saturday, April 9, 2011

Update on Sunday 4/9

First of all, I should mention that one of our veteran members, Squall Line, was able to intercept a tornado today in West-central Iowa - nice job Squall Line. I nominate Squall Line for the 1st ever Chaser of the Month award, though he's got a bit of a home-court advantage...!

Now that I owe Squall Line a burrito because I lost our bet of under 2.5 tornado reports before dark, I want to point out something. I think severe weather forecasting has come a long way even within the past few years. For example, I was watching the weather channel today (which, if you hold an atmospheric degree, is illegal in some states), and the severe weather expert Greg Forbes, who was a grad students for the legend Ted Fujita, was pointing out how well SPC's "significant tornado parameter" coincided with the 3 or 4 supercells occuring around 8pm in Iowa and Nebraska: see image below. This location was under the gun from about 2 days out, and I would argue that it wouldn't have drawn a moderate risk based on the tools we had 5 years ago. Sure, some improvement is merely from increasing resolution, but that cannot explain all of it.


Anyways, enough with the flattery, we've got an impressive setup for severe weather tomorrow close to the good ol' Badger State. However, as always, there's uncertainty ... For tomorrow, in my mind, there are two uncertainties:

1. Evolution of nighttime convection, and it's impact (through mid & high-level cloud "debris") on surface heating tomorrow.
2. Whether it's worth chasing a potential tornado when you're dealing with the Mississippi River, hilly terrain and ~50mph storm motion.

My Go Zone forecast is below and here's the explanation for it: the surface cyclone, currently fairly broad will consolidate into one center by later tonight. The supercells and other small convective clusters look to merge into an MCS-looking blob and carry on north and east through the night. The GFS looks like it's suffering from a case of an underactive convective parameterization scheme and generates splotchy precip covering Iowa, Minn and Wisconsin for the next 18 hours straight. I think this model's out to lunch - I like the NAM a lot more.

At the surface, the cyclone's triple point will move northeast with the mean flow and will be positioned near Willmar, Mn at 18Z and Hayward, Wi at 00Z. Looks like convective initiation will be around 20Z west of the Mississippi and the storms may be discrete all the way down the cold front due to the high sfc-500mb shear and some veering even on the front itself. However, the best shot for discrete cells may be closer to the triple point, like today, which is why I'm thinking of going a bit north towards the warm front and backing surface winds.


Now it's time to figure out whether its worth braving the trees, hills and river crossings to chase...

Friday, April 8, 2011

Chasing update Saturday and Sunday

The amount of uncertainty for the severe weather threat on Saturday and Sunday seems to finally be subsiding, but there are still issues.

Let's start with Saturday, the map below shows a few key features that will dictate the Go Zone at 00Z Sunday (Saturday evening). First, let me state that we're only considering conditions during normal business hours (i.e. before sunset). The impressive trough currently in the west will crawl east so that by 00Z the best forcing is just coming off the Front range. There's also a decent upper-level ridge positioned just east of the Mississippi. The sfc low is around Sterling, CO with a diffuse occluded dryline/warm front boundary extending towards Hastings, NE where the triple point is positioned. My concerns are:

1) Forcing too far away to initiate storms before sunset (or even twilight, ahem, Squall Line).

2) Models have large discrepancy in precip output. In fact, only two models generate precip before 00Z: the GFS and the NMM. The NMM's precip is in areas with dewpoint depressions of 10 C and higher, making this a good shot for isolated, great looking supercells, but not a good tornadic threat. The GFS's precip output basically summarizes my best guess for a pre-sunset Go Zone. Initiation would be ~6pm with any storms that do go quickly becoming tornadic. However, the chance of precip, based on the GFS ensembles and SREF is <25%, making me guesstimate a pre-sunset tornado threat of 2-5%. My over/under for daytime tornadoes Saturday is 1.5.


Now moving on to Sunday afternoon: much more interesting the past few runs. All models have been slowly the progression of the low, now the position at 00Z Monday is near Albert Lea, MN. There is a high probability of elevated nighttime convection Saturday night, which may actually provide a few strong tornadoes initially as the cells are still surface-based, say 9-11pm in western Iowa? This elevated convection will very slowly crawl east because the upper-wave is moving NNE making it difficult to sustain any MCS that move towards the east. South of the residual cloud cover from the morning MCS should see ample heating, with a nicely veering wind profile, good speed shear, good BL moisture and forcing coming into the area by 00Z. Initiation of discrete supercells should be earlier than Sunday, say 4pm with my Go Zone being MSP south to Tripoli, Iowa. Because the frontal boundary will be crawling along, we may see a prolonged discrete threat. Over-under for daytime tornadoes is 15.

4/9 & 4/10 Severe Weather Update ***Updated***

Updates coming this afternoon once ARW and NMM are available...

Alright since Dima did a pretty good layout of the forecast based on the 12z runs this morning I'll focus on a few other areas we may have over looked. How and why has the entire system slowed down over the past 3 days in the models and now the evolution goes from a positively tilted trough off in Cali to a negatively tilted trough in MN?

First of all since there are no observations off the west coast the model does not know the strength or location of the subtropical jet. Once it moves on shore where radiosondes are launched a much different evolution occurs. Due to the location of the upper trough from the mid latitudes this allows for the angular momentum to be reduced allowing for the subtropical jet to be further north (Due to the angular momentum typically out flow from tropical convection struggles to make it past ~20N). This allows the unstable tropical air to get wrapped up in the upper wave producing a much higher tropopause! What are the implications of this higher tropopause? Simple really, greater instability! Lets look at some observation and forecast soundings...

First 12z from this morning
The air above 200mb is the first we see of this tropical air being included into the wave. Below is another look at it from a forecast sounding 6hrs later in the same region.
It appears the tropopause begins at 250 but then the thermal profile suggest there is something else present...
Here is what a cross section through the area would look like...
Once these two jet structures "phase together" (for lack of a better term) the tropopause is consequently higher, moving the EL closer to 150mb. All the while the subtropical jet has been destabilizing the air out ahead of the upper wave at 500mb, setting the stage for 2,500+ J/kg of CAPE, seen below.

Then, as a result of this destabilization convection occurs, transportating low PV air near the surface upward and eastward, enhancing the jet along the ridge, amplifying it, enhancing the dynamics and the entire upper wave in just 48hrs goes from this...
to this...
Pretty crazy? And now the jet structure has a greater depth, with the subtropical and polar jet vertically stacked, enhancing the upper level dynamics and forcing...Sounds like a moderate and potentially major tornadic outbreak set up to this guy.

Did I say, "Can't Wait!"?



Convergence