Surprise Chase

[Paul Sherman]

Hi Guys

The Coming Set-Up looks Insane, there are a lot of Senior Chasers talking of a possible Super Outbreak and Once in a Lifetime Charts appearing for this upcoming week. It looks too good for me too pass up and I have booked flights leaving tomorrow to Denver, Chasing the Upcoming week with Tony Gilbert & Possibly M Humpage and Partner. The Possible Tornado Parameters are at (17) for Wednesday, Just Bear in Mind Greensburg was a (12) puts it into perspective.

Will post reports in the Usa thread and hopefully bag some amazing Tornadoes

Paul Sherman

[pottyprof]

An interesting discussion on these absolutely incredible model runs is taking place on stormtrack. Makes for a good read..

http://www.stormtrack.org/forum/showthread.php?t=12754

Also some debate in the Wednesday forecast thread over there

http://www.stormtrack.org/forum/showthread.php?t=12755

Nice to see someone enlarging their carbon footprint..

[NL]

Good luck on ya chase Paul, will be watchin and postin as usual...

[pottyprof]

Here is what the SPC have to say on the 4-8 day outlook

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0409 AM CDT SUN JUN 03 2007

VALID 061200Z - 111200Z

...DISCUSSION...

GFS AND ECMWF REMAIN CONSISTENT THROUGH DAY 5 /THU. JUNE 7/...WITH

SOME DIVERGENCE IN MODEL SOLUTIONS BEGINNING DAY 6 /FRI. JUNE 8/.

AFTER DAY 6...DIVERGENCE IN THE MODELS IS SIGNIFICANT ENOUGH SUCH

THAT NO SEVERE WEATHER AREAS WILL BE DELINEATED THIS FORECAST FOR

DAYS 7 AND 8. IN THE MEAN TIME...A FEW DAYS OF FAIRLY

WIDESPREAD/SIGNIFICANT SEVERE WEATHER ARE EXPECTED.

IT APPEARS THAT THE SEVERE THREAT WILL SHIFT FROM THE PLAINS DAY 4

/WED. JUNE 6/ INTO THE MID MS/OH VALLEYS DAY 5...AS A FAIRLY STRONG

SHORT-WAVE TROUGH -- ACCOMPANIED BY BELT OF 60-PLUS KT WSWLY

MID-LEVEL FLOW -- SHIFTS NEWD ACROSS THE PLAINS AND INTO THE UPPER

GREAT LAKES REGION. ASSOCIATED COLD FRONT WILL LIKELY SUPPORT

VIGOROUS STORM DEVELOPMENT DAY 4 OVER THE PLAINS...AND THEN AGAIN

DAY 5 AS THE BOUNDARY BECOMES MORE NE-SW ORIENTED ACROSS THE

MIDWEST. WITH MOIST/UNSTABLE AIRMASS FORECAST TO BE IN PLACE

BENEATH BELT OF STRONG WSWLYS ALOFT...NUMEROUS SEVERE STORMS APPEAR

LIKELY.

A SECOND TROUGH IS FORECAST TO BEGIN TO EMERGE FROM THE ROCKIES DAY

6...WITH SEVERE STORMS AGAIN FORECAST FROM THE MIDWEST -- ALONG

LINGERING FRONTAL ZONE -- WSWWD INTO THE CENTRAL PLAINS WHERE A NEW

LOW SHOULD BE DEVELOPING ALONG THE FRONT/IN LEE OF THE ROCKIES AHEAD

OF APPROACHING UPPER TROUGH.

It also looks possible that the severe weather could occur on Tuesday over the plains.

DAY 3 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0236 AM CDT SUN JUN 03 2007

VALID 051200Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN HIGH PLAINS INTO

THE CENTRAL/SRN PLAINS...

...SYNOPSIS...

UPPER PATTERN TO BECOME MORE PROGRESSIVE OVER THE CONUS THIS

PERIOD...AS LARGE ERN TROUGH LIFTS NEWD AHEAD OF ADVANCING WRN U.S.

TROUGH. AT THE SURFACE...LOW PRESSURE IS FORECAST TO DEVELOP OVER

THE NRN HIGH PLAINS...WITH WRN FRINGES OF A BAROCLINIC ZONE --

EXTENDING FROM E OF THE APPALACHIANS WWD ACROSS THE GULF COAST

STATES AND THEN INTO THE SRN PLAINS AT THE START OF THE PERIOD --

FORECAST TO LIFT NWD ACROSS THE PLAINS AS A WARM FRONT THROUGH THE

END OF THE PERIOD.

...NRN HIGH PLAINS INTO THE CENTRAL/SRN PLAINS...

WARM FRONT SHOULD LIFT ACROSS THE PLAINS STATES WITH TIME...WHILE A

LEE TROUGH SHOULD DEVELOP/SHIFT EWD ACROSS THE HIGH PLAINS. WHILE

THIS REGION SHOULD BE UNDER NWLY FLOW ALOFT THROUGH THE FIRST HALF

OF THE PERIOD...UPPER RIDGE WILL CONTINUE TO MOVE INTO THE PLAINS

WITH TIME AHEAD OF ADVANCING WRN TROUGH. ASSOCIATED LARGE-SCALE

SUBSIDENCE SHOULD THEREFORE INCREASE SLOWLY THROUGH LATE

AFTERNOON/EVENING...BUT WEAK DISTURBANCES MOVING SEWD THROUGH

RETREATING NWLY FLOW ALOFT SHOULD ALLOW SCATTERED STORMS TO DEVELOP

DURING THE AFTERNOON -- INVOF LEE TROUGH AND RETREATING FRONT.

WITH MOIST/DESTABILIZING WARM SECTOR FORECAST ALONG WITH FAVORABLE

VEERING/SHEAR...STORMS THAT DO DEVELOP SHOULD ORGANIZE/BECOME

SEVERE. THEREFORE....SLIGHT RISK FOR HAIL AND DAMAGING WINDS IS

ANTICIPATED FROM MT SEWD INTO THE CENTRAL PLAINS...AND THEN SSWWD

ACROSS WRN OK AND INTO WRN N TX. THOUGH STORMS SHOULD

CONTINUE/SPREAD EWD WITH TIME AS LOW-LEVEL JET DEVELOPS...SEVERE

THREAT SHOULD SLOWLY DECREASE OVERNIGHT.

...THE SOUTHEAST/GULF COAST STATES...

MOIST AIRMASS INVOF LINGERING FRONT SHOULD AGAIN CONTRIBUTE TO AN

UNSTABLE AIRMASS AS BOUNDARY LAYER HEATS THROUGH THE AFTERNOON.

WHILE STRONGER FLOW IS EXPECTED TO REMAIN TO THE COOL SIDE OF THE

BOUNDARY...A FEW STRONGER STORMS ARE EXPECTED TO DEVELOP ALONG THE

FRONT -- WHICH GIVEN DEGREE OF INSTABILITY MAY BE CAPABLE OF

PRODUCING MARGINAL HAIL/LOCALLY-DAMAGING WINDS THROUGH THE

AFTERNOON.

..GOSS.. 06/03/2007

[Joneseye]

Hey Paul,

who can blame ya for booking a trip at such short notice with the current forecast!

Have a safe trip and hope you bag a Nado or 7.. looking forward to the piccies!

[Roger J Smith]

Looks very juicy for Wednesday in the high plains and Thursday in eastern SD and most of Nebraska, southern MN and western IA. After that, the main severe cluster tracks rapidly east and dies out over Michigan, so storm chasers would probably want to circle back towards developing secondary low in w OK and nw TX around Friday.

Very hot, humid air being indicated on current models in warm sector, approaching 38 C (100 F) with 24 C (75 F) dewpoints.

Could easily see F4 type activity by Thursday around Omaha to north central KS out of this with much colder air being drawn in from the Pacific mixing with an arctic flow by late tomorrow over coastal BC here. We have some lightning from time to time here tonight, which is unusual around here, always a good sign of severe weather developing I've found in recent years. We only see lightning here three or four times a year.

[AudMun]

Possible Tornado Parameters are at (17) for Wednesday, Just Bear in Mind Greensburg was a (12) puts it into perspective.

Wow!

Have fun and good hunting.

[Nick F]

Good luck Paul, wish I could join you. Looks like you're in for a treat on Wednesday, GFS shows very strong jet streak nose with strong PVA roaring towards Kansas, Nebraska, with some very juicy CAPE over Eastern/Central KS, OK and NE:

Thursday 00z (18z Central time):

Guess who's going to win the June photo comp.

[Joneseye]

Good luck Paul, wish I could join you. Looks like you're in for a treat on Wednesday, GFS shows very strong jet streak nose with strong PVA roaring towards Kansas, Nebraska, with some very juicy CAPE over Eastern/Central KS, OK and NE:

Those charts are stunning! No wonder the excitement is as high as it is... I noticed in the discussions that there was a lot of talk about a really strong CAP, does this look like proving a hinderance?

IJ

[Paul Sherman]

Good luck Paul, wish I could join you. Looks like you're in for a treat on Wednesday, GFS shows very strong jet streak nose with strong PVA roaring towards Kansas, Nebraska, with some very juicy CAPE over Eastern/Central KS, OK and NE:

Thursday 00z (18z Central time):

Guess who's going to win the June photo comp.

I live In Hope Nick Thanks for all your best wishes, I really think this could be an insane day, just about to leave for Gatwick just now.

Those charts are stunning! No wonder the excitement is as high as it is... I noticed in the discussions that there was a lot of talk about a really strong CAP, does this look like proving a hinderance?

IJ

The Stronger the cap the stronger the Storms, so a Very Large Destructive Tornado could break out as the Cap goes, so it is not a bad thing but there is always the chance of 2,000 Chasers having a very expensive BUST!

Paul Sherman

[Joneseye]

The Stronger the cap the stronger the Storms, so a Very Large Destructive Tornado could break out as the Cap goes, so it is not a bad thing but there is always the chance of 2,000 Chasers having a very expensive BUST!

Thanks Paul - let's hope it does happen but away from areas where too much destruction can take place!

[Paul Sherman]

Okay this is MODERATE For Wednesday already but everyone in Chasing Circles is talking about a certain "HIGH" Risk for Wednesday, the Text is also VERY Interesting

DAY 3 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0240 AM CDT MON JUN 04 2007

VALID 061200Z - 071200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS ERN SD...ERN NEB...SWRN

MN...AND WRN IA...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE

CENTRAL AND NRN PLAINS AND INTO THE UPPER MS VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE MID OH VALLEY ESEWD

ACROSS THE CAROLINAS...

...SYNOPSIS...

POTENT MID-LEVEL TROUGH IS FORECAST TO EMERGE FROM THE ROCKIES INTO

THE PLAINS THIS PERIOD...ACCOMPANIED BY AN UNSEASONABLY-STRONG SWLY

JET STREAK. AS THIS LOW MOVES INTO THE PLAINS...STRONG CYCLOGENESIS

IS FORECAST OVER THE NRN PLAINS -- YIELDING A 975 MB LOW OVER ERN ND

LATE IN THE PERIOD. ASSOCIATED/TRAILING COLD FRONT IS FORECAST TO

SWEEP EWD/SEWD ACROSS THE PLAINS THROUGH THE PERIOD...WITH THIS

FRONT -- AND A LEADING DRYLINE -- LIKELY TO SERVE AS FOCI FOR THE

DEVELOPMENT OF WIDESPREAD SEVERE STORMS.

...CENTRAL AND NRN PLAINS INTO THE UPPER MS VALLEY...

MODELS CONTINUE TO DEPICT THE POTENTIAL FOR A WIDESPREAD/SIGNIFICANT

SEVERE WEATHER OUTBREAK ACROSS PARTS OF THE PLAINS STATES THIS

PERIOD.

VERY MOIST BOUNDARY LAYER /UPPER 60S TO LOW 70S DEWPOINTS/ IS

FORECAST TO STREAM NWD ACROSS THE PLAINS THIS PERIOD...BENEATH

ELEVATED MIXED-LAYER AND ASSOCIATED CAPPING INVERSION. BY

AFTERNOON...MOISTENING BOUNDARY LAYER COMBINED WITH STRONG HEATING

AND STEEP LAPSE RATES ALOFT SHOULD YIELD EXTREME INSTABILITY ACROSS

PARTS OF THE CENTRAL AND NRN PLAINS. CAPPING WILL LIKELY HINDER

CONVECTIVE DEVELOPMENT IN MOST AREAS UNTIL LATE AFTERNOON...WHEN

SCATTERED STORMS SHOULD DEVELOP OVER THE DAKOTAS AND SWD INTO NEB.

CAP MAY BE BREACHED LOCALLY ALLOWING ISOLATED STORM DEVELOPMENT

ALONG DRYLINE AS FAR S AS SRN KS/OK/WRN N TX.

WITH 60 TO 80 KT SWLY MID-LEVEL FLOW FORECAST TO SPREAD NEWD ACROSS

THE PLAINS DURING THE AFTERNOON/EVENING ABOVE STRONG/INTENSIFYING

SLY LOW-LEVEL FLOW...SHEAR SHOULD BE EXCEPTIONALLY-FAVORABLE --

GIVEN DEGREE OF AVAILABLE INSTABILITY -- FOR LARGE/INTENSE SUPERCELL

STORMS. ALONG WITH THE POTENTIAL FOR VERY LARGE HAIL AND WIDESPREAD

DAMAGING WINDS...TORNADOES ARE ALSO ANTICIPATED -- WITH A FEW

SIGNIFICANT/LONG-TRACK TORNADOES POSSIBLE. GREATEST THREAT APPEARS

TO EXIST ATTM ACROSS THE ERN HALVES OF SD AND NEB AND INTO SWRN

MN/WRN IA.

OVERNIGHT...SEVERE THREAT IS FORECAST TO SPREAD EWD INTO THE UPPER

MS VALLEY REGION...AS COLD FRONT SURGES EWD AND LOW-LEVEL JET

INTENSIFIES TO 70 KT INTO THIS AREA. SEVERE THREAT SHOULD CONTINUE

THROUGH THE NIGHT...PERHAPS EXTENDING AS FAR E AS THE WRN UPPER

GREAT LAKES BY THE END OF THE PERIOD.

...MID OH VALLEY SEWD INTO THE CAROLINAS...

SCATTERED STORMS ARE FORECAST TO DEVELOP ALONG BAROCLINIC ZONE

EXTENDING ESEWD ACROSS THE OH VALLEY AND INTO THE CAROLINAS...AS

AIRMASS DESTABILIZES THROUGH THE AFTERNOON AND WEAK SHORT-WAVE

TROUGH MOVES EWD THROUGH LARGER-SCALE RIDGE. WITH MID-LEVEL WNWLY

FLOW NEAR 40 KT...POTENTIAL FOR A FEW ORGANIZED STORMS/STORM

CLUSTERS WILL EXIST...ACCOMPANIED BY A THREAT FOR LOCALLY-DAMAGING

WINDS AND/OR HAIL THROUGH EARLY EVENING.

[Pale Blue Sky]

Have a great and safe chase, Paul!

We'll be there with you in spirit!

-PBS-

[Paul R]

Bloody hell eh? Just when I thought things were starting to quieten down. Have a smashing chase Paul.

[Paul R]

step away from the steaks and stay safe!

Ah, now we know why he's going back. Chase my I have a problem, he's making an excuse for a triumphant return to the Big Texan in Amarillo.

[pottyprof]

I remember someone saying that he is on a diet.............. :lol:

[Gorky]

Good luck out there Paul... Can't say I hadn't been tempted myself to try and take some more time off work, but I doubt anything would have been possible at such short notice. It's amazing see how this has just setup had just got better and better as the days have gone on. I'm really busy with work still so I don't know how much I'll be able to partake with regards to nowcastings and offering start locations etc, but I'll try to offer what I can. Good luck and stay safe!

[Kent Snow]

Wow! Have another good chase, hope you see some cool storms etc.

[Thundersquall]

Guess who's going to win the June photo comp.

Wow, that dewpoint gradient - it's huge! In parts of mid-Texas there's an

extremely sharp temperature range of 40C!

Is it this massive gradient that counts towards a super outbreak of tornadoes?

[WhiteFox]

Local weather forecasts and TWC should be interesting this week. Even up here in Chicago we could see some pretty severe storms, with a higher probability the further south and west you go. Oddly enough, I had a very vivid dream last week where a strong tornado hit Chicago; I sure hope that doesn't happen!

[Paul Sherman]

Am just getting to Bed now in Denver, currently 1145pm and have been up 22 Hours so a nice 7 hours kip before looking at the Models tomorrow. Thanks for all the kind words, will try to bag a Big Un For you guys

Paul Sherman

[Nick F]

Boy are you in for action packed few days! SLGT risk today over Ern Colorado North across Wern Nebraska into parts of Wyoming. Tomorrow and Thursday there's a MDT risk over Ern Nebraska and South Dakota, so option is to haul ass towards there for tomorrow maybe seeing some storms on the way today.

Day 1:

Day 2:

Day 3:

Liking these three paragraphs for day 3:

...SYNOPSIS...

POTENT MID-LEVEL TROUGH IS FORECAST TO EMERGE FROM THE ROCKIES INTO

THE PLAINS THIS PERIOD... ACCOMPANIED BY AN UNSEASONABLY-STRONG SWLY

JET STREAK . AS THIS LOW MOVES INTO THE PLAINS...STRONG CYCLOGENESIS

IS FORECAST OVER THE NRN PLAINS -- YIELDING A 975 MB LOW OVER ERN ND

LATE IN THE PERIOD. ASSOCIATED/TRAILING COLD FRONT IS FORECAST TO

SWEEP EWD/SEWD ACROSS THE PLAINS THROUGH THE PERIOD...WITH THIS

FRONT -- AND A LEADING DRYLINE -- LIKELY TO SERVE AS FOCI FOR THE

DEVELOPMENT OF WIDESPREAD SEVERE STORMS.

...CENTRAL AND NRN PLAINS INTO THE UPPER MS VALLEY...

MODELS CONTINUE TO DEPICT THE POTENTIAL FOR A WIDESPREAD/SIGNIFICANT

SEVERE WEATHER OUTBREAK ACROSS PARTS OF THE PLAINS STATES THIS

PERIOD.

VERY MOIST BOUNDARY LAYER /UPPER 60S TO LOW 70S DEWPOINTS/ IS

FORECAST TO STREAM NWD ACROSS THE PLAINS THIS PERIOD...BENEATH

ELEVATED MIXED-LAYER AND ASSOCIATED CAPPING INVERSION. BY

AFTERNOON...MOISTENING BOUNDARY LAYER COMBINED WITH STRONG HEATING

AND STEEP LAPSE RATES ALOFT SHOULD YIELD EXTREME INSTABILITY ACROSS

PARTS OF THE CENTRAL AND NRN PLAINS. CAPPING WILL LIKELY HINDER

CONVECTIVE DEVELOPMENT IN MOST AREAS UNTIL LATE AFTERNOON...WHEN

SCATTERED STORMS SHOULD DEVELOP OVER THE DAKOTAS AND SWD INTO NEB.

CAP MAY BE BREACHED LOCALLY ALLOWING ISOLATED STORM DEVELOPMENT

ALONG DRYLINE AS FAR S AS SRN KS/OK/WRN N TX.

[Joneseye]

The outlook certainly looks tasty!!

[Roger J Smith]

Looking at the model output, this moderate risk should be upgraded to high risk for late Wednesday and all day Thursday.

Low pressure deepens to 978 mbs across the Dakotas, by late Wednesday a very strong cold front comes out of the Rockies into the high plains, best chase opportunity should be western Nebraska, northeast CO and far northwest KS. The severe storms should then stay intact all night (last time I said that, we had Greensburg), and Thursday should be mega-severe across eastern SD, most of Nebraska, spreading into MN, IA and parts of KS as the day progresses. With temps 95-100 F in the warm sector and 55-60 F behind the second of two cold fronts, this outbreak has very impressive dynamics and I am fully expecting F4-5 activity with it both late Wednesday and especially on Thursday.

Not sure when Paul arrives in Denver, the warm fronts with this should be quite active late Tuesday across central NE and KS, could be some tornadic storms developing with any wave action on the warm front, somewhat to the northeast of Salina KS most likely for this. Probably a long haul out of Denver for this, but there you have it. Action central.

By Friday the main low is into Hudson Bay, trailing cold front still severe across parts of Michigan and Wisconsin, but another severe cluster likely to develop with trailing wave over se CO, nw OK and n TX.

[pottyprof]

Looks like Paul and Co could be in for a start today.

Quoting Mark Farnik over on Storm Track http://www.stormtrack.org/forum/showthread.php?t=12767

Where he quotes tomorrow, read today..

Tomorrow is starting to look extremely interesting for eastern Colorado. Per the latest model soundings, temps in the high 70's with dewpoints in the low to mid 50's give 2000-3000 j/kg of CAPE over eastern Colorado by late tomorrow afternoon. The surface flow is forecast to veer to a south/southeasterly direction by tomorrow afternoon, which when combined with the west/southwesterly flow aloft, will provide a strongly backed shear profile over the area. It has all the ingredients to be a classic High Plains Day 2 post-frontal severe weather outbreak. The Denver WFO, which rarely gets too excited about severe weather situations, has some pretty strong wording in this afternoon's AFD in regards to tomorrow's severe potential:

THE INCREASING WINDS WILL LEAD TO A SIGNIFICANT

THREAT OF SEVERE STORMS TUESDAY EVENING AS THE WIND PROFILE BECOMES VERY FAVORABLE FOR SUPERCELLS. LOW LEVEL JET INCREASES IN THE EVENING WITH NAM SOUNDING AT AKRON SHOWING SOUTH WINDS AT 35 KT AT 800 MB...GIVING 0-3 KM HELICITY OF 360 M2/S2. SO...SIGNIFICANT TORNADO POTENTIAL IF THE SITUATION SETS UP AS THE NAM SHOWS.

If a Denver Cyclone does indeed develop tomorrow as forecast, this would only further enhance the tornadic potential over eastern Colorado. It also appears there will be an area of convergence over the northeastern corner of the state between easterly winds coming out of Nebraska, southeasterly winds coming out of Kansas, and westerly winds coming off of the lee side of the Continental Divide, which would serve as a focusing mechanism for intense convection and potential tornadic activity.

It'd be awesome to bag a few 'naders in my own backyard before heading to Nebraska for Wednesday's outbreak...

If it pans out anything like the NAM solution shows, there could be a considerable mini-tornado outbreak over the Colorado plains tomorrow evening, and with 3000 j/kg of CAPE, LCL's around 1000 meters AGL and almost 400 ms/2 of helicity, there is the distinct possibility of an isolated strong tornado occurring somewhere in eastern Colorado tomorrow.

This situation bears very close watching indeed...