Model Outlook For Chase Team 3

[multi cellular thunderstorm]

Thought i'd start this as it's only just over a week until the start of Tour 3.

It's not yet in any kind of reliable time frame, but it's still interesting to see what the GFS throws up.

Cape/Li for first couple of days...

Temps...

Even further into the run temps are up in the mid 30s!

Looks promising to me, but i'm no expert, hopefully someone with a bit more experience will add some updates in the coming days :o

[Arron]

CAPE looks a long way from DFW!

[Nick F]

Doesn't look great from ECM for the first few days ... as far as it goes out. With a big omega ridge drifting east over the Plains. Hopefully it won't hang around too long!

Tues 19th 12z - Thurs 21st 12z:

12 GFS not too great either with an anticyclonic upper flow with the high over Wern USA, perhaps some storms way up over the Dakotas and Minnesota by the Thursday:

- Weds 20th 00z

- Thurs 21st 00z

- Fri 22nd 00z

Hoping it changes - otherwise we'll be getting through alot of suncream ... lol

[Nick F]

Looking somewhat better from 00z GFS this morning for next week as it flattens the ridge across SW USA more, perhaps some opportunities over the Nern Plains - so alot of driving N. ECM also looks flatter with the ridge and again the strong upper flow with storm potential reserved for the Nern Plains.

Hopeful that the following weekend and following week will see a major Pacific trough move in across Wern USA and then slow towards the Plains - this would perhaps bring a major outbreak - but a long way off for now.

[Nick F]

Beginning of next week looks on the quiet side for the Plains as cold front moving S/SE clears moisture away south to the Gulf of Mexico and death ridge builds in from the west.

ZCZC SPCSWOD48 ALL

ACUS48 KWNS 130854

SPC AC 130854

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0354 AM CDT WED MAY 13 2009

VALID 161200Z - 211200Z

THE MEDIUM RANGE MODELS MOVE A BROAD UPPER-LEVEL TROUGH INTO THE MS

VALLEY ON SATURDAY/DAY 4 AND ACROSS THE ERN SEABOARD ON SUNDAY/DAY

5. THUNDERSTORMS...WITH SOME POTENTIALLY SEVERE...SHOULD DEVELOP

EACH DAY ALONG AND SOUTH OF A COLD FRONT FORECAST TO MOVE ACROSS THE

MID MS VALLEY AND GULF COAST STATES THIS WEEKEND. ATTM...THE SYSTEM

DOES NOT APPEAR TO BE FOCUSED ENOUGH TO WARRANT A SEVERE WEATHER

THREAT AREA. AS THE COLD FRONT MOVES INTO THE NRN GULF OF

MEXICO...LOW-LEVEL MOISTURE RETURN SHOULD BE IMPEDED THROUGH EARLY

NEXT WEEK. IN ADDITION...AN UPPER-LEVEL RIDGE IS FORECAST OVER MUCH

OF THE ERN AND CNTRL U.S. BY TUESDAY. FOR THESE REASONS...A CLUSTER

OF SEVERE STORMS WARRANTING A SEVERE THREAT AREA IS NOT ANTICIPATED

THROUGH EARLY NEXT WEEK.

..BROYLES.. 05/13/2009

However, later next week 00z ECM shows a major long-wave trough heading east off the Pacific across Western USA and this would create decent height falls combined with moisture return for severe storms to make a come-back - perhaps even an outbreak if the trough slows.

Only 6 days to go until I fly out to join Paul Sherman, better start finding everything to pack.

[multi cellular thunderstorm]

Thanks for the updates Nick.

Looks like we might be the first team not chasing on landing day, at least we can get settled after the flight

Some very impressive Cape/Li charts way into the run...

I wish!

[Nick F]

Yes, looks a slow start still from the 12z output, so a few down days possible. But hints that the ridge building in from the west across the mid-west early next week will be transitory and that heights will slowly fall from the west again by late week with perhaps a series of short-waves ejecting east or NE across the central and northern Plains which may bring severe storms back.

Some low confidence in the medium range outlook from models recently - so anything could happen!

[multi cellular thunderstorm]

Still looking quite quiet for the first few days...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0351 AM CDT THU MAY 14 2009

VALID 171200Z - 221200Z

THE MEDIUM RANGE MODELS MOVE A BROAD UPPER-LEVEL TROUGH EWD INTO THE

ERN SEABOARD SUNDAY/DAY 4 AS A COLD FRONT ADVANCES SEWD ACROSS THE

GULF COAST STATES. THUNDERSTORMS SHOULD DEVELOP SUNDAY AFTERNOON IN

RESPONSE TO SFC HEATING ALONG THE BOUNDARY. RELATIVELY WEAK VERTICAL

SHEAR PROFILES OVER THE WARM SECTOR SHOULD KEEP THE SEVERE THREAT

LOCALIZED. BEYOND DAY 4...THE MEDIUM RANGE MODELS DEVELOP A

PERSISTENT UPPER-LEVEL RIDGE OVER THE CNTRL U.S. THIS SHOULD IMPEDE

MOISTURE RETURN FROM THE GULF OF MEXICO UNTIL LATE IN THE DAY 4 TO 8

PERIOD. FOR THIS REASON...AN EXTENSIVE REGIONAL SEVERE THREAT IS NOT

EXPECTED THROUGH MOST OF NEXT WEEK.

..BROYLES.. 05/14/2009

Hopefully just building up to something big!

[Nick F]

Great uncertainty from model guidance still from the medium range outlook during next week. Though there is consensus of a ridge affecting Sern Plains and SW USA for the first half of next week ... after that, 00z ECM brings height falls from the west towards the mid-west - so hopefully we'll see storms in the 2nd half of next week - though it may mean a trek up into Colorado, Nebraska, Wyoming, etc.

Here' the prelim HPC discussion this morning:

VALID 12Z MON MAY 18 2009 - 12Z THU MAY 21 2009

A TREMENDOUSLY UNCERTAIN FORECAST COMING UP IN THE MEDIUM RANGE

FCST PERIOD. THE OPERATIONAL MODELS INCLUDING THE GFS/ECMWF SHOW

POOR RUN TO RUN CONTINUITY... THE OPERATIONAL GFS AND ECMWF LOOK

DIFFERENT ENOUGH WHEN COMPARED TO IT MEANS AND THE MEANS INDICATE

ENOUGH SPREAD WITH ITS MEMBERS BEYOND D4/MON.

THE FORECAST PERIOD STARTS OFF VERY WELL AS THE GUIDANCE INDICATES

ANOTHER POTENT SHORT WAVE TROUGH ROLLING THROUGH THE GRT LAKES

INTO THE ERN SECTION OF THE COUNTRY... WHILE A STRONG UPPER RIDGE

COVERS MUCH OF THE WEST INTO THE SRN PLAINS. HOWEVER... A POSSIBLE

DEEP CLOSED LOW AND UPPER TROUGH OVER THE NERN PAC IS HANDLED IN

VARIOUS WAYS BY THE GUIDANCE. THE 00Z GFS/CANADIAN/UKMET AND GFS

ENSMEAN ALL DIG THIS FEATURE INTO THE PAC NW/NRN INTER-MOUNTAIN

WEST IN VARIOUS SPEEDS AND AMPLITUDE BY TUES EVENING... WHILE THE

OPERATIONAL ECMWF AND ITS 12Z/13 MEAN KEEP THE RIDGE MAINLY INTACT

AND JUST SLIGHT TROUGHING PASSING THROUGH THE PAC NW. WHILE THIS

OCCURS... THE ABOVE MENTIONED FOURSOME BUILD THE RIDGE FROM THE

FOUR CORNERS REGION/SRN PLAINS NEWRD THROUGH THE MS VLY INTO THE

OH VLY/GRT LAKES AND THE FRONT PUSHING OFF THE ERN SEABOARD STALLS

ALONG THE SOUTHEAST COAST POSSIBLY INDUCING A CUT-OFF LOW

SOMEWHERE NEARBY TO POSSIBLY THE ERN GULF. THE ECMWF AND ITS MEAN

KEEP THE RIDGE FLAT FROM THE FOUR CORNERS INTO THE SRN PLAINS...

KEEP A LARGE NEGATIVE ANOMALY PRESENT OVER NRN HUDSON BAY WHICH

KEEPS HEIGHTS LOW THROUGH THE GRT LAKES INTO THE NORTHEAST AND A

POSSIBLE WEAKNESS/CUT-OFF LOW OVER FL/ERN GULF. BY WED THOUGH...

THE OPERATIONAL RUNS LOOK VERY LITTLE LIKE THE MEANS... WHILE THE

MEANS SHOW VERY LARGE SPREAD ACROSS THE NRN TIER OF THE COUNTRY

THROUGH ALL OF CANADA. AFTER D3/SUN... HPC RELIED HEAVILY ON THE

MEANS... ESPECIALLY THE 00Z GFS ENSMEAN WHICH HAS MORE SUPPORT

FROM MOST OF THE 00Z GUIDANCE THAN THE 12Z/13 ECMWF MEAN. NEEDLESS

TO SAY... NO SOLUTION OVER THE NEXT WEEK OFFERS A BUNCH OF

CONFIDENCE... JUST MORE CHAOS AND UNCERTAINTY.

MUSHER

[Nick F]

Don't like the look of the cut-off low sat over Ern GoM and Florida next week - which may hinder moisture return from the Gulf especially as cold front scrapes most moisture south to the Gulf this weekend. Otherwise upper pattern becomes more favourable later next week - but could be northern Plains and Nern half of the High Plains that sees any action if we get some moisture up there.

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0341 AM CDT FRI MAY 15 2009

VALID 181200Z - 231200Z

...DISCUSSION...

A RELATIVELY QUIET SEVERE CONVECTIVE PATTERN WILL DOMINATE MUCH OF

NEXT WEEK AS A BROAD UPPER RIDGE PERSISTS OVER THE WESTERN/SOUTHERN

CONUS. CONTINENTAL TRAJECTORIES AND LIMITED MOISTURE RETURN NEXT

WEEK SHOULD PRECLUDE ANY WIDESPREAD SEVERE EPISODES THROUGH THE

MIDDLE PART OF THE WEEK. THUS...NO 30% DAY-1 EQUIVALENT SEVERE

PROBABILITIES ARE WARRANTED AT THIS TIME.

EVEN WITH LIMITED MOISTURE...A FEW SEVERE TSTMS MAY BE POSSIBLE ON

DAY 4/MONDAY ACROSS THE UPPER MIDWEST...AS A COLD FRONT CROSSES THE

REGION IN ASSOCIATION WITH A SOUTHEAST MOVING UPPER TROUGH/JET

STREAK ACROSS SOUTH-CENTRAL CANADA...AND/OR PERHAPS ACROSS THE HIGH

PLAINS OF EASTERN MT VIA AN UPSLOPE REGIME. FOR DAYS 5/6 TUESDAY AND

WEDNESDAY...A FEW HIGH BASED SEVERE TSTMS/PERHAPS SUPERCELLS MAY BE

POSSIBLE ACROSS THE NORTH CENTRAL HIGH PLAINS IN VICINITY OF COLD

FRONT/LEE TROUGH AND/OR WITHIN A POST-FRONTAL LOW LEVEL UPSLOPE

REGIME INTO THE HIGHER TERRAIN/FRONT RANGE.

[nsrobins]

It's a bit early for the switch to High Plains activity just yet, but it does indeed look quiet on the macro-scale for many days. Mind you, never say never in this game and even in flat spells the odd thing crops up to make it all worthwhile. I'd be making provisional plans to get up into high KS or NB even to start with (19th May) if the current long range is right.

[Arron]

booooo B) Oh well, will give us chance to settled in and maybe a few lessons out the way

[Nick F]

Looking at 12z GFS, first opportunity for team 3 maybe some upslope storms over Colorado and Wyoming on Thursday afternoon/evening:

00z-06z 22nd UTC (18z 21st - 00z 22nd CDT):

... a long-way off, but it gives us all day Wednesday and Thursday to get up there - as its a long old drive if this were to come off.

[Nick F]

GFS still indicates some upslope storms perhaps moving off the Front Range across the High Plains of Colorado and also Wyoming and perhaps storms over Nebraska as cold front sags south Thursday and Friday. This idea supported by the SPC's 4-8 day outlook. Opportunity for some good structure shots, perhaps some LP supercells ... Otherwise, much of the Plains under the influence of a ridge and staying dry.

Thurs 21st 17z and 23z MDT (Fri 22nd 00z-06z UTC)

High Plains for Friday?

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0330 AM CDT SAT MAY 16 2009

VALID 191200Z - 241200Z

...DISCUSSION...

A RELATIVELY QUIET SEVERE CONVECTIVE PATTERN FOR MID MAY SHOULD

CONTINUE THROUGH THE MIDDLE PART OF NEXT WEEK...AS AN AMPLIFIED

LARGE SCALE REGIME AND BROAD UPPER RIDGE OVER THE SOUTHERN CONUS

GENERALLY DOMINATES. WITH PROGRESSIVE WESTERLIES ACROSS THE NORTHERN

TIER...LIMITED MOISTURE RETURN SHOULD PRECLUDE ANY

WIDESPREAD/APPRECIABLE SEVERE EPISODES THROUGH THE MIDDLE PART OF

THE WEEK. NO 30% DAY-1 EQUIVALENT SEVERE PROBABILITIES ARE WARRANTED

AT THIS TIME.

EVEN WITH LIMITED MOISTURE...SOME SEVERE TSTMS MAY BE POSSIBLE ON

TUESDAY/DAY 4 ACROSS ID/MT IN ASSOCIATION WITH A PROGRESSIVE

SHORTWAVE TROUGH/COLD FRONT CROSSING THE NORTHERN ROCKIES. AS THIS

SHORTWAVE TROUGH LIKELY SHIFTS EASTWARD ACROSS THE NORTHERN TIER ON

WEDNESDAY/DAY 5...A RISK FOR SEVERE TSTMS MAY DEVELOP INTO THE

DAKOTAS/MN AND PERHAPS ADJACENT NEB...BUT AGAIN MODEST MOISTURE

WOULD LIKELY CURB THE POTENTIAL EVEN WITH FAVORABLE KINEMATICS/LAPSE

RATES. THEREAFTER...FOR THURSDAY-SATURDAY DAYS 6-8...CURRENT

THINKING IS THAT THE MAIN PROSPECTS FOR ANY SEVERE TSTMS WILL BE

PRIMARILY CONFINED TO THE NORTH CENTRAL HIGH PLAINS/FRONT RANGE VIA

AN UPSLOPE REGIME.

[Gorky]

I'm a;ready making my way north in preparation for next week. Going to visit a few state parks and hope for some storms in the Dakotas for the middle of next week. I'll gladly take a small high based pulse storm over the grungefest from yesterday

[Gorky]

Wednesday actually looks half decent now. The half that looks decent is the Kinematics, where as the moisture return is marginal unfortunately. Still, the Euro model seems to suddenly removed the ridge completely by Wednesday and we have a good SW flow aloft. Dews will struggle to reach 15 degrees but there is an axis of 1500 j kg instability forecast from the Central NE/SD border up through into Northern Minesota. I'm sure thigns will change a little before then, and any less moisture and things would really struggle to get interesting, butI'm certainly going to make sure I'm in position to play this area on Wednesday if the models improve somewhat. I'm planning on Spending Monday in the Badlands in SD anyway so I may just hang around for an extra day there...

[multi cellular thunderstorm]

Here's the latest outlook from NWS...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0351 AM CDT SUN MAY 17 2009

VALID 201200Z - 251200Z

...DISCUSSION...

AN AMPLIFIED LARGE SCALE PATTERN WILL LIKELY CONTINUE FROM THE

MIDDLE INTO LATTER PART OF THE WEEK. THIS REGIME WILL GENERALLY BE

CHARACTERIZED BY A BROAD UPPER RIDGE OVER THE SOUTHWEST/SOUTH

CENTRAL CONUS...WITH THE STRONGER WESTERLIES LARGELY CONFINED TO

CANADA AND THE NORTHERN TIER OF THE LOWER 48. WHILE PERIODIC SEVERE

TSTMS WILL BE POSSIBLE...LIMITED MOISTURE RETURN WILL LIKELY

PRECLUDE ANY WIDESPREAD SEVERE EPISODES FOR AT LEAST THE FIRST PART

OF THE DAY 4-8 PERIOD...AND NO 30% DAY-1 EQUIVALENT SEVERE

PROBABILITIES ARE WARRANTED AT THIS TIME.

WITH RELATIVELY GOOD GEFS/ECMWF CONSENSUS...SOME SEVERE TSTMS WILL

BE POSSIBLE ACROSS THE UPPER MIDWEST/NORTH CENTRAL PLAINS ON

WEDNESDAY/DAY 4...IN ASSOCIATION WITH A PROGRESSIVE SHORTWAVE TROUGH

AND EASTWARD ADVANCING COLD FRONT. IN SPITE OF EXPECTATIONS FOR

RELATIVELY STRONG KINEMATICS/AMPLE LAPSE RATES...MEAGER BOUNDARY

LAYER MOISTURE SHOULD PRECLUDE A MORE APPRECIABLE THREAT. FOR

THURSDAY-SATURDAY DAYS 5-7...CURRENT THINKING IS THAT THE MAIN

PROSPECTS FOR ANY SEVERE TSTMS WILL BE PRIMARILY CONFINED TO THE

NORTH CENTRAL HIGH PLAINS/FRONT RANGE VIA A POST-FRONTAL UPSLOPE

REGIME...ALTHOUGH WESTERLIES WILL TEND TO REMAIN MODEST.

OTHERWISE...SEVERE TSTMS MAY BE POSSIBLE ACROSS THE NORTHEAST

STATES/NEW ENGLAND AROUND DAY 6/FRIDAY ALONG/AHEAD OF A COLD FRONT

AND PARENT UPPER TROUGH...BUT PREDICTABILITY IS INHERENTLY LOW ALONG

WITH UNKNOWNS REGARDING MOISTURE.

..GUYER.. 05/17/2009

[multi cellular thunderstorm]

Still not looking too good, but signs of improvement at the weekend...

DAY 4-8 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0357 AM CDT MON MAY 18 2009

VALID 211200Z - 261200Z

...DISCUSSION...

MEDIUM RANGE MODEL CONSENSUS SUGGESTS A RATHER AMPLIFIED/SUMMERTIME

LARGE SCALE PATTERN WILL LIKELY CONTINUE INTO THE LATTER PART OF THE

WEEK...WITH THE STRONGER WESTERLIES CONFINED TO THE NORTHERN TIER OF

THE LOWER 48. LIMITED MOISTURE RETURN AND/OR WEAK WESTERLIES WILL

LIKELY PRECLUDE ANY WIDESPREAD SEVERE EPISODES INTO THE

WEEKEND...AND NO 30% DAY-1 EQUIVALENT SEVERE PROBABILITIES ARE

WARRANTED AT THIS TIME.

MAIN PROSPECTS FOR ANY SEVERE TSTMS INTO THE WEEKEND WILL GENERALLY

BE CONFINED TO THE NORTH-CENTRAL HIGH PLAINS AND ADJACENT FRONT

RANGE WITHIN A LOW LEVEL UPSLOPE REGIME...ALTHOUGH WESTERLIES WILL

TEND TO REMAIN WEAK SOUTH OF MT. WHILE SPECIFIC PREDICTABILITY WITH

THE EVOLUTION OF THE STAGNANT UPPER LOW OVER THE GULF OF MEXICO IS

LIMITED...IT SEEMS PROBABLE THAT RICHER BOUNDARY LAYER MOISTURE WILL

FINALLY BEGIN TO RETURN NORTHWESTWARD INTO THE PLAINS AND MIDWEST

THIS WEEKEND. THIS COULD LEAD TO A BIT OF AN UPSWING IN TSTMS ACROSS

THE PLAINS/CENTRAL STATES...ALTHOUGH WEAK FORCING/WINDS ON THE LARGE

SCALE ARE SUGGESTIVE OF A LIMITED ORGANIZED SEVERE POTENTIAL AT THIS

JUNCTURE.

..GUYER.. 05/18/2009

[Nick F]

Still looks like there will be an opportunity for some upslope storms over Colorado, N Mexico and Wyoming Thursday onwards, with perhaps some storms breaking out across Nebraska and S Dakota too as shortwaves eject east and cold front moves down ... though we'll be working with rather limited moisture and weak upper winds, chance for some pulse type LP structures at least coming off the Front Range:

Fri 22nd 00z UTC (Thurs 17Z MDT):

Sat 23rd 00z UTC (Fri 17z MDT):

Sun 24th 00z UTC (Sat 17z MDT):

Chances for severe outbreak with tornadoes, to be brutally honest, looks pretty slim until at least sometime next week. With a pretty weak flow aloft across central USA for next 7 days or more - though shortwaves may allow at least some storms to develop over the north/central High Plains and the Nern Plains - but working with limited moisture.

[nsrobins]

I agree with Nick in that there's slim pickings for a while now. However . . .

You might want to look North towards the high plains on Wednesday and especially Thursday. The 06NAM continues to offer the chance of upslope-forced action from the NE Panhandle (achievable) up into the Dakotas. Afternoon heating and modest mid-50s dps generate about 1800 mean CAPE which assuming topography can break the cap should be enough for some structure. Actually although flows are fairly weak at all levels, there must be some vector components as NAM is offering 1.50 EHI in a line up into SD (presumably the cold front axis).

Worth a punt?

Longer term, and the 06GFS has me in the mood to lay me tackle on the line and predict a significant improvement in moisture return for the weekend. The upper pattern suggests a de-amplification (made up term LOL) with richer juice making its way back into the southern plains as an upper low develops over the four corners.

[stevestorms]

Sorry you guys are looking at a bit of a D/R but yer know these things do move off eventually in the mean time I have me feet up back in the UK and enjoying the one thing you cant get in the USA, a nice Cuppa

[Paul Sherman]

Sorry you guys are looking at a bit of a D/R but yer know these things do move off eventually in the mean time I have me feet up back in the UK and enjoying the one thing you cant get in the USA, a nice Cuppa

Finish me off and Order a Chicken Madras, Mushroom Pilau Rice and Garlic Naan Bread why dont ya! GIT

[nsrobins]

Finish me off and Order a Chicken Madras, Mushroom Pilau Rice and Garlic Naan Bread why dont ya! GIT

I can do footie on Sky, a pint of London Pride and a curry ordered for delivery in an hour.

Will that do?

For you downtimers, there is a change afoot - trust me!

[multi cellular thunderstorm]

I can do footie on Sky, a pint of London Pride and a curry ordered for delivery in an hour.

Will that do?

For you downtimers, there is a change afoot - trust me!

I hope you're right and it's just building up to something big for next week

Still i'm sure the odd isolated storm this week would be 100x better than what I see in the North East. Can't remember a proper overhead storm since August 05.

Just packing the last few things and i'll be leaving for Heathrow in a couple of hours!

[Nick F]

Finished my packing - everything charged ... early rise to get the train into London then a tube out to Heathrow, which will be the worst part of the journey. Then think I will have a cooked breakfast before my flight at 12.15pm.

See ya at the car rentals at DFW airport probably MCT, have a nice flight, the food ain't too great though on AA!!!

Confident that we will some storms Thursday onwards across the High Plains of Colorado and into Nebraska and Wyoming ... for once I am actually looking forward to not having to chase HP supercell monsters like we had last year in Kansas and Nebraska where we were constantly trying to avoid being munched by HP cores that bring zero visibility from heavy rain, strong RFD, large hail and possibly hidden rain-wrapped tornadoes. LP structures can be rewarding too.