Chase 2010 - Day 16 Discussion

[Paul Sherman]

Slight Risk From the SPC - 10% For Tornadoes so a much better chance for some Spin Ups

Going to Target the N Central Oklahoma and SE & S Kansas area today.

We will be starting in the 5% Box in Enid (Ok)

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0100 AM CDT WED MAY 12 2010

VALID 121200Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN AND

CNTRL PLAINS...MID-MS VALLEY AND OH VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE

MID-ATLANTIC...

...SRN AND CNTRL PLAINS/MID-MO VALLEY

AN UPPER-LEVEL LOW IN THE CNTRL ROCKIES TODAY WILL ACCELERATE NEWD

AS A MID-LEVEL JET EJECTS NEWD ACROSS THE CNTRL AND SRN PLAINS. AT

THE SFC...A COLD FRONT WILL MOVE SSEWD ACROSS THE CNTRL PLAINS WITH

A MOIST AND VERY UNSTABLE AIRMASS IN PLACE ACROSS THE SLIGHT RISK

AREA. FORECAST SOUNDINGS JUST AHEAD OF THE FRONT AT 21Z FROM THE

MID-MO VALLEY TO THE SRN PLAINS SHOW MLCAPE VALUES IN THE 3000 TO

4000 J/KG RANGE. FORECAST SOUNDINGS DURING THE DAY SUGGEST THE WARM

SECTOR WILL REMAIN CAPPED UNTIL LATE AFTERNOON WHEN THE MODELS

INTIATE NUMEROUS THUNDERSTORMS FROM NRN MO SSWWD ACROSS ERN KS INTO

NRN OK. THIS ACTIVITY WILL BE LOCATED ON THE ERN EDGE OF A 60 TO 80

KT MID-LEVEL JET CREATING STRONG VERTICAL SHEAR PROFILES FAVORABLE

FOR SUPERCELLS. SUPERCELL DEVELOPMENT SHOULD BE RATHER QUICK DUE TO

THE STRONG INSTABILITY IN PLACE WITH VERY LARGE HAIL POSSIBLE WITH

THE MORE DOMINANT CELLS.

THE CURRENT THINKING IS THAT A BROKEN LINE OF INTENSE STORMS WILL

DEVELOP IN THE LATE AFTERNOON FROM NRN MO SSWWD ACROSS ERN KS INTO

NRN OK ON THE WRN EDGE OF THE LOW-LEVEL JET. THE JET SHOULD CREATE

STRONG LOW-LEVEL SHEAR PROFILES FAVORABLE FOR TORNADOES WITH THE

MORE DOMINANT SUPERCELLS. MODEL FORECASTS ALSO SUGGEST STORM MODE

MAY GRADUALLY TRANSITION TO A LINEAR STRUCTURE DURING THE EVENING AS

A LARGE MCS ORGANIZES FROM THE OZARKS SWWD TO THE LOW-ROLLING PLAINS

OF WEST TX. LARGE HAIL AND WIND DAMAGE WILL BE LIKELY WITH THE

STRONGER CELLS ELEMENTS IN THE MCS.

[Nick F]

My target zone would be pretty much where the team are staying overnight now in Enid, OK. Hang around the area and see what fires I think, may end up chasing into SE/E Kansas where the cap will probably erode first before storms back build SW into Oklahoma. Looking at 00z WRF/NAM, it breaks out precip in this area of N central OK by 00z (18z CDT), then more generally from SW Oklahoma NE up to Kansas City:

0-3km SR Helicity looks quite good too over N central OK by 00z (18z CDT), so enhancing potential for tornadoes:

Need to get on storms that form later today fairly quickly while discrete, as the cold front is forecast to move back SE again through the overnight period, which will tend to turn merge storms into a linear MCS.

[NL]

Updated Forecast from the NWS SPC.

Tornado probability.

SPC AC 121629

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1129 AM CDT WED MAY 12 2010

VALID 121630Z - 131200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM NW TX INTO THE MID MS AND

LOWER OH VALLEYS...TO THE MID ATLANTIC COAST...

...CENTRAL/SOUTHERN PLAINS...

A LARGE UPPER TROUGH REMAINS OVER THE WESTERN STATES TODAY...WITH

BAND OF 70-90 KNOT MID LEVEL WINDS EXTENDING FROM AZ/NM INTO THE

CENTRAL PLAINS. THE MAIN SURFACE BAROCLINIC ZONE LIES FROM CENTRAL

MO INTO SOUTH CENTRAL KS WHERE A WEAK SURFACE LOW IS EVIDENT. THIS

BOUNDARY WILL PROVIDE THE PRIMARY FOCUS FOR STRONG/SEVERE

THUNDERSTORM DEVELOPMENT LATER TODAY AND TONIGHT. 12Z RAOBS IN THE

WARM SECTOR SUGGEST THAT THE STRONG CAP WILL INHIBIT DEEP CONVECTION

AWAY FROM THE BOUNDARY THROUGH MOST OF THE DAY.

HOWEVER...INCREASING LOW LEVEL WARM ADVECTION AND LIFT ASSOCIATED

WITH WEAK SHORTWAVE TROUGH OVER EASTERN NM/WEST TX MAY EVENTUALLY

ERODE THE CAP OVER NORTHERN OK/SOUTHERN KS. THIS WILL LEAD TO

SCATTERED SEVERE STORMS ALONG THE FRONT...AND THE POTENTIAL FOR AT

LEAST ISOLATED CELLS FORMING DISCRETELY IN THE WARM SECTOR.

THERMODYNAMIC PROFILES IN THIS AREA WILL BE VERY UNSTABLE WITH

DEWPOINTS NEAR 70F AND MLCAPE VALUES OF 3000-4000 J/KG. FORECAST

SOUNDINGS SUGGEST STRONG EFFECTIVE SHEAR /OVER 50 KNOTS/ WILL

SUPPORT SUPERCELL STORMS CAPABLE OF VERY LARGE HAIL AND DAMAGING

WINDS. ANY DISCRETE STORM THAT FORMS OFF THE FRONT WILL ALSO HAVE

SUFFICIENT LOW LEVEL VERTICAL SHEAR /ESPECIALLY AFTER 00Z/ FOR THE

THREAT OF A FEW TORNADOES. ACTIVITY SHOULD TRACK/DEVELOP

NORTHEASTWARD ACROSS SOUTH CENTRAL KS AND INTO WESTERN MO THROUGH

THE EVENING WITH THE RISK OF RATHER WIDESPREAD HAIL.

FARTHER SOUTHWEST...IT APPEARS LIKELY AT LEAST ISOLATED

THUNDERSTORMS WILL DEVELOP ALONG THE SURFACE DRYLINE OVER WESTERN OK

AND WESTERN NORTH TX. THESE STORMS WILL TRACK EAST-NORTHEASTWARD

THIS EVENING AND WILL ALSO POSE A RISK OF LARGE HAIL AND DAMAGING

WINDS.

...KY/WV INTO VA...

A LARGE MCS IS ONGOING THIS MORNING OVER PARTS OF KY/WV. GIVEN THE

MESOSCALE ORGANIZATION OF THIS SYSTEM...IT APPEARS LIKELY TO

MAINTAIN ITS INTENSITY THROUGH THE DAY AS IT CROSSES THE

APPALACHIANS INTO VA. SUNNY SKIES AHEAD OF THE STORMS...COMBINED

WITH DEWPOINTS CLIMBING THROUGH THE 60S WILL PROVIDE SUFFICIENT

DESTABILIZATION FOR THE RISK OF SEVERE STORMS. DAMAGING WINDS

APPEAR TO BE THE MAIN THREAT.

..HART/SMITH.. 05/12/2010

[Nick F]

Looking at the latest model output, some difference in timing of the cold front clearance later, NAM slightly faster clearing it through southern Kansas than GFS and RUC, ideally want to get on a discrete cell before it is swallowed up by the likely linear goup of storms likely to develop on the cold fornt shifting SE. Best wind shear fields have shifted further west into south central Kansas, and this likewise reflected by the 16z SPC update which has shifted 10% tornado prob area. Quite like the look of Medicine Lodge to Harper as a target area which looks to have best wind fields for tornadoes should a storm move into this area, though hanging around Enid may keep you in easy reach of any storms that fire in south central-KS or over north-central OK.

[Paul]

Paul's put his briefing online:

http://www.netweather.tv/index.cgi?action=storm-chase-highlights;sess=

[John Hanrahan]

Paul's put his briefing online:

http://www.netweather.tv/index.cgi?action=storm-chase-highlights;sess=

LOL

[Stuart]

love the briefing

[Nick F]

Lol, some late nights for tour 2 team.

[Paul]

Hey all, as per my request at the top of the page, please can you help Paul S's wife out - she's hoping to win some tickets for her and their kids and need as many people as poss to visit this page - it's all legit (linked in with capital radio)

http://winsummertime....aspx/louise_80

Thanks

[Tornado Researcher]

Nice briefing, although I was waiting for Paul to yell "WAKE UP!!!" at the end lol

[John Hanrahan]

Hey all, as per my request at the top of the page, please can you help Paul S's wife out - she's hoping to win some tickets for her and their kids and need as many people as poss to visit this page - it's all legit (linked in with capital radio)

http://winsummertime....aspx/louise_80

Thanks

OK Done that on 1 computer. Will power up the other 4 in the house and were there

[Paul]

Woohoo, made it

Now back to the chasing!!

[pottyprof]

Was it ok me using a proxy or 2?

[NL]

Heavy night in Enid...? Dont think Paul had a 'tube of glue' what day it was...!!!

Anyway latest from NWS spc.

909

ACUS11 KWNS 121921

SWOMCD

SPC MCD 121921

KSZ000-OKZ000-122015-

MESOSCALE DISCUSSION 0527

NWS STORM PREDICTION CENTER NORMAN OK

0221 PM CDT WED MAY 12 2010

AREAS AFFECTED...PARTS OF SERN KS / W-CNTRL OK

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 121921Z - 122015Z

A LARGE PORTION OF SERN KS EXTENDING INTO W-CNTRL OK IS BEING

MONITORED FOR THE ISSUANCE OF A TORNADO WATCH.

RECENT SATELLITE TRENDS SHOW THE CU FIELD BECOMING MORE AGITATED IN

THE PAST HOUR OR SO--ACROSS THE I-35 CORRIDOR IN S-CNTRL KS AND

N-CNTRL OK AND AREAS IMMEDIATELY TO THE W AHEAD OF A SLOWLY MOVING

BAROCLINIC ZONE. 19Z SURFACE ANALYSIS PLACES A SURFACE LOW OVER

NWRN OK WITH A STALLED SURFACE FRONT LOCATED FROM 10 MI N HUT DRAPED

NEWD TO THE KANSAS CITY METRO. A COLD FRONT EXHIBITING ANAFRONTAL

CHARACTER IS SLOWLY BEGINNING TO PUSH EWD OVER PRATT COUNTY SWWD

INTO NWRN OK AS THE UPSTREAM UPPER TROUGH EJECTS EWD INTO THE SRN

HIGH PLAINS. A COMPLICATING FACTOR TO STORM INITIATION SCENARIO IS

THE EWD PROGRESSION OF A GRAVITY WAVE FROM NEAR EMP SWWD TO CNTRL

OK.

STORMS THAT CAN MOVE OFF OF OR DEVELOP IMMEDIATELY AHEAD OF THE EWD

MOVING COLD FRONT/DRYLINE AND REMAIN S OF THE STATIONARY FRONT IN

THE WARM SECTOR WILL BE CAPABLE OF LARGE HAIL/DMMG WINDS AND AN

ISOLD TORNADO. OTHERWISE...PREVIOUSLY DESCRIBED FRONTAL CHARACTER

ACROSS S-CNTRL KS WILL LIKELY HAVE A DETRIMENTAL IMPACT UPON STORM

LONGEVITY/SEVERITY AS MEAN FLOW IS LARGELY MORE PARALLEL TO THE

FRONTAL BOUNDARY ACROSS THE I-135 CORRIDOR.

REGARDLESS OF FEATURES/MECHANISMS SPAWNING CONVECTIVE INITIATION...A

MOIST/MODERATE TO VERY UNSTABLE AIRMASS /2000-3500 MLCAPE/ ACCORDING

TO 18Z OUN RAOB...IS CONTINUING TO DESTABILIZE WITH THE CAP EXPECTED

TO GRADUALLY WEAKEN TOWARDS MID-AFTERNOON. LOW LEVEL FLOW /AOA 20

KTS 0-1 KM SHEAR/ HAS BEEN NOTED TO BE STRONGER FARTHER N AND E

ACROSS SERN KS SWD INTO CNTRL OK PER RECENT AREA VWP/UPPER AIR DATA.

MORE THAN ADEQUATE SHEAR PROFILES WILL BE SUPPORTIVE OF SUPERCELLS

CAPABLE OF LARGE TO VERY LARGE HAIL...DMGG WINDS...AND ISOLD TORNADO

OR TWO.

..SMITH.. 05/12/2010

[NL]

Tornado watch....

802

WWUS20 KWNS 121942

SEL5

SPC WW 121942

KSZ000-OKZ000-TXZ000-130300-

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 155

NWS STORM PREDICTION CENTER NORMAN OK

245 PM CDT WED MAY 12 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

SOUTH CENTRAL AND EASTERN KANSAS

WESTERN OKLAHOMA

WESTERN NORTH TEXAS

EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 245 PM UNTIL

1000 PM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE

MILES NORTH AND SOUTH OF A LINE FROM 10 MILES NORTHEAST OF TOPEKA

KANSAS TO 45 MILES WEST SOUTHWEST OF ALTUS OKLAHOMA. FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR

TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS.

OTHER WATCH INFORMATION...CONTINUE...WW 154...

DISCUSSION...ISOLATED THUNDERSTORMS ARE EXPECTED TO INTENSIFY ALONG

THE SURFACE FRONT OVER SOUTH CENTRAL AND EASTERN KS...AND ALONG THE

DRYLINE OVER WESTERN OK THIS AFTERNOON AND EVENING. AIRMASS IS VERY

UNSTABLE WITH SUFFICIENT VERTICAL SHEAR TO PROMOTE SUPERCELLS

CAPABLE OF VERY LARGE HAIL AND ISOLATED TORNADOES.

[NL]

A couple of storms 50+ miles from the team are severe Td's warned.

[Gorky]

A couple of storms 50+ miles from the team are severe Td's warned.

I spent the night in Alva as that was my target area for today. Of course, I changed my mind this morning, concerned that things would go linear quickly, and it would be down to chance rather than forecasting skill if you could get on the storm whilst still discrete. I am actually down on I40 hoping for some more isolated cells to pop near SW OK.

Of course, I see the cell near Alva is currently isolated and it will probably producce.. Such is life!

[ian cameron]

Unfortunately we are screwed at the moment. Pat has been bitten by a Recluse Spider and is receiving treatment, until he is out of the Clinic we are not able to Chase anything. In other words we are a Man Down!

Paul S (On Ians Account)

[NL]

I spent the night in Alva as that was my target area for today. Of course, I changed my mind this morning, concerned that things would go linear quickly, and it would be down to chance rather than forecasting skill if you could get on the storm whilst still discrete. I am actually down on I40 hoping for some more isolated cells to pop near SW OK.

Of course, I see the cell near Alva is currently isolated and it will probably producce.. Such is life!

Always go with ya first instinct Nathan...!!! Good luck i'm sure you'll score today...

[Nick F]

Sorry to hear that Paul. Hope nothing serious.

[NL]

Unfortunately we are screwed at the moment. Pat has been bitten by a Recluse Spider and is receiving treatment, until he is out of the Clinic we are not able to Chase anything. In other words we are a Man Down!

Paul S (On Ians Account)

Oh jeez... The 'fiddle-back' hope he feels ok after treatment. Keep that wound covered...

Those larger cells just over the border into Kansas are now tornado warned.

[craig1uk]

Sorry to hear that, hope Pat is ok

[Stuart]

Hope put is ok

Edited May 12, 2010 by Stuart

[Nick F]

Watch out McPherson area, apparently tornado on the ground to the SW that prob will miss town to the south but will cross I-135, can see a hook like feature with storm:

Live coverage on storms in central KS here: http://www.ksn.com/content/weather/liveradar.aspx

BULLETIN - EAS ACTIVATION REQUESTED

TORNADO WARNING

NATIONAL WEATHER SERVICE WICHITA KS

342 PM CDT WED MAY 12 2010

THE NATIONAL WEATHER SERVICE IN WICHITA HAS ISSUED A

* TORNADO WARNING FOR...

SOUTHEASTERN MCPHERSON COUNTY IN CENTRAL KANSAS...

* UNTIL 415 PM CDT

* AT 339 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE

TRACKING A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO. THIS

DANGEROUS STORM WAS LOCATED NEAR INMAN...OR 11 MILES SOUTH OF

MCPHERSON...AND MOVING NORTHEAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...

MCPHERSON...MOUNDRIDGE...GALVA...CANTON AND MCPHERSON AIRPORT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS TORNADO WARNING REPLACES THE SEVERE THUNDERSTORM WARNING THAT

WAS IN EFFECT FOR THE SAME AREA.

[Gorky]

Yikes. Recluse Spider bites are NOT GOOD... All I can say is I'm glad he is getting treatment for it already. If it goes untreated, the results are usually pretty horrendous.... treated immediately, it's not usually too problematic... (Do not Google 'recluse spider bite' if you are squeamish!)