Chase 2010 - Day 22 Discussion

[Paul Sherman]

Back to Back Chase Days Coming Up - The 1st being a Great Chance for Tornadoes for the last day of Tour 2!

Following this is a Day 2 Moderate Risk for Tornadoes on Wednesday!

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

1259 AM CDT TUE MAY 18 2010

VALID 181200Z - 191200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL/SOUTHERN

HIGH PLAINS...

...SYNOPSIS...

SPLIT UPPER FLOW REGIME WILL REMAIN OVER NORTH AMERICA DURING THE

PERIOD. LARGELY CUT-OFF UPPER LOW CURRENTLY OVER THE OH RIVER VALLEY

WILL CONTINUE TO WEAKEN/MIGRATE EAST-NORTHEASTWARD...WHILE A

SOUTHERN STREAM SHORTWAVE TROUGH CURRENTLY OVER CA/NV ADVANCES

EASTWARD OVER THE FOUR CORNERS VICINITY TODAY...AND THE

SOUTH-CENTRAL HIGH PLAINS LATE TONIGHT.

AT THE SURFACE...IN RESPONSE TO UPSTREAM HEIGHT FALLS...LEE

CYCLOGENESIS WILL FAVOR A MORE PROMINENT LOW LEVEL UPSLOPE REGIME

ACROSS A BROAD-NORTH SOUTH EXTENT OF THE ROCKIES FRONT RANGE/HIGH

PLAINS...WHILE A CONVECTIVELY MODIFIED FRONTAL ZONE OTHERWISE

RETREATS NORTHWARD ACROSS TX. IN THE EAST...A COLD

FRONT/OCCLUSIONARY FRONTAL ZONE WILL REMAIN A FOCUS FOR

SHOWERS/TSTMS ACROSS PORTIONS OF THE SOUTHEAST STATES/CAROLINAS.

...CENTRAL/SOUTHERN HIGH PLAINS TO SOUTH TX...

MULTIPLE MCS/S WILL LIKELY BE ONGOING AT THE BEGINNING OF THE PERIOD

THIS MORNING ACROSS NORTHWEST TX/PERHAPS ADJACENT OK...AS WELL AS

SOUTH TX. A FEW SEVERE TSTMS MAY REMAIN POSSIBLE EARLY THIS MORNING

IN ASSOCIATION WITH THIS ACTIVITY.

LATER THIS AFTERNOON...LEADING BRUNT OF LARGE SCALE HEIGHT FALLS AND

STRENGTHENING/DIFFLUENT FLOW ALOFT...COMBINED WITH SURFACE

CYCLOGENESIS ACROSS EASTERN NM/SOUTHEAST CO AND NNW-WARD MOISTURE

RETURN...WILL LEAD TO AN APPRECIABLE SEVERE POTENTIAL ACROSS THE

CENTRAL/SOUTHERN HIGH PLAINS. STRONG/SEVERE TSTMS SHOULD INCREASE

THROUGH MID/AFTERNOON...VIA MOIST SOUTHEASTERLY UPSLOPE AND

DIFFERENTIAL HEATING ALONG THE EASTERN CO/NORTHEAST NM HIGHER

TERRAIN...AS WELL AS THE NORTH-SOUTH EXTENT OF THE DRYLINE ACROSS

FAR EASTERN NM/FAR WEST TX. VERY STEEP LAPSE RATES/MODERATE

INSTABILITY AND STRONG VERTICAL SHEAR/VEERING WIND PROFILES WILL BE

MORE THAN ADEQUATE FOR SUPERCELLULAR DEVELOPMENT...WITH LARGE HAIL

AND SOME TORNADOES ESPECIALLY DURING THE LATE AFTERNOON/EARLY

EVENING HOURS ACROSS SOUTHEAST CO/FAR EASTERN NM AND MUCH OF WEST

TX. WITH A MODERATE LOW LEVEL JET EXPECTED TO INCREASE DURING THE

EVENING...THE RELATIVELY GREATEST TORNADO THREAT MAY EXIST ACROSS

PORTIONS OF THE TX PANHANDLE/ADJACENT TX SOUTH PLAINS IN VICINITY OF

A SURFACE LOW/WARM FRONT/DRYLINE /AND PERHAPS CONVECTIVE OUTFLOW/

FOCUSED TRIPLE POINT.

OTHERWISE...THE NOCTURNALLY INCREASING/MODERATELY STRONG SOUTHERLY

LOW LEVEL JET SHOULD CONTRIBUTE TO THE ORGANIZATION/SUSTENANCE OF

ONE OR MORE SOUTHEAST MOVING MCS/S TONIGHT...WITH CONTINUED BOUTS OF

SEVERE HAIL ALONG WITH THE POSSIBILITY OF AN INCREASING DAMAGING

WIND THREAT DURING THE EVENING /MOST PROBABLE ACROSS NORTHWEST TX

AND PERHAPS ADJACENT WESTERN OK/.

[Roger J Smith]

Agreed on the location, just a heads up that the energy peak appears quite early (21z) which may get these storms firing as early as 19z (2 p.m. CDT) ... and it's a strong energy peak so good luck with the chase. My guess as to best location would be southwest of Lubbock.

[Nick F]

Moderate Risk for tomorrow, a nice treat for tour 3:

DAY 2 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0100 AM CDT TUE MAY 18 2010

VALID 191200Z - 201200Z

...THERE IS A MDT RISK OF SVR TSTMS ACROSS PARTS OF WRN OK AND NW

TX...

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

CNTRL PLAINS...

...SIGNIFICANT SEVERE WEATHER EVENT BECOMING LIKELY ACROSS PARTS OF

WRN/CNTRL OK AND NW TX WEDNESDAY AFTERNOON AND EVENING...

...SRN AND CNTRL PLAINS...

AN UPPER-LEVEL LOW IN THE CNTRL ROCKIES AND ASSOCIATED

NEGATIVELY-TILTED UPPER-LEVEL TROUGH WILL MOVE EWD INTO THE HIGH

PLAINS WEDNESDAY. AHEAD OF THE SYSTEM...A 35 TO 45 KT LOW-LEVEL JET

WILL BE IN PLACE ACROSS THE SRN PLAINS. WARM ADVECTION ASSOCIATED

WITH THE JET SHOULD RESULT IN SCATTERED ELEVATED THUNDERSTORMS

WEDNESDAY MORNING ACROSS NRN OK AND SRN KS WITH THIS CONVECTION

MOVING NEWD AWAY FROM THE MODERATE RISK AREA BY AFTERNOON. THE

LOW-LEVEL JET WILL HELP TRANSPORT LOW-LEVEL MOISTURE NWD SETTING UP

A BROAD WARM SECTOR FROM THE ERN TX PANHANDLE EWD ACROSS OK AND

NORTH TX. MODERATE TO STRONG INSTABILITY SHOULD BE IN PLACE ALONG

THIS CORRIDOR BY WEDNESDAY AFTERNOON WITH SFC-BASED THUNDERSTORMS

INITIATING NEAR AND JUST NORTH OF A SFC LOW ACROSS THE ERN TX

PANHANDLE MOVING INTO WRN OK. THUNDERSTORMS MAY ALSO DEVELOP ACROSS

THE LOW ROLLING PLAINS OF NORTHWEST TX AND MOVE EWD ACROSS NORTH TX

BY EARLY EVENING.

ETA-KF FORECAST SOUNDINGS ACROSS THE MODERATE RISK AREA ARE

IMPRESSIVE SHOWING MLCAPE FROM 3000 J/KG IN WCNTRL OK TO 4000 J/KG

ACROSS PARTS OF NW TX. IN ADDITION TO THE STRONG INSTABILITY...DEEP

LAYER SHEAR IS FORECAST TO BE 40 TO 45 KT WITH 850 TO 500 MB LAPSE

RATES AROUND 7.5 C/KM. THIS ENVIRONMENT SHOULD BE FAVORABLE FOR

SUPERCELLS WITH VERY LARGE HAIL. IN ADDITION...THE NAM AND GFS

SOLUTIONS DEVELOP A 30 TO 40 KT LOW-LEVEL JET ACROSS THE SRN PLAINS

WHICH WILL CREATE FAVORABLE CONDITIONS FOR TORNADOES ESPECIALLY AS

SUPERCELLS MATURE. A POTENTIAL FOR STRONG TORNADOES MAY DEVELOP

DURING THE LATE AFTERNOON AND EARLY EVENING WITH THE GREATEST

POTENTIAL JUST TO THE WEST OF THE LOW-LEVEL JET MAX. SOME POTENTIAL

SHOULD ALSO EXIST FOR A DAMAGING WIND EVENT AS STORMS CONGEAL ACROSS

ECNTRL OK AND NCNTRL TX DURING THE EVENING. ISOLATED SUPERCELLS WITH

LARGE HAIL AND POSSIBLY A TORNADO OR TWO MAY DEVELOP SWD ALONG A

DRYLINE IN WCNTRL TX WHERE FORECAST SOUNDINGS SHOW A VERY UNSTABLE

AIRMASS WITH STRONG DEEP LAYER SHEAR AND STEEP MID-LEVEL LAPSE

RATES. SEVERE STORMS WITH A LARGE HAIL AND DAMAGING WIND THREAT WILL

ALSO BE POSSIBLE NWWD ACROSS SRN KS INTO FAR SE CO WHERE THE MODELS

SHOW AMPLE DEEP LAYER SHEAR AND MODERATE INSTABILITY.

SOME UNCERTAINTIES STILL EXIST WITH THE SCENARIO ABOVE. THE

GFS...NAM AND ETA-KF SOLUTIONS ARE NOT IN GOOD AGREEMENT CONCERNING

THE LOCATION OF CONVECTIVE INITIATION WEDNESDAY AFTERNOON WITH THE

GFS MUCH FURTHER EAST. THE NAM INITIATES CONVECTION ALONG THE WRN

EDGE OF INSTABILITY AND THIS SOLUTION SEEMS MOST REASONABLE.

HOWEVER...BOTH SOLUTIONS MAY BE SOMEWHAT CORRECT WITH THE GFS

FOCUSING MORE ON A SEVERE THREAT IN ERN OK AND THE ARKLATEX ON A

WING OF WARM ADVECTION.

..BROYLES.. 05/18/2010

[nsrobins]

THE RELATIVELY GREATEST TORNADO THREAT MAY EXIST ACROSS

PORTIONS OF THE TX PANHANDLE/ADJACENT TX SOUTH PLAINS IN VICINITY OF

A SURFACE LOW/WARM FRONT/DRYLINE /AND PERHAPS CONVECTIVE OUTFLOW/

FOCUSED TRIPLE POINT.

LOL. If you manage to get the position right from all those clues you should target an area of about 5 square miles!

Increased chances this morning of a structure AND tornado threat this evening and I would be targeting the area in the southern TS panhandle - RUC at lunchtime will give more pointers on this.

Tomorrow looks tasty - and maybe we'll see another HIGH risk by the morning.

[Nick F]

Based on WRF/NAM projections, I would target west of Lubbock near the NM border, probably somewhere like Morton. Nice dryline bulge indicated on Td charts pushing into a good reservoir of CAPE overlapped by strong 0-3km SR Helicity just ahead of the bulge which indicates an enhanced potential for tornadoes in this area of the Texas Panhandle up to Amarillo area, if supercells form or move into this area.

Chances are that intiation maybe over the border in far Ern NM before storms move SE over the border into W Texas.

[nsrobins]

Agree Nick, but beware the dreaded westward retrogression! 11Z RUC has put the surface low a little further NWrd as suspected and the DL only just reaches the NM/TX border by 23Z. I expect initiation to now be about due west of AMA on the border, with the imputus of topogrophy, but as you say parameters are conducive for rotation on any cell meandering (literally!) eastwards during the evening.

[NL]

Todays risk has now been upgraded to a moderate risk for the southern high plains.

SPC AC 181258

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0758 AM CDT TUE MAY 18 2010

VALID 181300Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE SRN HI PLNS...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE CNTRL HI PLNS INTO SW

TX...

...THERE IS A SLGT RISK OF SVR TSTMS OVER DEEP S TX...

...SYNOPSIS...

SLOWLY PROGRESSIVE SPLIT FLOW PATTERN WILL CONTINUE OVER THE LWR 48.

IN THE SRN STREAM...SRN GRT BASIN TROUGH SHOULD MOVE E TO THE SRN

HI PLNS BY THE END OF THE PERIOD AS OH VLY SYSTEM FURTHER ELONGATES

AND CONTINUES ENE INTO THE NRN/CNTRL APPALACHIANS.

AT LWR LVLS...LEE TROUGH EXPECTED TO STRENGTHEN THROUGH

PERIOD...WITH MAIN SFC CENTER FORMING OVER SE CO TODAY AND ADVANCING

SLOWLY ESE TO THE OK PANHANDLE EARLY WED. LOW LVL SSELY FLOW

WILL...HOWEVER...DEVELOP ALONG THE ENTIRE ERN EXTENT OF THE RCKYS

FROM NM TO MT. MEANWHILE...CONVECTIVELY-REINFORCED FRONT NOW OVER

TX SHOULD REDEVELOP N/NE ACROSS THE SRN PLNS...WITH THE BOUNDARY

LIKELY TO EXTEND FROM THE TX PANHANDLE SE ALONG THE RED RVR BY 12Z

WED. IN THE EAST...WEAK CYCLOGENESIS OFF THE NC CST SHOULD DRIVE

COMPLEX FRONTAL ZONE SLOWLY SE ACROSS MS/AL/GA AND THE CAROLINAS.

...CNTRL/SRN HI PLNS THROUGH EARLY WED...

INCREASING FORCING FOR ASCENT...STRENGTHENING/DIFFLUENT UPR FLOW

...LOW LVL MOISTURE RETURN...AND SFC CYCLOGENESIS WILL SUPPORT A

SUBSTANTIAL SVR POTENTIAL OVER THE CNTRL/SRN HI PLNS TODAY/TONIGHT.

STG/SVR TSTMS SHOULD FORM MORE OR LESS SIMULTANEOUSLY IN

CONFLUENT...MODERATELY UPSLOPE FLOW OVER ERN CO/NE NM...AND ALONG

N-S DRYLINE NEAR THE NM-TX BORDER.

STEEPENING LOW TO MID LVL LAPSE RATES...MODERATE INSTABILITY AND STG

VERTICAL SHEAR/VEERING WIND PROFILES WILL BE FAVORABLE FOR

SUPERCELLS...WITH LARGE HAIL AND SOME TORNADOES. THIS THREAT SHOULD

BE GREATEST LATE THIS AFTN/EARLY TONIGHT OVER SE CO/FAR ERN NM AND

MUCH OF W TX. WITH MODERATE SLY LLJ LIKELY TO INCREASE IN RESPONSE

TO CONTINUED EWD PROGRESSION OF GRT BASIN UPR TROUGH...THE

RELATIVELY GREATEST TORNADO THREAT A BIT LATER THIS EVE MAY EXIST

OVER PARTS OF THE TX PANHANDLE AND ADJACENT TX S PLNS...NEAR SFC

WARM FRONT/CONVECTIVE OUTFLOW/DRY LINE INTERSECTION.

OTHERWISE...THE INCREASING LLJ SHOULD SUPPORT UPSCALE DEVELOPMENT

INTO ONE OR MORE SE-MOVING MCSS TONIGHT. WITH EMBEDDED SUPERCELLS

AND SUSTAINED STORMS/BOWING SEGMENTS...THESE LIKELY WILL YIELD A

CONTINUED THREAT FOR SVR HAIL...DMGG WIND...AND PERHAPS AN ISOLD

TORNADO INTO PARTS OF NW TX AND POSSIBLY WRN OK.

...S TX THROUGH MIDDAY...

S TX MCS SHOULD CONTINUE SLOWLY ESE THROUGH LATE MORNING...

SUPPORTED BY MODEST BUT VERY MOIST SELY LOW LVL FLOW BENEATH LIGHT

WLY FLOW ALOFT. OTHER STORMS MAY CONTINUE TO FORM ALONG WEAKENING

W/E OUTFLOW BOUNDARY S OF CRP AND ALONG SEA/LAND BREEZE BOUNDARIES

NEAR BRO. CELL MERGERS...HI PW...AND ONSET OF DAYTIME HEATING MAY

SUPPORT ISOLD LOCALLY DMGG WIND GUSTS...MARGINALLY SVR HAIL...AND

PERHAPS A BRIEF TORNADO /REF WW 184/.

...MT AND ADJACENT NORTHERN HIGH PLAINS THIS AFTN/EARLY EVE...

MOISTURE WILL INCREASE TODAY OVER THE HI PLNS OF ERN MT...WITH PW

RISING TO AOA .75 INCHES AS LEE SIDE TROUGH STRENGTHENS. TSTMS

SHOULD FORM THIS AFTN ALONG THE TROUGH AND/OR ALONG TERRAIN-INDUCED

CIRCULATIONS AS HEATING BOOSTS SBCAPE TO 500-1000 J/KG /HIGHEST

ACROSS SE MT/. COUPLED WITH MODEST...DEEP...S TO SSELY FLOW AND

STEEP LOW TO MID LVL LAPSE RATES...SETUP MAY SUPPORT A FEW SMALL

CLUSTERS STG/SVR STMS. HAIL SHOULD BE THE MAIN THREAT.

Forecast Discus

Edited May 18, 2010 by NL

[Nick F]

Yep, a nice last show for tour 2 before they head back tomorrow.

Upgrade due to an increase in hail probabilities to 45% ... tornado probs remain 10%.

Going to be compulsive viewing later following the team.

[Paul Sherman]

I Have been saying to the guys for 3 days now that this would be the icing on the cake for them and a good old fashioned Texas Panhandle Chase. We also have to keep one eye on getting Tour 2 Close enough to Dallas for Tomorrow's drop off, I am then picking up some of the Tour 3 Guests and driving back upto Western Oklahoma for the Possible High Risk tomorrow and then back down to Irving again for Wednesday Night. It looks like another Risk for Thursday for Tour 3's proper first day somewhere east of DFW.

Going to need the Red Bulls and Vanilla Coffee's over the next 3 days

Paul S

[dallas]

I Have been saying to the guys for 3 days now that this would be the icing on the cake for them and a good old fashioned Texas Panhandle Chase. We also have to keep one eye on getting Tour 2 Close enough to Dallas for Tomorrow's drop off, I am then picking up some of the Tour 3 Guests and driving back upto Western Oklahoma for the Possible High Risk tomorrow and then back down to Irving again for Wednesday Night. It looks like another Risk for Thursday for Tour 3's proper first day somewhere east of DFW.

Going to need the Red Bulls and Vanilla Coffee's over the next 3 days

Paul S

I'm sure the adrenalin will help!

[nsrobins]

I'm not sure what the terrain or roads are like down there, but as things stand just now I'd be moving down the I60 towards Friona. Anything that does fire within 30 miles of there should be reachable easily given the sluggish storm motions.

[Nick F]

FWIW 12z WRF/NAM has intiation W and SW of AMA or NW of Lubbock close to the NM/TX border, dryline crossing into TX Panhandle by 00z (18z CDT):

Strong SR Helicity values holding up in the area too.

[Nick F]

Emphasis for tornado potential seems to have shifted further N and NW on latest SPC and model outlook, so maybe worth targeting NW of AMA, towards Dalhart:

1630z SPC tornado probs:

15z RUC seems also to favour more the NW quarter of the TX Panhandle towards OK Panhandle and SE corner of Colorado, certainly best wind shear in this area now towards triple Point along with good potential instability:

- SR Helicity at 00z (18z CDT)

- CAPE at 00z (18z CDT)

- Conv. precip at 00z (18z)

Dryline further south heading towards NM/TX border later looks more diffuse and less defined on the 15z RUC, probably more mixed out than previously indcated.

Therefore, the triple point of the dryline and warm front over Nern TX Panhandle maybe more productive for tornadic supercells later today.

[dallas]

If anyone is viewing ignore the offline status they are on the move and the stream is on

[John Hanrahan]

If anyone is viewing ignore the offline status they are on the move and the stream is on

Busy day for the guys and I know they are under pressure so they probably forgot to update before they hit the road.

I've just set their status to Online.

[NL]

Mesoscale discussion issued

Extreme south of the MD area is about 100 mile NW from Dumas, Texas.

MESOSCALE DISCUSSION 0607

NWS STORM PREDICTION CENTER NORMAN OK

1242 PM CDT TUE MAY 18 2010

AREAS AFFECTED...SERN WY...EXTREME SWRN NEB PNHDL...ERN CO

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 181742Z - 181945Z

MID-DAY MESOANALYSIS SHOWS THE LEE CYCLONE BEGINNING TO DEEPEN NE OF

KPUB AND AN EVOLVING DENVER CYCLONE. MID-LVL DRY SLOT WITHIN NOSE

OF THE UPR LVL JET STREAK WAS SURGING INTO CO. THERE HAVE BEEN

VARYING AMOUNTS OF MID/HIGH-LVL CIRROFORM CLOUDS TO THE LEE OF THE

MOUNTAINS...BUT MODEST HEATING HAS OCCURRED ACROSS ESPECIALLY ERN

CO. LLVL SELYS WERE TRANSPORTING UPR 40S/NEAR 50 DEG F SFC DEW

POINTS TO THE E/NE OF THE AFOREMENTIONED CYCLONES AND GIVEN STEEP

LAPSE RATE ENVIRONMENT...MLCAPES WERE ALREADY APPROACHING 1000 J/KG.

HIGH-BASED CBS HAVE BEEN INCREASING ALONG/W OF THE DIVIDE PER VSB

SATL IMAGERY. ACTIVITY MAY TRY TO ROOT INTO THE UNSTABLE BOUNDARY

LAYER E OF THE FRONT RANGE THROUGH THE AFTN AS CINH CONTINUES TO

ERODE /LIKELY WITH MID-60S TEMPERATURES/. INITIAL STORM DEVELOPMENT

MAY OCCUR INVOF THE DENVER CYCLONE WITH SUBSEQUENT DVLPMT SWD INTO

SERN CO AFTER 20-21Z. STORMS WILL MOVE ENE AND WILL GROW INTO

SUPERCELLS WITH VERY LARGE HAIL OWING TO INCREASING EFFECTIVE SHEAR.

TORNADO THREATS WILL BE MAXIMIZED WITHIN THE DENVER CYCLONE/N SIDE

OF PALMER DIVIDE...BUT ISOLD TORNADOES WILL BE POSSIBLE ANYWHERE IN

THE DISCUSSION AREA. EVENTUALLY... STORMS WILL CONGEAL INTO SVRL

LINEAR SEGMENTS AS THEY MOVE/DEVELOP INTO THE LWR PLAINS TOWARD

NEB/KS BORDER WITH HIGH WINDS AND LARGE HAIL.

[Nick F]

Team heading north to Dumas, currently near Tulia south of Amarillo.

What looks like an agitated cu field across NW TX panhandle, alot of thin high cloud on visible satellite and on the livestream:

[NL]

Tornado Watch issued.

543

WWUS20 KWNS 181843

SEL5

SPC WW 181843

COZ000-190300-

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 185

NWS STORM PREDICTION CENTER NORMAN OK

145 PM CDT TUE MAY 18 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

MUCH OF EASTERN COLORADO

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 145 PM UNTIL

1000 PM CDT.

TORNADOES...HAIL TO 3 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 70 STATUTE

MILES EAST AND WEST OF A LINE FROM 65 MILES NORTHEAST OF FORT

COLLINS COLORADO TO 35 MILES WEST SOUTHWEST OF SPRINGFIELD

COLORADO. 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.

DISCUSSION...THUNDERSTORMS EXPECTED TO INCREASE QUICKLY THIS

AFTERNOON IN NUMBER AND INTENSITY ACROSS THE WATCH AREA WITH THE

APPROACH OF UPR TROUGH AND VERY FAVORABLE SHEAR PROFILES IN PLACE.

WITH HEATING THE AIR MASS IS NOW MDTLY UNSTABLE...MLCAPES TO 1200

J/KG. MOST FAVORED AREAS INITIALLY FOR SUPERCELLS AND

TORNADOES/LARGE HAIL WILL BE ASSOCIATED WITH THE SURFACE CONVERGENCE

N OF PALMER DIVIDE. SUPERCELLS WILL BECOME MORE COMMON THRU

AFTERNOON AS ACTIVITY BUILDS EWD ACROSS THE WATCH. PRIMARY THREAT

WILL BE LARGE HAIL AND AT LEAST ISOLATED TORNADOES.

[nsrobins]

The latest RUC has put the cat amonst the pigeons and continued to shift the threat west and north and I think even Boise may be too far south for this play.

At 22Z a small, closed looking surface low has developed around Colorado Springs and the SPC warning text quite rightly has reflected the shift into SW CO for maximum tornado threat.

No-one ever said this forecasting business was easy!

[NL]

NWS SPC have issued MD for TX OK panhandle.

MESOSCALE DISCUSSION 0608

NWS STORM PREDICTION CENTER NORMAN OK

0202 PM CDT TUE MAY 18 2010

AREAS AFFECTED...NE NM...OK/TX PNHDLS

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 181902Z - 182100Z

WATER VAPOR IMAGERY SUGGESTS THAT LEADING EDGE OF MODEST HEIGHT

FALLS WAS BEGINNING TO SPREAD TO THE CONTINENTAL DIVIDE IN NRN NM

AND WILL ARRIVE ON THE HIGH PLAINS BY LATE AFTN. CONCOMITANT

PRESSURE FALLS OVER THE HIGH PLAINS HAVE CONTRIBUTED TO INCREASING

LLVL SELYS ACROSS THE PNHDLS INTO THE NE PLAINS OF NM...

TRANSPORTING MID/UPR 50S DEW POINTS NWWD. RECENT OBJECTIVE ANALYSIS

SHOWS MLCAPES INCREASING TO 1500 J/KG AND WITH ANOTHER FEW DEGREES

OF SFC HEATING...CINH WILL SUFFICIENTLY ERODE FOR TSTM INITIATION.

FIRST HIGH-BASED TSTMS ARE ALREADY FORMING INVOF THE RATON MESA IN

NE NM AND WILL POSE A RISK FOR LARGE HAIL. SUBSEQUENT STORMS SHOULD

DEVELOP WITHIN THE EVOLVING TCU FIELD ESE ALONG A FRONTAL ZONE

ACROSS NE NM INTO THE WRN TX PNHDL THROUGH LATE AFTN. WLY DEEP

LAYER SHEAR IN EXCESS OF 40 KTS AND NEARLY 8 DEG C PER KM H7-H5

LAPSE RATES WILL BE MORE THAN SUFFICIENT FOR SUPERCELLS WITH VERY

LARGE HAIL. TORNADOES WILL ALSO BE POSSIBLE... ESPECIALLY AS STORMS

MATURE ALONG THE NM/TX/OK BORDER. ACTIVITY SHOULD CONTINUE TO GROW

UPSCALE INTO AN MCS OR TWO BY MID-EVENING OVER THE TX PNHDL WITH

LARGE HAIL...HIGH WINDS AND ISOLD TORNADOES.

Edited May 18, 2010 by NL

[NL]

Update on Meso discussion

VALID 182005Z - 182100Z

UPDATE TO MCD 608

17Z VORTEX TEAM SOUNDING NEAR CLOVIS EXHIBITED ONLY A VERY SMALL CAP

WITH CONVECTIVE TEMPERATURE NEAR 26 DEG C. PER LATEST

TEMPERATURES...CINH WILL ERODE VERY SOON. CU CONTINUES TO CONGEST

DOWNSTREAM OF THE HIGHER-BASED STORMS NEAR THE RATON MESA/NCNTRL NM

MOUNTAINS. EXPECT THAT TSTMS WILL INITIATE IN ERNEST BETWEEN 21-22Z

OVER NERN NM ESE INTO THE NWRN TX PNHDL.

Updated Convective outlook for today.

SPC AC 181957

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0257 PM CDT TUE MAY 18 2010

VALID 182000Z - 191200Z

...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EVENING OVER

PARTS OF ERN CO...NERN NM...PARTS OF THE OK/TX PNHDLS INTO THE TX S

PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN CO/WRN KS INTO THE ERN

NM AND WRN INTO N-CNTRL TX...

...CNTRL/SRN HIGH PLAINS...

THE PRIMARY CHANGES TO THE CURRENT FORECAST ARE AS FOLLOWS: 1) A

SLIGHT NWD SHIFT OF THE CATEGORICAL SLIGHT RISK OVER SWRN TX...2) A

SLIGHT EWD SHIFT IN THE CATEGORICAL SLIGHT RISK ALONG THE RED RIVER

VALLEY OF SWRN OK/NWRN TX...3) A SWD EXTENSION OF THE TEN PERCENT

TORNADO PROBABILITY LINE IN THE TX PNHDL...AND 4) THE ADDITION OF A

30 PERCENT PROBABILITY WIND CONTOUR OVER PARTS OF THE OK/TX PNHDLS

INTO WRN OK.

TSTMS ARE EXPECTED TO INCREASE IN AREAL COVERAGE AND INTENSITY

THROUGH THE REMAINDER OF THE AFTERNOON INTO THIS EVENING FROM ERN CO

SWD THROUGH ERN NM INTO THE OK/TX PNHDLS AND WRN TX. HERE...

DIABATIC HEATING COUPLED WITH EWD PROGRESSION OF EML PRECEDING

MIDLEVEL TROUGH AND DEW POINTS IN THE 50S ARE CONTRIBUTING TO AIR

MASS DESTABILIZATION WITH MLCAPE APPROACHING 2000 J/KG BY LATE

AFTERNOON.

AT THE SAME TIME...A 40-50/50-70 KT MID/HIGH-LEVEL JET WILL DEVELOP

EWD THROUGH NM INTO THE SRN HIGH PLAINS...RESULTING IN STEADILY

STRENGTHENING VERTICAL SHEAR. AS SUCH...THE SETUP WILL BECOME

INCREASINGLY FAVORABLE FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL AND

TORNADOES. THE THREAT FOR TORNADOES MAY INCREASE NEAR OR SHORTLY

AFTER 00Z FROM FAR SERN CO SEWD INTO THE OK/TX PNHDLS IN CONCERT

WITH A STRENGTHENING...SELY LLJ.

BY LATE EVENING...STORMS MAY GROW UPSCALE INTO A MCS WITH AN

INCREASED THREAT FOR DAMAGING WINDS OVER THE OK/TX PNHDLS. THE

CONVECTIVE SYSTEM WILL LIKELY BE MAINTAINED OVERNIGHT EWD INTO

OK...SUPPORTED BY STRONG WAA TO THE N OF WARM FRONT RETREATING NWD

INTO NRN TX.

..MEAD.. 05/18/2010

[NL]

Tornado watch issued.

URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 186

NWS STORM PREDICTION CENTER NORMAN OK

335 PM CDT TUE MAY 18 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF

PARTS OF NORTHEAST NEW MEXICO

OKLAHOMA PANHANDLE

MUCH OF TEXAS PANHANDLE

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 335 PM UNTIL

1100 PM CDT.

TORNADOES...HAIL TO 3.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 125 STATUTE

MILES EAST AND WEST OF A LINE FROM 50 MILES WEST NORTHWEST OF

GUYMON OKLAHOMA TO 45 MILES SOUTHWEST OF AMARILLO TEXAS. FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU6).

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 185...

DISCUSSION...SEVERE THUNDERSTORMS EXPECTED TO DEVELOP OFF HIGHER

TERRAIN NERN NM AHEAD OF S/WV TROUGH APPROACHING THE AREA FROM THE

WEST. AIR MASS HAS BECOME MDTLY UNSTABLE WITH MLCAPES TO 2000 J/KG.

COUPLED WITH STEEP LAPSE RATES AND FAVORABLE VEERING SHEAR

PROFILES...SUPERCELLS WILL DEVELOP WITH THREAT OF VERY LARGE HAIL

AND POSSIBLE TORNADOES AS THEY MOVE EWD.

[ian cameron]

poor danny is being checked into the hospital nothing to serious he got a few mozzie bites and maybe a bit of food posioning so is a little poorly and on the safe side they are keeping hold of him for a while will update as soon as i hear anything

ian

[nsrobins]

Sorry to hear that, Ian. Has anyone stayed with him? I assume that was why you stopped on the west side of Amarillo.

The cell currently just east of Pueblo, CO has a reasonable signature and a scuddy wall cloud (TVN feed)

[NL]

Nice looking cell developing quite well heading towards Dumas, currently dropping 1.50" hail and growing...

Visible sat image .

Now 000

WUUS54 KAMA 182143

SVRAMA

TXC205-341-182245-

/O.NEW.KAMA.SV.W.0033.100518T2143Z-100518T2245Z/

BULLETIN - EAS ACTIVATION REQUESTED

SEVERE THUNDERSTORM WARNING

NATIONAL WEATHER SERVICE AMARILLO TX

443 PM CDT TUE MAY 18 2010

THE NATIONAL WEATHER SERVICE IN AMARILLO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...

EASTERN HARTLEY COUNTY IN THE PANHANDLE OF TEXAS

WEST CENTRAL MOORE COUNTY IN THE PANHANDLE OF TEXAS

* UNTIL 545 PM CDT

* AT 437 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS HAVE

DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE

HAIL. THIS STORM WAS LOCATED 12 MILES SOUTHWEST OF HARTLEY...OR

ABOUT 21 MILES SOUTH OF DALHART...MOVING NORTHEAST AT 25 MPH.

severe Td's warned.