May 8, 2015
Post date: May 8, 2015 2:09:16 PM
Friday, May 8, 2015 @ 0900 CDT: I neglected to post yesterday's travel map, so here it is:
For today, things are looking really really good for chasing, but perhaps not so good for the locals. For that matter, neither does tomorrow... but we'll hold off on that until tomorrow. Anyway, I hope everyone in north central Texas and south central Oklahoma will stay vigilant today and aware of conditions! Here's the SPC's view of things:
SPC AC 081253
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0753 AM CDT FRI MAY 08 2015
VALID 081300Z - 091200Z
...THERE IS A MDT RISK OF SVR TSTMS PORTIONS CENTRAL/SW OK AND NW
TX...
...THERE IS AN ENH RISK OF SVR TSTMS ELSEWHERE FROM PORTIONS TX/OK
PANHANDLES TO ERN OK AND N-CENTRAL TX...
...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING ENH RISK FROM SERN
CO TO SWRN MO...ARKLATEX AND PORTIONS SW TX...
...THERE IS A MRGL RISK OF SVR TSTMS ELSEWHERE FROM SW TX AND ERN CO
TO PORTIONS LOWER MI...
...SUMMARY...
SCATTERED TO PERHAPS WIDESPREAD THUNDERSTORMS MAY DEVELOP ACROSS
PORTIONS OF THE SOUTH-CENTRAL HIGH PLAINS TO NEAR THE RED
RIVER...MAINLY FROM MIDDAY THROUGH THIS EVENING. SOME OF THESE
STORMS WILL BECOME SEVERE...OFFERING DAMAGING WIND AND VERY LARGE
HAIL...ALONG WITH THE POTENTIAL FOR TORNADOES.
...SYNOPSIS...
IN MID-UPPER LEVELS...PRINCIPAL LARGE-SCALE FEATURE FOR THIS FCST
WILL BE TROUGH OVER WRN CONUS...CONTAINING TWO PRIMARY
PERTURBATIONS...
1. PRONOUNCED CYCLONE ALOFT...CENTERED ATTM OVER SRN CA AND FCST TO
PIVOT EWD TOWARD 4 CORNERS BY END OF PERIOD...AND
2. PRECURSORY SHORTWAVE TROUGH AND VORTICITY FIELD...EVIDENT IN
MOISTURE-CHANNEL IMAGERY OVER NM AND TRAILING SWWD ACROSS NRN
CHIHUAHUA AND SERN SONORA TO CENTRAL GULF OF CA. EMBEDDED WITHIN
DIFLUENT HEIGHT/FLOW REGIME DOWNWIND FROM AFOREMENTIONED
CYCLONE...THIS PERTURBATION WILL SHIFT NEWD ACROSS REMAINDER NM AND
SRN HIGH PLAINS THROUGH MIDDAY. BY 00Z...500-MB TROUGH AND
VORTICITY FIELD SHOULD EXTEND FROM W-CENTRAL/SWRN KS SSWWD ACROSS
ERN PANHANDLES TO PERMIAN BASIN AND ERN CHIHUAHUA. THIS
PERTURBATION SHOULD EJECT NEWD AND WEAKEN OVERNIGHT...PERHAPS
REPLACED BY ONE OR MORE CONVECTIVELY GENERATED VORTICITY MAXIMA.
AT SFC...COLD FRONT WAS EVIDENT FROM SERN IA SWWD THROUGH WEAK LOW
OVER NRN OK THEN WWD ACROSS N-CENTRAL TX PANHANDLE TO NERN
NM...WHERE IT HAS BECOME QUASISTATIONARY. PRESSURE RISES STILL
ANALYZED BEHIND THIS BOUNDARY OVER CENTRAL/WRN KS AND NRN
PANHANDLE...ALONG WITH REMAINING NLY SFC-WIND COMPONENT...INDICATE
ITS NWD RETREAT AS WARM FRONT ACROSS S-CENTRAL HIGH PLAINS WILL BE
DELAYED SEVERAL HOURS AT LEAST...PERHAPS AS LONG AS LATE AFTN OR
EARLY EVENING. DRYLINE EXTENDS FROM FRONTAL INTERSECTION OVER NERN
NM SWD ACROSS ERN NM TO TX BIG BEND REGION...AND SHOULD MIX EWD
ACROSS TX/NM BORDER AND OVER PORTIONS PERMIAN BASIN TODAY. OUTFLOW
BOUNDARY FROM THURSDAY NIGHT MCS WAS RETREATING NWD ACROSS N-CENTRAL
TX AND EXTENDED WSWWD ACROSS BIG COUNTRY TO MAF AREA. DIFFERENT
LOW-LEVEL COLD FRONT...PRECEDING SWRN-CONUS CYCLONE...IS FCST TO
BECOME BETTER-DEFINED AS IT MOVES EWD OUT OF SRN ROCKIES
TONIGHT...CATCHING UP TO PRE-EXISTING LEE TROUGH OVER CENTRAL/SRN
HIGH PLAINS BY 12Z.
MEANWHILE...SUBTROPICAL STORM ANA AND ASSOCIATED DEEP-TROPOSPHERIC
CYCLONE CORE ARE FCST BY NHC TO REMAIN OFFSHORE CAROLINAS THROUGH
PERIOD. ASSOCIATED OVERLAND INTRUSION OF INSTABILITY/SHEAR
PARAMETER SPACE SUPPORTING TORNADO POTENTIAL IS LIKELY TO HOLD OFF
UNTIL DAY-2...AS SYSTEM APCHS COAST AND STRUCTURE EVOLVES MORE
TOWARD WARM-CORE PER NHC DISCUSSIONS. REF NHC ADVISORIES FOR LATEST
TRACK/INTENSITY GUIDANCE ON ANA.
...SRN PLAINS TO LOWER MI...
POTENTIAL STILL EXISTS FOR SOME AREAS OF SUBSTANTIAL SVR TSTMS
TODAY...WITH DAMAGING HAIL...SVR GUSTS AND AT LEAST A FEW TORNADOES.
GREATEST RISK REMAINS FOCUSED FOR NOW NEAR RETREATING OUTFLOW
BOUNDARY AND E OF DRYLINE...IN KEEPING WITH SCENARIO DISCUSSED WELL
IN PREVIOUS OUTLOOK.
HOWEVER...AS SOMETIMES HAPPENS WITH OTHERWISE FAVORABLE
SYNOPTIC-SCALE PATTERNS PRONE TO EARLY CONVECTION...MORE UNCERTAINTY
IN CONVECTIVE TIMING...MODE AND LOCATION MAY DEVELOP...RELATED TO
POTENTIAL FOR EARLY STORMS DURING NEXT FEW HOURS UPSHEAR FROM
MDT-RISK AREA. IF THAT OCCURS...DOWNGRADE IN PROBABILITIES REMAINS
POSSIBLE FOR SOME PARTS OF CURRENT MDT/ENH AREAS IN SUCCEEDING
UPDATES.
N OF OUTFLOW BOUNDARY...AIR MASS HAS EXPERIENCED SUBSTANTIAL
CONVECTIVE OVERTURNING...RESULTING LOW-LEVEL THETAE DEFICIT BEING
MORE PRONOUNCED WITH NWD TO NEWD EXTENT...DEEPER INTO RESIDUAL
OUTFLOW POOL. BOUNDARY IS SHALLOWER ON W END OVER W-CENTRAL TX AND
SHOULD BECOME MORE DIFFUSE AND RETREAT NWD WITH TIME...EXCEPT WHERE
REINFORCED BY ADDITIONAL CONVECTION RELATED TO ONGOING ISENTROPIC
LIFT/WAA REGIME OVER THAT OUTFLOW AIR. LATTER PROCESS AND RELATED
ISENTROPIC LIFT OR MOIST RETURN AIR TO LFC APPEAR TO HAVE
CONTRIBUTED TO ISOLATED TSTM DEVELOPMENT PAST COUPLE HOURS N OF
BOUNDARY OVER SRN CAPROCK REGION. HOWEVER...CONTRARY TO SOME MORE
AGGRESSIVE CONVECTION-ALLOWING/HI-RES MODEL SCENARIOS...THAT
ACTIVITY DISSIPATED.
SEVERAL OPERATIONAL MODELS AND HI-RES PROGS DO DEVELOP/EXPAND
ADDITIONAL CONVECTIVE PRECIP ACROSS NW TX REGION AND SHIFT IT NEWD
TOWARD ERN TX PANHANDLE...NW TX AND WRN OK IN EITHER GRADUAL OR
PIECEMEAL FASHION THROUGHOUT MID-LATE MORNING INTO EARLY AFTN...AS
LOW-LEVEL WAA/MOISTURE TRANSPORT PERSIST. UNDER THIS
SCENARIO...INITIALLY ELEVATED CONVECTION EXPANDS UPSCALE INTO MCS
THAT BECOMES SFC-BASED OVER PORTIONS WRN OK/NW TX...AS FOREGOING
BOUNDARY LAYER DESTABILIZES FROM COMBINATION OF WAA/RECOVERY N OF
BOUNDARY AND LIMITED DIABATIC SFC HEATING. ANY SUCH EVOLUTION
REDUCES THREAT FOR EXTENSIVE/DAMAGING HAIL OVER CURRENT MDT-RISK
AREA...WHICH IS DRIVEN BY HAIL PROBABILITIES. ONGOING TSTM
DEVELOPMENT/EXPANSION OVER CENTRAL TX HAS NOT BEEN WELL-FCST BY
PROGS...AND MAY EXPAND NEWD TOWARD METROPLEX THROUGH REMAINDER
MORNING. THESE POSSIBILITIES WOULD CAST CONSIDERABLE UNCERTAINTY ON
GEOMETRY AND PLACEMENT OF MOST STRONGLY FOCUSED SVR POTENTIAL TODAY.
TRENDS WILL BE MONITORED FOR ANY NEEDED ADJUSTMENTS ACCORDINGLY.
OTHERWISE...CAPE/SHEAR PARAMETER SPACE WILL REMAIN MOST FAVORABLE
FOR SVR -- INCLUDING POTENTIALLY TORNADIC SUPERCELLS WITH DAMAGING
HAIL TODAY -- NEAR MODIFYING OUTFLOW BOUNDARY AND ALONG SRN RIM OF
ANY PRECIP AREAS THAT DO FORM. ADDITIONAL SVR TSTMS MAY DEVELOP
NEAR FRONTAL ZONE OVER S-CENTRAL HIGH PLAINS...ALTHOUGH COVERAGE
CONCERNS CONTRIBUTE TO SOMEWHAT LOWERED PROBABILITIES IN THIS
REGIME. WIDELY SCATTERED TO ISOLATED TSTMS IN CLUSTERS MAY PRODUCE
SPORADIC STG-SVR GUSTS AND HAIL IN CORRIDOR ASSOCIATED WITH COLD
FRONT NNEWD TOWARD LOWER MI.
..EDWARDS/ROGERS.. 05/08/2015
Friday, May 8, 2015 @ 1145 CDT: After a hearty breakfast, we're leaving Elk City now and heading back south. I'm starting to feel like a yo-yo! *lol*
Friday, May 8, 2015 @ 1205 CDT:
...S CNTRL HIGH PLNS E/SE INTO THE RED RV VLY TODAY/TNGT...
COMBINATION OF PERSISTENT RICH MOISTURE INFLOW... SFC HEATING... AND RELATIVELY COOL MID-LVL TEMPERATURES WILL YIELD STRONG INSTABILITY/SBCAPE AOA 3000 J PER KG/ ALONG AND S OF NW TX OUTFLOW BOUNDARY LATER TODAY. SOMEWHAT LESSER BUOYANCY WILL EXTEND E/NE ACROSS THE RED RVR INTO SRN AND ERN OK... AND SWD ALONG LEE TROUGH TO THE TX BIG BEND. SUFFICIENT BUOYANCY FOR STORMS ALSO SHOULD DEVELOP OVER SE CO...WHERE COOLER MID-LVL TEMPERATURES WILL SOMEWHAT OFFSET COMPARATIVELY MODEST LOW-LVL MOISTURE.
FORCING FOR ASCENT WITH LEAD UPR IMPULSE AND SFC HEATING SHOULD SUPPORT INCREASED STORM COVERAGE/STRENGTH ALONG AND N OF OUTFLOW BOUNDARY OVER W CNTRL AND NW TX TODAY /REF WT 142/... WHERE AMPLE DEEP SHEAR WILL EXIST FOR SUPERCELLS. THESE STORMS COULD EVOLVE INTO ONE OR MORE MESOSCALE CLUSTERS THAT MOVE/DEVELOP GENERALLY NE OR ENE INTO THE RED RVR VLY REGION AND INTO SRN OK LATER IN THE DAY. THE STORMS LIKELY WILL PRODUCE VERY LARGE HAIL... IN ADDITION TO A FEW TORNADOES AND LOCALLY DMGG WIND. SOME OF THIS ACTIVITY COULD CONTINUE INTO TNGT AS WAA/MOISTURE TRANSPORT STRENGTHEN ATOP OUTFLOW BOUNDARIES IN RESPONSE TO APPROACHING UPR LOW... WITH A CONTINUING RISK FOR SVR HAIL... LOCALLY DMGG WIND... AND POSSIBLY A COUPLE TORNADOES FROM SUSTAI8NED EMBEDDED CIRCULATIONS.
Friday, May 8, 2015 @ 1233 CDT: The SPC has issued a mesoscale discussion for our area now. It looks like a very difficult chase setup... :-( Loosly-clustered supercells, and chasing along the Red River is always tough, due to limited crossings. We pretty much have to choose a side and hope we guess right!
MESOSCALE DISCUSSION 0543
NWS STORM PREDICTION CENTER NORMAN OK
1222 PM CDT FRI MAY 08 2015
AREAS AFFECTED... WESTERN PART OF NORTH TX/SOUTHWEST OK
CONCERNING... SEVERE POTENTIAL... TORNADO WATCH LIKELY
VALID 081722Z - 081845Z
PROBABILITY OF WATCH ISSUANCE... 95 PERCENT
SUMMARY... SEVERE POTENTIAL IS EXPECTED TO STEADILY INCREASE EAST-NORTHEASTWARD THIS AFTERNOON ACROSS ADDITIONAL PORTIONS OF NORTH TX INTO WESTERN/SOUTHERN OK... INCLUDING A MULTI-MODAL-RELATED TORNADO/LARGE HAIL/DAMAGING WIND RISK. A TORNADO WATCH WILL LIKELY BE NEEDED EARLY THIS AFTERNOON.
DISCUSSION... A COMPLEX STORM MODE INCLUDING SOME LOOSELY CLUSTERED SUPERCELLS IS EVOLVING AT MIDDAY ACROSS THE SOUTHEAST TX PANHANDLE AND WESTERN PART OF NORTH TX. AIR MASS DESTABILIZATION CONTINUES TO STEADILY OCCUR NEAR/JUST NORTH OF A PRIOR OUTFLOW BOUNDARY ACROSS WESTERN NORTH TX... WHILE THICKER CLOUD COVER HAS TENDED TO LINGER INTO OK AS OF EARLY AFTERNOON. THINKING IS THAT CLUSTERED SUPERCELLS WILL TEND TO PERSIST EAST-NORTHEASTWARD POTENTIALLY AS AN UPSCALE-GROWING COMPLEX INTO ADDITIONAL PORTIONS OF NORTH TX AND ADJACENT WESTERN/SOUTHERN OK CENTERED ALONG THE RED RIVER VICINITY. LARGE HAIL WILL LIKELY REMAIN THE PRIMARY RISK IN THE SHORT-TERM/EARLY AFTERNOON/... BUT DAMAGING WINDS/SOME TORNADO RISK SHOULD BECOME MORE OF A CONCERN AS ADDITIONAL BOUNDARY LAYER HEATING OCCURS.
..GUYER/CORFIDI.. 05/08/2015