MESOSCALE DISCUSSION 0910 NWS STORM PREDICTION CENTER NORMAN OK 0246 PM CDT SAT MAY 26 2012 AREAS AFFECTED...PORTIONS ERN NM...W TX...EXTREME WRN OK...TX/OK PANHANDLES...SWRN KS...EXTREME SERN CO. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 261946Z - 262145Z PROBABILITY OF WATCH ISSUANCE...60 PERCENT SUMMARY...THROUGH 23Z...TSTMS MAY DEVELOP OVER TRANS-PECOS AND LOWER PECOS VALLEY REGIONS OF W TX AND SERN NM...THEN FARTHER N INVOF TX/NM BORDER. OTHER/ISOLATED CONVECTION IS DEEPENING OVER NRN TX PANHANDLE. COVERAGE SHOULD BECOME WIDELY SCATTERED AND LOCALLY CLUSTERED...WITH DAMAGING GUSTS BEING MAIN CONCERN. ISOLATED LARGE HAIL ALSO IS POSSIBLE. WW MAY BE NEEDED FOR SOME PORTION OF THIS AREA AS CONVECTIVE/MESOSCALE TRENDS BECOME BETTER FOCUSED. DISCUSSION...19Z SFC MESOANALYSIS SHOWED DEVELOPING/DEEPENING LEE-SIDE CYCLONE IN NRN CO WITH INTENSE WARM FRONT EXTENDING TO ITS E. SWD FROM THAT FRONT...DOUBLE DRYLINE STRUCTURE WAS ANALYZED--EACH BEING SOME WHAT DIFFUSE... 1. WRN BOUNDARY...SEGREGATING NATIVE 20S/30S F SFC DEW POINTS ORIGINATING IN DOWNSLOPE TRAJECTORIES FROM UPPER 40S/50S DEEP-MIXED AIR...AND DRAWN FROM ERN CO SSWWD NEAR SPD...CVS...ROW...AND GDP..THEN SSEWD INTO WRN BIG-BEND REGION OF TX. 2. ERN BOUNDARY...WITH DEW POINTS MID 50S TO 60S TO ITS E AND STG HEATING/MIXING OCCURRING ON BOTH SIDES...DRAWN FROM NEAR MCK TO BETWEEN HLC-HYS THEN SSWWD ACROSS BEAVER COUNTY OK...TO BETWEEN PYX-HHF...TO NEAR HOB AND INK...THEN SWD INTO BIG BEND AREA. MOISTURE GRADIENT MAY CONSOLIDATE SOMEWHAT AS HEATING/MIXING CONTINUES...BUT SHOULD REMAIN BROADER THAN CLIMATOLOGICAL SRN-PLAINS DRYLINES GIVEN SLY WIND COMPONENT ON BOTH SIDES AND LACK OF SUBSTANTIAL CONVERGENCE. VIS IMAGERY SHOWS TCU AND INCREASING COVERAGE OF DEEP CU OVER GUADALUPE/SACRAMENTO MOUNTAINS REGION OF SE NM AND W TX...SWD ACROSS NRN CHIHUAHUA. PATCHES OF DEEP CU ALSO ARE EVIDENT INVOF CVS NEAR WRN DRYLINE...AND OVER NERN TX PANHANDLE. MASS CONVERGENCE GENERALLY IS WEAK ACROSS ENTIRE REGION EXCEPT FOR SOME UPSLOPE COMPONENT IN SERN NM...WITH CINH RAPIDLY WEAKENING OVER BROAD AREA. HENCE...TSTM FORMATION AND AT LEAST ISOLATED SVR POTENTIAL COVERS BROAD SWATH OF SRN HIGH PLAINS. EVEN WHEN MODIFIED FOR LOWER DEW POINTS BETWEEN WRN BOUNDARY AND MOUNTAINS...FCST SOUNDINGS SUPPORT MAINTENANCE OF SFC-BASED EFFECTIVE-INFLOW PARCELS. MLCAPE SHOULD INCREASE WITH TIME FOR ANOTHER 1-2 HOURS....AND ALSO WITH EWD EXTENT ACROSS EACH DRYLINE. BY 22Z...EXPECT VALUES IN 500-1000 J/KG OVER ERN NM TO AROUND 2000 J/KG NEAR ERN BORDER OF TX PANHANDLE. SUBCLOUD LAYER WILL BE WELL-MIXED WITH NEAR DRY-ADIABATIC LAPSE RATES...SUPPORTING ENHANCED DOWNDRAFT POTENTIAL. DEEP-LAYER AND LOW-LEVEL SHEAR GENERALLY IS WEAK...EXCEPT FOR SMALL AREA OF 35-40 KT EFFECTIVE BULK SHEAR MAGNITUDES EVIDENT OVER PERMIAN BASIN REGION. HOWEVER...STG UPPER/ANVIL-LEVEL WINDS MAY AID IN TSTM ORGANIZATION.
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