MESO: Mesoscale Discussion 0473

ACUS11 KWNS 130037
SWOMCD
SPC MCD 130037
OKZ000-TXZ000-130230-

MESOSCALE DISCUSSION 0473
NWS STORM PREDICTION CENTER NORMAN OK
0737 PM CDT THU APR 12 2007

AREAS AFFECTED...FAR ERN TX PNHDL INTO NWRN TX AND WRN OK

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 130037Z - 130230Z

SEVERE THREAT /MAINLY IN THE FORM OF ELEVATED TSTMS CAPABLE OF LARGE
HAIL/ IS EXPECTED TO DEVELOP E OF WW 131 AFTER 02-03Z AND AN
ADDITIONAL WW MAY BECOME NECESSARY PRIOR TO THAT TIME.

AS OF 0020Z...REGIONAL RADAR IMAGERY INDICATED A CLUSTER OF STRONG
TO POTENTIALLY SEVERE STORMS /SOME OF WHICH HAVE EXHIBITED SUPERCELL
CHARACTERISTICS/ OVER ARMSTRONG...CASTRO...SWISHER...BRISCOE AND
FLOYD COUNTIES WITH A GENERAL MOTION OF 225/30-35 KT. RUC OBJECTIVE
FIELDS AND VISIBLE SATELLITE IMAGERY SUGGEST THAT THESE STORMS HAVE
LIKELY MOVED E OF PRIMARY SURFACE-BASED INSTABILITY AXIS IN PLACE
OVER THE HIGHER TERRAIN...AND INTO A PROGRESSIVELY MORE STABLE
BOUNDARY LAYER OVER THE LOW ROLLING PLAINS BASED ON BILLOW CLOUD
FORMATIONS IMMEDIATELY E OF ONGOING ACTIVITY.

THEREFORE...AS THESE STORMS CONTINUE TO MOVE EWD...THEY MAY TEND TO
WEAKEN AS THEY ENCOUNTER MORE STABLE BOUNDARY LAYER. BY AROUND
03Z...LATEST SHORT TERM MODEL GUIDANCE SUGGESTS THAT RAPID
INTENSIFICATION OF NOCTURNAL LLJ WILL OCCUR FROM W-CNTRL TX INTO THE
ERN TX PNHDL AND WRN OK. STEEPENING MID-LEVEL LAPSE RATES COUPLED
WITH INCREASING MOISTURE JUST ABOVE COLLAPSING BOUNDARY LAYER WILL
CONTRIBUTE TO AIR MASS DESTABILIZATION FOR ELEVATED PARCELS WITH
MUCAPES INCREASING TO 500-1000 J/KG.

ANY LINGERING DIURNAL STORMS MAY TEND TO REINTENSIFY AT THIS TIME
WHILE BECOMING SLIGHTLY ELEVATED WITH ADDITIONAL STORM DEVELOPMENT
LIKELY ACROSS DISCUSSION AREA WITHIN ZONE OF STRENGTHENING WAA.
GIVEN THE MODEST INSTABILITY AND STRONG SHEAR THROUGH THE CLOUD
BEARING LAYER...POTENTIAL WILL EXIST FOR ELEVATED SUPERCELLS.

.MEAD.. 04/13/2007

..PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...OUN...AMA...

34499994 34839997 34870034 35240038 35550028 35730005
35729959 35329874 34369835 33769852 33559902 33639984

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