MESO: Mesoscale Discussion 0474

ACUS11 KWNS 130235
SWOMCD
SPC MCD 130235
TXZ000-OKZ000-NMZ000-130430-

MESOSCALE DISCUSSION 0474
NWS STORM PREDICTION CENTER NORMAN OK
0935 PM CDT THU APR 12 2007

AREAS AFFECTED...TX S PLAINS AND PNHDL

CONCERNING...SEVERE THUNDERSTORM WATCH 131...

VALID 130235Z - 130430Z

POTENTIAL FOR SEVERE STORMS CAPABLE OF LARGE HAIL AND LOCALLY
DAMAGING WIND IS EXPECTED TO CONTINUE ACROSS WW AREA FOR THE NEXT
SEVERAL HOURS. CONTINUE WW.

LATEST MESOANALYSIS INDICATES PRIMARY SURFACE LOW OVER SERN NM /NE
OF ROW/ WITH AN OUTFLOW-REINFORCED BAROCLINIC ZONE STRENGTHENING
ACROSS THE TX S PLAINS AND LOW ROLLING PLAINS. THIS BOUNDARY THEN
EXTENDED ESEWD ACROSS NRN TX. A SECONDARY LOW-LEVEL
BOUNDARY...DELINEATING THE NRN EDGE OF RICHER BOUNDARY LAYER
MOISTURE...WAS ANALYZED FROM W-CNTRL TX SEWD TO THE UPPER TX COAST.

AS MENTIONED ABOVE...CONSIDERABLE OUTFLOW HAS BEEN GENERATED BY
DIURNAL TSTMS OVER THE PNHDL AND S PLAINS WITH ONGOING ACTIVITY
LIKELY BECOMING SLIGHTLY ELEVATED ABOVE A SHALLOW...NEAR SURFACE
INVERSION. LATEST NAM/WRF AND RUC GUIDANCE SUGGEST THAT PRIMARY
INSTABILITY AXIS WILL REMAIN IN PLACE ACROSS WRN TX OVERNIGHT AS
INCREASING LOW-LEVEL MOISTURE CONTINUES TO RETURN NWWD BENEATH STEEP
MID-LEVEL LAPSE RATES.

ISENTROPIC ASCENT ABOVE SOLIDIFYING S PLAINS BAROCLINIC ZONE WILL
LIKELY PROVIDE THE FOCUS FOR RENEWED TSTM DEVELOPMENT OVERNIGHT
WITHIN THERMODYNAMIC ENVIRONMENT CHARACTERIZED BY MUCAPES OF
500-1000 J/KG. STRONG CLOUD BEARING SHEAR WILL REMAIN SUPPORTIVE OF
ELEVATED SUPERCELLS WITH LARGE HAIL BEING THE PRIMARY SEVERE WEATHER
THREAT. HOWEVER...LOCALLY DAMAGING DOWNBURSTS WILL ALSO BE POSSIBLE
OWING TO THE RELATIVELY SHALLOW SURFACE INVERSION AND MODERATELY
STRONG POTENTIAL NEGATIVE BUOYANCY /DCAPES AROUND 1000 J PER KG/.

.MEAD.. 04/13/2007

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

ATTN...WFO...OUN...SJT...LUB...AMA...MAF...ABQ...

36610308 36590040 34860026 34819993 32759984 32920330
34160426 35370427 35970332

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