MESO: Mesoscale Discussion 0612

ACUS11 KWNS 291014
SWOMCD
SPC MCD 291013 COR
TXZ000-291215-

MESOSCALE DISCUSSION 0612
NWS STORM PREDICTION CENTER NORMAN OK
0513 AM CDT SUN APR 29 2007

AREAS AFFECTED...PORTIONS SW TX -- BIG BEND/LOWER
PECOS...TRANS-PECOS AND PERMIAN BASIN REGIONS.

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 291013Z - 291215Z

CORRECTED FOR TYPO

INCREASING CONVECTIVE COVERAGE AND INTENSITY IS EXPECTED ACROSS THIS
REGION THROUGH MIDMORNING...WITH OCCASIONAL LARGE HAIL POSSIBLE.

SFC MESOANALYSIS SHOWS WARM FRONT MOVING SLOWLY NWD TOWARD I-10
CORRIDOR BETWEEN JCT-FST...BENEATH 25-35 KT LLJ. RELATED SFC THETAE
ADVECTION AND MOIST ADVECTION ABOVE SFC WILL BOOST BUOYANCY FROM
S-N...SUPPORTING BOTH TSTMS MOVING NWD FROM MEX AND ACTIVITY
DEVELOPING N OF RIO GRANDE. THIS REGION WILL REMAIN IN ZONE OF
STRONG UPPER LEVEL DIFLUENCE NE OF UPPER LOW LOCATED INVOF
SONORA/CHIHUAHUA BORDER. WITH LITTLE MOVEMENT EXPECTED OF UPPER
VORTEX DURING NEXT SEVERAL HOURS...MID/UPPER LEVEL WINDS AND
THEREFORE DEEP-LAYER BULK SHEAR WILL WEAKEN SUBSTANTIALLY WITH NWD
EXTENT. THIS FACTOR...ALONG WITH DIMINISHING INSTABILITY NWD ACROSS
PERMIAN BASIN TOWARD S PLAINS...WILL LIMIT SVR POTENTIAL NEAR AND N
OF I-20 THROUGH MIDMORNING. EXPECT SFC-BASED EFFECTIVE INFLOW
PARCELS WITH MLCAPES 1000-1500 J/KG ALONG RIO GRANDE...DROPPING TO
LESS THAN 500 J/KG ALONG WARM FRONT...THOUGH ELEVATED MUCAPES
500-1000 J/G MAY SUSTAIN ACTIVITY FOR 50-80 NM N OF WARM FRONT
BEFORE WEAKENING. BULK SHEAR SHOULD REMAIN MAXIMIZED OVER BIG BEND
AND SWRN TRANS-PECOS AREAS NEAR RIO GRANDE...WITH 0-6 KM VALUES
35-40 KT.

.EDWARDS.. 04/29/2007

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

ATTN...WFO...EWX...SJT...MAF...EPZ...

31130566 31380201 31020068 30220045 28920061 29740140
29770173 29850230 29730259 28970311 29280395 29600445
29880463 30180467 30660502 30810522

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