SWODY1
SPC AC 041259
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 AM CDT SUN OCT 04 2009
VALID 041300Z - 051200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
MODERATE WSW FLOW WILL PREVAIL FROM THE SRN GRT BASIN ACROSS THE
CNTRL PLNS/MID MS VLY TO THE MID ATLANTIC CST...ON SRN FRINGE OF
ELONGATED UPR TROUGH AND ATTENDANT UPR LOWS OVER THE GRT BASIN AND
UPR GRT LKS. A BIT FARTHER S...SUBTROPICAL JET WILL PERSIST FROM
AZ/NM ACROSS THE OZARKS TO THE TN VLY. SATELLITE AND VWP DATA
SUGGEST PRESENCE OF A WEAK DISTURBANCE IN THE LATTER BAND OF FLOW
NOW OVER CNTRL TX. THIS IMPULSE SHOULD CONTINUE E TO THE LWR MS
VLY/CNTRL GULF CST BY EVE...WITH SLIGHT SHORTWAVE RIDGING EXPECTED
OVER THE SRN PLNS IN ITS WAKE.
AT THE SFC...COMPLEX WARM/STNRY FRONTAL ZONE WILL PERSIST FROM S
CNTRL/SE TX INTO THE NRN GULF. THE ERN PART OF THIS FRONT MAY
MOVE/REDEVELOP SOMEWHAT N INTO SRN LA LATER TODAY AS UPR IMPULSE
CONTINUES EWD AND SFC HEATING DESTABILIZES REGION. BUT SUBSTANTIAL
NEWD MOVEMENT INTO THE CNTRL GULF CST STATES IS NOT EXPECTED GIVEN
LIKELY PERSISTENCE OF SFC RIDGE OVER GA AND THE TN VLY.
...S CNTRL/SE TX TO CNTRL GULF CST...
UPR IMPULSE SHOULD SUPPORT CONTINUED DEVELOPMENT OF SHOWERS/STORMS
FROM THE MIDDLE/UPR TX CSTL PLN EWD INTO SRN LA LATER TODAY. MID
LVL LAPSE RATES WILL REMAIN WEAK. BUT VERY MOIST/WEAKLY CONFLUENT
LOW-LVL FLOW WILL REMAIN FAVORABLE INVOF WARM FRONTAL
SEGMENTS...WHERE MODEST SFC HEATING AND DEW POINTS IN THE 70S F MAY
YIELD POCKETS OF 2000-3000 J/KG SBCAPE. 30+ KT MID LVL WLY FLOW MAY
SUPPORT A FEW SHORT-LIVED SUPERCELLS WITH HEAVY RAIN AND A THREAT
FOR A TORNADO OR TWO...ESPECIALLY WHERE LOW LCL DIRECTIONAL SHEAR IS
ENHANCED BY BOUNDARY INTERACTIONS. ISOLD STG/DMGG WINDS MAY ALSO
OCCUR...MAINLY IN ANY AREAS OF GREATER SFC HEATING.
...SRN HI PLNS...AFTER 5/06Z...
WDLY SCTD TO SCTD TSTMS MAY FORM EARLY MON FROM W CNTRL TX NWD INTO
NW TX AND THE TX PANHANDLE....AS WAA STRENGTHENS DOWNSTREAM FROM
SLOWLY PROGRESSIVE GRT BASIN TROUGH. NARROW...MERIDIONAL PLUME OF
MOISTURE ADVECTION WILL OCCUR ALONG 30+ KT SSELY LLJ. . VERTICAL
SHEAR PROFILES SHOULD BE FAVORABLE FOR AT LEAST WEAK STORM
ORGANIZATION...WITH 30-35 KT CLOUD LAYER SHEAR. ELEVATED CAPE OF
1000-1500 J/KG SUGGESTS THE POTENTIAL FOR SVR HAIL WITH ANY
SUSTAINED/MAINLY DISCRETE STORMS THAT DO FORM. HOWEVER... OUTSIDE
OF LOW LVL WAA...LARGE SCALE FORCING FOR ASCENT WILL REMAIN WEAK/NON
EXISTENT. THUS...SVR POTENTIAL APPEARS TOO CONDITIONAL TO ASSIGN
PROBABILITIES ATTM.
..CORFIDI/SMITH.. 10/04/2009
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