SPC AC 101258
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0658 AM CST WED MAR 10 2010
VALID 101300Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN PARTS OF THE CNTRL/SRN
PLNS SE TO THE CNTRL GULF CST...
...SYNOPSIS...
AN ACTIVE/COMPLEX SVR WEATHER PATTERN WILL EXIST OVER THE S CNTRL
U.S. THROUGH EARLY THU...WITH SEVERAL DISTINCT EPISODES/MODES OF SVR
TSTMS EXPECTED FROM ERN PARTS OF THE CNTRL/SRN PLNS TO THE MID/LWR
MS VLYS.
POTENT NM UPR LOW WILL TRACK ENE INTO N CNTRL OK THIS EVE...BEFORE
TURNING NE INTO NW MO EARLY THU AS UPSTREAM TROUGH AMPLIFIES SE
ACROSS THE SWRN DESERTS. FARTHER S...FAST/NEARLY ZONAL SUBTROPICAL
JET WILL PERSIST FROM THE TX BIG BEND TO THE NRN GULF OF MEXICO.
AT THE SFC...LOW NOW OVER THE TX PANHANDLE SHOULD MOVE SLOWLY E INTO
CNTRL OK BY THIS EVE...BEFORE CONTINUING NE INTO NRN MO EARLY THU.
COLD FRONT EXTENDING S FROM THE LOW WILL ACCELERATE E ACROSS OK AND
TX TODAY...AND OVERTAKE DRY LINE/CONFLUENCE ZONE LEFT FROM PREVIOUS
UPR SYSTEM NOW IN IA. THE COMBINED BOUNDARY SHOULD CONTINUE RAPIDLY
E/NE ACROSS AR/MO TONIGHT AND EARLY THU...AND MORE SLOWLY E ACROSS
LA/MS.
...NE TX/ERN OK/SE KS INTO MO/AR AND THE MS VLY TODAY/TONIGHT...
LOW-LVL MOISTENING WILL CONTINUE NWD AHEAD OF MERGING COLD FRONT/DRY
LINE TODAY/TONIGHT...WITH SFC DEWPOINTS IN THE UPR 50S F EXPECTED BY
LATE AFTN OVER ERN OK/AR. A SEPARATE AREA OF RELATIVELY MOIST AIR
WILL SPREAD N FROM THE AR/MS DELTA INTO SE MO AND WRN KY/TN.
COUPLED WITH SFC HEATING AND COOL MID LVL TEMPERATURES...SETUP
SHOULD YIELD SBCAPE OF 1000-1500 J/KG IN AR...AND VALUES AOA 1000
J/KG FROM ERN OK INTO SRN MO/W TN.
COMBINATION OF DESTABILIZATION AND STRONG ASCENT AHEAD OF NM UPR
VORT SHOULD SUPPORT VIGOROUS STORM DEVELOPMENT ALONG AND AHEAD OF
THE FRONT FROM SE KS THROUGH ERN OK INTO NE TX BY MID/LATE AFTN.
THE STORMS SHOULD CONSOLIDATE INTO BROKEN BANDS AND MOVE/DEVELOP
E/NE INTO MO/AR BY EARLY EVE.
BAND OF 80+ KT SSWLY 500 MB FLOW SHIFTING ENE ATOP LOW-LVL SLY FLOW
WILL BE FAVORABLE FOR SUPERCELLS. HOWEVER...SUBSTANTIAL
SPATIAL/TEMPORAL VARIATION OF WIND FIELD AHEAD OF COMPACT UPR
VORT...AND NW-TO-SE VARIATION OF MOISTURE AVAILABILITY ACROSS REGION
COMPLICATE FORECAST OF DOMINANT STORM MODE. NEVERTHELESS...OVERALL
COMBINATION OF STRENGTHENING INSTABILITY...SHEAR...AND LIFT SUGGEST
STRONG LIKELIHOOD FOR SVR WEATHER...ESPECIALLY LARGE HAIL.
TORNADOES ALSO WILL BE POSSIBLE...NOT ONLY WITH THE MORE DISCRETE
STORMS THIS AFTN...BUT ALSO WITH BROKEN BANDS/LEWPS OVER AR/MO AND
PERHAPS WRN TN TONIGHT/EARLY THU AS THE ACTIVITY ENCOUNTERS
INCREASING MOISTURE MOVING N UP THE MS RVR VLY.
...N CNTRL OK INTO SRN KS THIS AFTN/EVE...
LOW-TOPPED TSTMS EXPECTED TO FORM IMMEDIATELY N/NE OF MAIN UPR VORT
CROSSING CNTRL OK THIS AFTN...WHERE SUSTAINED/DEEP CONVERGENCE WILL
EXIST NEAR ASSOCIATED SFC LOW. THESE STORMS SHOULD MOVE/DEVELOP NE
INTO PARTS OF SRN KS BY EARLY EVE. COMBINATION OF VERY COOL AIR
ALOFT /AOA MINUS 24 C AT 500 MB/ AND AMPLE SHEAR FOR ROTATING
UPDRAFTS WILL SUPPORT A THREAT FOR LARGE HAIL. TORNADOES MAY ALSO
OCCUR...ESPECIALLY IN ZONE OF BACKED LOW-LVL FLOW ALONG STNRY FRONT
EXTENDING NE FROM SFC LOW. THE SVR THREAT SHOULD DIMINISH TONIGHT
AS STORMS FARTHER S AND E STABILIZE INFLOW AIR...AND DIURNAL COOLING
OCCURS.
...CNTRL/E TX MIDDAY THROUGH EVE...
SATELLITE AND SFC OBS SHOW LOW-LVL MOISTURE SPREADING STEADILY NNW
ACROSS E CNTRL AND S CNTRL TX ATTM AS CONFLUENCE ZONE/DRY LINE FROM
YESTERDAY RETURNS N/W AHEAD OF NM UPR VORT. STORMS MAY FORM ALONG
THE CONFLUENCE ZONE OVER CNTRL TX LATER THIS MORNING OR EARLY THIS
AFTN IN RESPONSE TO INCREASING MOISTURE...DAYTIME HEATING AND
GLANCING INFLUENCE OF NM VORT. THE STORMS SHOULD MOVE E TOWARD THE
ARKLATEX AND SE TX LATER TODAY AS COLD FRONT ACCELERATES EWD ON S
SIDE OF THE UPR TROUGH. ALTHOUGH PW DATA SUGGEST THAT TOTAL
MOISTURE AVAILABILITY WILL REMAIN SOMEWHAT LIMITED /BELOW .75
IN/...SUFFICIENT DESTABILIZATION SHOULD OCCUR TO SUPPORT A THREAT
FOR SVR WIND/HAIL...ESPECIALLY IN E TX.
...CNTRL GULF CST STATES...
SCTD TO BROKEN TSTMS WILL PERSIST OVER PARTS OF SRN LA/MS AND AL
TODAY...IN AREA OF SUSTAINED LOW-LVL CONFLUENCE/WAA BENEATH BROADLY
DIFFLUENT UPR FLOW. ALTHOUGH THIS ACTIVITY INITIALLY WILL BE
SLIGHTLY ELEVATED...WARMING/MOISTENING OF BOUNDARY LAYER SUGGESTS
THAT SOME OF THE STORMS COULD BECOME NEARLY SFC-BASED WITH TIME AS
THEY EVOLVE INTO ONE OR MORE REGENERATIVE CLUSTERS. COUPLED WITH 40
KT 500 MB WSWLY FLOW AND 30 KT SSWLY LLJ...THE THREAT FOR SVR
WEATHER /MAINLY IN THE FORM OF TORNADOES...HAIL AND HEAVY RAIN/ MAY
SLOWLY INCREASE THROUGH THE DAY. THIS THREAT MAY FURTHER INCREASE
THIS EVE OR EARLY THU FROM SE LA INTO SRN MS...SRN AL...AND THE FL
PANHANDLE AS LOW-LVL SLY FLOW STRENGTHENS AHEAD OF E TX/LA COLD
FRONT. DESPITE NEARLY MOIST ADIABATIC PROFILES...FAVORABLE
VEERING/INCREASING WINDS WITH HEIGHT AND PROXIMITY OF STRONG
SUBTROPICAL JET COULD SUPPORT SUPERCELLS AND TORNADOES.
..CORFIDI/SMITH.. 03/10/2010
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z
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