SPC AC 210537
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1137 PM CST WED DEC 20 2006
VALID 211200Z - 221200Z
...NO SVR TSTM AREAS FORECAST...
...CENTRAL GULF COAST...
UPPER LOW OVER SWRN KS WILL FINALLY EJECT EWD ACROSS KS AS HIGH
LEVEL FLOW INCREASES DOWNSTREAM ACROSS NRN AR INTO MO. RESULTANT
LARGE SCALE FORCING FROM THIS FEATURE SHOULD FOCUS WELL NORTH OF ANY
MEANINGFUL BOUNDARY LAYER INSTABILITY...MAINLY CONFINED TO THE
IMMEDIATE CNTRL GULF COAST. LATE EVENING SATELLITE IMAGERY...AND
00Z MODEL DATA...DO SUGGEST A MORE SLY UPPER SHORTWAVE OVER THE NRN
BAJA PENINSULA THAT WILL SHEAR EWD INTO THE BASE OF THE CNTRL U.S.
TROUGH...THEN EJECT NEWD TOWARD THE CNTRL GULF COAST. THIS SYSTEM
MAY ENHANCE DEEP CONVECTIVE POTENTIAL DESPITE THE MEAGER LOW LEVEL
RESPONSE TO THIS DEAMPLIFYING SHORTWAVE. FORECAST SOUNDINGS SUGGEST
DEEP LAYER SHEAR WILL BE SUPPORTIVE OF ORGANIZED UPDRAFTS...HOWEVER
WEAK LOW LEVEL CONVERGENCE/SHEAR WILL PROVE PROBLEMATIC IN
MAINTAINING ORGANIZED SEVERE UPDRAFTS. AT THIS TIME IT
APPEARS...ASIDE FROM ISOLATED SEVERE GUSTS...WEAK SUPERCELL
STRUCTURES SHOULD REMAIN MOSTLY NON-SEVERE WITH THE STRONGEST
ACTIVITY NEAR THE IMMEDIATE COAST OF LA/MS.
...ELSEWHERE...
VERY STEEP LAPSE RATES WILL DEVELOP AHEAD OF UPPER LOW ACROSS
PORTIONS OF CNTRL/ERN KS AND SERN LA. DESPITE MEAGER LOW LEVEL
MOISTURE...SFC BASED PARCELS SHOULD PROVE BUOYANT ENOUGH FOR LOW
TOPPED CONVECTION CAPABLE OF GENERATING ISOLATED LIGHTNING. THIS
ACTIVITY SHOULD PEAK IN THE AFTERNOON HOURS WITH RAPID WEAKENING
AFTER BOUNDARY LAYER COOLS.
OTHER ISOLATED THUNDERSTORMS WILL DEVELOP DOWNSTREAM WITHIN BROAD
WARM ADVECTION ZONE FROM NRN MS INTO IND. WEAK LAPSE
RATES/INSTABILITY SUGGEST MOST CONVECTION WILL PRODUCE ISOLATED
LIGHTING AT BEST.
..DARROW.. 12/21/2006
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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