SWODY1
SPC AC 301245
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0645 AM CST WED DEC 30 2009
VALID 301300Z - 311200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
BROAD CYCLONIC FLOW...WITH THE TROUGH AXIS CENTERED OVER ERN PLNS
...WILL PREVAIL OVER THE LWR 48 THIS PERIOD. WITHIN THE BROADER
TROUGH...SMALLER SCALE DISTURBANCES WILL CONTINUE TO AMPLIFY SE
ACROSS THE GRT BASIN/RCKYS...AND DEAMPLIFY AS THEY CONTINUE NE
ACROSS THE TN/OH VLYS.
AIR OF RECENT POLAR OR ARCTIC ORIGIN WILL PERSIST AT LWR LVLS OVER
MOST AREAS. SATELLITE AND SFC OBSERVATIONS DO SHOW MODEST BOUNDARY
LAYER MODIFICATION IN PROGRESS OVER THE WRN AND SRN GULF OF MEXICO.
BUT DEVELOPING PRECIPITATION OVER THE NWRN GULF WILL OFFSET THE
MODIFICATION PROCESS...AND LOW LVL THERMAL/MOISTURE RETURN ACROSS
THE NRN GULF WILL BE LIMITED BY VEERED LOW LVL FLOW AND ABSENCE OF A
STRONG LLJ.
...TX GULF CST TO LWR MS VLY/CNTRL GULF CST...
CONFLUENT UPR FLOW OVER THE LWR MS VLY SUGGESTS THAT WEAK SFC WAVE
NOW OVER THE NWRN GULF WILL WEAKEN AS IT MOVES ENE TO THE CNTRL GULF
CST LATER TODAY/TONIGHT. ALTHOUGH MODERATE S TO SELY LOW LVL FLOW
WILL EXIST AHEAD OF THE WAVE...IT IS UNLIKELY THAT TRUE GULF AIR
WILL MOVE ONSHORE THOUGH THE PERIOD. GRADUAL MOISTENING OF 850-700
MB FLOW ATOP RESIDUAL MODIFIED POLAR AIR AT THE SFC SHOULD LEAD TO
INCREASING COVERAGE OF ELEVATED CONVECTION/EMBEDDED THUNDER OVER THE
NWRN GULF TODAY. THIS ACTIVITY SHOULD SPREAD ENE TO THE CNTRL GULF
CST LATER TODAY/TONIGHT.
MODEST MOISTURE INFLOW AND WEAK MID LVL LAPSE RATES SHOULD KEEP
MUCAPE AOB 200 J/KG...THUS POTENTIAL FOR HAIL WILL REMAIN LIMITED.
THE SHOWERS/EMBEDDED STORMS MAY BECOME NEARLY SFC-BASED OVER SE LA
AND FAR SRN PORTIONS OF MS/AL BETWEEN 03 AND 09Z THUR. BUT
COINCIDENT TEMPORAL VEERING OF LOW LVL FLOW...AND LIMITED MOISTURE
AVAILABILITY...SUGGEST THAT ANY ASSOCIATED WIND/TORNADO THREAT WILL
REMAIN VERY ISOLD.
..CORFIDI.. 12/30/2009
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