SWODY1
SPC AC 101937
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0137 PM CST TUE JAN 10 2012
VALID 102000Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CENTRAL GULF
STATES...
...CENTRAL GULF STATES...
MINOR CHANGES HAVE BEEN MADE TO THE WRN PART OF THE CONVECTIVE
OUTLOOK...PRIMARILY TO ACCOUNT FOR A DIMINISHED THUNDER/SEVERE
THREAT IN THE WAKE OF FRONTAL PASSAGE. ELSEWHERE...PROBABILITIES
REMAIN UNCHANGED.
THUNDERSTORMS HAVE STRUGGLED TO DEVELOP ACROSS THE WARM SECTOR OVER
ERN LA/MS AND CERTAINLY HAVE YET TO ATTAIN ANY ORGANIZED SEVERE
STATUS. WEAK LAPSE RATES AND LIMITED INSTABILITY APPEAR LARGELY
RESPONSIBLE...THOUGH RECENT TRENDS DO SUGGEST UPDRAFTS ARE GRADUALLY
DEEPENING ALONG THE ADVANCING COLD FRONT FROM SWRN MS INTO
SUBSEQUENT REGIONS OF LA ALONG THE WIND SHIFT. THIS REGION HAS
EXPERIENCED A FEW BREAKS IN CLOUD COVER WHICH MAY BE AIDING THIS
DEVELOPMENT. EARLIER THOUGHTS PREVAIL REGARDING THE OVERALL SEVERE
THREAT AND WILL MAINTAIN SEVERE PROBS DOWNSTREAM AHEAD OF ADVANCING
COLD FRONT TO ACCOUNT FOR ORGANIZED CONVECTIVE POTENTIAL.
..DARROW.. 01/10/2012
.PREV DISCUSSION... /ISSUED 1029 AM CST TUE JAN 10 2012/
...PARTS OF LOWER MS VALLEY EWD TO AL/FL PANHANDLE THROUGH
TONIGHT...
A MIDLEVEL LOW OVER NE TX THIS MORNING WILL PROGRESS EWD TO MS/AL BY
THE END OF THE PERIOD IN RESPONSE TO A NRN STREAM TROUGH AMPLIFYING
OVER THE NRN ROCKIES/HIGH PLAINS. AN ASSOCIATED SURFACE LOW WILL
DEEPEN GRADUALLY WHILE MOVING NEWD FROM LA TO WRN TN...AS A TRAILING
COLD FRONT TRANSLATES EWD ACROSS THE LOWER MS VALLEY. THERE WILL BE
SOME NWD SPREAD OF THE SURFACE WARM/MOIST SECTOR ACROSS
MS/AL...THOUGH SATELLITE IMAGERY SHOWS WIDESPREAD CLOUDS THROUGHOUT
THE WARM SECTOR THAT WILL INHIBIT SURFACE HEATING. ADDITIONALLY...A
LARGE THUNDERSTORM CLUSTER OVER THE N CENTRAL GULF OF MEXICO WILL
HELP MAINTAIN CLOUDS AND INTERFERE SOME WITH INLAND PROGRESS OF THE
MARINE WARM FRONT AND NWD TRANSPORT OF LOW-LEVEL MOISTURE. THE NET
RESULT WILL BE MAINLY WEAK INSTABILITY IN THE CLOUDY WARM SECTOR
FROM SE LA ACROSS SRN MS/AL THIS AFTERNOON. THERE WILL BE SOME RISK
FOR NEAR-SURFACE-BASED STORMS ALONG THE COLD FRONT LATER TODAY INTO
TONIGHT...AND SOME OF THE STRONGER STORMS OVER THE GULF COULD ALSO
APPROACH THE COAST. OVERALL...THE MESSY THERMODYNAMIC SITUATION
SUGGESTS THAT THE SEVERE THREAT WILL LIKELY REMAIN ON THE LOWER
MARGINS OF A CATEGORICAL SLIGHT RISK.
FARTHER N...THE STRONGER FORCING FOR ASCENT WITH THE SHORTWAVE
TROUGH WILL SPREAD ENEWD FROM NRN LA/AR TOWARD CENTRAL/NRN MS AND
WRN TN BY THIS EVENING...AND CONTINUE ENEWD OVERNIGHT. THE 12Z SHV
SOUNDING REFLECTED A POCKET OF RELATIVELY STEEP MIDLEVEL LAPSE RATES
AND ELEVATED CAPE...AND A SIMILAR ENVIRONMENT WITH SOME LOW-LEVEL
DESTABILIZATION IS EXPECTED THIS AFTERNOON/EVENING IMMEDIATELY IN
ADVANCE OF THE SURFACE LOW/COLD FRONT. SCATTERED THUNDERSTORMS ARE
EXPECTED TO DEVELOP IN A BROKEN BAND NEAR AND SE OF THE SURFACE
LOW...SOME OF WHICH COULD DEVELOP SUPERCELL CHARACTERISTICS GIVEN
MUCAPE OF 1000-1500 J/KG AND EFFECTIVE BULK SHEAR OF 35-45 KT.
LOW-LEVEL WINDS AND VERTICAL SHEAR WILL NOT BE PARTICULARLY
STRONG...AND FORECAST HODOGRAPHS DEPICT BACKING FLOW ALOFT WITH
TIME...SO THE TORNADO RISK APPEARS SOMEWHAT MARGINAL ACROSS A
RELATIVELY BROAD AREA. OTHERWISE...THE MAGNITUDE OF INSTABILITY AND
RELATIVELY COOL MIDLEVEL TEMPERATURES WILL SUPPORT A RISK FOR LARGE
HAIL AND DAMAGING GUSTS WITH THE STRONGER STORMS INTO AT LEAST EARLY
TONIGHT.
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