SWODY1
SPC AC 101254
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0654 AM CST TUE JAN 10 2012
VALID 101300Z - 111200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER MS
VALLEY EWD ACROSS THE CNTRL GULF STATES...
...SYNOPSIS...
MID- AND UPPER-LEVEL LOW OVER THE SRN PLAINS IS FORECAST TO
INTENSIFY AND GRADUALLY ASSUME A SLIGHT NEGATIVE TILT WHILE
PROGRESSING INTO THE LOWER MS VALLEY. THIS WILL OCCUR AS ATTENDANT
MID- AND UPPER-LEVEL JET STREAKS ROUND THE TROUGH BASE INTO PORTIONS
OF AL/GA OVERNIGHT...SUPPORTING A CORRIDOR OF 12-HR HEIGHT FALLS AT
500 MB IN EXCESS OF 100 M ALONG THE SYSTEM TRACK. IN THE LOW
LEVELS...SURFACE LOW NEAR POE AS OF 12Z...WILL DEEPEN WHILE
DEVELOPING NEWD TO THE MS DELTA REGION BY 11/00Z AND TO NEAR THE
TN/KY BORDER /W OF HOP/ BY 11/12Z. AN ASSOCIATED WARM FRONT WILL
CONCURRENTLY LIFT NWD THROUGH MS/AL INTO THE TN VALLEY BY TONIGHT
WHILE A TRAILING COLD FRONT ADVANCES EWD THROUGH THE LOWER MS VALLEY
AND CNTRL GULF COAST.
...LOWER MS VALLEY INTO CNTRL GULF STATES...
SUSTAINED SLY LOW-LEVEL FLOW WITHIN EXPANDING WARM SECTOR WILL ALLOW
FOR THE NWD FLUX OF AN INCREASINGLY MOIST BOUNDARY LAYER ACROSS
MS/AL TODAY. THIS PROCESS WILL OCCUR BENEATH COOLING MIDLEVEL
TEMPERATURES AND A RESULTANT STEEPENING OF MIDLEVEL LAPSE RATES
ASSOCIATED WITH THE APPROACH OF THE UPPER LOW. HOWEVER...WIDESPREAD
CLOUDS AND ONGOING CONVECTIVE PRECIPITATION FROM NRN LA EWD INTO
SRN/CNTRL PARTS OF MS/AL WILL HINDER THE DESTABILIZATION PROCESS
WITH MLCAPE VALUES REMAINING BELOW 1000 J/KG AT MOST LOCATIONS.
A RECENT INCREASE IN ELEVATED TSTM COVERAGE AND INTENSITY OVER NWRN
LA APPEARS TO BE THE MANIFESTATION OF WHERE THE STRONGER FORCING FOR
ASCENT ALIGNS WITH THE STEEP MIDLEVEL LAPSE RATES AND NWRN EXTENSION
OF A MORE MOIST ENVIRONMENT /REF. 12Z SHV SOUNDING/. EXPECT THIS
REGIME TO SPREAD NEWD TODAY IN ADVANCE OF THE MIGRATORY SURFACE LOW
WITH THE STRONGEST STORMS CAPABLE OF PRIMARILY SEVERE HAIL.
THE TIMING OF SURFACE-BASED STORM EVOLUTION ALONG THE COLD FRONT IS
A BIT MORE UNCERTAIN BASED ON THE DISPERSIVE SOLUTIONS OF THE LATEST
MESOSCALE AND CONVECTION-ALLOWING MODELS. THIS IS PERHAPS
SYMPTOMATIC OF VARYING DEGREES OF INSTABILITY GENERATED BY EACH
MODEL. REGARDLESS...AS THE STRONGER LARGE-SCALE FORCING FOR ASCENT
BEGINS TO OVERSPREAD THE WARM SECTOR...EXPECT A GRADUAL INCREASE IN
SURFACE-BASED TSTM DEVELOPMENT FROM THE VICINITY OF THE SURFACE LOW
OVER THE ARKLAMISS SWD/SEWD ALONG THE COLD FRONT. WHILE INSTABILITY
WILL REMAIN MARGINAL...THE STRENGTHENING FORCING FOR ASCENT AND
VERTICAL SHEAR WILL SUPPORT SUPERCELL AND BOWING STRUCTURES
INITIALLY ACROSS PARTS OF MS AND SERN LA...AND CONTINUING OVERNIGHT
ACROSS AL AND THE FL PNHDL. DAMAGING WINDS AND A FEW TORNADOES WILL
BE THE PRIMARY HAZARDS WITH THESE STORMS.
..MEAD/BOTHWELL.. 01/10/2012
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