SPC AC 261640
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1140 AM CDT THU OCT 26 2006
VALID 271200Z - 281200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE LOWER MS VALLEY
/CENTRAL AND ERN GULF COAST REGION...
...SYNOPSIS...
THOUGH UPPER LOW FORECAST OVER ERN OK/WRN AR SHOULD WEAKEN WITH
TIME...VIGOROUS/ASSOCIATED TROUGH WILL PROGRESS RAPIDLY EWD ACROSS
THE S CENTRAL AND SERN CONUS THIS PERIOD. AS THIS TROUGH MOVES
EWD...RIDGE WILL ALSO PROGRESS EWD FROM THE ERN PACIFIC INTO THE WRN
CONUS.
AT THE SURFACE...A WELL-DEFINED COLD FRONT WILL SWEEP EWD ACROSS THE
SOUTHEAST...TRAILING SWD FROM A LOW WHICH SHOULD MOVE FROM AR TO VA
THROUGH THE PERIOD. WITH MOIST GULF AIRMASS SPREADING NWD AHEAD OF
THE FRONT AND STRONG QG FORCING ASSOCIATED WITH THIS STORM
SYSTEM...EXPECT WIDESPREAD PRECIPITATION TO SHIFT EWD ACROSS THE
SERN QUARTER OF THE CONUS THROUGH THE PERIOD.
...GULF COAST STATES...
PRE-FRONTAL SQUALL LINE IS FORECAST TO BE ONGOING ACROSS THE LOWER
MS VALLEY/WRN GULF COAST REGION AT THE START OF THE PERIOD. FURTHER
E...WIDESPREAD PRECIPITATION SHOULD ALSO BE ONGOING ACROSS THE
CENTRAL GULF COAST/MID-SOUTH REGION WITHIN ZONE OF WARM ADVECTION
ASSOCIATED WITH 50 KT SSWLY LOW-LEVEL JET.
WITH WIDESPREAD CLOUDS/PRECIPITATION EXPECTED TO PERSIST AHEAD OF
FRONT/SQUALL LINE THROUGH THE DAY...POTENTIAL FOR AIRMASS
DESTABILIZATION SHOULD REMAIN LIMITED DESPITE MOIST GULF AIRMASS
ADVECTING NWD. ATTM...IT APPEARS THAT GREATEST INSTABILITY /500 TO
1000 J/KG MEAN-LAYER CAPE/ SHOULD REMAIN CONFINED TO SERN LA...THE
SRN HALVES OF MS AND AL...AND INTO SRN GA AND NWRN FL.
WITHIN THE REGION OF GREATER INSTABILITY...SHARP FRONT AND STRONG
UPPER TROUGH SHOULD SUPPORT VIGOROUS STORMS...AIDED BY STRONG WIND
FIELD YIELD SHEAR FAVORABLE FOR SUPERCELLS. THEREFORE...SEVERE
THREAT -- PRIMARILY IN THE FORM OF LOCALLY-DAMAGING WINDS WITHIN
PRE-FRONTAL LINE OF STORMS -- SHOULD SHIFT EWD ACROSS THE GULF COAST
STATES THROUGH THE PERIOD.
...ERN CAROLINAS...
STRONG WIND FIELD IS FORECAST TO SPREAD INTO THE CAROLINAS DURING
THE SECOND HALF OF THE PERIOD AS UPPER TROUGH PROGRESSES EWD. WITH
SLY/SELY LOW-LEVEL FLOW BENEATH MID-LEVEL WSWLYS...SHEAR WILL BECOME
INCREASINGLY-FAVORABLE FOR UPDRAFT ROTATION.
NAM SUGGESTS THAT BOUNDARY LAYER WILL MOISTEN AS ATLANTIC/GULF
STREAM MOISTURE SPREADS INLAND ON PERSISTENT LOW-LEVEL SELYS.
HOWEVER...WEAK/MOIST-ADIABATIC LAPSE RATES ARE ALSO ANTICIPATED --
WHICH SHOULD LIMIT THE POTENTIAL FOR ANY APPRECIABLE
DESTABILIZATION. THUS -- IT APPEARS ATTM THAT POTENTIAL FOR
VIGOROUS CONVECTION SHOULD LIKEWISE REMAIN LIMITED.
NONETHELESS...GIVEN DEGREE OF LOWER TROPOSPHERIC SHEAR ANTICIPATED
ATTM...LOW-LEVEL UPDRAFT ROTATION WOULD APPEAR LIKELY EVEN WITHIN
RELATIVELY WEAK CONVECTION. THEREFORE...WILL MAINTAIN
LOW-PROBABILITY SEVERE THREAT -- MAINLY FOR THE POTENTIAL FOR AN
ISOLATED TORNADO.
..GOSS.. 10/26/2006
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0800Z
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