[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 150612
SWODY2
SPC AC 150611

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0111 AM CDT SUN OCT 15 2006

VALID 161200Z - 171200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE TX GULF COAST ACROSS
THE LOWER MS VALLEY AND THE NRN GULF COAST...

...SYNOPSIS...
POTENTIAL FOR SEVERE STORMS AND PERHAPS TORNADOES APPEARS TO BE
INCREASING OVER PARTS OF THE NRN GULF COAST AND MS DELTA REGIONS
DURING MONDAY AS A VIGOROUS SHORT WAVE IMPULSE EJECTS NEWD FROM THE
SRN PLAINS. THIS WILL OCCUR DOWNSTREAM FROM STRONG HEIGHT FALLS AND
LARGE SCALE TROUGH DEVELOPMENT FROM THE NORTHWEST/GREAT BASIN AREAS
TO THE ROCKIES. RIDGING...SURFACE AND ALOFT...WILL REMAIN SITUATED
ACROSS THE ERN SEABOARD...AND OVER FL AND THE ERN GULF OF MEX.

THERE CONTINUE TO BE TIMING DIFFERENCES AMONG NAM-WRF AND GFS
GUIDANCE WITH RESPECT TO THE EJECTING SHORT WAVE TROUGH. THE GFS
CONTINUES TO FORECAST A MORE PROGRESSIVE IMPULSE AND LATEST NAM-WRF
GUIDANCE IS TRENDING TOWARD A LESS AMPLIFIED UPPER WAVE...SIMILAR TO
WHAT THE GFS HAS BEEN FORECASTING. ECMWF AND SREF MEAN ALSO SUGGEST
THAT THE SHORT WAVE TROUGH WILL DEAMPLIFY WHILE ACCELERATING NEWD
FROM TX/OK TO THE MIDWEST FROM MONDAY AFTERNOON THROUGH EARLY
TUESDAY. LARGE SCALE FORCING ASSOCIATED WITH THE WRN U.S. TROUGH
WILL INDUCE STRONG CYCLOGENESIS ACROSS THE NRN PLAINS THROUGH THE
PERIOD. MEANWHILE...VERY STRONG WIND FIELDS ACCOMPANYING THE
EJECTING SRN PLAINS TROUGH WILL ALLOW WARM SECTOR TO EXPAND NNEWD
FROM THE UPPER TX COAST ACROSS THE LOWER MS VALLEY THROUGH THE
PERIOD.

...ERN TX ACROSS THE LOWER MS VALLEY...
PRONOUNCED GULF MOISTURE TRANSPORT WILL PRECEDE THE EJECTING UPPER
TROUGH WITH INTENSIFYING SLY LOW LEVEL JET OF 50KT TO 70KT EXTENDING
FROM THE NWRN GULF INLAND TO THE OZARKS DURING MONDAY. INTENSE
DYNAMIC ASCENT ACROSS DEVELOPING WARM SECTOR WILL SUPPORT WIDESPREAD
CONVECTION OVER THE REGION OF CONCERN. LATEST GUIDANCE SUGGESTS WARM
SECTOR WITH 70S DEWPOINTS SHOULD EXPAND NWD AND EWD FROM ERN TX TO
SRN AR...AND INTO TO MS FROM MONDAY MORNING THROUGH MONDAY NIGHT.
DESPITE NEARLY MOIST ADIABATIC LAPSE RATES DEPICTED IN FORECAST
SOUNDINGS...POCKETS OF WEAK TO MODEST INSTABILITY MAY DEVELOP DURING
THE DAY AND SUPPORT STRONGER EMBEDDED CONVECTION. ACTIVITY NEAR THE
WARM FRONT...AND NEAR ANY WEAK FRONTAL WAVES...WILL ENCOUNTER
EXTREME LOW LEVEL SHEAR AND HELICITY. EFFECTIVE SRH VALUES IN EXCESS
OF 500 M2/S2 WILL EASILY SUPPORT MESOCYCLONE FORMATION AND
PERSISTENCE IN ANY UPDRAFTS THAT CAN REMAIN DISCRETE/LONG-LIVED.

INITIALLY...ROTATING STORMS OR FAST-MOVING LINE SEGMENTS MAY REMAIN
ROOTED ABOVE THE BOUNDARY LAYER...OR CROSS INTO MORE STABLE AIR MASS
NORTH OF THE WARM FRONT. HOWEVER...WITH TIME...SUFFICIENT
SURFACE-BASED DESTABILIZATION APPEARS POSSIBLE ACROSS THE WARM
SECTOR TO SUPPORT SUPERCELLS...AND POSSIBLY LINE SEGMENTS...WITH
TORNADO AND WIND DAMAGE POTENTIAL. INCREASINGLY STRONG FLOW THROUGH
THE TROPOSPHERE WILL ALSO RESULT IN FAST STORM MOTION AND AN
ENHANCED THREAT OF DAMAGING WINDS. AT PRESENT...GREATEST RISK 
APPEARS TO BE FROM ERN TX ACROSS LA AND INTO WRN MS THROUGH MONDAY
NIGHT. RAPID TRANSLATION OF THE UPPER TROUGH ALSO NECESSITATES A
LARGE SLGT RISK AREA GIVEN FAST STORM MOTION. PARTS OF THE REGION
MAY REQUIRE HIGHER PROBABILITIES IN LATER OUTLOOKS AS DETAILS BECOME
MORE CERTAIN.

..CARBIN.. 10/15/2006