[SWODY2] SWODY2

[Severe Weather Outlook - Day 2]

ACUS02 KWNS 221725
SWODY2
SPC AC 221724

DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1224 PM CDT FRI SEP 22 2006

VALID 231200Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES REGION
SWWD INTO E TX...

...SYNOPSIS...
LARGE/POSITIVELY-TILTED UPPER TROUGH IS FORECAST TO INITIALLY EXTEND
FROM THE PLAINS INTO THE ROCKIES/GREAT BASIN...WITH A COLD FRONT
MOVING EWD/SEWD ACROSS MO/CENTRAL OK/NRN AND WRN TX.  FAIRLY
SUBSTANTIAL DIFFERENCES EXIST BETWEEN THE NAM AND GFS HOWEVER...IN
PROGRESSION OF THE SYNOPTIC-SCALE ENVIRONMENT THROUGH THE PERIOD. 
THE GFS IS FASTER THAN THE NAM WITH REGARDS TO THE EWD MOVEMENT OF
THE UPPER TROUGH -- AND THEREFORE WITH THE ASSOCIATED COLD FRONTAL
PROGRESSION.  IN GENERAL HOWEVER...EXPECT THE UPPER TROUGH AND
ASSOCIATED SURFACE FRONT TO PROGRESS EWD WITH TIME...WHILE MOIST
WARM SECTOR AND STRONG FLOW ALOFT CONTINUE TO SUPPORT A FAIRLY
SIGNIFICANT SEVERE THREAT -- LIKELY CENTERED ON THE MID MS/OH VALLEY
REGION.

...GREAT LAKES/OH VALLEY REGION SWWD INTO E TX...
STRONG/SEVERE STORMS SHOULD BE ONGOING AT THE START OF THE
PERIOD...BOTH ALONG AND AHEAD OF COLD FRONT AS WELL AS ACROSS THE OH
VALLEY/MIDWEST REGION IN WARM ADVECTION REGIME.  THOUGH DEGREE OF
DAYTIME DESTABILIZATION IS DIFFICULT TO DETERMINE ATTM DUE TO
WIDESPREAD CLOUDS/PRECIPITATION...MOIST WARM SECTOR WILL LIKELY
SUPPORT A SUFFICIENT THERMODYNAMIC ENVIRONMENT FOR A DIURNAL
INCREASE IN STORM COVERAGE AND INTENSITY.  

GREATEST INSTABILITY IS EXPECTED TO DEVELOP FROM THE MID MS/LOWER OH
VALLEY SSWWD...WHILE STRONGER KINEMATIC ENVIRONMENT SHOULD REMAIN
FROM OK ENEWD INTO THE MIDWEST/OH VALLEY REGION.  THEREFORE --
DESPITE DIFFERENCES IN TIMING AMONGST THE MODELS...MOST FAVORABLE
COMBINATION OF SHEAR AND INSTABILITY SHOULD EXTEND FROM SERN OK
ENEWD ACROSS THE OH VALLEY REGION.  THEREFORE...WILL MAINTAIN
HIGHEST PROBABILITY SEVERE THREAT ACROSS THIS REGION.  GIVEN MOIST
BOUNDARY LAYER AND STRENGTH OF SHEAR...TORNADO POTENTIAL WILL LIKELY
EXIST ONCE AGAIN.  HOWEVER...WITH SOMEWHAT MORE UNIDIRECTIONAL SWLY
FLOW ALOFT...AND STRONGER LINEAR FORCING THIS PERIOD...DAMAGING
WINDS WITH A MORE LINEAR CONVECTIVE MODE MAY PREVAIL ON DAY 2.

ATTM...WILL NOT INTRODUCE MODERATE RISK -- PRIMARILY DUE TO MODEL
DIFFERENCES WHICH MAKE HIGHLIGHTING THE MOST CONCENTRATED AREA OF
SEVERE THREAT DIFFICULT ATTM.  HOWEVER...LARGE-SCALE ENVIRONMENTAL
FACTORS SUGGEST THAT AN UPGRADE TO MODERATE RISK MAY BE NECESSARY IN
LATER OUTLOOKS.

..GOSS.. 09/22/2006