[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 280549
SWODY1
SPC AC 280547

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1147 PM CST FRI JAN 27 2006

VALID 281200Z - 291200Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 60 SE
PSX SAT 50 ENE JCT CHK END CNU SGF 15 WNW ARG 10 ENE DYR 15 ESE HSV
30 NE CEW 60 SSE PNS.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 70 SSW MRF MAF PVW
GAG 30 E DDC EAR SLB 30 SW ALO CGX FWA LEX CSV ATL CSG 15 SSW PFN 50
SSW PFN.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 70 ENE BLI 25 W DLS
10 S MFR 50 WNW ACV.

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS A LARGE PORTION OF THE
SRN PLAINS AND LWR MS VALLEY....

IMPULSES EMANATING FROM STRONG NORTH CENTRAL/NORTHEAST PACIFIC POLAR
JET ARE PROGGED TO REMAIN PROGRESSIVE THROUGH THIS FORECAST PERIOD
AS THEY MOVE INTO/ACROSS THE WESTERN AND CENTRAL UNITED STATES. 
LEAD SHORT WAVE TROUGH IS ALREADY ADVANCING ACROSS THE SOUTH CENTRAL
ROCKIES...AND WILL COME INCREASINGLY IN PHASE WITH AN IMPULSE IN THE
SUBTROPICAL STREAM...AS IT ACCELERATES EASTWARD ACROSS THE SOUTHERN
PLAINS LATER TODAY...INTO THE LOWER OHIO/TENNESSEE VALLEYS BY 12Z
SUNDAY.  UPSTREAM SYSTEM WILL RAPIDLY PROGRESS ACROSS THE PACIFIC
NORTHWEST COAST...INTO AND THROUGH THE NORTHERN AND CENTRAL ROCKIES.

MODELS SUGGEST DEVELOPING UPPER FLOW PATTERN WILL SUPPORT INITIATION
OF LOW-LEVEL CYCLOGENESIS ACROSS THE SOUTH CENTRAL PLAINS EARLY
TODAY. MORE RAPID DEEPENING MAY NOT OCCUR UNTIL LATER TODAY AND
TONIGHT AS SURFACE LOW CENTER DEVELOPS NORTHEASTWARD THROUGH THE
OZARKS AND MIDDLE MISSISSIPPI VALLEY.  CONSIDERABLE VARIABILITY
EXISTS AMONG THE MODELS...HOWEVER...AND THIS...IN CONJUNCTION WITH
SOMEWHAT WEAK RETURN FLOW OFF THE WESTERN GULF OF MEXICO IS
CONTRIBUTING TO SUBSTANTIAL UNCERTAINTY WITH REGARD TO EXTENT OF
SEVERE THREAT. GIVEN STRENGTH OF MID/UPPER FORCING FOR UPWARD
VERTICAL MOTION...THE VIRTUAL CERTAINTY OF THE DEVELOPMENT OF STRONG
VERTICAL SHEAR PROFILES IN THE PRESENCE OF WEAK DESTABILIZATION
SUPPORTS AT LEAST A LOW SEVERE RISK ACROSS A BROAD AREA OF THE SOUTH
CENTRAL STATES.

...SOUTH CENTRAL STATES...
IT CURRENTLY APPEARS THAT A BROAD SWATH OF CONVECTION/ PRECIPITATION
COULD BE ONGOING FROM TEXAS THROUGH THE CENTRAL PLAINS AND MIDDLE
MISSISSIPPI VALLEY AT 28/12Z.  THIS WILL BE MOSTLY IN RESPONSE TO
FORCING WITH THE SUBTROPICAL STREAM...AND RELATIVELY WARM MID-LEVEL
ENVIRONMENT WITH WEAK LAPSE RATES WILL TEND TO LIMIT VIGOR OF
ACTIVITY AS IT SPREADS EASTWARD DURING THE DAY. 
HOWEVER...STRENGTHENING SOUTHERLY LOW-LEVEL JET IN A BROAD BELT
ACROSS THE EASTERN PLAINS/LOWER MISSISSIPPI VALLEY WILL CONTRIBUTE
TO INCREASINGLY FAVORABLE SHEAR PROFILES FOR SUPERCELLS. 
AND...BOUNDARY LAYER DESTABILIZATION COULD BECOME SUFFICIENT TO
SUPPORT TORNADO/WIND THREAT ACROSS PARTS OF THE CENTRAL GULF
COAST/LOWER MISSISSIPPI VALLEY BY LATE THIS AFTERNOON.

A BETTER SEVERE THREAT SEEMS LIKELY TO ACCOMPANY THE PROPAGATION OF
A STRONG POLAR JET STREAK AROUND THE BASE OF UPPER TROUGH ACROSS THE
SOUTHERN PLAINS.  MID-LEVEL COOLING/LIFT IN THE EXIT REGION OF THIS
FEATURE IS EXPECTED TO SUPPORT THE DEVELOPMENT OF THUNDERSTORMS
ACROSS CENTRAL/EASTERN OKLAHOMA AND NORTH CENTRAL/NORTHEAST TEXAS BY
LATE THIS AFTERNOON.  ALTHOUGH BOUNDARY LAYER DESTABILIZATION MAY BE
MINIMIZED BY CLOUD COVER/ PRECIPITATION...AT LEAST A NARROW CORRIDOR
OF STRONGER INSTABILITY SHOULD DEVELOP EAST OF LOW-LEVEL THERMAL
RIDGE AXIS WRAPPING INTO DEVELOPING CYCLONE CENTER.  MIXED LAYER
CAPE OF 500 TO 1000 J/KG WILL BE SUPPORTIVE OF SUPERCELLS WITH LARGE
HAIL...PERHAPS DAMAGING WIND GUSTS AND ISOLATED TORNADOES.  A SQUALL
LINE COULD BRIEFLY EVOLVE...BEFORE DEVELOPING EASTWARD TOWARD THE
LOWER MISSISSIPPI VALLEY AND WEAKENING EARLY THIS EVENING.

THEREAFTER...MUCH UNCERTAINTY EXISTS.  HOWEVER...IN RESPONSE TO
FORCING ACCOMPANYING MORE RAPID DEEPENING OF SURFACE LOW...
DESTABILIZATION COULD BECOME SUFFICIENT FOR NEW CONVECTIVE
DEVELOPMENT FARTHER TO THE EAST...THROUGH MUCH OF THE LOWER HALF OF
THE MISSISSIPPI AND LOWER OHIO VALLEY. THIS WILL SUPPORT AT LEAST
ISOLATED TORNADO/WIND DAMAGE RISK THROUGH THE EVENING AND MUCH OF
THE OVERNIGHT HOURS.

..KERR.. 01/28/2006

...NOTICE...
THE STATION RELATIVE POINTS IN THIS PRODUCT WILL BE
DISCONTINUED ON 14 FEBRUARY 2006 BUT WILL REMAIN AVAILABLE
IN THE FOLLOWING PRODUCTS:

   WMO HEADER:       AWIPS ID:
   WUUS01            PTSDY1
   WUUS02            PTSDY2
   WUUS03            PTSDY3

A SERVICE CHANGE NOTICE ...SCN05-39... PROVIDES DETAILS
ON THE TRANSITION. FOR ADDITIONAL DETAILS SEE THE FOLLOWING
WEB ADDRESS USING LOWER CASE LETTERS:
WWW.NWS.NOAA.GOV/OM/NOTIF.HTM