[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 240556
SWODY1
SPC AC 240554

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1254 AM CDT WED MAY 24 2006

VALID 241200Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM ERN IA/SRN WI/IL SWWD TO
CENTRAL OK...

...SYNOPSIS...
UPPER TROUGH TOPPING THE MEAN RIDGE DURING THE FIRST FEW HOURS OF
THE DAY 1 FORECAST PERIOD ACROSS THE ERN DAKOTAS IS EXPECTED TO THEN
TRACK SEWD OVER THE UPPER MS VALLEY/WRN GREAT LAKES REGION TODAY. 
PRIMARY SURFACE LOW IS PROGGED TO TRACK EWD FROM ND INTO NRN/CENTRAL
MN BY THIS AFTERNOON.  AT 12Z TODAY...AN OCCLUDED FRONT SHOULD
EXTEND SEWD INTO WRN IA...THEN SWWD AS A COLD FRONT THROUGH ERN KS
TO NWRN OK.  THESE BOUNDARIES WILL MOVE EWD EXTENDING FROM THE UPPER
MS VALLEY THROUGH ERN IA TO NRN MO AND THEN SWWD INTO CENTRAL OK BY
25/00Z.  MEANWHILE...A QUASISTATIONARY FRONT WILL PERSIST FROM THE
GULF COAST STATES NNWWD INTO THE MID MS VALLEY WHERE IT WILL
INTERSECT THE COLD FRONT.

...ERN IA/SRN WI/IL SWWD THROUGH MO TO CENTRAL OK...
THUNDERSTORMS SHOULD BE ONGOING AT THE START OF THE FORECAST PERIOD
ACROSS PARTS OF IA/NRN MO WITHIN WAA REGIME ALONG NOSE OF SWLY LLJ. 
THIS ACTIVITY SHOULD SPREAD EWD INTO SRN WI/IL AND TEND TO DIMINISH
IN INTENSITY AS THE LLJ WEAKENS.  HOWEVER...IF STORMS PERSIST INTO
THE LATE MORNING/AFTERNOON...IT IS POSSIBLE FOR THIS ACTIVITY TO
INGEST INCREASINGLY HIGHER THETA-E AIR FROM THE DESTABILIZING WARM
SECTOR AND INTENSIFY.  

SSWLY LOW LEVEL FLOW EXPECTED IN ADVANCE OF THE SURFACE FRONTS WILL
ADVECT SURFACE DEWPOINTS IN THE MID 60S...NOW RESIDING ACROSS SERN
PLAINS/OZARKS TO WRN IA...NEWD INTO IL/WI.  SURFACE HEATING MAY BE
LIMITED ACROSS PARTS OF IL/IND DUE TO ANY ONGOING THUNDERSTORMS/
ATTENDANT CLOUDINESS SPREADING ESE THROUGH THESE STATES INTO THE
AFTERNOON.  STRONGER SURFACE HEATING WILL BE MORE LIKELY IN THE WAKE
OF THIS MORNING ACTIVITY FROM ALONG/E OF THE COLD FRONT IN CENTRAL
OK/SERN KS THROUGH MO TO SWRN WI...WHERE SURFACE DEWPOINTS IN THE
MIDDLE 60S WILL RESULT IN MODERATE INSTABILITY /MLCAPE UP TO 2500
J/KG/.

BAND OF 40-55 KT WNWLY MID LEVEL FLOW ACCOMPANYING UPPER TROUGH WILL
SPREAD ESE ACROSS THE COLD FRONT AND WARM SECTOR THIS AFTERNOON
RESULTING IN 35-45 KT OF DEEP LAYER SHEAR.  THUNDERSTORMS SHOULD
DEVELOP ALONG THE ADVANCING FRONTS FROM WRN WI SSWWD THROUGH ERN IA
BY MID-LATE AFTERNOON...WITH POTENTIAL FOR DEVELOPMENT ALSO ALONG
ANY CONVECTIVE BOUNDARIES LEFT OVER BY MORNING CONVECTION IN IL/MO. 
MODERATE INSTABILITY COMBINED WITH INCREASING DEEP LAYER SHEAR
SUPPORTS POTENTIAL FOR SUPERCELLS WITH MODELS SUGGESTING POTENTIAL
FOR LINEAR STRUCTURE/SQUALL LINE DEVELOPMENT ALONG THE COLD
FRONT...ESPECIALLY OVER WI INTO IL.

AS ASCENT AHEAD OF THE UPPER TROUGH CONTINUES TO SPREAD SE...
THUNDERSTORMS SHOULD CONTINUE TO DEVELOP SWWD ALONG THE COLD FRONT
INTO NERN OK...AND EVENTUALLY CENTRAL OK AS THE SWLY LLJ
STRENGTHENS.  POTENTIAL EXISTS FOR STORMS TO CONTINUE THROUGH THE
NIGHT SPREADING EWD INTO THE OH VALLEY AND SWD THROUGH THE OZARKS
AND OK.  SEVERE THREAT INTO OH VALLEY SHOULD BE MITIGATED BY EWD
EXTENT OF AIR MASS DESTABILIZATION.

...ERN DAKOTAS/MUCH OF MN...
THUNDERSTORMS WILL BE POSSIBLE FARTHER N ALONG THE TRACK OF THE
SURFACE LOW AND ASSOCIATED WITH COLDER MID LEVEL TEMPERATURES WITH
THE UPPER TROUGH.  WEAK INSTABILITY/SHEAR SHOULD PRECLUDE
DEVELOPMENT OF SEVERE WEATHER WITH THIS ACTIVITY.

..PETERS/JEWELL.. 05/24/2006