[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 120605
SWODY1
SPC AC 120603

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1203 AM CST SUN MAR 12 2006

VALID 121200Z - 131200Z

...THERE IS A HIGH RISK OF SVR TSTMS FOR THIS AFTERNOON AND EVENING
ACROSS PARTS OF CENTRAL/NRN MO INTO SERN IA AND PARTS OF WRN/CENTRAL
IL...

...THERE IS A MDT RISK OF SVR TSTMS EXTENDING FROM AR NWD TO SRN IA
AND EWD INTO THE LOWER OH RIVER VALLEY...

...THERE IS A SLGT RISK OF SVR TSTMS EXTENDING FROM NERN TX TO THE
MID MS/OH RIVER VALLEYS AND SRN GREAT LAKES REGION...

...SIGNIFICANT OUTBREAK OF TORNADOES IS FORECAST THIS AFTERNOON AND
EVENING ACROSS PARTS OF THE LOWER MO AND MID MS RIVER VALLEYS...

STRONG MID/UPPER LEVEL TROUGH WITH 100+ KT MID LEVEL JET...
CURRENTLY MOVING EWD ACROSS THE LOWER CO RIVER VALLEY...WILL TRACK
NEWD OVER THE CENTRAL/SRN PLAINS TODAY REACHING THE WRN GREAT LAKES
REGION BY 12Z MONDAY.  60-120 METER HEIGHT FALLS EXPECTED WITH THIS
TROUGH AS IT TRACKS NEWD WILL AID IN THE DEVELOPMENT OF A STRONG
SSWLY LLJ /50+ KT/ FROM THE ARKLATEX REGION TO THE MID MS RIVER
VALLEY BY THIS AFTERNOON.  FURTHER STRENGTHENING /60-80 KT/ OF THIS
LLJ IS EXPECTED SECOND HALF OF FORECAST PERIOD AS IT VEERS TO SWLY
FROM THE MID MS RIVER VALLEY TOWARD THE UPPER OH RIVER VALLEY/ LOWER
GREAT LAKES REGION. 

IN THE LOW-LEVELS...A SURFACE FRONT IS EXPECTED TO INITIALLY EXTEND
FROM LOWER MI SWWD ACROSS THE MID MS RIVER VALLEY TO OK...AND THEN
WNWWD TO A SURFACE LOW OVER ERN CO.  THIS BOUNDARY WILL RETREAT NWD
AS A WARM FRONT TODAY IN RESPONSE TO STRONG SURFACE PRESSURE FALLS
TRANSLATING FROM THE CENTRAL PLAINS TOWARD THE GREAT LAKES REGION. 
SURFACE LOW IS PROGGED TO TRACK EWD ACROSS NRN KS REACHING FAR NRN
MO BY 00Z...WITH THE WARM FRONT EXTENDING EWD ACROSS NRN PARTS OF
IL/IN/OH.  INCREASING LOW-LEVEL CONVERGENCE IN THE VICINITY OF THE
SURFACE LOW AND SWD ALONG A PRE-FRONTAL TROUGH/DRY LINE ACROSS FAR
ERN PARTS OF KS/OK INTO NERN TX ARE EXPECTED TO BE THE FOCI FOR
THUNDERSTORM INITIATION THIS AFTERNOON.  BROAD ZONE OF RICH MOISTURE
RETURN...ALREADY UNDERWAY AT THIS TIME...WILL CONTINUE SPREADING NWD
TODAY FROM THE SERN PLAINS/LOWER MS RIVER VALLEY TO THE MID MS/OH
RIVER VALLEYS. SURFACE DEWPOINTS IN THE UPPER 60S SHOULD REACH AS
FAR NORTH AS SERN MO/PARTS OF SRN IL...WITH LOWER 60S DEWPOINTS
EXTENDING FROM THE MID MS RIVER VALLEY EWD TO WRN PA.

WHILE CONSIDERABLE CONVECTION...SOME POSSIBLY SEVERE...ASSOCIATED
WITH A LEAD SRN PLAINS SHORT WAVE IMPULSE SHOULD BE ONGOING AT 12Z
SUNDAY ACROSS LOWER OH RIVER VALLEY...MUCH OF THE EAST CENTRAL
PLAINS AND MID MS RIVER VALLEY ARE EXPECTED TO BE RELATIVELY FREE OF
CONVECTION/PRECIPITATION.  WITH INSOLATION...STEEP MID-LEVEL LAPSE
RATES ON NOSE OF RETURNING ELEVATED MIXED LAYER...AND SURFACE DEW
POINTS IN THE 60S...SHOULD CONTRIBUTE TO MIXED LAYER CAPE ON THE
ORDER OF 2000 J/KG IN SURFACE WARM SECTOR.  DEEP LAYER SHEAR WILL BE
MORE THAN SUFFICIENT FOR SUPERCELLS...WITH INITIAL ACTIVITY LIKELY
BEING DISCRETE FROM THE SURFACE LOW SWD ALONG THE DRY LINE.  STRONG
LLJ WILL CONTRIBUTE TO LARGE HODOGRAPHS SUPPORTING TORNADOES...SOME
STRONG TO SIGNIFICANT ACROSS CENTRAL/ NRN MO INTO SERN IA AND
WRN/CENTRAL IL.  IN ADDITION...GIVEN STEEP LAPSE RATES AND MODERATE
INSTABILITY...LARGE HAIL WILL BE LIKELY ALONG WITH DAMAGING WINDS.

INITIAL ACTIVITY IS EXPECTED TO EVOLVE INTO A SQUALL LINE THIS
EVENING SPREADING EWD FROM THE MID MS RIVER VALLEY TO THE OH RIVER
VALLEY WITH DAMAGING WINDS BEING THE GREATER THREAT INTO THE
OVERNIGHT PERIOD INTO IND/WRN KY.

..PETERS/GRAMS.. 03/12/2006