[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 241616
SWODY1
SPC AC 241614

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT WED MAY 24 2006

VALID 241630Z - 251200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PORTIONS OF SWRN WI AND FAR
ERN IA...

...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN MS RIVER
VALLEY/WRN GREAT LAKES INTO THE OZARKS...

...SYNOPSIS...
COMPACT...VERTICALLY STACKED LOW OVER THE ERN DAKOTAS WILL SHIFT
SLOWLY EWD TOWARD THE NRN MS RIVER VALLEY TODAY...WITH TRAILING COLD
FRONT/SURFACE TROUGH ADVANCING STEADILY ESEWD INTO WRN WI/ERN IA/NRN
MO.  TAIL END OF THIS BOUNDARY WILL SLOW AND LIKELY STALL INTO
CENTRAL OK/SERN KS/WRN MO BY LATER TODAY.  STRONG HEATING AND DEEP
BOUNDARY LAYER MIXING WILL TEND TO ERODE CURRENT MID/UPPER 60F
SURFACE DEW POINT AXIS NOW EXTENDING FROM ERN OK INTO ERN IA. 
HOWEVER...INCREASING SSWLY BOUNDARY LAYER FLOW AHEAD OF THIS SYSTEM
WILL LIKELY MAINTAIN AT LEAST MID/UPPER 50F SURFACE DEW POINTS NWD
ACROSS THE LOWER MO AND INTO THE NRN MS RIVER VALLEYS.

...NRN MS RIVER VALLEY ACROSS ERN IA AND INTO NWRN IL/WI...
STRONGEST ASCENT ALONG NOSE OF 50+ KT MID/UPPER LEVEL JET AND JUST
AHEAD OF DEEP CONVERGENCE AXIS/FAST MOVING SHORTWAVE TROUGH NOW
EVIDENT ON WV IMAGERY MOVING INTO SWRN MN/ERN IA WILL OVERSPREAD THE
NRN MS RIVER VALLEY TODAY.  THIS IS EXPECTED TO FOCUS GREATEST
POTENTIAL/COVERAGE OF SEVERE THUNDERSTORMS ALONG NRN EXTENT OF
MODEST LOW LEVEL MOISTURE AXIS DURING THE MID TO LATE AFTERNOON. 
INITIATION MAY OCCUR INTO FAR ERN MN/W-CENTRAL WI BY THE MID
AFTERNOON WITH DEVELOPMENT INCREASING SSWWD INTO ERN IA/NWRN IL BY
THE EARLY EVENING.  MLCAPE AROUND 1000 J/KG IS ANTICIPATED INTO SWRN
WI WITH CINH WEAKENING/DIMINISHING PRIOR TO 21Z.  FORECAST SOUNDINGS
INDICATE 35-45 KT EFFECTIVE SHEAR WILL DEVELOP ACROSS THIS
REGION...WITH NEAR UNIDIRECTIONAL WIND PROFILES AND STRONG/DEEP
ASCENT LIKELY SUPPORTING QUICK EVOLUTION INTO ONE OR MORE LINES OF
STORMS.  EMBEDDED OR PRECEEDING SUPERCELLS MAY HAVE BRIEF TORNADO
POTENTIAL GIVEN MAGNITUDE OF LOW AND DEEP LAYER SHEAR. 
HOWEVER...SUPERCELLS WILL LIKELY BECOME OUTFLOW DOMINANT WITHIN
LARGE T-TD SURFACE SPREADS/STEEP LOW LEVEL LAPSE RATES AND MAY
ENHANCE BOW ECHO DEVELOPMENT WITHIN EWD MOVING LINEAR MCS.  E-SEWD
EXTENT OF SEVERE THREAT WILL BE LIMITED BY NARROW INSTABILITY AXIS
ACROSS WI AND LOSS OF HEATING THIS EVENING.

...MO ESEWD INTO LOWER OH RIVER VALLEY AND SWWD INTO SERN KS/OK...
WEAKER ASCENT SUGGESTS HEATING WILL DRIVE DEVELOPMENT SSWWD ALONG
AND AHEAD OF APPROACHING SURFACE TROUGH THIS AFTERNOON ACROSS MO AND
INTO PORTIONS OF SERN KS/NERN OK AND POSSIBLY INTO CENTRAL/SWRN OK. 
SHEAR DIMINISHES WITH SWWD EXTENT INTO THE SRN PLAINS AND RESULTANT
STORMS WILL DEVELOP WEAKER ORGANIZATION SOUTHWEST OF THE OZARK
PLATEAU.

CONVECTIVE EVOLUTION A BIT MORE DIFFUSE ACROSS THIS REGION AS ALL
THE MORNING MODELS INCREASE THUNDERSTORMS AHEAD OF SURFACE TROUGH
ACROSS MUCH OF MO BY THE EARLY AFTERNOON.  THOUGH SHEAR AND ASCENT
WILL BE WEAKER SOUTH OF IA...AIR MASS WILL BECOME MODERATE TO
STRONGLY UNSTABLE EARLY THIS AFTERNOON.  SHOULD THIS DEVELOPMENT
INCREASE AS CAP WEAKENS ACROSS THIS WARM SECTOR...30-40 KT OF
EFFECTIVE SHEAR WILL SUPPORT ORGANIZATION INTO MULTICELL
CLUSTERS/LINES WITH EMBEDDED SUPERCELLS.  LARGE HAIL AND DAMAGING
WINDS WILL ACCOMPANY THESE STORMS AS THEY INCREASE IN
COVERAGE/INTENSITY AND SPREAD SLOWLY ESEWD THROUGH THE EVENING.
AS CAP BREAKS SWWD INTO OK EARLY THIS EVENING...ISOLATED STORMS MAY
PRODUCE DAMAGING WINDS GIVEN VERY STRONG HEATING.  HOWEVER... SEVERE
THREAT WILL BECOME MORE PULSE IN NATURE/ISOLATED WITH SWWD EXTENT.

...ERN ND AND VICINITY...
RUC INDICATES SUFFICIENT HEATING LATER TODAY WITHIN RELATIVELY MOIST
LOW LEVEL AIR MASS INTO NWRN MN/ERN ND WHERE SURFACE DEW POINTS ARE
AROUND 60F.  GIVEN COLD AIR ALOFT UNDER -12C MID LEVEL COLD POCKET
AND EXPECTED 500-750 J/KG SBCAPE ACROSS THIS REGION... STORMS MAY
PRODUCE HAIL AND WILL INTRODUCE LOW SEVERE PROBABILITIES INTO THE
EARLY EVENING.

..EVANS/CROSBIE.. 05/24/2006