[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 231622
SWODY1
SPC AC 231620

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1120 AM CDT TUE MAY 23 2006

VALID 231630Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER MUCH OF THE NRN AND
CENTRAL PLAINS...

...NRN/CENTRAL PLAINS...
COMPACT MID/UPPER LEVEL SYSTEM WITH ASSOCIATED 45+ KT SSWLY MID
LEVEL JET WILL SPREAD EWD ACROSS THE CENTRAL AND NRN PLAINS TODAY. 
SYSTEM WILL OVERSPREAD A MODEST LATE-MAY BOUNDARY LAYER WITH CURRENT
SURFACE DEW POINTS IN THE LOWER-MID 60S AS FAR NORTH AS SERN SD THIS
MORNING.  STRONG HEATING WILL BE COMMON TODAY AHEAD OF ADVANCING
SURFACE COLD FRONT/TROUGH MOVING W-E ACROSS THE PLAINS AND SUPPORT
TEMPERATURES APPROACHING 90F INTO NEB/SD.  HEATING AND MID LEVEL DRY
INTRUSION WILL SUPPORT STRONG MIXING/DRYING ALONG WRN EDGE OF LOW
LEVEL MOIST AXIS...THOUGH MORNING UA ANALYSES/SOUNDINGS INDICATE
BOUNDARY LAYER MOISTURE REMAINS SUFFICIENTLY DEEP FOR 60-65F SURFACE
DEW POINTS TO SURVIVE DEEP MIXING ACROSS ERN KS INTO SERN SD.  THIS
WILL SUPPORT A MODERATE TO STRONGLY UNSTABLE AIR MASS BY THE LATE
AFTERNOON...WITH RAPID SEVERE THUNDERSTORM DEVELOPMENT LIKELY AROUND
20-21Z ALONG SURFACE TROUGH FROM CENTRAL SD INTO NEB/FAR NRN KS. 
SHEAR WILL BECOME INCREASINGLY FAVORABLE FOR SUPERCELLS...AND
POSSIBLY A FEW TORNADOES...AS REGION IS PLACED UNDER 35-40 KT SLY
LLJ.  LARGE SURFACE T/TD SPREADS SHOULD RESULT IN RELATIVELY HIGH
CLOUD BASES/LCLS AND MAY INHIBIT PERSISTENT TORNADO THREAT WITH
DEVELOPING SUPERCELLS. LARGE HAIL AND DAMAGING WINDS WILL BE
PREVAILING SEVERE THREAT AS STORMS CONSOLIDATE INTO ONE OR MORE
SQUALL LINES/CLUSTERS AND SHIFT ENEWD THROUGH THE EVENING.  MORE
ORGANIZED CLUSTERS/MCSS WILL LIKELY TURN MORE ESEWD AFTER DARK AND
SPREAD ISOLATED SEVERE THREAT INTO MORE OF WRN IA/MO AND SRN/ERN KS.
 

STRONG ASCENT/CONVERGENCE WILL ALSO SUPPORT THUNDERSTORM DEVELOPMENT
NEAR LOW CENTER/OCCLUDED FRONT OVER WRN HALF OF ND INTO FAR NERN MT
PRIOR TO 21Z.  MLCAPE AND DEEP LAYER SHEAR WILL BE WEAKER IN CLOSER
PROXIMITY TO MID LEVEL LOW AND ALONG NWRN PORTION OF LOW LEVEL
MOISTURE AXIS. HOWEVER...MLCAPE AROUND 1000 J/KG AND STRONG ASCENT
WILL LIKELY SUPPORT A SEPARATE CLUSTER OF SEVERE THUNDERSTORMS INTO
WRN ND/FAR NERN MT THROUGH THE EARLY EVENING.

...PAC NW EAST OF THE CASCADES...
WELL DEFINED SHORTWAVE TROUGH WILL REMAIN NEGATIVELY TILTED AS IT
MOVES NNEWD ACROSS ORE AND WA TODAY.  CLOUDS AHEAD OF THIS FEATURE
MAY LIMIT HEATING/OVERALL INSTABILITY ACROSS CENTRAL/ERN ORE/WA. 
HOWEVER...SUFFICIENT HEATING WILL OCCUR FOR MODEST INSTABILITY AND A
GENERAL INCREASE IN DEEP MOIST CONVECTION SPREADING NWD THROUGH THE
AFTERNOON AHEAD OF APPROACHING SYSTEM. OVERALL SETUP APPEARS
MARGINAL FOR SUSTAINED SEVERE THREAT...THOUGH AN ISOLATED SEVERE
THUNDERSTORM OR TWO IS STILL POSSIBLE.

..EVANS/CROSBIE.. 05/23/2006