[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 231250
SWODY1
SPC AC 231248

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0748 AM CDT TUE MAY 23 2006

VALID 231300Z - 241200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
PLNS...

...SYNOPSIS...
NEG TILT TROUGH NOW EJECTING NE ACROSS THE CNTRL RCKYS SHOULD TURN
MORE ELY AND EVOLVE INTO A CLOSED LOW AS IT MOVES OFF THE HIGHER
TERRAIN LATER TODAY/TONIGHT.  THE LOW SHOULD REACH NE SD BY 12Z
WEDNESDAY AS DEEP LOW PERSISTS OFF THE BC CST. AT LWR LEVELS...
SURFACE LOW NOW OVER SE MT SHOULD CONTINUE NE INTO CANADA AND WEAKEN
AS A NEW CIRCULATION CENTER DEVELOPS CLOSER TO TRACK OF UPR LOW IN
NRN SD.  TRAILING COLD FRONT/LEE TROUGH ATTENDING THE LOW SHOULD
BECOME BETTER DEFINED ACROSS THE CNTRL PLNS DURING THE DAY TODAY AS
EFFECTS OF OVERNIGHT MCS DIMINISH.  WARM FRONT SHOULD ALSO BECOME
BETTER DEFINED...EXTENDING S/SE FROM THE LOW INTO LWR MO AND LWR TN
VLYS.

...CNTRL/NRN PLNS...
FOCUS FOR ANOTHER FAIRLY ACTIVE SEVERE WEATHER DAY WILL SHIFT E/NE
INTO THE CNTRL/NRN PLNS...WHERE ASCENT AND SHEAR WILL BE MAXIMIZED
AHEAD OF CNTRL RCKYS/HI PLNS TROUGH.  SURFACE HEATING AND MID LEVEL
COLD ADVECTION WILL FOSTER SUBSTANTIAL DESTABILIZATION AHEAD OF
MERGING PACIFIC COLD FRONT/LEE TROUGH FROM SD SWD INTO KS.  SBCAPE
SHOULD RANGE FROM 1000 TO 2000 J/KG FROM SD SWD INTO NRN/ERN KS
...WITH GREATER MOISTURE AVAILABILITY/STRONGER HEATING COMPENSATING
FOR WARMER MID LEVEL TEMPS/WEAKER FORCING WITH SWD EXTENT.  AMPLE
SHEAR WILL BE PRESENT FOR SUSTAINED STORMS/SUPERCELLS.

FORCING/INSTABILITY CONSIDERATIONS SUGGEST THAT TSTMS WILL FIRST
DEVELOP IN SD/NRN NEB...CLOSER TO DEVELOPING SURFACE WAVE.  ACTIVITY
SHOULD THEN BUILD SWD WITH TIME...LIKELY INTO KS BY EARLY EVENING. 
MODERATE TO STRONG /35-45 KT/ SWLY MID LEVEL JET...CHARACTER OF
FORCING AND LIKELIHOOD FOR DEEP MIXING SUGGEST THAT STORMS IN NEB
SHOULD TEND TO BE OUTFLOW-DOMINANT...WITH FAIRLY RAPID EVOLUTION
INTO FORWARD-PROPAGATING LINES/BANDS WITH HIGH WIND.  CELLS ON THE
SRN FRINGE OF THIS ACTIVITY COULD ALSO POSE A THREAT FOR LARGE HAIL
AND POSSIBLY A TORNADO OR TWO INTO NRN KS.  THE STORMS SHOULD EVOLVE
INTO AN MCS THAT EVENTUALLY TURNS MORE ESE TOWARD MO/WRN AND SRN IA
TONIGHT.

IN SD AND NRN ND...CLOUDS AND PROXIMITY OF DEVELOPING SURFACE LOW
SHOULD KEEP BOUNDARY LAYER MIXING MORE LIMITED.  WHILE DEEP SHEAR
WILL BE WEAKER RELATIVE TO POINTS FARTHER S...BACKED NEAR-SURFACE
FLOW WILL CONTRIBUTE TO ENHANCED LOW LEVEL SHEAR.  STORMS IN THIS
CORRIDOR MAY THEREFORE POSE A THREAT FOR TORNADOES IN ADDITION TO
HAIL AND LOCALLY DAMAGING WIND.

FARTHER N/NW...LOW LEVEL CONVERGENCE INVOF DEFORMATION ZONE NW OF
EJECTING TROUGH...COUPLED WITH DAYTIME HEATING...MAY YIELD A FEW
SMALL CLUSTERS OF STORMS WITH MARGINALLY SEVERE HAIL/WIND IN ERN
MT/WRN ND.  IN ADDITION...WIDELY SCATTERED ELEVATED STORMS... A FEW
POSSIBLY WITH HAIL...MAY PERSIST/DEVELOP IN WARM ADVECTION ZONE OVER
ERN ND/NRN MN.

...PAC NW INTO NRN ID...
LARGE SCALE ASCENT WILL INCREASE OVER PARTS OF WA/ORE AND ID LATER
TODAY AS SHORTWAVE IMPULSE NOW APPROACHING THE NRN CA CST SWEEPS
NEWD.  WHILE INSTABILITY WILL REMAIN LIMITED AND LOW LEVEL
CONVERGENCE WEAK...DIFFERENTIAL HEATING AND LARGE SCALE FORCING MAY
PROVE SUFFICIENT FOR SCATTERED LATE DAY/EVENING STORMS.  SHEAR
PROFILES AND COOL AIR ALOFT COULD YIELD A FEW SEVERE CELLS...
ESPECIALLY ALONG/E OF THE WA/ORE CASCADES.

..CORFIDI/MEAD/GRAMS.. 05/23/2006