[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 201243
SWODY1
SPC AC 201242

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0742 AM CDT SAT MAY 20 2006

VALID 201300Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM SE KS/THE OZARKS TO THE TN
VLY...N GA...SC...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF MT...

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF WI AND MI...

...SYNOPSIS...
AMPLIFIED PATTERN WILL PREVAIL AGAIN TODAY ACROSS THE CONUS.  THE
MAIN LARGE SCALE FEATURES WILL CONTINUE TO BE RIDGE ALONG THE
RCKYS... BROAD TROUGH OVER ONTARIO/QUEBEC...AND MORE ELONGATED
TROUGH OFF THE W CST.  SEVERAL SHORTWAVE IMPULSES LIKELY WILL
MODULATE TSTM DEVELOPMENT TODAY.  THE FIRST OF THESE...NOW OVER ERN
ORE...SHOULD CONTINUE NNE INTO SE AB BY THIS EVENING.  FARTHER
DOWNSTREAM IN SAME BAND OF FLOW...SATELLITE AND RUC ANALYSES DEPICT
A SERIES OF WEAKER DISTURBANCES SHEARING SEWD FROM THE DAKOTAS
THROUGH THE LWR MO VLY INTO TN AND THE CAROLINAS.  IN THE NRN
STREAM...A MUCH STRONGER IMPULSE NOW IN FAR WRN ONTARIO SHOULD REACH
LK SUPERIOR/UPR MI BY TONIGHT...AND LK HURON EARLY SUNDAY.

...SE KS/OZARKS INTO TN/N GA/SC...
WEAK FRONT NOW IN PLACE FROM SRN KS/SRN MO INTO MIDDLE TN AND SRN NC
SHOULD REMAIN MORE OR LESS STATIONARY OR SETTLE JUST SLIGHTLY S
TODAY. THE BOUNDARY LIKELY WILL SERVE AS A FOCUS FOR DIURNAL STORM
DEVELOPMENT...ESPECIALLY FROM N GA WNW INTO NRN AL AND MIDDLE/WRN
TN...WHERE HEATING SHOULD BE STRONGEST AND CINH RELATIVELY WEAK.
TRUE/DEEPLY MIXED BOUNDARY LAYER DEWPOINTS SHOULD REMAIN IN THE UPR
50S TO LOW 60S.  BUT GIVEN STRONG HEATING AND STEEP MID LEVEL LAPSE
RATES ON SWRN FRINGE OF GRT LKS TROUGH...AFTERNOON SBCAPE SHOULD
RANGE FROM 1500-2000 J/KG.  A BIT LATER IN THE DAY...STORMS MAY ALSO
FORM WWD ALONG FRONT INTO NRN AR/SRN MO.

30 KT WNWLY MID LEVEL FLOW AND WEAK IMPULSES ALOFT SHOULD SUPPORT
ORGANIZED STORMS/STORM CLUSTERS WITH HAIL AND HIGH WIND.  WHILE A
FEW ROTATING STORMS MAY OCCUR...FAIRLY LARGE TEMP-DEWPOINT SPREADS
AND FOCUSED LOW LEVEL FORCING SUGGEST PREFERRED EVOLUTION TOWARD
COLD-POOL DRIVEN CLUSTERS WITH BOWING SEGMENTS/HIGH WIND.

FARTHER W/SW...SUBSTANTIAL CAP EXPECTED TO PROHIBIT WARM SECTOR
DEVELOPMENT...EXCEPT PERHAPS FOR A BRIEF PERIOD LATE THIS
AFTERNOON/EARLY THIS EVENING INVOF LEE TROUGH OVER WRN OK AND THE TX
PANHANDLE.  LATER TONIGHT/EARLY SUNDAY...ADDITIONAL STORMS MAY FORM
IN WAA AREA ALONG AND N OF STALLED FRONT IN SE KS AND SRN/CNTRL MO. 
IT APPEARS THAT LLJ WILL STRENGTHEN AS A RESULT OF BOTH DIURNAL
INFLUENCES...AND THE CONTINUED SE MOTION OF WRN ONTARIO DISTURBANCE.
 SUFFICIENT SHEAR/INSTABILITY MAY BE PRESENT FOR ELEVATED STORMS
WITH HAIL AND POSSIBLY HIGH WIND.

...MT/NRN PLNS...
SCATTERED TSTMS SHOULD FORM OVER THE MOUNTAINS OF WRN MT TODAY
...WITH MOVEMENT/DEVELOPMENT EXPECTED TO SPREAD E/NE INTO THE NRN HI
PLAINS AS ORE UPR IMPULSE CONTINUES NNEWD.  SUSTAINED FORCING FOR
ASCENT AND MODERATE TEMP-DEWPOINT SPREADS SHOULD FAVOR EVOLUTION
INTO A LINE/CLUSTER MODE WITH DAMAGING WIND AND MARGINALLY SEVERE
HAIL.  BACKED/SLIGHTLY UPSLOPE FLOW ALONG LEE TROUGH OVER THE CNTRL
PART OF THE STATE SHOULD ENHANCE LOW LEVEL CONVERGENCE...AND FORWARD
PROPAGATION OF STORMS INTO ERN MT BY MID TO LATE EVENING.

LATER TONIGHT...WAA MAY INCREASE OVER THE WRN DAKOTAS ON BACK SIDE
OF SURFACE RIDGE BUILDING SWD IN WAKE OF ONTARIO DISTURBANCE. 
ENHANCED FRONTAL UPLIFT AND LARGE SCALE ASCENT IN ENTRANCE REGION OF
ASSOCIATED UPR LEVEL JET STREAK MAY SUSTAIN SOME OF THE STORMS INTO
EARLY SUNDAY OVER THE WRN DAKOTAS/NE WY.

...WI/MI...
LARGE SCALE FORCING FOR ASCENT WILL INCREASE SUBSTANTIALLY ACROSS
THE UPR GRT LKS REGION TODAY AS POTENT WRN ONTARIO TROUGH DROPS SE
TOWARD LK SUPERIOR.  BOUNDARY LAYER MOISTURE WILL BE LIMITED... WITH
AVERAGE SURFACE DEWPOINTS LIKELY REMAINING IN THE MID 40S ACROSS WI
AND MI.  BUT COINCIDENTAL ARRIVAL OF STRONG FRONTOGENETIC FORCING
WITH DAYTIME HEATING/STEEPENING LOW LEVEL LAPSE RATES...AND
STRENGTHENING OF MEAN WNWLY FLOW TO AOA 40 KTS...ALL SUGGEST
POTENTIAL FOR A STRONGLY FORCED LINE OF LOW-TOPPED/ LOW-REFLECTIVITY
STORMS WITH DAMAGING WIND.  THIS ACTIVITY MAY REACH AS FAR S AS THE
MKE/GRR/MBS AREAS BEFORE WEAKENING OVER SERN LWR MI LATER TONIGHT.

..CORFIDI/GRAMS.. 05/20/2006