[SWODY1] SWODY1

[Severe Weather Outlook Day 1]

ACUS01 KWNS 210109
SWODY1
SPC AC 210107

DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
0807 PM CDT SAT MAY 20 2006

VALID 210100Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS SE KS TO SC COAST...

...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS ERN MT...NERN
WY...EXTREME WRN SD...

...SYNOPSIS...
LARGE SCALE PATTERN CONTINUES TO FEATURE ERN CONUS MEAN TROUGH AND
RIDGE FROM N-CENTRAL MEX ACROSS CENTRAL ROCKIES TO CANADIAN NW
TERRITORIES.  EMBEDDED IN PREVAILING NW FLOW...WEAK SHORTWAVE TROUGH
IS EVIDENT IN MOISTURE CHANNEL IMAGERY AND VWP/PROFILER DATA OVER
PORTIONS IL/MO.  THIS FEATURE IS FCST TO TURN ESEWD THEN EWD ACROSS
SRN APPALACHIANS AS IT MOVES THROUGH MEAN TROUGH POSITION...REACHING
INVOF TIDEWATER REGION OF ATLANTIC COAST BY END OF PERIOD.

AT SFC...QUASISTATIONARY BAROCLINIC ZONE -- MODULATED/SHIFTED ON
MESOBETA SCALE BY CONVECTIVE OUTFLOWS TO ITS S -- IS ANALYZED FROM
ERN VA WSWWD ACROSS TN...AR/MO BORDER REGION AND KS/OK BORDER
REGION...BECOMING DIFFUSE WWD INTO S-CENTRAL ROCKIES.
SECONDARY/REINFORCING FRONTAL SURGE -- ASSOCIATED WITH GREAT LAKES
MID/UPPER TROUGH -- IS ANALYZED FROM LH WSWWD ACROSS NRN/WRN LOWER
MI...NRN IA...WRN SD...E-CENTRAL MT.  THIS FRONT SHOULD CONTINUE TO
MOVE SEWD THROUGH REMAINDER LM/LH AND ADJOINING PARTS MI/WI...SWD
ACROSS N-CENTRAL PLAINS AND SLOWLY WWD OVER NRN HIGH PLAINS.

...OZARK REGION TO CAROLINAS COAST...
REF SPC WWS 368...370...371 AND RELATED MESOSCALE DISCUSSIONS FOR
NOWCAST SCENARIO ACROSS THIS REGION.  LARGE SCALE ASCENT AHEAD OF
MIDLEVEL PERTURBATION...30-40 KT LLJ AND NARROW PLUME OF AT LEAST
MRGL 925-850 MB LAYER MOISTURE WILL SUPPORT CLUSTERS OF TSTMS
THROUGH MUCH OF THIS SWATH...WITH EPISODIC POTENTIAL FOR SVR HAIL
AND DAMAGING GUSTS.  LATE THIS EVENING INTO OVERNIGHT
HOURS...CORRIDOR OF MOST FAVORABLE SEVERE POTENTIAL WILL BE NARROWED
FROM N-S AND RENDERED MORE ELEVATED/MRGL.  THIS WILL OCCUR AS
1. COLLECTIVE CONVECTIVE OUTFLOWS EFFECTIVELY SHUNT FRONTAL ZONE
SWD...AND AS
2. POCKETS OF RELATIVELY DRY AND WELL MIXED BOUNDARY LAYER AIR --
NOW ANALYZED IN SFC CHARTS FROM CENTRAL MS TO CENTRAL GA -- ADVECT
ENEWD WHILE DIABATICALLY COOLING AND DESTABILIZING.

...NRN HIGH PLAINS...
AREA OF OPTIMAL SEVERE POTENTIAL IS SHRINKING AS PRIMARY CENTRAL MT
MCS MOVES INTO SUBSTANTIALLY MORE STABLE AIR MASS ALONG AND E OF SFC
FRONT...REPRESENTED BY 00Z GGW RAOB.  REF WW 367 AND LATEST
ACCOMPANYING MESOSCALE DISCUSSION FOR MORE DETAILS.  OVERALL SEVERE
POTENTIAL SHOULD DIMINISH AFTER DARK AS BOUNDARY LAYER COOLS BETWEEN
FRONT AND CONVECTIVE FORCING BOUNDARIES.  WAA AND WEAK MOIST
ADVECTION -- ASSOCIATED WITH SELY-SSELY LLJ OF 30-40 KT -- MAY HELP
TO SUSTAIN SOME OF THIS CONVECTION AFTER 6Z...WITH HAIL/GUSTS TO
NEAR SVR LEVELS POSSIBLE.

..EDWARDS.. 05/21/2006