SWODY1
SPC AC 020059
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0759 PM CDT FRI AUG 01 2008
VALID 020100Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS GREAT LAKES TO MID MS
VALLEY AND OH VALLEY...
...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS ND...
...SYNOPSIS...
UPPER AIR PATTERN BECOMING MORE AMPLIFIED ACROSS CONUS WITH UPPER
TROUGHING OVER GREAT LAKES AND PACIFIC NW...HIGH OVER S-CENTRAL
PLAINS...AND RIDGING NEWD OVER MB. SHORTWAVE TROUGH AND
ACCOMPANYING STG VORTICITY LOBE -- NOW EVIDENT IN MOISTURE CHANNEL
IMAGERY OVER LS AND UPPER MI -- ARE FCST TO MOVE SEWD ACROSS LOWER
MI TO SRN ONT AND LE THROUGH END OF PERIOD. MEANWHILE...SFC LOW
ASSOCIATED WITH SEPARATE UPPER PERTURBATION WILL REMAIN ANCHORED
OVER WRN QUE...WITH COLD FRONT MOVING SEWD ACROSS SERN
ONT...LE...NRN OH...CENTRAL INDIANA AND SRN IL. MEANWHILE...WRN
SEGMENT OF FRONT -- INITIALLY ANALYZED ACROSS N-CENTRAL/NW
KS...SHOULD MOVE/RE-DEVELOP NWD ACROSS N-CENTRAL HIGH PLAINS
OVERNIGHT. SFC ANALYSIS ALSO INDICATES DRYLINE INVOF ERN MT BORDER
SWD ACROSS NEB PANHANDLE. SFC COLD FRONT FROM SWRN SASK SWWD ACROSS
CENTRAL/SWRN MT IS EXPECTED TO KEEP MOVING EWD OVER MOST OF MT
THROUGH REMAINDER PERIOD...LINKING WITH INITIALLY SEPARATE SFC LOW
OVER SERN MT BEFORE DAYBREAK.
...GREAT LAKES TO MID MS VALLEY AND OH VALLEY...
SEVERAL BANDS AND CLUSTERS OF STG-SVR TSTMS ARE EVIDENT FROM LOWER
MI SWD ACROSS INDIANA/OH AND SRN IL. REF WW 788 AND RELATED
MESOSCALE DISCUSSIONS FOR NEAR-TERM GUIDANCE OVER SRN PORTIONS
IL/INDIANA. BUOYANCY SHOULD DIMINISH WITH EWD EXTENT GIVEN 00Z
RAOBS AND RUC FCST SOUNDINGS...WHILE DEEP-LAYER BULK SHEAR GENERALLY
INCREASES...GREATEST OVERLAP BEING OVER CATEGORICAL SLGT RISK AREA.
ALTHOUGH NOCTURNAL MCS DEVELOPMENT REMAINS CONDITIONAL ON
STORM-SCALE PROCESSES LEADING TO UPSCALE COLD-POOL ACCUMULATION --
MOST PROBABLE AREA FOR THIS PROCESS TO OCCUR STILL APPEARS TO BE
OVER PORTIONS OH OR INDIANA...WHERE DEEP-LAYER ASCENT ABOVE SFC MAY
INCREASE LATER THIS EVENING AND TONIGHT AS MID/UPPER TROUGH APCHS.
SPORADIC/MRGL SVR HAIL REMAINS POSSIBLE ACROSS LOWER MI WHERE
STRONGEST LARGE SCALE FORCING FOR ASCENT IN IMMEDIATE PROXIMITY TO
TROUGH WILL HELP TO MAINTAIN SUPPORTIVE BUOYANCY...DESPITE DIABATIC
SFC COOLING.
...NRN HIGH PLAINS...
ISOLATED SVR TSTMS EVIDENT OVER WRN ND ATTM...IN ENVIRONMENT
CHARACTERIZED BY VERY STG SFC HEATING AND DEEP/WELL-MIXED SUBCLOUD
LAYERS SUPPORTING POTENTIAL FOR STG=SVR GUSTS AND HAIL GENERATED
ALOFT TO REACH SFC....AMIDST 40-50 KT DEEP-LAYER SHEAR SUPPORTING
POTENTIAL FOR ORGANIZED/ROTATING UPDRAFTS. CAPPING SHOULD CONTINUE
TO LIMIT COVERAGE OF REMAINING DIURNALLY DRIVEN ACTIVITY.
ALSO...BULK OF DEVELOPMENT IS EXPECTED TO REMAIN E OF SFC
DRYLINE...WHICH MAY RETREAT SLIGHTLY WWD THIS EVENING BEFORE BEING
OVERTAKEN BY SFC COLD FRONT OVERNIGHT. LOW LEVEL WAA AND NARROW
MOISTURE RETURN PLUME IS EXPECTED N OF SFC WARM FRONT AND NEARLY
PARALLEL WITH 850 MB WARM FRONT OVERNIGHT. THIS REGIME SHOULD
SUPPORT INCREASING POTENTIAL FOR TSTMS INVOF NOSE OF 25-35 KT
SLY/SSWLY LLJ ACROSS WRN ND...POSSIBLY EXTREME ERN MT. DAMAGING
GUSTS AND LARGE HAIL WILL BE POSSIBLE FROM MOST INTENSE ACTIVITY.
CUMULATIVE/SPATIALLY OVERLAPPING POTENTIAL FROM REMAINDER OF ONGOING
ACTIVITY PLUS THAT FROM OVERNIGHT CONVECTION TRIGGERS 15-PERCENT
PROBABILITY AND CATEGORICAL SLGT RISK FOR PARTS OF THIS AREA.
..EDWARDS.. 08/02/2008
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