DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 160635
SWODY2
SPC AC 160634

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1234 AM CST FRI NOV 16 2012

VALID 171200Z - 181200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
IN MID-UPPER LEVELS...SERIES OF SHORTWAVES IS FCST TO CROSS NERN PAC
AND WRN CONUS...WHILE MEAN TROUGHING IS MAINTAINED INVOF W COAST.
SHORTWAVE TROUGH -- NOW EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
SWRN AK AND WRN GULF OF AK -- IS FCST TO MOVE SEWD ACROSS NERN PAC
DAY-1 AND AMPLIFY. VORTICITY BANNERS ASSOCIATED WITH SRN/WRN
PORTION OF THIS PERTURBATION ARE PROGGED TO MOVE ASHORE PAC NW
OVERNIGHT DAY-2. MEANWHILE...SPLIT-FLOW PATTERN IS FCST TO DEVELOP
DAY-2 OVER ERN CONUS. POSITIVELY TILTED TROUGH IS MOVING SEWD
ACROSS UPPER GREAT LAKES...MID-MS RIVER VALLEY...MO AND OK
ATTM...WHILE WEAKER PERTURBATION IS MOVING ESEWD ACROSS MS...LA AND
ADJOINING NWRN GULF OFFSHORE TX. VORTICITY FIELD ASSOCIATED WITH
SRN PORTION OF GREAT LAKES/OK TROUGH IS EXPECTED TO SPLIT FROM NRN
PORTION DAY-1...WHILE LEADING/WEAKER PERTURBATION MOVES ESEWD ACROSS
NRN/ERN GULF. BY 18/00Z...THESE FEATURES WILL BE ROTATING AROUND
BROAD CYCLONE CENTERED OVER SC/GA REGION.

LOW-LEVEL COLD FRONTAL ZONE -- NOW DECELERATING OVER ATLC GULF
STREAM....S FL AND SERN GULF -- IS EXPECTED TO STALL AND WEAKEN
THROUGH DAY-2...WHILE BECOMING INCREASINGLY SHALLOW IN SLOPE AND
DIFFUSE IN DEFINITION.

...COASTAL NW...
ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE...MAINLY OFFSHORE
BUT WITH SOME POTENTIAL FOR CONVECTION TO MOVE ONSHORE AND SLIGHTLY
INLAND BEFORE SUPPORTIVE AIR MASS STABILIZES TOO MUCH IN LOW LEVELS.
LOW-MIDDLE LEVEL LAPSE RATES OVER COASTAL/OFFSHORE WATERS ARE FCST
TO STEEPEN CONSIDERABLY DURING MID-LATE PERIOD IN STEP WITH APCH OF
MID-UPPER TROUGH...AND AT LEAST MRGLLY DESTABILIZING INFLUENCE OF
RELATED LARGE-SCALE ASCENT. FCST SOUNDINGS SUGGEST SFC-BASED
EFFECTIVE INFLOW PARCELS WITH MLCAPE UP TO 250 J/KG POSSIBLE ATOP
MARINE BOUNDARY LAYER.

...S FL...
ISOLATED TO WIDELY SCATTERED TSTMS ARE POSSIBLE...PRIMARILY DURING
MIDDAY TO AFTERNOON HOURS INLAND AND ALONG IMMEDIATE COASTAL AREAS
SUBSEQUENTLY. RELATIVELY MAXIMIZED BUOYANCY WILL BE OVER STRAITS
AND GULF STREAM...WITH LOW-LEVEL THETAE ADVECTION ONSHORE E COAST
RESPONSIBLE FOR SOME DIURNAL ENHANCEMENT TO BUOYANCY. MAIN CONCERNS
FOR TSTM COVERAGE AND DURATION WILL BE WEAKNESS OF LOW-LEVEL
LIFT...AND LACK OF MORE ROBUST LAPSE RATES ALOFT.

..EDWARDS.. 11/16/2012

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