DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 241730
SWODY2
SPC AC 241728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT WED OCT 24 2012

VALID 251200Z - 261200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
A BROAD LONGWAVE TROUGH WILL CONTINUE TO ENCOMPASS THE WRN/CENTRAL
PORTION OF THE LOWER 48 STATES. A LEAD MID MO VALLEY SHORTWAVE
TROUGH WILL TRACK THROUGH THE UPPER MS VALLEY THU...AND THEN INTO
ONTARIO TO HUDSON BAY THU NIGHT...WHILE AN UPSTREAM TROUGH AMPLIFIES
ESEWD REACHING THE CENTRAL HIGH PLAINS BY 12Z FRI.

AT THE SURFACE...AN AREA OF LOW PRESSURE SHOULD BE LOCATED OVER
NWRN-NRN WI AT 12Z THU...WITH THIS FEATURE DEEPENING AS IT TRACKS
NNEWD THROUGH NRN ONTARIO THU EVENING. THE TRAILING COLD FRONT WILL
ADVANCE E THROUGH THE GREAT LAKES AND SEWD THROUGH THE MID MS VALLEY
AND SRN PLAINS. BY 26/12Z...THIS BOUNDARY SHOULD EXTEND FROM LAKE
HURON SSWWD THROUGH WRN OH...NRN MS TO THE TX COASTAL PLAIN AND DEEP
S TX.

...WRN GREAT LAKES/MIDWEST/MID MS VALLEY...
TIMING DIFFERENCES REMAIN BETWEEN THE 12Z GFS/NAM WITH THE EWD
ADVANCEMENT OF THE COLD FRONT THU ACROSS THE WRN GREAT LAKES AND
INTO THE MID MS VALLEY...WITH THE GFS SLOWER. GIVEN THIS FACTOR...
THE STRONGEST FORCING FOR ASCENT ATTENDANT TO THE PROGRESSIVE MID MO
VALLEY TROUGH MAY CONTINUE TO BE JUXTAPOSED WITH THE NRN EXTENT OF
THE COLD FRONT THROUGH 26/00Z...BEFORE IT SPREADS NEWD AND/OR THEN
REMAINS IN THE POST-FRONTAL ENVIRONMENT.

NEAR THE EASTWARD-ADVANCING COLD FRONT AND NORTHEAST-MOVING SURFACE
LOW...SCATTERED SHOWERS/TSTMS ARE LIKELY TO BE ONGOING THU MORNING
ACROSS THE UPPER MS VALLEY/UPPER GREAT LAKES VICINITY. WHILE THE
MAIN BRUNT OF THE UPPER TROUGH/ASSOCIATED FORCING FOR ASCENT MAY
CONTINUE TO AFFECT UPPER MI...WI AND ERN IA/NRN IL INTO THU
AFTERNOON...THE POTENTIAL FOR A MORE ROBUST SEVERE WEATHER THREAT IS
EXPECTED TO BE LIMITED DUE TO UNCERTAINTY IN THE DEGREE OF
DESTABILIZATION. INDICATIONS REMAIN THAT THE SPATIALLY NARROW
/ESPECIALLY WITH NORTHWARD EXTENT/ PRE-FRONTAL MOIST SECTOR WILL
HAVE WEAK INSTABILITY WITH MLCAPE GENERALLY AOB 800 J/KG. THIS
MEAGER INSTABILITY WILL BE PRIMARILY DUE TO LIMITED SURFACE HEATING.

HOWEVER...EVEN WITH THE POTENTIAL FOR WEAK DESTABILIZATION DURING
THE DAY...IT IS POSSIBLE THAT SCATTERED/FAST-MOVING LOW-TOPPED
CONVECTION COULD DIURNALLY INTENSIFY THU AFTERNOON ALONG/AHEAD OF
THE COLD FRONT. THIS WOULD LEAD TO THE DEVELOPMENT/PERSISTENCE OF
SOME STRONG LINE SEGMENTS ACROSS THE WESTERN GREAT LAKES REGION. THE
PRESENCE OF A STRONG WIND FIELD WITH 60-100 KT SWLY MIDLEVEL WINDS
AND AT LEAST 50 KT SSWLY 850 MB FLOW FROM ERN IA/NRN IL INTO THE
UPPER GREAT LAKES WOULD SUPPORT AN ISOLATED DAMAGING WIND THREAT AS
THE PRIMARY CONCERN.

FARTHER SOUTH...WHILE INSTABILITY MAY BE SLIGHTLY GREATER...
CONVECTION SHOULD TEND TO BE MORE POST-FRONTAL INTO THE MIDDLE MS
VALLEY/OZARKS REGIONS.

...SE TO EAST CENTRAL FL PENINSULA...
GIVEN THE LATEST NHC GUIDANCE /AS OF 1100 AM EDT/ FOR TROPICAL
SYSTEM SANDY...THE FAVORABLE THERMODYNAMIC AND KINEMATIC ENVIRONMENT
THAT WOULD SUPPORT A TORNADO THREAT IS EXPECTED TO REMAIN OFFSHORE
OF THE SOUTHEAST-E CENTRAL FL PENINSULA THU NIGHT.

..PETERS.. 10/24/2012

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