DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 220559
SWODY2
SPC AC 220558

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1258 AM CDT MON OCT 22 2012

VALID 231200Z - 241200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
LARGE SCALE PATTERN AMPLIFICATION WILL CONTINUE TO OCCUR ON
TUESDAY...HIGHLIGHTED BY AN INCREASINGLY PROMINENT WESTERN STATES
LONGWAVE TROUGH. A MIGRATORY SHORTWAVE TROUGH AND WARM ADVECTION
REGIME WILL CONTRIBUTE TO TSTM POTENTIAL ACROSS THE MIDDLE/UPPER MS
VALLEY AND GREAT LAKES REGION...BUT GRADUALLY RISING UPPER HEIGHTS
ARE OTHERWISE ANTICIPATED OVER THE MIDWEST/GREAT LAKES REGION.

...MIDDLE/UPPER MS VALLEY AND GREAT LAKES...
GIVEN THE LARGE SCALE SCENARIO AS PREVIOUSLY DESCRIBED...A SHORTWAVE
TROUGH IS EXPECTED TO WEAKEN AS IT SPREADS EAST-NORTHEASTWARD TOWARD
THE MIDDLE MS VALLEY/OH VALLEY ON TUESDAY. A WARM ADVECTION REGIME
WILL OTHERWISE ACCOUNT FOR SOME TSTMS ACROSS THE LOWER GREAT LAKES
REGION DURING THE PERIOD.

ACROSS PARTS OF IA/NORTHERN MO INTO ADJACENT SOUTHERN MN/SOUTHERN WI
AND NORTHERN IL...WITHIN A RELATIVELY MOIST/POTENTIALLY UNSTABLE
AIRMASS NEAR A WEAKENING SURFACE LOW AND/OR WARM FRONT...THE
POTENTIAL FOR DIURNAL SURFACE BASED CONVECTION CURRENTLY APPEARS
LOW. THIS IS ATTRIBUTABLE TO THE POTENTIAL FOR CAPPING /PERHAPS
UNDER REFLECTED BY 00Z NAM GUIDANCE/ AND LITTLE OR NO READILY
DISCERNIBLE BROAD SCALE ASCENT AND MODEST MASS CONVERGENCE. OF MORE
POTENTIAL WILL BE FOR ELEVATED CONVECTION TO INCREASE TUESDAY NIGHT
TO THE NORTH OF A NORTHWARD-SHIFTING WARM FRONT ACROSS THE UPPER
MIDWEST/UPPER MS VALLEY. SOME SEVERE HAIL CANNOT BE RULED OUT IN
THIS SCENARIO GIVEN THE PROXIMITY OF A RELATIVELY MOIST/POTENTIALLY
UNSTABLE AIRMASS. WHILE SCENARIO UNCERTAINTY AND SEEMINGLY LIMITED
POTENTIAL PRECLUDES SEVERE PROBABILITIES AT THIS TIME...PORTIONS OF
THE UPPER MS RIVER VALLEY WILL BE REEVALUATED IN SUBSEQUENT OUTLOOKS
FOR SOME SEVERE RISK.

...COASTAL ORE/NORTHERN CA...
COINCIDENT WITH RELATIVELY STEEP LAPSE RATES...ISOLATED/EMBEDDED
LOW-TOPPED TSTMS WILL BE POSSIBLE FOR COASTAL AREAS AND PERHAPS
PORTIONS OF INTERIOR NORTHERN CA ON TUESDAY. THIS WILL BE WITHIN THE
POST-FRONTAL ENVIRONMENT IN THE WAKE OF AN INITIAL FRONT...AND/OR
NEAR AN APPROACHING SECONDARY FRONT/TROUGH LATE IN THE PERIOD. WHILE
SOME SMALL HAIL MAY BE POSSIBLE...ORGANIZED/SUSTAINED SEVERE TSTMS
ARE UNLIKELY GIVEN MEAGER INSTABILITY AND THE LOW-TOPPED NATURE OF
THE CONVECTION.

..GUYER.. 10/22/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.