DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 280601
SWODY2
SPC AC 280600

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT MON OCT 28 2013

VALID 291200Z - 301200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE SOUTHERN HIGH
PLAINS...

...SYNOPSIS...
AN AMPLIFIED LARGE-SCALE PATTERN WILL REMAIN OVER THE CONUS INTO
TUESDAY...HIGHLIGHTED BY AN INCREASINGLY EASTWARD-PROGRESSIVE UPPER
TROUGH OVER THE ROCKIES AND SOUTHWEST STATES. THE INFLUENCES OF THIS
UPPER TROUGH...COINCIDENT WITH A VERY MOIST AIRMASS FOR THE SEASON
ACROSS THE SOUTH-CENTRAL CONUS...WILL LEAD TO TSTM POTENTIAL
/INCLUDING SOME SEVERE/ ACROSS THE CENTRAL/SOUTHERN PLAINS TO THE
LOWER/MIDDLE MO RIVER VALLEY AND MIDDLE MS VALLEY.

...SOUTHERN/CENTRAL PLAINS TO LOWER/MIDDLE MO VALLEY...
INFLUENCED BY LEE SIDE TROUGHING AND A SOUTHEAST STATES
ANTICYCLONE...PERSISTENT SOUTHERLY LOW-LEVEL TRAJECTORIES AND A VERY
MOIST SOURCE REGION WILL CONTINUE TO HELP ESTABLISH A RELATIVELY
HIGH MOISTURE CONTENT BOUNDARY LAYER ACROSS MUCH OF THE
SOUTHERN/CENTRAL PLAINS TUESDAY. THIS MOISTURE WILL LIKELY
CONTRIBUTE TO A MODERATELY UNSTABLE AIRMASS TO THE EAST OF A
SOUTHERN HIGH PLAINS SURFACE LOW AND LEE TROUGH/DRYLINE...AND TO THE
SOUTH/SOUTHEAST OF WHAT WILL LIKELY BE A CONVECTIVELY REINFORCED
FRONTAL BOUNDARY ACROSS PARTS OF KS AND THE ADJACENT LOWER MO
VALLEY/MIDDLE MS VALLEY.

HOWEVER...CONFIDENCE IN AFTERNOON SURFACE-BASED DEVELOPMENT
NEAR/EAST OF THE SOUTHERN HIGH PLAINS SURFACE LOW AND DRYLINE HAS
DIMINISHED OVER THE PAST 24 HR...MAINLY ATTRIBUTABLE TO CAPPING AND
MODEST MASS CONVERGENCE UNDER NEUTRAL BROAD-SCALE INFLUENCES.
THUS...SOME QUESTIONS EXIST REGARDING THE NECESSITY OF A SLIGHT RISK
ESPECIALLY GIVEN WHAT NOW APPEARS TO BE A NOCTURNAL PEAK CONVECTIVE
POTENTIAL. THAT SAID...SOME LATE AFTERNOON/EARLY EVENING
SURFACE-BASED TSTMS CANNOT BE ENTIRELY RULED OUT ACROSS PARTS OF
WEST TX/TX PANHANDLE...AND PERHAPS EVEN SOUTHERN/EASTERN
KS...ALTHOUGH THE IMPACTS OF EARLY DAY ELEVATED CONVECTION ACROSS KS
ARE UNCERTAIN.

A VERY MOIST/UNSTABLE AIRMASS WILL RESIDE TO THE EAST OF THE HIGH
PLAINS SURFACE LOW AND LEE TROUGH/DRY LINE...WITH STRONG VERTICAL
SHEAR /40-55 KT/ OVERSPREADING THE WARM SECTOR...WHICH WOULD SUPPORT
A CONDITIONAL/ISOLATED SEVERE RISK. OF MORE CERTAINTY IS THAT AT
LEAST WIDELY SCATTERED STORMS WILL INCREASE TUESDAY
NIGHT...ESPECIALLY OVERNIGHT/EARLY WEDNESDAY...WITHIN A GENERAL
CORRIDOR FROM WEST TX NORTHEASTWARD INTO FAR WESTERN OK AND PORTIONS
OF KS AS STRONGER FORCING FOR ASCENT BEGINS TO INFLUENCE THE REGION.
ISOLATED BOUTS OF SEVERE HAIL WILL BE POSSIBLE GIVEN AMPLE ELEVATED
INSTABILITY/CLOUD-BEARING SHEAR...BUT A FEW NEAR-SURFACE BASED TSTMS
CANNOT BE ENTIRELY DISCOUNTED ACROSS THE SOUTHERN HIGH PLAINS
TUESDAY NIGHT.

..GUYER.. 10/28/2013

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