DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 200601
SWODY2
SPC AC 200600

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0100 AM CDT SAT OCT 20 2012

VALID 211200Z - 221200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS SOUTHWEST TX...

...SYNOPSIS...
AS LARGE SCALE TROUGH AMPLIFICATION OCCURS OVER THE WESTERN STATES
ON SUNDAY...BROAD/RELATIVELY STRONG CYCLONIC UPPER FLOW WILL BE
PREVALENT FOR CONUS AREAS WEST OF THE MS RIVER VALLEY. SURFACE
CYCLOGENESIS IS ANTICIPATED ACROSS THE CENTRAL PLAINS...WITH
MOISTURE STEADILY RETURNING NORTHWARD ACROSS THE SOUTHERN PLAINS TO
THE LOWER/MIDDLE MO VALLEY DURING THE PERIOD.

...SOUTHERN NM AND WEST/SOUTHWEST TX...
AN UPPER LOW CURRENTLY OFF THE COAST OF BAJA IS EXPECTED TO CROSS
NORTHERN MEXICO AS IT SPREADS NORTHEASTWARD AND REACHES FAR SOUTHERN
NM AND SOUTHWEST TX SUNDAY NIGHT. THIS UPPER SYSTEM AND ASSOCIATED
FORCING FOR ASCENT WILL ACCOUNT FOR INCREASING TSTM POTENTIAL AS IT
ENCOUNTERS A RELATIVELY MOIST AIRMASS ACROSS SOUTHWEST
TX...ESPECIALLY LATE SUNDAY AFTERNOON INTO SUNDAY NIGHT. STEEPENING
LAPSE RATES ALOFT AND WEAK/MODERATE BUOYANCY...ALONG WITH
STRENGTHENING/VEERING WIND PROFILES...WILL ACCOUNT FOR SOME
SUSTAINED/ORGANIZED SEVERE TSTMS WITH LARGE HAIL AS THE PRIMARY
HAZARD.

...CENTRAL PLAINS/MO VALLEY/MIDDLE MS VALLEY...
MOISTURE IS EXPECTED TO STEADILY RETURN ACROSS THE REGION WITH AID
OF A SOUTHWESTERLY LOW LEVEL JET...ESPECIALLY SUNDAY NIGHT/EARLY
MONDAY. THIS WILL BE TO THE EAST OF A DEVELOPING SURFACE LOW ACROSS
KS AND AN ADJACENT SHARPENING SURFACE TROUGH/DRY LINE...AND TO THE
SOUTHEAST OF A FRONTAL BOUNDARY ACROSS THE UPPER MIDWEST/MIDDLE MO
VALLEY.

REGARDING DIURNAL CONVECTIVE POTENTIAL FOR AREAS SUCH AS THE CENTRAL
PLAINS/LOWER MO VALLEY...THE STRENGTH OF THE ELEVATED MIXED LAYER
ALOFT AND RELATIVELY NEBULOUS BROAD SCALE ASCENT SUGGESTS THAT THE
POTENTIAL FOR SURFACE BASED CONVECTIVE POTENTIAL SHOULD BE LIMITED
SUNDAY AFTERNOON. NEVERTHELESS...SOME POTENTIAL CANNOT BE COMPLETELY
RULED OUT NEAR THE CENTRAL PLAINS SURFACE LOW/TROUGH IN THE PRESENCE
OF LOW-LEVEL MIXING/MODEST MASS CONVERGENCE. SHOULD SURFACE BASED
DEVELOPMENT OCCUR WITHIN A RELATIVELY MOIST AIRMASS...SEVERE TSTMS
WOULD BE FAVORABLE GIVEN FAVORABLE BUOYANCY/SHEAR.

A MORE PROBABLE SCENARIO IS FOR ELEVATED TSTMS TO INCREASE SUNDAY
NIGHT ACROSS PORTIONS OF THE MO VALLEY/MIDWEST/MIDDLE MS VALLEY WITH
AID OF THE AFOREMENTIONED STRENGTHENING LOW LEVEL JET/ELEVATED
MOISTURE TRANSPORT REGIME. SUFFICIENT ELEVATED INSTABILITY/SHEAR
THROUGH THE CLOUD BEARING LAYER SUGGESTS THAT ISOLATED SEVERE HAIL
WILL BE POSSIBLE WITH THE STRONGEST TSTMS.

..GUYER.. 10/20/2012

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.