DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 220551
SWODY1
SPC AC 220549

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1249 AM CDT MON OCT 22 2012

VALID 221200Z - 231200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
AS UPPER TROUGHING WEAKENS/RETREATS EWD AWAY FROM THE NERN
CONUS...LARGE-SCALE RIDGING IS FORECAST OVER MOST OF THE ERN HALF OF
THE COUNTRY. MEANWHILE...LARGE-SCALE TROUGHING IS FORECAST TO
EXPAND ACROSS THE WESTERN HALF OF THE COUNTRY...WITH A BROAD BELT OF
SWLY FLOW ALOFT ACROSS THE ROCKIES AND PLAINS STATES. WITHIN THIS
SWLY FLOW ALOFT...TWO SHORT-WAVE TROUGHS WILL SHIFT ACROSS THE
CENTRAL U.S. -- ONE CROSSING OK AND N TX AND SHIFTING INTO THE
OZARKS LATE...AND THE OTHER TO MOVE ACROSS THE UPPER MIDWEST AND
INTO THE UPPER GREAT LAKES WITH TIME.

AT THE SURFACE...A COLD FRONT IS FORECAST TO PROGRESS EWD ACROSS THE
WRN U.S. WITH TIME...AS THE LARGE UPPER TROUGH ADVANCES. FARTHER
E...A LOW INITIALLY OVER THE CENTRAL PLAINS IS FORECAST TO WEAKEN
WITH TIME...RESULTING IN A FAIRLY DIFFUSE PRESSURE FIELD DURING THE
AFTERNOON AND EVENING. MEANWHILE...HIGH PRESSURE SHOULD PREVAIL
FROM THE GULF OF MEXICO INTO THE SOUTHEAST AND MID-ATLANTIC REGION
THROUGH THE PERIOD.

...UPPER MIDWEST...
SHOWERS AND ELEVATED STORMS WILL BE ONGOING ACROSS PARTS OF THE AREA
EARLY IN THE PERIOD WITHIN A ZONE OF WARM ADVECTION/QG FORCING.
WHILE LIMITED HAIL THREAT WILL EXIST WITH THIS
CONVECTION...POTENTIAL SHOULD DECREASE THROUGH THE DAY AS STORMS
MOVE FARTHER N AWAY FROM THE MORE FAVORABLE INSTABILITY.

IN THE WAKE OF THIS CONVECTION -- AND THE PASSING SHORT-WAVE
TROUGH...CAPPING IS HINTED AT BY THE MODELS -- LIKELY ASSOCIATED
WITH SUBSIDENCE IN THE WAKE OF THE TROUGH. THIS -- AND QUESTIONS
REGARDING DESTABILIZATION POTENTIAL IN WHAT IS LIKELY TO BE A
SOMEWHAT CLOUDY/RAIN-COOLED AIRMASS CASTS UNCERTAINTY WITH RESPECT
TO SUBSEQUENT AFTERNOON AND EVENING CONVECTIVE POTENTIAL.
ATTM...WILL MAINTAIN ONLY 5% HAIL/WIND THREAT AS STORMS SHOULD
GENERALLY REMAIN SCATTERED AND GENERALLY DISORGANIZED.

...N TX/OK...
CLOUDS -- AND PERHAPS SOME ONGOING CONVECTION -- SHOULD SPREAD
ACROSS THE N TX/OK AREA EARLY IN THE PERIOD...AS A SHORT-WAVE TROUGH
SHIFTS ACROSS THE REGION. WITH THIS LIKELY TO HAMPER MORE
SUBSTANTIAL HEATING/DESTABILIZATION...QUESTIONS EXIST REGARDING THE
DEGREE OF AFTERNOON CONVECTIVE/SEVERE POTENTIAL WITHIN A SOMEWHAT
COOL/POTENTIALLY CAPPED BOUNDARY LAYER WHERE NEBULOUS LOW-LEVEL
FORCING WILL LIKELY BE PRESENT.

GIVEN THESE FACTORS...WILL OPT TO MAINTAIN ONLY LOW-PROBABILITY
SEVERE RISK IN THIS AREA. A FEW AFTERNOON STORMS MAY POSE MARGINAL
HAIL/WIND POTENTIAL...BUT SHOULD DIMINISH BY EVENING AS CONVECTION
CROSSES ERN OK AND MOVES TOWARD THE OZARKS IN CONJUNCTION WITH THE
UPPER SYSTEM.

..GOSS/GARNER.. 10/22/2012

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