DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 011723
SWODY2
SPC AC 011721

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1221 PM CDT MON OCT 01 2012

VALID 021200Z - 031200Z

...THERE IS A SLGT RISK OF SVR TSTMS FOR THE CNTRL OH VALLEY ON TUE
AFTERNOON/EARLY EVENING...

...SYNOPSIS...
LARGE-SCALE MID-LEVEL TROUGH WILL REMAIN ANCHORED ACROSS THE MID-MS
VALLEY TO THE WRN GULF COAST AS A SHORT WAVE IMPULSE OVER THE NRN
PLAINS DIVES SWD AND ROTATES THROUGH THE BASAL PORTION OF THE
TROUGH. THIS WILL AID IN STRENGTHENING MID/UPPER-LEVEL S/SWLYS
DOWNSTREAM...CENTERED FROM THE CNTRL GULF COAST TO THE OH VALLEY TUE
AFTERNOON. AT THE SURFACE...A CYCLONE WILL WEAKEN AS IT MOVES NWD
FROM THE TN VALLEY INTO THE MIDWEST...OCCLUDING LATE IN THE PERIOD.

...OH VALLEY...
IT APPEARS PROBABLE THAT A FOCUSED CORRIDOR OF ROBUST HEATING SHOULD
OCCUR WITHIN A MID-LEVEL DRY SLOT TO THE NE OF THE WEAKENING SURFACE
CYCLONE. ALTHOUGH THE NAM IS STILL ON THE AGGRESSIVE SPECTRUM OF
GUIDANCE WITH THE DEGREE OF DESTABILIZATION BY TUE AFTERNOON...IT IS
SUPPORTED BY SEVERAL SREF MEMBERS WITH THE DEPICTION OF MLCAPE NEAR
1000 J/KG. DEEP SHEAR WILL BE SUBSTANTIAL AND LIKELY YIELD ELONGATED
HODOGRAPHS. LARGE-SCALE ASCENT SHOULD BE MODEST...BUT SUFFICIENT FOR
ISOLATED TO WIDELY SCATTERED DISCRETE TSTMS WITH POTENTIAL SUPERCELL
STRUCTURES DURING THE MID-AFTERNOON TO EARLY EVENING.

LIMITING FACTORS TO A MORE SUBSTANTIAL SEVERE THREAT WILL BE THE
MODEST LOW-LEVEL FLOW WHICH SHOULD TEMPER TORNADO POTENTIAL. IN
ADDITION...HIGH-LEVEL LAPSE RATES WILL REMAIN WEAK...LIMITING LARGE
HAIL GROWTH. AS SUCH...LOW-END SLIGHT RISK PROBABILITIES REMAIN
WARRANTED WITH MINIMAL CHANGES MADE FROM PREVIOUS OUTLOOK.

...LEE OF THE CNTRL APPALACHIANS TO THE S ATLANTIC COAST..
ALTHOUGH LARGE-SCALE FOCUS IS NOT QUITE AS APPARENT AS FARTHER
NW...ISOLATED TO WIDELY SCATTERED TSTMS SHOULD FORM ALONG/AHEAD OF
THE COLD FRONT ADVANCING ACROSS THE SOUTHEAST TUE AFTERNOON. WITH
STRONGER FLOW LARGELY LAGGING THE FRONT...DEEP SHEAR WILL BE
PROGRESSIVELY WEAKER WITH ERN EXTENT. A RELATIVELY NARROW OVERLAP OF
MODERATE DEEP SHEAR AND BUOYANCY MAY OCCUR TO SUPPORT WEAK SUPERCELL
STRUCTURES. HOWEVER...WEAK MID-LEVEL LAPSE RATES AND LOW-LEVEL FLOW
MAY RESULT IN ONLY A MARGINAL SEVERE THREAT.

..GRAMS.. 10/01/2012

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