DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 052002
SWODY1
SPC AC 052000

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT FRI OCT 05 2012

VALID 052000Z - 061200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS AR...

...AR VICINITY...
NO CHANGES NEEDED TO THE PRIOR CONVECTIVE OUTLOOK...SEE DISCUSSION
BELOW. TSTMS ARE STILL EXPECTED TO INCREASE IN COVERAGE/INTENSITY
THROUGH LATE AFTERNOON ACROSS AR...ESPECIALLY NEAR THE COLD FRONT
AND NEAR/EAST OF A SURFACE FRONTAL WAVE NOTED ACROSS WEST-CENTRAL AR
AT MID AFTERNOON. SEVERE HAIL IS THE PRIMARY THREAT...BUT A SEVERE
WIND GUST CANNOT BE DISCOUNTED WITH ANY NEAR-SURFACE BASED
CONVECTION.

..GUYER.. 10/05/2012

.PREV DISCUSSION... /ISSUED 1129 AM CDT FRI OCT 05 2012/

...SYNOPSIS...
A BROAD ZONE OF STRONG CYCLONIC MID LEVEL FLOW RESIDES OVER MUCH OF
THE CONUS TO THE SOUTH OF A LARGE COLD CORE CYCLONE ACROSS S-CNTRL
CANADA. A NUMBER OF LOW AMPLITUDE SHORT WAVE TROUGHS WERE EMBEDDED
WITHIN THE DEEP-LAYER CYCLONIC FLOW FROM THE NW/GREAT BASIN ACROSS
THE ROCKIES AND INTO THE SRN HIGH PLAINS. MEANWHILE...AT THE SFC...A
LARGE ANTICYCLONE AND COOLER DRIER AIR WILL CONTINUE TO INFILTRATE
THE MID/LOWER MS VALLEY AND OH VALLEY THROUGH TODAY. THE COLD FRONT
MARKING THE LEADING EDGE OF THIS COOLER/DRIER AIR...IN CONCERT WITH
LIFT FROM THE LOW AMPLITUDE SHORT WAVE TROUGHS AND WEAK DIURNAL
DESTABILIZATION...SHOULD SUSTAIN SCATTERED TSTMS ALONG/NEAR THE
FRONT...FROM MO/AR INTO THE PARTS OF THE LOWER MS VALLEY...THROUGH
LATER TODAY. MORE WIDELY SCATTERED STORMS...ROOTED ABOVE THE
POST-FRONTAL STABLE BOUNDARY LAYER...ALSO APPEAR POSSIBLE WITH
NORTHEAST EXTENT ALONG THE LOW THROUGH MID LEVEL FRONTAL ZONE INTO
THE OH VALLEY.

...AR...
LATEST STORM SCALE MODELS...AS WELL AS NAM-WRF AND SREF
GUIDANCE...INDICATE THE POTENTIAL FOR SEVERAL STRONG TO SEVERE
STORMS THROUGH LATE AFTERNOON ALONG/NEAR THE COLD FRONT AND WEAK SFC
FRONTAL WAVE MOVING ACROSS AR. MORNING SOUNDINGS TO THE WEST AND
SOUTHWEST OF THE REGION INDICATE A PLUME OF STEEP MID LEVEL LAPSE
RATES THAT WILL LIKELY SPREAD EAST COINCIDENT WITH A SHORT WAVE
TROUGH COMING OUT OF CO AND STRONGER DIURNAL HEATING ACROSS THE WARM
SECTOR. FOCUSED ASCENT NEAR THE SFC WAVE AND FRONT...WHEN COUPLED
WITH A NARROW AXIS OF GREATER MLCAPE PERHAPS APPROACHING 1000
J/KG...AND STRENGTHENING MID LEVEL FLOW/EFFECTIVE SHEAR...SHOULD
CONTRIBUTE TO A COUPLE OF INTENSE AND PERSISTENT STORM UPDRAFTS
CAPABLE OF PRODUCING SOME HAIL AND GUSTY WINDS. ANY SEVERE STORM
POTENTIAL DOES APPEAR TO BE QUITE FOCUSED IN SPACE/TIME AND CONFINED
PRIMARILY FROM SRN/ERN AR TO THE MS RIVER THROUGH EARLY EVENING. THE
GENERAL CONSENSUS IN GUIDANCE WITH RESPECT TO
THERMODYNAMIC/KINEMATIC ENVIRONMENT AS WELL AS A MODEST UVV/QPF
SIGNAL ACROSS AR SUGGEST A SMALL INCREASE IN HAIL PROBABILITIES IS
WARRANTED WITH THIS UPDATE.

...FL...
VERY UNSTABLE CONDITIONS ARE AGAIN INDICATED ACROSS FL PENINSULA
THROUGH THE AFTERNOON WITH EXTENSIVE CU FIELD ALREADY GROWING ALONG
WWD MOVING EAST COAST SEA BREEZE. WITH LITTLE OR NO
INHIBITION...EXPECT TSTMS TO EXPAND AND SPREAD GENERALLY TOWARD THE
WEST COAST THROUGH THE LATE AFTERNOON. SOME WEAK DIRECTIONAL SHEAR
BUT LITTLE IN THE WAY OF SPEED SHEAR AND ONLY WEAK SUBTLE FORCING
ALOFT SHOULD LIMIT UPDRAFT ORGANIZATION/LIFETIME. NONETHELESS...A
COUPLE OF STRONGER STORMS AND/OR RANDOM STORM MERGERS MAY RESULT IN
AN ISOLATED WET DOWNBURST OR TWO.

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