DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 111734
SWODY2
SPC AC 111732

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1232 PM CDT TUE JUN 11 2013

VALID 121200Z - 131200Z

...THERE IS A MDT RISK OF SVR TSTMS FROM PARTS OF IL...IND INTO
OH...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A LARGE PART OF THE OH
VALLEY...SRN GREAT LAKES AND MID ATLANTIC...

...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NRN
ROCKIES REGION...

...SYNOPSIS...

SYNOPTIC BLOCKING PATTERN WILL PERSIST INTO WEDNESDAY WITH AN UPPER
RIDGE OVER THE CNTRL U.S. FLANKED BY MEAN TROUGHS OVER THE NWRN AND
NERN STATES. A FAIRLY VIGOROUS SHORTWAVE TROUGH APPROACHING SWRN WY
EARLY THIS AFTERNOON WILL CREST THE CNTRL U.S. UPPER RIDGE AND
SUBSEQUENTLY MOVE SEWD INTO THE UPPER MS VALLEY WEDNESDAY AFTERNOON
AND OH VALLEY WEDNESDAY EVENING. THIS FEATURE WILL INDUCE A WEAK SFC
CYCLONE OVER THE MID MS VALLEY THAT WILL DEVELOP INTO THE OH VALLEY
DURING THE EVENING. A WARM FRONT EXTENDING EWD FROM THE LOW SHOULD
LIFT NWD THROUGH THE THROUGH THE OH VALLEY AND MID ATLANTIC DURING
THE DAY...WHILE A COLD FRONT DROPS SWD THROUGH THE MID MS VALLEY AND
CNTRL PLAINS REGION.

...MID-UPPER MS VALLEY AND OH VALLEY REGION AND SRN GREAT LAKES...

POTENTIAL EXISTS FOR A WIDESPREAD SEVERE WEATHER EVENT /MAINLY IN
THE FORM OF DAMAGING WIND AND LARGE HAIL/ TO OCCUR OVER A PORTION OF
THE OH VALLEY BEGINNING WEDNESDAY AFTERNOON INTO THE EVENING. RICH
GULF MOISTURE WITH LOW 70S DEWPOINTS RESIDE OVER THE LOWER MS
VALLEY. BROAD ZONE OF SWLY LOW-LEVEL WINDS WILL ADVECT THIS MOISTURE
NEWD INTO THE OH VALLEY BENEATH EWD EXPANDING PLUME OF STEEP
MID-LEVEL LAPSE RATES. THESE PROCESSES AND DIABATIC WARMING WILL
CONTRIBUTE TO A FAIRLY LARGE RESERVOIR OF STRONG INSTABILITY
/2500-3000 J/KG MLCAPE/ OVER THE OH VALLEY GENERALLY ALONG AND SOUTH
OF THE NWD ADVANCING WARM FRONT.

STORMS WILL LIKELY BE ONGOING WITHIN ZONE OF ISENTROPIC ASCENT ALONG
E-W BAROCLINIC ZONE SUPPORTED BY A SWLY LLJ FROM THE UPPER MS VALLEY
INTO A PORTION OF THE OH VALLEY. INFLOW TO THESE STORMS WILL BECOME
INCREASINGLY UNSTABLE AS THE WARM SECTOR DESTABILIZES AND POTENTIAL
WILL EXIST FOR SOME OF THIS ACTIVITY TO INTENSIFY AS IT MOVES SEWD
DURING THE DAY FROM THE SRN GREAT LAKES INTO THE OH VALLEY. OTHER
STORMS MAY DEVELOP LATER IN THE DAY OVER THE UPPER MS VALLEY NEAR
SFC LOW/WARM FRONT AND SOME DISTANCE SWWD ALONG THE COLD FRONT
ASSOCIATED WITH SEWD ADVANCING SHORTWAVE TROUGH. VERTICAL WIND
PROFILES WITH EFFECTIVE SHEAR FROM 35-40 KT WILL SUPPORT ORGANIZED
STRUCTURES INCLUDING A FEW SUPERCELLS. HOWEVER...TENDENCY SHOULD BE
FOR ACTIVITY TO GROW UPSCALE INTO CLUSTERS AND LINE SEGMENTS WITH
POTENTIAL FOR SIGNIFICANT AND WIDESPREAD DAMAGING WIND AND LARGE
HAIL AS ACTIVITY DEVELOPS EWD AND SEWD.

...MID ATLANTIC REGION...

HAVE EXPANDED THE SLIGHT RISK EWD AS SWLY WINDS WILL LIKELY ADVECT
MID-UPPER 60S DEWPOINTS IN THIS REGION WITH DIABATIC HEATING
SUPPORTING MODERATE INSTABILITY. THIS AREA WILL EXIST ON SRN FRINGE
OF STRONGER MID LEVEL WINDS...AND STORMS MAY DEVELOP OVER THE HIGHER
TERRAIN AND SPREAD EWD INTO THE WARM SECTOR. OTHER STORMS THAT
DEVELOP OVER OH VALLEY MAY SURVIVE AS THEY CROSS THE MOUNTAINS.
PRIMARY THREATS WILL BE ISOLATED DAMAGING WIND AND LARGE HAIL.


...NRN INTERMOUNTAIN REGION...
AS THE UPPER TROUGH CREEPS EWD ACROSS THE WRN U.S. THIS
PERIOD...ASCENT IS FORECAST TO INCREASE ACROSS ID/WRN MT THROUGH THE
AFTERNOON -- WHERE A MODESTLY DESTABILIZING AIRMASS IS FORECAST.
WITH MODERATELY STRONG /35 TO 45 KT/ SWLY MID-LEVEL FLOW SPREADING
ATOP THE NRN INTERMOUNTAIN REGION IN CONJUNCTION WITH THE ADVANCE OF
THE UPPER TROUGH...SHEAR WILL SUPPORT ORGANIZED/ROTATING UPDRAFTS.
THUS -- EXPECT ISOLATED SEVERE STORMS TO EVOLVE WITHIN BROADER AREA
OF DEVELOPING CONVECTION -- WITH DAMAGING WINDS AND HAIL POSSIBLE.
LATER INTO THE EVENING...STORMS MAY SPREAD/INCREASE EWD AS A SELY
LOW-LEVEL JET DEVELOPS OVER THE HIGH PLAINS. CONTINUED WIND/HAIL
POTENTIAL MAY LINGER WITH A FEW STRONGER STORMS AS A RESULT.

..DIAL.. 06/11/2013

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