DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 081729
SWODY2
SPC AC 081728

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT FRI JUN 08 2012

VALID 091200Z - 101200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE NRN PLAINS...

...NRN AND CNTRL PLAINS...
AN UPPER-LEVEL RIDGE IS FORECAST TO BE IN PLACE ACROSS THE UPPER MS
VALLEY SATURDAY WITH AN UPPER-LEVEL LOW LOCATED IN THE NRN ROCKIES.
SOUTHWEST FLOW IS FORECAST ACROSS THE NRN HIGH PLAINS SATURDAY WITH
THE ENTRANCE REGION OF A WELL-DEVELOPED MID-LEVEL JET LOCATED ACROSS
ERN MT. AT THE SFC...A COLD FRONT WILL MOVE EWD INTO THE NRN PLAINS
EARLY IN THE DAY WITH ELEVATED MORNING CONVECTION POSSIBLE ALONG THE
FRONT. TO THE EAST OF THE FRONT...MODERATE TO STRONG INSTABILITY
SHOULD BE IN PLACE ACROSS THE ERN DAKOTAS EXTENDING NNEWD INTO NW MN
BY MIDDAY. HOWEVER...A STRONG CAPPING INVERSION WILL LIKELY PREVENT
CONVECTIVE INITIATION ACROSS THE WARM SECTOR UNTIL LATE AFTERNOON.
MODEL FORECASTS DIFFER CONCERNING CONVECTIVE DEVELOPMENT. THE NAM
DEVELOPS CONVECTION ON THE ERN SIDE OF THE INSTABILITY AXIS FROM NW
MN EXTENDING SSWWD INTO ERN SD WITH THE NAMKF FOCUSING CONVECTIVE
DEVELOPMENT FURTHER TO THE WEST ACROSS ERN ND SSWWD INTO NCNTRL SD.
THE GFS KEEPS CONVECTION MORE ISOLATED IN THE NRN PLAINS LATE
SATURDAY AFTERNOON INTO EARLY SATURDAY EVENING WHICH ADDS
CONSIDERABLE UNCERTAINTY TO THE FORECAST. THE MODELS DO AGREE THAT A
SECOND AREA OF ELEVATED CONVECTION WILL DEVELOP ACROSS NE WY...SE MT
AND WRN SD LATE SATURDAY EVENING.

FORECAST SOUNDINGS ACROSS THE WARM SECTOR AT GRAND FORKS LATE
SATURDAY AFTERNOON SHOW AN IMPRESSIVE THERMODYNAMIC ENVIRONMENT WITH
MLCAPE OF 3500 TO 4000 J/KG AND 700 TO 500 MB LAPSE RATES OF 8.5
C/KM. THIS ALONG WITH 30 TO 40 KT OF 0-6 KM SHEAR SHOULD EASILY
SUPPORT SUPERCELLS WITH LARGE HAIL. HAIL GREATER THAN 2 INCHES IN
DIAMETER WILL BE POSSIBLE WITH THE MORE DOMINANT SUPERCELLS.
HOWEVER...WARM TEMPS ALOFT AND CONSIDERABLE CIN ON THE FORECAST
SOUNDINGS MAKES CONVECTIVE COVERAGE UNCERTAIN. IF SEVERAL SUPERCELLS
CAN INTENSIFY ALONG THE INSTABILITY AXIS BY EARLY EVENING...THEN AN
ENHANCED THREAT FOR LARGE HAIL WILL BE POSSIBLE. AN ISOLATED TORNADO
THREAT MAY ALSO DEVELOP ACROSS THE SLIGHT RISK AREA. FORECAST
SOUNDINGS SUGGEST THE GREATEST TORNADO THREAT MAY OCCUR NORTH OF THE
GRAND FORKS AREA NEAR THE CANADIAN BORDER WHERE INSTABILITY AND
SHEAR PARAMETERS ARE MAXIMIZED AND COINCIDE WITH LOWER LCL HEIGHTS.
WIND DAMAGE MAY ALSO OCCUR ESPECIALLY IF CONVECTION CAN PERSIST INTO
THE EVENING ACROSS THE ERN DAKOTAS AND NW MN AS SOME OF THE MODELS
SUGGEST.

SEVERE CONVECTION WILL BE POSSIBLE SWWD ACROSS CNTRL SD AND POSSIBLE
IN NRN NEB BUT CONVECTIVE COVERAGE DURING THE LATE AFTERNOON AND
EARLY EVENING SHOULD BE INCREASINGLY ISOLATED WITH SWWD EXTENT. A
HAIL THREAT MAY ALSO DEVELOP DURING THE OVERNIGHT PERIOD WITH
ELEVATED THUNDERSTORMS THAT MOVE EWD INTO THE NRN HIGH PLAINS.

...SRN AND WRN NY/PA/NJ...
NORTHWEST FLOW WILL BE IN PLACE ACROSS THE NERN STATES SATURDAY AS A
SUBTLE UPPER-LEVEL DISTURBANCE APPROACHES THE REGION FROM THE
NORTHWEST. AHEAD OF THE DISTURBANCE...A NARROW AXIS OF MODERATE
INSTABILITY IS FORECAST BY AFTERNOON EXTENDING FROM LAKE ONTARIO
SEWD ACROSS WRN NY INTO NE PA. THE MODELS DEVELOP THUNDERSTORMS
ALONG THIS AXIS OF INSTABILITY WITH CONVECTION PERSISTING INTO THE
EARLY EVENING. FORECAST SOUNDINGS AT BINGHAMTON AT 21Z SHOW MLCAPE
VALUES OF 750 TO 1000 J/KG WITH 0-6 KM SHEAR VALUES OF 35 TO 40 KT
SUGGESTING THE ENVIRONMENT MAY SUPPORT ROTATING STORMS WITH HAIL
POTENTIAL. UNIDIRECTIONAL WLY FLOW SHOULD ALSO BE FAVORABLE FOR
STRONG GUSTY WINDS. HOWEVER...THE SEVERE THREAT IS EXPECTED TO BE
CONFINED TO A NARROW AXIS OF INSTABILITY AND UNCERTAINTY STILL
EXISTS CONCERNING THE MAGNITUDE AND SPATIAL LOCATION OF THE GREATEST
SEVERE THREAT.

..BROYLES/BUNTING.. 06/08/2012

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