DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 071724
SWODY2
SPC AC 071723

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1223 PM CDT THU JUN 07 2012

VALID 081200Z - 091200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF ERN MT...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NY AND NEW
ENGLAND...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF NE MN...NRN WI
AND UPPER MI...

...NRN AND CNTRL HIGH PLAINS...
AN UPPER-LEVEL LOW IS FORECAST TO MOVE INTO THE PACIFIC NORTHWEST
FRIDAY WITH SOUTHWEST FLOW IN PLACE ACROSS THE NRN ROCKIES AND NRN
PLAINS. AT THE SFC...A LOW IS FORECAST TO DEVELOP ACROSS SCNTRL MT
FRIDAY WITH BACKED SELY SFC WINDS LOCATED OVER THE NRN HIGH PLAINS.
THE BACKED FLOW WILL ORIENT THE MOIST AXIS FROM SOUTHEAST TO
NORTHWEST EXTENDING NWWD ACROSS ECNTRL MT WHERE SFC DEWPOINTS SHOULD
INCREASE INTO THE LOWER 50S F. SFC HEATING AND DESTABILIZATION
SHOULD BE ENOUGH FOR THE DEVELOPMENT OF MODERATE INSTABILITY AT
LEAST ACROSS ERN MT. A BIT FURTHER WEST...THE EXIT REGION OF A
MID-LEVEL JET WILL OVERSPREAD THE NRN ROCKIES FRIDAY HELPING TO
INCREASE DEEP LAYER SHEAR AND LARGE-SCALE ASCENT IN THE NRN HIGH
PLAINS. AS THIS OCCURS...THE MODELS DEVELOP THUNDERSTORMS NEAR GREAT
FALLS LATE FRIDAY AFTERNOON AND MOVE THE CONVECTION EWD ACROSS ERN
MT DURING THE EARLY TO MID EVENING.

FORECAST SOUNDINGS TO THE EAST OF GREAT FALLS AND NORTH OF BILLINGS
AT 09/00Z SHOW MLCAPE VALUES REACHING 1000 J/KG WITH 0-6 KM SHEAR
INCREASING TO AROUND 50 KT. THIS COMBINED WITH MID-LEVEL LAPSE RATES
AROUND 8.0 C/KM SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL.
THE SEVERE THREAT SHOULD CONTINUE THROUGH THE EARLY TO MID EVENING
AS STORMS INCREASE IN COVERAGE AND MOVE EWD INTO THE WRN EDGE OF THE
STRONGER LOW-LEVEL FLOW. AN ISOLATED WIND DAMAGE THREAT MAY ALSO
EXIST WITH THE STORM CLUSTER.

CONVECTION INITIATION WILL ALSO BE POSSIBLE SWD ALONG THE
INSTABILITY AXIS FRIDAY AFTERNOON FROM FAR ERN WY AND WRN SD SWD
INTO WRN NEB AND ERN CO. HOWEVER...WEAK LARGE-SCALE ASCENT SHOULD
KEEP THIS ACTIVITY VERY ISOLATED LIMITING SEVERE THREAT COVERAGE.

...NRN AND ERN NY/NEW ENGLAND...
A SHORTWAVE TROUGH IS FORECAST TO MOVE SEWD ACROSS QUEBEC FRIDAY
AFTERNOON AND INTO THE NERN STATES FRIDAY EVENING. AHEAD OF THE
SHORTWAVE TROUGH...A SFC TROUGH IS FORECAST TO TAKE SHAPE ACROSS NEW
ENGLAND WITH A MOIST AXIS LOCATED FROM THE ERN GREAT LAKES EXTENDING
EWD INTO NEW ENGLAND. SFC DEWPOINTS ARE ONLY FORECAST TO BE IN THE
LOWER TO MID 50S F FRIDAY AFTERNOON BUT MODEL FORECASTS DEVELOP
MODERATE INSTABILITY AS SFC TEMPS WARM DURING THE DAY. AS
LARGE-SCALE ASCENT INCREASES FROM THE NORTHWEST...SCATTERED
THUNDERSTORMS APPEAR LIKELY TO DEVELOP ACROSS THE WARM SECTOR DURING
THE AFTERNOON.

FORECAST SOUNDINGS IN ERN NY AT 21Z FRIDAY SHOW MLCAPE AROUND 1500
J/KG WITH 0-6 KM SHEAR OF 30 TO 40 KT. THIS COMBINED WITH
UNIDIRECTIONAL WINDS FROM THE WEST AND STEEP LOW-LEVEL LAPSE RATES
AROUND 8.0 C/KM SHOULD BE FAVORABLE FOR MULTICELLS CAPABLE OF
PRODUCING WIND DAMAGE. THE DEEP LAYER SHEAR SHOULD ALSO SUPPORT
SUPERCELL DEVELOPMENT BUT STORM MODE REMAINS UNCERTAIN. WITH COLD
TEMPS ALOFT ASSOCIATED WITH THE APPROACHING SHORTWAVE TROUGH AND
STEEP MID-LEVEL LAPSE RATES..ISOLATED LARGE HAIL COULD OCCUR WITH
SUPERCELL STRUCTURES.

...UPPER MS VALLEY/WRN GREAT LAKES...
AN UPPER-LEVEL RIDGE IS FORECAST ACROSS THE UPPER MS VALLEY FRIDAY
WITH MODEL FORECASTS MOVING A SUBTLE DISTURBANCE EWD ACROSS THE TOP
OF THE RIDGE. BENEATH THE RIDGE FRIDAY AFTERNOON...AN AXIS OF
MODERATE INSTABILITY IS FORECAST TO EXTEND NEWD FROM SD INTO ERN MN
AND NRN WI WHERE THE MODELS DEVELOP THUNDERSTORMS DURING THE
AFTERNOON. FORECAST SOUNDINGS NEAR AND TO THE NORTH OF MINNEAPOLIS
AT 21Z SHOW MLCAPE AROUND 1500 J/KG WITH 20 TO 30 KT OF SOUTHWEST
FLOW IN THE LOW TO MID-LEVELS. THIS ALONG WITH STEEP LOW-LEVEL LAPSE
RATES NEAR 8.5 C/KM SHOULD BE FAVORABLE FOR MULTICELLS WITH WIND
DAMAGE POTENTIAL. WEAKER DEEP LAYER SHEAR AND SOMEWHAT WARM
MID-LEVEL TEMPS ASSOCIATED WITH THE UPPER-LEVEL RIDGE MAY KEEP WIND
DAMAGE AS THE MAIN THREAT AS A CONVECTIVE CLUSTER ORGANIZES AND
MOVES EWD INTO THE NRN WI.

..BROYLES.. 06/07/2012

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