Sunday, June 5, 2011

DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 051732
SWODY2
SPC AC 051730

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT SUN JUN 05 2011

VALID 061200Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF MT...NRN
WY...SW ND AND NW SD...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE UPPER MS
VALLEY AND SRN LOWER MI...

....MT/WRN-SRN ND/NW ND...
A WELL-DEVELOPED UPPER-LEVEL LOW WILL MOVE NEWD ACROSS THE
INTERMOUNTAIN WEST MONDAY AS THE NOSE OF A 60 TO 75 KT MID-LEVEL JET
OVERSPREADS THE NRN ROCKIES. AT THE SFC...A MOIST AXIS WILL BE IN
PLACE FROM SD EXTENDING WNWWD ACROSS SRN AND WRN MT WHERE MODEL
FORECASTS DEVELOP MODERATE INSTABILITY BY MONDAY AFTERNOON. A
WEAKENING CAP AND STRONG LOW-LEVEL CONVERGENCE ON THE NRN SIDE OF A
DEEPENING SFC LOW SHOULD ALLOW FOR THUNDERSTORM INITIATION ALONG THE
INSTABILITY AXIS BY LATE AFTERNOON. FORECAST SOUNDINGS ACROSS SRN MT
AT 00Z TUESDAY SHOW AN IMPRESSIVE ENVIRONMENT WITH MLCAPE VALUES IN
THE 2000 TO 2500 J/KG RANGE AND 0-6 KM SHEAR VALUES AROUND 60 KT.
THIS ALONG WITH STEEP MID-LEVEL LAPSE RATES EXCEEDING 8.5 C/KM
SHOULD EASILY SUPPORT SUPERCELL DEVELOPMENT WITH LARGE HAIL. THE
MORE DOMINANT SUPERCELLS MAY PRODUCE ISOLATED HAIL GREATER THAN 2
INCHES IN DIAMETER WHERE A 30 PERCENT SIGNIFICANT SEVERE PROBABILITY
HAS BEEN INTRODUCED. FORECAST SOUNDINGS ALSO SHOW 0-3 KM STORM
RELATIVE HELICITIES OF 250 TO 450 M2/S2 SUGGESTING TORNADOES MAY
OCCUR WITH THE MORE ORGANIZED ROTATING STORMS WITH AN ISOLATED
POSSIBILITY OF A STRONG TORNADO. FURTHER TO THE EAST ACROSS WRN ND
AND NW SD...THE CAPPING INVERSION SHOULD HOLD FOR MOST OF THE
AFTERNOON. AS THE LOW-LEVEL JET STRENGTHENS DURING THE EVENING AND
HEIGHTS FALL AHEAD OF THE APPROACHING UPPER-LEVEL TROUGH...A FEW
SEVERE STORMS MAY DEVELOP.

...UPPER MS VALLEY/LOWER MI...
AN UPPER-LEVEL RIDGE WILL REMAIN IN PLACE ACROSS THE MID-MS VALLEY
WITH WLY FLOW ALOFT LOCATED IN THE NCNTRL STATES. AT THE SFC...A
COLD FRONT IS FORECAST TO MOVE SWD ACROSS THE NRN PLAINS EXTENDING
EWD ACROSS SRN MN AND SCNTRL WI BY LATE AFTERNOON. THUNDERSTORMS ARE
FORECAST TO DEVELOP ALONG THE BOUNDARY BY EARLY EVENING IN A
STRONGLY UNSTABLE ENVIRONMENT AS THE LOW-LEVEL JET STRENGTHENS.
FORECAST SOUNDINGS AT 00Z TUESDAY FROM SRN MN TO SRN WI SHOW MLCAPE
VALUES OF 3500 TO 4500 J/KG AND 30 TO 40 KT OF DEEP LAYER SHEAR
SUGGESTING SUPERCELL OR BOW ECHO DEVELOPMENT WILL BE POSSIBLE.
CONSIDERING MID-LEVEL LAPSE RATES WILL BE QUITE STEEP...A POTENTIAL
FOR LARGE HAIL WILL EXIST. UNIDIRECTIONAL WIND PROFILES AND 850 MB
FLOW OF 25 KT MAY ALSO RESULT IN A WIND DAMAGE THREAT ESPECIALLY
WITH PERSISTENT LINE-SEGMENTS.

...CNTRL AND ERN GULF COAST...
ABUNDANT LOW-LEVEL MOISTURE WILL EXIST ALONG THE IMMEDIATE GULF
COAST MONDAY WHERE SFC DEWPOINTS ARE FORECAST TO BE IN THE LOWER 70S
F FROM SRN LA EWD INTO THE FL PANHANDLE AND SRN GA. STRONG
INSTABILITY SHOULD DEVELOP BY MONDAY AFTERNOON WITH FORECAST
SOUNDINGS SHOWING MLCAPE VALUES IN THE 2000 TO 3500 J/KG RANGE. AS
SCATTERED THUNDERSTORMS INITIATE...A THREAT FOR ISOLATED WET
DOWNBURSTS COULD EXIST MAINLY DUE TO THE VERY MOIST AIRMASS AND
STEEP LOW-LEVEL LAPSE RATES.

..BROYLES.. 06/05/2011

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