Re: Oklahoma Severe Weather Discussion - July & August 2011
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 773
NWS STORM PREDICTION CENTER NORMAN OK
320 PM CDT FRI AUG 12 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
CENTRAL OKLAHOMA
EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 320 PM UNTIL
1000 PM CDT.
SCATTERED DAMAGING WINDS
ISOLATED WIND GUSTS TO 90 MPH POSSIBLE
SCATTERED LARGE HAIL
ISOLATED HAIL TO 2.0 INCHES IN DIAMETER POSSIBLE
ISOLATED TORNADOES
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 70
STATUTE MILES EAST AND WEST OF A LINE FROM 20 MILES NORTH OF
PONCA CITY OKLAHOMA TO 20 MILES SOUTH SOUTHWEST OF ARDMORE
OKLAHOMA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 771...WW 772...
DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN BOTH COVERAGE AND
INTENSITY ACROSS MUCH OF CENTRAL OK THROUGH LATE AFTERNOON AND INTO
THIS EVENING. THE WATCH AREA IS CURRENTLY SURROUNDED ON THREE SIDES
BY DEVELOPING DEEP CONVECTION AND AIRMASS ACROSS CENTRAL OK
CONTINUES TO DESTABILIZE. PULSE TO MULTICELLULAR STORMS POSING
PRIMARILY A THREAT OF DAMAGING DOWNBURST WINDS WILL CONTINUE TO COME
UP ALONG/WITHIN CONFLUENCE ZONE COINCIDENT WITH HIGHER BOUNDARY
LAYER THETA-E FROM NWRN TX NWD TO OKC METRO AREA. THIS DEVELOPMENT
WILL OCCUR ATOP A VERY HOT BOUNDARY LAYER WHERE DCAPE WELL IN EXCESS
OF 1000 J/KG WILL RESULT IN LOCALLY DAMAGING DOWNBURSTS BENEATH THE
STRONGER CORES. TO THE EAST...OUTFLOW BOUNDARY FROM MORNING STORMS
OVER TULSA AREA WILL PROVIDE A FOCUS FOR NEW SURFACE-BASED
DEVELOPMENT INTO THE EVENING. POTENTIALLY MORE ENHANCED LOW LEVEL
SHEAR ALONG THE OUTFLOW COULD INDUCE SUPERCELL STRUCTURE IN THIS
CONVECTION WITH LARGE HAIL AND HIGH WINDS POSSIBLE. LASTLY...MCS
DEVELOPMENT IS ANTICIPATED ALONG OUTFLOW BOUNDARY INTERSECTION
ACROSS SRN KS. THIS COMPLEX...SIMULATED BY STORM SCALE MODELS...MAY
DEVELOP SEWD ACROSS NRN/NERN AND CNTRL OK THROUGH THE EVENING WITH
AN INCREASING CHANCE OF DAMAGING WIND AND HAIL IN THESE AREAS.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 80
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27020.
SEVERE THUNDERSTORM WATCH PROBABILITIES FOR WS 0773 NWS STORM PREDICTION CENTER NORMAN OK
0321 PM CDT FRI AUG 12 2011
WS 0773
PROBABILITY TABLE:
PROB OF 2 OR MORE TORNADOES : 20%
PROB OF 1 OR MORE STRONG /F2-F5/ TORNADOES : 05%
PROB OF 10 OR MORE SEVERE WIND EVENTS : 40%
PROB OF 1 OR MORE WIND EVENTS >= 65 KNOTS : 50%
PROB OF 10 OR MORE SEVERE HAIL EVENTS : 40%
PROB OF 1 OR MORE HAIL EVENTS >= 2 INCHES : 30%
PROB OF 6 OR MORE COMBINED SEVERE HAIL/WIND EVENTS : 90%
&&
ATTRIBUTE TABLE:
MAX HAIL /INCHES/ : 2.0
MAX WIND GUSTS SURFACE /KNOTS/ : 80
MAX TOPS /X 100 FEET/ : 500
MEAN STORM MOTION VECTOR /DEGREES AND KNOTS/ : 27020
PARTICULARLY DANGEROUS SITUATION : NO
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Originally Posted by OKCisOK4me
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