

675 

WWUS20 KWNS 152029

SEL6

SPC WW 152029

MIZ000-LEZ000-LHZ000-160100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 76

NWS STORM PREDICTION CENTER NORMAN OK

430 PM EDT THU MAR 15 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHEAST LOWER MICHIGAN

       LAKE ERIE

       LAKE HURON



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 430 PM UNTIL

900 PM EDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES EAST AND WEST OF A LINE FROM 10 MILES NORTHWEST OF

BAD AXE MICHIGAN TO 35 MILES SOUTH OF ANN ARBOR MICHIGAN.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU6).



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 75...



DISCUSSION...STORMS ARE INTENSIFYING ALONG A CONVERGENCE ZONE FROM

JUST WEST OF SAGINAW BAY TO NORTHWEST OF TOLEDO.  ANOMALOUSLY WARM

AND MOIST LOW LEVEL AIR MASS WITH SEASONABLY COOL MID LEVEL

TEMPERATURES ARE RESULTING IN STEEP LAPSE RATES AND STRONG

INSTABILITY WITH MLCAPE OF 2000 J PER KG /SEE 18Z DTX RAOB/.

ALTHOUGH WINDS ALOFT ARE NOT PARTICULARLY STRONG, 30 KT WESTERLY MID

LEVEL FLOW IS ASSOCIATED WITH SUFFICIENT DEEP LAYER SHEAR FOR

ORGANIZED UPDRAFTS AND THREAT FOR LARGE HAIL AND ISOLATED DAMAGING

WIND GUSTS.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 26020.





...WEISS

