Archive for July 10, 2007

Severe Thunderstorm Watch 506

By Dan ( July 10, 2007 at 3:32 pm) · Filed under Severe 

RGENT - IMMEDIATE BROADCAST REQUESTED  
SEVERE THUNDERSTORM WATCH NUMBER 506  
NWS STORM PREDICTION CENTER NORMAN OK  
145 PM CDT TUE JUL 10 2007  

THE NWS STORM PREDICTION CENTER HAS ISSUED A  
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF   

       NORTHERN ILLINOIS  
       SOUTHEAST WISCONSIN  
       LAKE MICHIGAN  

EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 145 PM UNTIL  
900 PM CDT.  

HAIL TO 1 INCH 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 75  
STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES NORTHEAST OF  
OSHKOSH WISCONSIN TO 45 MILES SOUTH SOUTHWEST OF ROCKFORD  
ILLINOIS.  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 504...WW 505...  

DISCUSSION...THUNDERSTORMS WILL INTENSIFY GRADUALLY THROUGH THE  
AFTERNOON ALONG A SURFACE COLD FRONT IN WI AND A SEPARATE  
PRE-FRONTAL TROUGH ACROSS NRN IL/EXTREME SE WI.  THOUGH MID LEVEL  
LAPSE RATES ARE NOT PARTICULARLY STEEP...BOUNDARY LAYER DEWPOINTS IN  
THE LOW 70S AND SURFACE TEMPERATURES WELL INTO THE 80S ARE  
SUPPORTING MLCAPE VALUES OF 1500-2000 J/KG IN THE WARM SECTOR.  THE  
STRONGER LOW-MID LEVEL FLOW AND ASSOCIATED WIND DAMAGE POTENTIAL  
SHOULD BE ACROSS THE WI PORTION OF THE WATCH AREA...WITH A SOMEWHAT  
LOWER THREAT TO THE SOUTH IN IL WHERE WIND FIELDS WEAKEN WITH  
INCREASING DISTANCE FROM THE PRIMARY MID LEVEL TROUGH OVER MN/NW WI.  

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