Archive for July 18, 2007

Severe Thunderstorm Watch 536

By Dan ( July 18, 2007 at 7:34 pm) · Filed under Severe 

URGENT - IMMEDIATE BROADCAST REQUESTED  
SEVERE THUNDERSTORM WATCH NUMBER 536  
NWS STORM PREDICTION CENTER NORMAN OK  
730 PM CDT WED JUL 18 2007  

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

       NORTHERN ILLINOIS  
       NORTHERN INDIANA  
       SOUTHERN LOWER MICHIGAN  
       LAKE MICHIGAN  

EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 730 PM  
UNTIL 300 AM CDT.  

HAIL TO 2 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 60  
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 50 MILES WEST  
SOUTHWEST OF MEIGS FIELD ILLINOIS TO 20 MILES EAST NORTHEAST OF  
FORT WAYNE INDIANA.  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 529...WW 531...WW  
532...WW 533...WW 534...WW 535...  

DISCUSSION...TSTMS/POSSIBLE EMBEDDED SUPERCELLS EXPECTED TO  
CONTINUING DEVELOPING E/SE ALONG WARM ADVECTION WING ASSOCIATED WITH  
ERN IA MCS.  SUFFICIENT SHEAR AND LOW LEVEL MOISTURE ARE PRESENT FOR  
A BRIEF TORNADO OR TWO...BUT EXPECTED QUASI-LINEAR STORM MODE AND  
EVENTUAL ARRIVAL OF FORWARD-PROPAGATING/BOWING PART OF IA SYSTEM  
EXPECTED TO KEEP WIND/HAIL THE PRIMARY SVR THREATS.  

Comments

Moderate Risk of Severe Weather

By Dan ( July 18, 2007 at 8:11 am) · Filed under Severe 

...SEVERE THUNDERSTORMS EXPECTED OVER PARTS OF THE MIDWEST THIS  
AFTERNOON AND TONIGHT...  

THE NWS STORM PREDICTION CENTER IN NORMAN OK IS FORECASTING THE  
DEVELOPMENT OF WIDESPREAD DAMAGING WINDS AND LARGE HAIL OVER PARTS  
OF THE MIDWEST THIS AFTERNOON AND TONIGHT.  

THE AREAS MOST LIKELY TO EXPERIENCE THIS ACTIVITY INCLUDE  

       MUCH OF IOWA  
       NORTHERN ILLINOIS  
       NORTHEAST NEBRASKA  
       SOUTHEAST SOUTH DAKOTA  

SURROUNDING THE MODERATE RISK AREA...THERE IS A SLIGHT RISK OF  
SEVERE THUNDERSTORMS FROM SOUTHEAST MONTANA...ACROSS THE MID  
MISSISSIPPI VALLEY...INTO PARTS OF OHIO AND KENTUCKY.  

A VERY MOIST AND EXTREMELY UNSTABLE AIR MASS IS FORECAST TO DEVELOP  
THIS AFTERNOON ALONG AND SOUTH OF A SURFACE BOUNDARY EXTENDING FROM  
PARTS OF SOUTH DAKOTA AND NEBRASKA...ACROSS IOWA AND INTO NORTHERN  
IL.  AN UPPER LEVEL IMPULSE WILL APPROACH THE AREA FROM THE WEST BY  
LATE AFTERNOON...LEADING TO THE DEVELOPMENT OF SCATTERED  
THUNDERSTORMS ALONG THE BOUNDARY.  FAVORABLE WIND FIELDS  
ALOFT...EXTREME INSTABILITY...AND APPROACHING UPPER SYSTEM WILL  
PROMOTE THE DEVELOPMENT OF ONE OR MORE LARGE CLUSTERS OF SEVERE  
THUNDERSTORMS.  THESE CLUSTERS WILL MOVE RAPIDLY EASTWARD ALONG THE  
BOUNDARY WITH A RISK OF WIDESPREAD DAMAGING WINDS AND LARGE HAIL.  

Comments