

961 

WWUS20 KWNS 181304

SEL6

SPC WW 181304

IAZ000-MNZ000-WIZ000-LMZ000-182000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 656

NWS STORM PREDICTION CENTER NORMAN OK

805 AM CDT MON JUL 18 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       FAR NORTHEAST IOWA

       FAR SOUTHEAST MINNESOTA

       CENTRAL AND SOUTHERN WISCONSIN

       LAKE MICHIGAN



EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 805 AM UNTIL 300

PM 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES SOUTHWEST

OF LA CROSSE WISCONSIN TO 35 MILES SOUTH OF MANITOWOC WISCONSIN.

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.



DISCUSSION...ELEVATED TSTMS HAVE RECENTLY INTENSIFIED ACROSS WATCH

AREA IN RESPONSE TO WEAK LOW-LEVEL WAA AND POTENTIAL INFLUENCE OF

MCV MOVING ACROSS THE REGION.  12Z OBSERVED SOUNDING SHOW THE

PRESENCE OF AN ALREADY VERY UNSTABLE ENVIRONMENT WITH MUCAPE VALUES

OF 5000-6000 J/KG.  WITH TIME...STORMS SHOULD BECOME ROOTED IN A

VERY MOIST BOUNDARY LAYER WITH THE POTENTIAL FOR UPSCALE GROWTH INTO

AN MCS.  DAMAGING WINDS AND HAIL WILL BE THE PRIMARY HAZARDS WITH

THESE STORMS.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 30030.





...MEAD

