WATCHES: Tornado Watch Number 673

WWUS20 KWNS 202047
SEL3
SPC WW 202047
MNZ000-210300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 673
NWS STORM PREDICTION CENTER NORMAN OK
345 PM CDT THU SEP 20 2007

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

CENTRAL AND SOUTHERN MINNESOTA

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 345 PM UNTIL
1000 PM CDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 40 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 50 MILES NORTHWEST OF
REDWOOD FALLS MINNESOTA TO 25 MILES EAST NORTHEAST OF MINNEAPOLIS
MINNESOTA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

DISCUSSION...ELEVATED CONVECTION CONTINUES WELL N OF THE SURFACE
WARM FRONT...WHICH HAS NOW DEVELOPED NWD INTO THE MSP AREA. THE
BOUNDARY LAYER CONTINUES TO WARM/MOISTEN S OF THE BOUNDARY...AND
CONVECTIVE INHIBITION IS BEGINNING TO WEAKEN FOR SURFACE-BASED
PARCELS ACROSS SW AND S CENTRAL MN. THE NEWER STORM DEVELOPMENT TO
THE W OF MSP MAY STILL BE SLIGHTLY ELEVATED...BUT IT IS VERY CLOSE
TO SURFACE BOUNDARY. GIVEN THE STRONG VERTICAL SHEAR PRESENT...ANY
STORMS ROOTED IN THE NEAR-SURFACE LAYER WILL BE CAPABLE OF PRODUCING
TORNADOES. OTHERWISE...LARGE HAIL AND A FEW DAMAGING GUSTS CAN BE
EXPECTED THROUGH LATE EVENING.

AVIATION...TORNADOES AND 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 26030.

..THOMPSON

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@PO.UIUC.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.