WATCHES: Severe Thunderstorm Watch Number 442

WWUS20 KWNS 221850
SEL2
SPC WW 221850
IAZ000-MOZ000-230200-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 442
NWS STORM PREDICTION CENTER NORMAN OK
150 PM CDT FRI JUN 22 2007

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

IOWA
FAR NORTHEASTERN MISSOURI

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 150 PM UNTIL 900
PM CDT.

HAIL TO 2.5 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 90
STATUTE MILES EAST AND WEST OF A LINE FROM 25 MILES EAST
NORTHEAST OF FORT DODGE IOWA TO 55 MILES SOUTH SOUTHWEST OF
OTTUMWA IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

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...STORMS ALREADY INCREASING ACROSS CENTRAL IA INVOF SLOW
MOVING MCV AND NEAR SURFACE OUTFLOW BOUNDARY. AIR MASS IS QUITE
UNSTABLE...AND WILL DESTABILIZE FURTHER INTO ERN IA GIVEN MODERATE
TO STRONG HEATING. SHEAR ACROSS MUCH OF CENTRAL IA REMAINS
SUFFICIENT FOR SUPERCELLS NEAR A 40 KT WLY MID SPEED MAX ASSOCIATED
WITH SLOW MOVING MCV. ACTIVITY WILL LIKELY CONSOLIDATE LATER TODAY
INTO A MCS. LARGE HAIL AND ISOLATED DAMAGING WINDS SHOULD OCCUR
WITH THESE STORMS.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27015.

..EVANS

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