[LeArc] Severe Thunderstorm Watch for Macomb, IL

[Weather Underground Email Service]

Severe Thunderstorm Watch
urgent - immediate broadcast requested
Severe Thunderstorm Watch number 661
NWS Storm Prediction Center Norman OK
935 am CDT Wed Jul 21 2004

The NWS Storm Prediction Center has issued a
Severe Thunderstorm Watch for portions of

Eastern Iowa
northern Illinois
Lake Michigan

Effective this Wednesday morning and afternoon from 935 am until
300 PM CDT.

Hail to 2 inches in diameter...thunderstorm wind gusts to 80
mph...and dangerous lightning are possible in these areas.

The Severe Thunderstorm Watch area is along and 60 statute miles
north and south of a line from 55 miles west northwest of Ottumwa
Iowa to 15 miles south southeast of Meigs Field Illinois.

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...thunderstorms will increase/intensify rapidly across
watch area as MCV upstream provides upward motion and 40 kt mid
level flow.  Air mass becoming very unstable with only a weak cap
remaining.  Storms expected to evolve into short line segments/bows
enhancing wind damage potential.

Aviation...a few severe thunderstorms with hail surface and aloft
to 2 inches. Extreme turbulence and surface wind gusts to 70
knots. A few cumulonimbi with maximum tops to 550. Mean storm
motion vector 26035.


...Hales