Friday, April 30, 2010

Current risks tonight.




New photos for tonight

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Excerpt from tonight's Chicago forecast

Strong thunderstorms likely. Storms may produce large hail and strong winds. Low 61F. Winds SSW at 20 to 30 mph. Chance of rain 80%.

UPDATE ON PDS

A squall line currently entering illinois is producing hail, mesocyclones, and winds. You are urged to secure your outdoors belongings by about 6pm

Tornado watch until 8pm CDT



A tornado watch means conditions are favorable for tornadoes

Article from WGN Weather blog

With strong winds surface and aloft, increasing moisture and an approaching cold front all systems are go for severe thunderstorms and possible tornadoes in the Chicago area and the Midwest.

Currently a line of severe thunderstorms is racing northeast from Iowa towards northwest Illinois and southwest Wisconsin at speeds approaching 70 mph. These storms have produced wind damage to trees and powerline in Iowa and dropped hail up to 1 inch in diameter.

Currently these storms pose no threat to Chicago but are targeting areas in northwest Illinois west of Rockford to Dubuque and areas in southwest Wisconsin west of Madison and Janesville to the Mississippi River.

Wind gusts from yesterday



This means high wind shear, which is favorable for tornadoes.
This is probable tonight

Map for midnight tonight



Outlined green area is thunderstorm activity

Current weather maps watches and warnings



The yellow is tornado watch

Rainfall map through Saturday (tomorrow)

Word of the day

Mesocyclone: A rotating column of air in the clouds. Can produce tornadoes.

Current Radar image as of 3:50pm CDT



These storms have produced mesocyclones and are moving strictly northeast

severe map as of 130pm CDT

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The big threat probably has shifted eastward

SPC Pictures for severe threat




Tornado Watch

Tornado watch over north Illinois

PARTICULARLY DANGEROUS SITUATION

TONIGHT, EVERYONE IN THE MIDWEST IS STRONGLY ADVISED TO BR PREPARED FOR WIDESPREAD AND INTENSE SEVERE WEATHER.

Notice...

There is unstable information that has been gathered for the Chicagoland area. For this reason, no maps will be put up this morning.