Funnel clouds today... no, seriously!

They're called "cold air funnels" and while they seldom cause any harm, at least one such cloud caused quite the stir in Kankakee County around lunch today.  As the Bears were holding their first practice of the season in Bourbonnais, wind and humidity conditions were just right to create a funnel cloud.  Several photos have appeared in print (I posted one on my Facebook page, btw) taken between 12:10 and 12:30 over Kankakee, Bradley and Bourbonnais.  Cold air funnels are weaker cousins of true tornadic funnel clouds.  They are almost always higher in the sky, are not associated with thunderstorms, and typically don't touch down.  Sometimes, after a cold frontal passage, there's just enough turning of the atmosphere to generate a rotating motion in a cloud.  If there's enough moisture present, that rotation can appear as a condensation funnel, protruding down from the base of the cloud.  Sirens sounded but nothing ever touched ground.

Mike

Watch in effect

The Storm Prediction Center has placed portions of the ABC-7 viewing area under a Severe Thunderstorm Watch until 7pm this evening.  Generally speaking, the watch covers areas south of I-80. Kendall, Will, Grundy, La Salle, Kankakee, Livingston, Lake, Porter, Newton, Jasper & La Porte Counties are included in the watch.  Gusty winds and brief heavy downpours will be possible in he stronger cells.

Mike

4th place

Thanks to the deluge late Friday into Saturday, July 2010 now ranks as the 4th wettest on record.  8.16" is our current rainfall total at O'Hare, ranking just behind 8.33" in 1982, 8.98" in 1957, and 9.56" in 1889.  I think there at least one more chance to add to the total before month's end.  That comes on what will be the hottest day of the week, Wednesday.  A cold front will trigger scattered storms before ushering in a 10-degree temperature drop for Thursday and Friday.  With ample moisture in place by that time, any storm could produce significant rainfall.  I think first place is safe, but 2nd is in jeopardy!

Mike

Severe Weather Risk

Most of Chicagoland is under a Severe Thunderstorm Watch until 9:00 pm.  At this point, Indiana counties are not included in the watch, but as the storms develop and move east, your time will likely come too.  Damaging winds and torrential rainfall will be possible with the storms.

Mike

Flooding north... sweltering south

This may end up being the hottest day of the year so far, if we top out at 94 or higher.  While we've had 14 days of 90-degree temperatures already (far more than in either of the past two summers) the highest temperature we've reached is 93.  Whether it's a 92, or a 94 today, the combination of the hot air plus high moisture content of the atmosphere will result in heat index readings exceeding 100.  For that reason, a Heat Advisory is in effect until this evening for the city and points south. It's important to stay hydrated while outdoors, and minimize stressful activity.  Make sure your dogs, if kept outside, have a place to cool down and have access to plenty of water too.  On the subject of water... there's more than plenty of it in the far northern suburbs.  Rainfall in southern Wisconsin and the northern tier of Illinois counties exceeded 3" in many locations overnight and this morning.  Milwaukee, where the main airport is closed as of this writing, picked up nearly a half foot of rain.  With a stationary front in the vicinity and a highly unstable atmosphere loaded with moisture, storms are likely to flare up again either late this afternoon or tonight.  Unfortunately, current model predictions point at the same soaked areas as being in the target zone for this next drenching assault.  Once we get past tomorrow evening, a cold front will have passed, ending the storm threat and providing some relief from the heat.

Mike

Cooler... at least as of noon time

A fairly thick layer of stratus cloud cover has held back temperatures this morning.  Readings in the low 70s are common, but when the clouds break, and they should, temperatures should climb into the 80s.  That may lead to a slightly more unstable atmosphere, more capable of producing a few thundershowers.  As for any widespread soakers, it just doesn't look likely.  Computer models are screaming about better rain/thunder prospects late Thursday.  Then again, these same models had been screaming the same song for Monday and today.  

Mike

Storms tonight

As of late morning, skies remain partly sunny across Chicagoland, as a complex of intense thunderstorms moves through western IL and eastern MO.  More storms are firing up in Iowa as another disturbance feeds on the instability of the atmosphere.  The storm axis currently would favor areas southwest of Chicago for the most activity.  Later this evening however, another impulse will be moving in from farther north. This is the one most notable for our area.  Strong to possibly severe storms will be possible with this feature.  Right now it looks like an "after-dark" event to me, with locally heavy rainfall possible as well.  Jerry will have the latest on the forecast this afternoon.

Mike

Summer lovers, rejoice!

No matter what the weather is doing, someone is bound to be happy and someone else is bound to be complaining about it.  So it goes with the summer of 2010.  Those who enjoy tropical summer conditions here are in 7th heaven, while those who wither under the scorching sun and humidity can't wait for October!No question... after enduring a remarkably hot-weather-free summer last year, mother nature has really cranked it up this year.  Since June15, only 4 days have had cooler-than-normal temperatures.  That distinction shows no signs of changing in the week ahead.  While there will be some epsiodes of thunderstorm activity which will briefly cool us of, a rather persistent ridge of high pressure covering the East will prevent any Canadian air from slipping in here. Highs for the next seven days (at least) will flirt with 90. Humidity levels today are refreshingly lower, but gulf moisture is poised to make a comeback this weekend.  As that happens, it appears thunderstorms will develop to our northwest late Saturday, then move toward Chicagoland by Sunday morning.  I'll have the updated weekend forecast at 4pm, but count on seeing several days of 90+ in the 7-day!

Mike

Scattered storms today and tomorrow

Radar is sparking to life to Chicago's west this afternoon.  A few storms will be possible through Monday night, as a frontal system encroaches on the area.  Locally heavy rain will be possible, and while widepsread severe weather is not likely, a few stronger cells could have strong winds and small hail.  Tuesday and Wednesday look quiet, although temperatures are likely to build into the 90s starting Wednesday.

Mike

Modest relief on the way

Four days in a row of 90s has some complaining about the heat already.  As I pointed out yesterday, since May 20th, 82% of the days have been warmer than normal.  That's a huge turnaround from 2009 when we couldn't buy a warm summer day!  Accompanying the heat and humidity here will be a few scattered thundershowers this afternoon and evening.  Storms should be more numerous Thursday as a frontal boundary moves into Chicagoland.  With so much water vapor being held in the air, any storm could be a prolific rain producer.  Severe storms, while not impossible, seem unlikely at this time.  After the fron passes tomorrow evening, the threat of rain will end and slightly less humid and less hot air will filter in.  Highs for the rest of the week will be in the mid 80s with modest humidity levels.  I have seen some forecasts calling for highs in the upper 70s later this week.  Not gonna happen.  In fact, it is more likely that our string of warmer-than-normal days (now at 5) will be extended to at least 12. 

Mike