While not as strong as yesterday's howling southerlies, winds will again be up in the 35+ mph range this afternoon. As of midday, a severe thunderstorm watch is up for eastern Iowa and northern Missouri as a cold front bumps into the warm air bathing the area in near-80 degree warmth. The Storm Prediction Center continues to include Chicagoland on the eastern fringe of a slight risk for severe storms area from now until tomorrow morning. While a few storms could pop up in the area later this afternoon, the main show is likely to happen well after dark as a line of strong to possibly severe storms plows through. Those storms will be long gone tomorrow, affording another partly sunny and warm day before the next round of t'showers rolls in tomorrow night into early Sunday. The heaviest rain from the 2nd system is likely to fall south of Chicago. Well have the latest on any watches and warnings throughout the day on ABC-7.
A weak disturbance along the edge of a warm front is responsible for the clouds late this morning. A few sprinkles managed to leak out of that deck across the northern suburbs, but that "event" is now over. For the remainder of the day, rippin' southerly winds will usher in warmer air and the clouds will scatter, allowing the mercury to climb into the 70s. Due to the very strong low level jet stream over the area, winds at the surface will gust to more than 40mph at times, prompting the wind advisory now in effect for the area this afternoon. The focus then shifts to an approaching frontal system and the risk of severe weather tomorrow night. The Storm Prediction Center has placed Chicagoland in the slight risk zone for storms with large hail and/or damaging winds during this time frame. However, ABC7's MicroCast computer model and the NAM model suggest the ingedients for rain, much less severe weather are not coming together well for tomorrow night. I will have more on what may be another "less-than-feared" rainfall event on the 4pm broadcast this afternoon. Hold on to your parasols!
Yesterday, we barely nudged into 50s. Today, most of us will see 60s. Tomorrow, prepare to relish in 70-degree warmth. High pressure dominating the arera will assure nearly total sunshine today. The afternoon's relative warmth follows a frosty morning. While the official low at O'Hare was 33, many suburbs dipped below freezing. Plants at the Chicago Botanic Garden had to suffer through a low of 30, while it was even colder at the Morton Arboretum where it tanked to 28. As the high pressure system moves off to our east, a more southerly wind flow will bring warmer air into the region. 70s will be likely tomorrow and a cinch for Friday.
On the flip side, a deepening trough of low pressure threatens showers and storms by late Friday, with another potential round of showers late Saturday into early Sunday. Like last weekend, I do not foresee a weekend washout with many dry hours in between the showers. Parameters supporting severe storms are looking more impressive especially late Friday here. When the atmosphere features rapidly changing wind speed and/or direction with height, it is said to be "sheared." Shear, in an unstable atmosphere, is one of the indicators we look for to support super-cell thunderstorms capable of producing tornadoes. It would not surprise me if the Chicago area ends up under a watch for tornadoes or severe thunderstorms during the evening on Friday.
While it was far from a DRY weekend, it turns out my initial expectations that the computer models would be overblown in the rainfall department were correct. Officially, Chicago had only .64" rainfall from Friday night through yesterday... hardly the 2-3" soakfest which had been advertised by some models. Furthermore, the total number of hours with rainfall was less, with most areas experiencing plenty of dry time both Saturday and Sunday. Now I know some of you, especially in Indiana, did better with the wetter! Valparaiso picked up about 1.5" total rainfall with many more hours of rainfall.
Today we enjoy bright sunshine on a day which point-and-click forecasts pegged for rainfall last week. I expect the sunshine will dominate, although a weak disturbance off to our west might bring a few clouds to western suburbs later on. Rain from that system misses us completely. Tomorrow will be cooler, with highs mainly in the 50s. But a nice warmup is in store later this week. The mercury should crack the 70-degree mark starting Thursday. As for any precipitation, the models emphatically slam us with showers and storms Friday. I'll be awaiting the latest model runs including our in-house microcast to offer you the latest on the rain threat starting this afternoon at 4pm.
Most areas saw about 2/3 of an inch of rain this past weekend which is the most rain we have seen in the past two weeks. The weather will turn dry but cool the next couple of days with a stout north to northeast wind keeping temperatures below average.
After a possbly frosty start on Wednesday temperatures will rebound nicely by the afternoon. Our next chance of rain will be Thursday night into Friday when showers and heavy thunderstorms will overspread the area.
Rain as of mid afternoon Friday is having a tough time advancing northward due to a dry flow off of Lake Michigan. This will be the first of several rounds of rainfall to eventually affect Chicagoland this weekend. A more robust wave will bring more substantial showers and possibly a few embedded thunderstorms to the area later tonight. I expect that to move away tomorrow morning, affording several rain-free hours tomorrow during the day. While it could shower any time tomorrow, the concentrated rainfall will be over. The respite will end tomorrow night, when another area of heavier rainfall is forecasted to return from the south. Sunday may begin dry, but more showers will return to the area during the day. Looks like the heavier rainfall solution will beat my earlier drier expectations, which will actually be welcomed by your yards and plants since we've had virtually no significant rainfall for more than 2 weeks.
The quandary begun here Monday is unchanged. For days, a big blob of rainfall has been depicted on the major computer models for us this weekend. That blob used to be there from Friday through Monday. Now the blob is looking more ragged over Chicago, the "heavy" stuff doesn't get in until Friday late, and whatever blobs are all gone before Monday. My doubts that a needed 1"+ rainfall will drench the entire area remain. And once again, the latest computer run of the NAM (North American Model) is trending with a drier look here. In fact, it only spits out .19" rainfall by Saturday 7pm for Chicago. That of course leaves Saturday night and Sunday to get through, but it's much less rainfall than it HAD been predicting during the same time frame. Plenty of prognosticatory evidence remains to support the "weekend washout" hypothesis, but it's far from a done deal. Mostly sunny and cool today, btw!
And no... I'm not referring to the long-running SNL fake newscast! Here's my latest thinking on the tricky weekend outlook. Had you relied on "point and click" forecasts, as one of my meteorological heroes, Joe Bastardi calls them, you would have been under the impression that it would rain almost incessantly fom Friday through Monday here. As I have opined here and on the air, HOOEY! Now the computer models are trending in my direction. First of all, the models are slower with the approach of a sprawling low pressure system. Translation: Rain is much less likely to get here by Friday. Next, the models are less robust with the heaviest rainfall. Translation: Rainfall if/where it occurs will be less. The models are also a little farther south with the body of the rainfall. Translation: Could this thing go far enough south that the old "Chicago Split" sends precip north and south of here with very little in between? Finally, the models show the precip being shut down after the low passes instead of wrapping around for a prolonged and extended bout of showers. Translation: No rain period on Monday. I'll be honest. My position is still a minority report. There is plenty to suggest that the weekend will be wet. But one of my responsibilites as a forecaster is not to blindly follow the computer "point and click" projections. I look for ways for those to bust and while the likelihood of NO rain falling this weekend is remote, I still think the 2"-3" of rainfall I've heard on some outlets is outrageous. That's my contrarian view!!! In the short term, backdoor cold front is knocking temperatures down into the 40s! If you live south of Chicago, enjoy the remaining hours of warmth!
Another beautiful day is in progress with just a few high thin cirrus clouds decorating the sky. Temperatures will climb into the 60s, although the lake breeze will do its thing. Tomorrow will feature a weak cold front sliding through the area, knocking afternoon temperatures back into the 50s. Generally smooth sailing until we get to the weekend. Computer models are all jazzed up for rain starting Friday and continuing off and on through Monday. Here's the thing... it's only rained .01" in the past 13 days. That's a dry pattern. It was suppoed to rain last Friday. It didn't. We've had only two calendar days on which we picked up .50" or more rainfall since March 1st. I am banking on persistence, and cutting back drastically on rainfall prospects. This is a minority position, and there is plenty of "paper" evidence I will be wrong. It's still several days away, and I might change my mind as the storm system draws closer, but for now, I'm going with a drier look for the 4-day period.
