Friday, September 20, 2019

Heavy Rain Possible Over the Weekend


Following heavy rainfall yesterday, the leftover moisture did bring some patchy fog to the Stateline to start our Friday morning. Visibility did fall below a mile in a few spots at times. But the good news is, most of the morning has been quiet and dry. Many dry hours are in store for us as partly sunny skies will stick around through the rest of our day today. However, the atmosphere still is moisture-rich which could lead to a few very isolated showers or thunderstorms later in the day. There isn’t much of a lifting mechanism for widespread development like yesterday, so that is why today's activity will be more isolated. If you are heading to Friday Night Football, game of the week is Orangeville vs Du-Pac, or to City Market, I would keep the umbrella in the car just in case. But this evening should be fairly dry and muggy for you to enjoy the festivities.  Highs today climb into the low 80s. 

Saturday may start with dry weather, but rain chances will continue as the day progresses. If you have outdoor plans for Saturday, your best chance for dry weather will be before noon. For people that are participating in the Thin Mint Sprint, including yours truly, clouds will be quick to increase tomorrow morning and showers will be very spotty in nature. Overnight Saturday into Sunday is the period of most concern for flash flooding.

Several rounds of heavy rainfall are poised to slide into the Stateline. As of this morning, a Flash Flood Watch was issued for Stephenson, Jo Daviess, Carroll, and Whiteside Counties until 1 A.M. Monday. The source of our moisture is related to the remnants of former Tropical Depression Imelda. This is the same system that has brought over 40" of rainfall to parts of Southeast Texas. In fact, a preliminary report of 43.31" of rainfall was recorded in Jefferson County, TX. That places Imelda 5th in the record books for wettest tropical cyclones to impact the lower 48. Now, record to near-record atmospheric moisture gets picked up by the jet stream and lifted northward into northern Illinois. We won't be seeing 40" of rain, but this high level of moisture could lead to rainfall rates of 1″ to 2″ per hour as stated in the flash flood watch. Especially Saturday night into Sunday morning. And with how wet September has been so far, the Stateline does not need this extra rainfall.


Recent model trends have decreased overall rainfall totals locally, as it looks like the axis of heaviest rain will be just south and west of us. However, most places could end up with 1 to 3 inches when this is all said and done. Regardless of how much actually falls, it will be falling on top of an already saturated ground. Be on the lookout for any flooded roadways as you travel this weekend. Remember, turn around - don't drown. Rain chances remain high through much of our Sunday. The stubborn cold front finally clears the region by Monday morning, bringing a cooler temperatures just in time for the first official day of fall. Not only that, a high pressure system will follow the cold front and bring a dry start to not only Fall, but for the start of the work week as well.

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