Area Forecast Discussion
Issued by NWS Chicago, IL
Issued by NWS Chicago, IL
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933 FXUS63 KLOT 072353 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 653 PM CDT Fri Jun 7 2024 .KEY MESSAGES... - Tomorrow will be marked by isolated to scattered rain showers. A repeat of the washout last Saturday is not expected. - Pleasant conditions are expected Sunday through the middle of next week with limited (15% or lower) chances for rain and seasonable temperatures. - A shift toward warmer temperatures and higher humidity appears on track to arrive after the 2nd week of June. && .DISCUSSION... Issued at 219 PM CDT Fri Jun 7 2024 Through Saturday night: National satellite fields augmented by RAP-analyzed pressure fields indicate a decaying low pressure system in central Ontario and an expanding high pressure system across the middle United States beneath broad upper-level northwesterly flow. A pair of upper-level shortwaves are evident, first over the central Plains and the second near the Montana and Saskatchewan border. Meanwhile, closer to home, our area is being treated to a delightful early June day with mostly sunny skies, a northwesterly breeze, low humidity levels, and temperatures in the mid to upper 70s. Tonight, upper-level clouds will increase in advance of the leading shortwave in the Plains. Initial thunderstorms now developing in central Kansas are poised to grow upscale into a loosely organized convective system overnight, which will likely move along the instability gradient well to our southwest across Missouri. Meanwhile, a few showers may attempt to develop near the Mississippi River after sunset associated with ephemeral filaments of frontogenesis. A residual dry low-level airmass will be eager to chew up initial raindrops throughout the night, so we will continue a dry forecast. A passing surface pressure ridge will encourage winds to become nearly calm overnight. Lows will range from the upper 50s to lower 60s. Chances for isolated showers will begin to tick upward toward and after daybreak Saturday as weak WAA approach from the west ahead of the secondary upper-level shortwave. The continued dry airmass may continue to prove hostile for raindrops to survive to the surface through the morning, but felt advertising gradually increasing PoPs toward 20 to 30% by noon was a good idea. A slightly better push of WAA during the afternoon (and corresponding lowering cloud bases) should be enough to support a few areas of scattered showers through the evening hours. Overall, limited moisture and scant instability should limit the coverage and intensity of showers and curtail more than an isolated rumble of thunder. (In other words, tomorrow should not be a repeat washout like last Saturday). Overcast skies will limit highs to the low to mid 70s. Tomorrow night, a weak cold front will slip through the area causing southwesterly winds to turn northwesterly. Lows will dip to the low to mid 50s. Borchardt Sunday through Friday: We are entering what looks to be a pretty quiet period through next week. High pressure will begin building into the area on Sunday bringing sunny skies and temperatures in the mid-to-upper 70s. Strong northerly flow will cause temperatures to be cooler Monday and Monday night with highs in the upper 60s and low 70s and lows potentially dipping below 50 degrees. However, temperatures will rebound over the following days. On Monday, a shortwave is expected to propagate through the backside of the trough that will be pushing off to the east, however, a very dry moisture profile should inhibit any precipitation from forming. The next potential for precipitation comes Wednesday as a low tracks through Canada with a cold front draped to its south. However, model guidance is not in good agreement about the progression of the upper- level shortwave/low, so PoPs remain low (15% and below). A signal continues to be present in long range ensemble guidance for a pattern shift to warmer temperatures by the end of the forecast period. Temperatures look poised to push into the upper 80s and perhaps even lower 90s by the end of the work week. Carothers && .AVIATION /00Z TAFS THROUGH 06Z SUNDAY/... Issued at 653 PM CDT Fri Jun 7 2024 Key Messages: - Rain showers at times tomorrow - MVFR ceilings possible tomorrow afternoon A pair of disturbances traveling through the region will bring rain showers into the area tomorrow. Light showers may be observed as early as the morning, but the better chances look to hold off until the afternoon hours. During the afternoon, MVFR ceilings may accompany the showers, and some sub-VFR visibility reductions will be possible beneath the steadiest rainfall rates as well. Winds will be light and variable tonight with high pressure in the region before they become southerly and trend southwesterly with time during the daytime tomorrow. The passage of a cold front will then shift winds to a more northerly direction late tomorrow afternoon or evening, with rain chances ending and low clouds likely to scatter out behind it. Ogorek && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory until 7 PM CDT this evening for Winthrop Harbor IL to Gary IN. && $$ Visit us at weather.gov/chicago