Area Forecast Discussion
Issued by NWS Central Illinois
Issued by NWS Central Illinois
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236 FXUS63 KILX 030452 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1152 PM CDT Thu May 2 2024 .KEY MESSAGES... - Concern remains for some strong to locally severe storms through sunset, primarily west of I-55. - While some quieter periods are expected during the weekend, an active weather pattern re-establishes itself early next week. && .UPDATE... Issued at 930 PM CDT Thu May 2 2024 Storms have diminished in intensity and coverage across central Illinois late this evening with loss of daytime heating and the severe threat has ended. Outflow boundaries from earlier severe storms have gusted to near the I-57 corridor as of 925pm but the synoptic cold front is still off to our west, likely near the Mississippi River, but not well defined in surface obs due to the earlier convection. A few storms remain possible over the next several hours but mainly expect light showers through the overnight hours. Deubelbeiss && .DISCUSSION... Issued at 251 PM CDT Thu May 2 2024 Isolated convection has begun to fire early this afternoon near Peoria, along a subtle surface boundary. Latest SPC mesoanalysis shows close to 1500 J/kg of surface based CAPE across much of central Illinois, with steep low level lapse rates of around 8.5 C/km. Already have received some pea size hail reports with the Peoria cell. On a broader scale, numerous thunderstorms continue to develop over central Missouri and are traveling northeast. A general expansion northeast along the Illinois/Iowa border is expected over the next few hours, with storms becoming numerous over west central Illinois. Area remains in a Level 1 severe risk this afternoon and early evening, with some brief wind/hail risks. High-res models show some general weakening after sunset, though PoP`s will remain high over the eastern half of the forecast area through about 3-4 am. Timing of the overall system appears to have sped up though, and rain chances on Friday were significantly lowered and primarily limited to near/east of I-57. Overall, the upper air pattern over the coming days has not changed in the morning model suite. As the upper low over southern Saskatchewan lifts northeast, a larger low will track into northern California/Nevada this weekend, before ejecting into the Plains on Monday. The international models keep the closed low more or less intact through the period, while the GFS opens it up for a time. Net effect of this will be periods of showers and thunderstorms into the middle of next week. There are some signs of extended drier periods Friday night, and again later in the weekend, with more of an increase in PoP`s as the low moves into the Plains and gets more wound up. Tuesday remains a period of concern for potential for strong storms, with a number of European ensemble members featuring CAPE values upwards of 1500 J/kg. Overnight CSU machine learning probabilities also highlight Tuesday as a concern. Geelhart && .AVIATION... (For the 06z TAFs through 06z Friday Night) Issued at 1152 PM CDT Thu May 2 2024 Light rain and a couple isolated storms will accompany a cold front overnight. Winds will be a bit variable due to outflow from earlier storms, but will eventually set up out of the NW/NNW overnight as the synoptic cold front moves through. Precip will diminish behind the front but MVFR ceilings will overspread the terminals for several hours. Winds will veer to the NE Friday with VFR conditions returning the remainder of the period. Deubelbeiss && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$