Area Forecast Discussion
Issued by NWS Chicago, IL
Issued by NWS Chicago, IL
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582 FXUS63 KLOT 080731 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 231 AM CDT Sat Jun 8 2024 .KEY MESSAGES... - Scattered showers with a few rumbles of thunder today. - Northeast wind shift with a cold front this afternoon, bringing cooler temps and a short period of choppy 2-4 foot waves to Lake Michigan beaches. - Northwest winds gusting to 30 mph Sunday. - A shift toward warmer temperatures and higher humidity remains on track for the third week of June && .DISCUSSION... Issued at 230 AM CDT Sat Jun 8 2024 Through Sunday: Scattered showers are expected later this morning and into the afternoon and there has been an overall trend upward in coverage with the 00z guidance. Given current precip coverage with this wave across MN, this upward shift looks reasonable and have raised pops to likely for areas along and north of I-80. Still some timing uncertainty which may need later refinement. There will likely still be some dry hours, but after mid/late morning, difficult to pin down when those would be. Areas south of I-80 may stay mainly dry this morning and then as the activity across the northern cwa shifts southeast, best precip chances will be in the late afternoon and early evening. Instability remains quite limited with perhaps the best chance for thunder southeast of I-57 later this afternoon into this evening but maintained slight chance (15-20%) for thunder areawide this afternoon. This expected precipitation and mainly cloudy skies will likely keep high temps only in the lower to mid 70s and once the showers begin, temps may drop back into the upper 60s. A cold front will be moving south down Lake Michigan today and all of the guidance has sped up the arrival of this front, likely moving through northeast IL during the mid afternoon hours and then into northwest IN by late afternoon. Winds will shift to the northeast and depending on where temps are at, they will likely fall further into the lower/mid 60s behind the front. While it may be brief, an increase in winds over southern Lake Michigan will likely lead to a period of increased waves of 2-4 feet and a moderate risk for rip currents. Lows tonight are expected to dip into the mid 50s for most of the area with clouds slowly clearing. Mostly sunny to start Sunday with increasing clouds later in the afternoon. Winds will steadily increase during the morning with gusts into the 30 mph range during the afternoon, especially north of I-80. cms Sunday Night through Friday: Pleasant conditions are forecast through the first half of the upcoming week. An expansive surface high will remain to our northwest at the start of the workweek resulting in northerly surface flow across the area. This will result in notably cooler temperatures on Monday with highs only in the 60s to lower 70s. Overnight lows Monday night could even dip into the 40s outside of Chicago. Long range guidance is beginning to come into a bit better agreement with the handling of the upper level pattern though there remain timing differences. The general trend is toward drier conditions through midweek due to dry low levels amidst an expansive area of surface high pressure limiting precip potential as weak disturbances move within the upper jet. It is possible portions of northern Illinois are grazed by showers moving across Wisconsin toward midweek. Temperatures very gradually through midweek with highs back into the 80s by Wednesday and near 90 on Thursday. A frontal passage Thursday night into Friday could bring our next chance of showers and storms (currently at 20%). There continues to be a longer range signal for above normal temperatures and higher humidity across the region for the third full week of June as upper level ridging builds across the eastern half of the CONUS. Petr && .AVIATION /06Z TAFS THROUGH 12Z SUNDAY/... Issued at 1255 AM CDT Sat Jun 8 2024 Key Messages: - SHRA potential mid-late morning through early evening with associated MVFR CIGS/VSBYS - Northeast wind shift with cold front mid-late afternoon A pair of disturbances moving across the region are still on track to bring periods of showers to the area today. Have sped up the SHRA arrival time with this update based on the latest hi-res guidance trends. Also opted to convert the prevailing VCSH to -SHRA due to an anticipated broader time window for scattered showers across the area. Ceilings will also gradually trend down to MVFR as shower coverage increases along with associated reductions in visibility to MVFR in the steadiest showers. IFR cigs/vsbys are not out of the question though confidence is not high enough to include with this update. While no TS is officially included in the TAF a few embedded lightning strikes cannot be fully ruled out at the terminals. The better potential remains mainly south of I-80. Light and variable winds are expected early this morning, eventually prevailing SSW after daybreak. A cold front will move across the area mid-late afternoon. As it does so, a strong northeast wind shift may occur across the Chicago area terminals. Accordingly have introduced an 020 direction with this update at ORD/MDW at 22Z. The timing of this wind shift will be refined with later updates. Winds then gradually ease and settle back into a NW direction after sunset. Petr && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at weather.gov/chicago