Area Forecast Discussion
Issued by NWS Chicago, IL
Issued by NWS Chicago, IL
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187 FXUS63 KLOT 302042 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 342 PM CDT Thu May 30 2024 .KEY MESSAGES... - Dry and pleasant weather continues into tomorrow. - Rain (possibly with a few thunderstorms) on Saturday. - Periodic chances for showers and storms early to mid-week next week. && .DISCUSSION... Issued at 341 PM CDT Thu May 30 2024 Through Friday: Another spring-like day wraps up this afternoon, as temps climbed into the low 70s inland with 60s from the lakeshore to a few miles inland. High pressure will continue to track through the lower Great Lakes region into the Appalachians by Friday. The cooler overnight temperatures linger once again with forecast lows tonight in the upper 40s to low 50s. Easterly winds will shift to southerly heading into Friday, ushering warmer temperatures into the region to end the work week. Although sustained winds will remain nearly the same as today, some gusts in excess of 18-20 mph are anticipated Friday midday, bringing highs in the early afternoon near 80 inland while low to mid 70s hang around the lakeshore on the Illinois side. The only major difference featured tomorrow will be the arrival of clouds during the afternoon into the evening ahead of the next weather system. Baker Friday Night through Thursday: This year`s meteorological summer will start off on a crummy note as a low pressure system lifts northeastward into the area, encouraging an influx of moisture towards the lower Great Lakes. Increasing mid-level DPVA and low-level isentropic ascent/warm air advection will serve to erode dry antecedent air and bring a relatively expansive precipitation shield into the area overnight Friday into Saturday morning, which will then likely linger around in some capacity through most or all of the daytime on Saturday. Instability will remain meager at best and should stay mainly confined to our southern counties, which will thus stand the best chance to get a few rumbles of thunder before the system departs to the east. Precipitable water values as high as 1.50"-1.75" are progged to get drawn into our forecast area on Saturday and should support some healthy 1+" rainfall totals wherever the rain falls steadiest and longest. The introduction of any convective elements to locally enhance rainfall rates could lead to a need to watch for some localized minor flooding -- particularly in the most heavily urbanized areas of the Chicago metro -- but otherwise, not expecting any more notable concerns on the hydrologic front. With the rain and associated stratus expected to linger throughout much of the day, temperatures on Saturday should struggle to climb much above the 70 degree mark, and will likely remain mired in the low-mid 60s closer to the lakeshore as winds there turn northeasterly in response to the surface low passing by. Sunday looks like it should be dry as we find ourselves in between weather systems, though just enough moisture may be present to where we can`t completely rule out some isolated showers developing during the afternoon. With the jet stream remaining displaced to our north early to mid-week next week, it looks like we will enter a period featuring generally above normal temperatures and periodic shower and thunderstorm chances originating from disturbances tracking to our northwest. An initial shortwave trough will zip through the Upper Midwest Sunday into Monday, spawning a surface low whose cold front should eventually make its way towards our CWA on Monday. Much uncertainty remains at this time about the strength of the front, its timing of arrival, and whether a preceding outflow boundary may be generating convection out ahead of it before it arrives, among other things, but enough of a QPF signal exists in the latest EPS and GEFS to continue carrying the NBM`s likely PoPs and chance thunder probabilities in our gridded forecast for Monday. There should be enough pre-frontal instability to support the potential for some strong to severe storms as hinted at in CSU`s machine learning probabilities and CIPS analog guidance, but whether this potential will be realized will depend on the aforementioned factors and others, and these finer scale details probably won`t be able to be resolved for at least a few more days. Another opportunity for thunderstorms (and quite possibly strong to severe thunderstorms somewhere in the region) should then come late Tuesday and/or Wednesday as a more potent upper-level trough careens into the Upper Midwest, though Ogorek && .AVIATION /18Z TAFS THROUGH 00Z SATURDAY/... Issued at 1202 PM CDT Thu May 30 2024 VFR conditions with cirrus are expected through the period. NE winds around 10 knots will diminish tonight while veering SSE by sunrise Friday. Variability between 160-190 degrees is expected Friday morning before a lake-enhanced wind shift settles directions ESE mid to late afternoon. Kluber && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at weather.gov/chicago