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Area Forecast Discussion
Issued by NWS Chicago, IL
Issued by NWS Chicago, IL
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646 FXUS63 KLOT 190516 AFDLOT Area Forecast Discussion National Weather Service Chicago/Romeoville, IL 1216 AM CDT Fri Jul 19 2024 .KEY MESSAGES... - Generally quiet weather pattern persists through the weekend. - Chances for showers and thunderstorms return early next week (20-40%). && .DISCUSSION... Issued at 153 PM CDT Thu Jul 18 2024 A deep, positively tilted upper level trough prevails over Quebec and Ontario extending southwestward over the Great Lakes and mid-Mississippi Valley. With lingering mid level moisture and some diurnal heating, some light fair weather cumulus around 5000 feet dot the skies. Otherwise quiet conditions will continue as the upper level trough axis very gradually moves to the east. Models are suggesting some minor ridging and height rises through tonight providing higher confidence in drier conditions. Another weak wave is forecast to move down the longer wave on Friday, but with higher p-wats to the southwest away from the area, no precipitation is expected. Surface high pressure will grow into the weekend allowing temperatures inland to gradually creep up into the low 80s, while east to northeast winds will help keep cooler 70s along the lakeshore. Ensemble models are still suggesting a strengthening upper level low early next week over the Plains will slowly drift over the forecast area early next week. The potential for scattered shower and thunderstorm activity could be to our west as early as Sunday before gradually moving east through Wednesday. Guidance has kept the bulk of the activity in the traditional diurnal range, so felt it was appropriate to keep precip chances around 30 to 40 percent. Temperatures are currently projecting to be around seasonal norms as they nudge toward the mid 80s next week. DK && .AVIATION /06Z TAFS THROUGH 12Z SATURDAY/... Issued at 1215 AM CDT Fri Jul 19 2024 VFR conditions are forecast through the TAF period with FEW-to- SCT 5000-6000 ft diurnal cumulus. Winds will be light westerly to at times variable overnight through midday before an expected inland push of the lake breeze turns winds easterly at GYY/MDW/ORD. Guidance has trended a bit faster with the lake breeze arrival at MDW and accordingly nudged up the wind shift to 19Z. Have maintained 20Z at ORD for now but will continue to monitor trends. Winds then return to light and variable Friday evening with increasing high clouds toward Saturday morning. Petr && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at weather.gov/chicago