The Rise Before The Fall Then A Bigger Rise
Some sunshine early today will help our highs climb into the lower 60s for most areas but a bit cooler along the lakefront. A brisk breeze off the lake will kick in late this afternoon and temps will fall into the 40s along the lakeshore with that cool air sweeping well inland temps will fall into the 50s in the burbs. The HRRR model shows the warmest part of today will be around 2 to 3 this afternoon but beginning around 6 this evening temps drop dramatically.
HRRR Forecast 3 PM Temps HRRR Forecast 7 PM Temps
The hourly forecast for O'Hare shows that sudden drop in temps during the latter part of the afternoon. That drop coincides with the wind shifting off the lake late in the afternoon. Temps bounce back well into the 60s for most tomorrow but a southeast breeze will keep it cooler again along the lakefront with upper 50s there on Wednesday.
On average our first high of 70° occurs on May 15th. We should see highs near 70° on Thursday and into the lower 70s by Friday. The GFS model shows 70s Friday west and south of the city but cooler north and along the lakefront.
Warmer weather this time of the year usually means wet weather at times as we make the transition to a warmer and more humid air mass. Showers and thunderstorms are likely Thursday into early Friday and again later Saturday into early Sunday. Some of the storms Thursday could be strong south and west of the city according to the Storm Prediction Center.
On average the first day with highs of 80° occurs on June 15th. We could see our second day this year with highs hitting 80° or more on Tuesday next week. If we top 80° it would be the warmest day of the year so far and the warmest in over 7 months. The last time we had a high over 80° was October 1st last year when the high hit 86°.
The latest 6 to 10 and 8 to 14 day temperature probability outlooks have us favored for above average temperatures from May 17th through the 25th. This represents a pattern shift that kept the west warmer than average and nearly everyone from the Rockies east cooler than average the past several weeks. April came in .6° below average for O'Hare and May so far is 5.6° below average. Phoenix, on the other hand, came in 1.5° above average for April and 7.2° above average for May so far. The warmer spring pattern indicated by these latest outlooks could be the beginning a longer stretch, maybe through most of the summer, of above average temps overall.
Here is my 7 day forecast:
Today: Partly to mostly sunny High: 60 (55 Lakefront) Temps Fall Late
Wednesday: Partly to mostly cloudy Low: 43 High: 64 (60 Lakefront)
Thursday: On & off showers/thunderstorms Low: 52 High: 70
Friday: Sct. showers/t-storms early then partly sunny Low: 55 High: 71 (59 Lakefront)
Saturday: Partly to mostly cloudy, pm sct. shwr/t-strms Low: 51 High: 70 (60 Lakefront)
Sunday: Shower possible early then partly sunny Low: 56 High: 71 (59 Lakefront)
Monday: Partly to mostly sunny Low: 38 High: 75 (67 Lakefront)