Summer Is Here!
Updated: Jun 2, 2021
Starting The Season Off With Sunshine
We kick off meteorological summer today with plenty of sunshine and typical temperatures for the first day of the season. A big warm up is on the way for the weekend when it should feel like we jumped right into July.
Before I get into this week's forecast I want to review our spring which ended yesterday. It was a very warm and very dry season. Only 3.75" of rain fell in March, April and May making it the 3rd driest spring record. The average temperature was 52.1° to rank this past spring as the 7th warmest on record.
Average highs for the first day of summer are around 76°. Highs today should be right around average. A light breeze off the lake will keep it about 10° cooler at the lakefront.
Our wind will shift off the lake by midday and then stay off the lake through Wednesday. We will remain cooler lakeside through Thursday.
Our best chance of rain over the next two days comes tomorrow afternoon. The threat isn't that high but a spotty shower or isolated thunderstorm can't be ruled out especially south of the city.
The meteogram below considers several different model forecasts of temperatures. Our temperatures really take off later this week setting us up for a rather warm (some would say hot) weekend. Highs both Saturday, Sunday and even Monday will be near 90°.
The GFS model shows southwest winds bringing the heat all the way through the lakefront by Saturday. Highs soar well into the 80s. If the model verifies and we are at least in the upper 80s both Saturday and Sunday, this could be the warmest weekend in nearly nine months.
The temperature anomaly forecast has temperatures on Saturday around 10° to 15° above average. That means typical temperatures for the middle of July. Much of the country will be basking in mid-summer like warmth with temperatures from 10° to 20° above average.
We Need Some Summer Rain
As we shift into the new season the need for rain becomes even more critical for parched portions of northern Illinois. We need rain now before we move into July, the driest summer month on average.
Here is a recap of the drought situation that I shared in a recent post:
The latest analysis from the U.S. Drought Monitor showed virtually no change from last week. The area of the state in a moderate drought remains at 6.58%. There was also no change in the area in a severe drought. Nearly 3% of northern Illinois is in that category. That includes the north side of the city, northern DuPage & Cook counties, northeastern Kane county, all of Lake county and most of McHenry county. The percentage of the state that is abnormally dry dropped just .01%.
O'Hare ended up down 2.70" of rain below average for May making it the 23rd driest in the past 151 years. We ended up 6.49" of rain below average for spring.
The GFS model suggests some spotty showers or thunderstorms possible Wednesday afternoon but then dry weather through the weekend. Better chances for more significant are hinted at for late next Tuesday into Wednesday.
The GFS model total rainfall forecast through the weekend only spits out light rainfall amounts. The range of rainfall forecast varies from just a few hundredths of an inch to about a quarter of an inch. That means the drought should deepen this week.
Strong Warm Signal Continues
The longer range temperature probability forecasts are again showing a strong signal for a warmer than average period into the middle of June. The 6-10 day forecast strongly favors us for above average temperatures overall from June 6th through June 10th with probabilities between 80% and 90%. The longer range 8-14 day forecast continues to favor the Chicago area for above average temperatures overall from June 8th through June 14th with probabilities between 60% and 70%.
The even longer range Subseasonal Experiment (SubX) temperature anomaly forecast is favoring the Chicago area for a warmer than average middle and later part of June. The average highs for this period are in the lower 80s. The temperature anomaly forecast for the week ending June 18th has us outlooked for above average temperatures overall. The forecast for the following week ending on June 25th also has Chicago outlooked for above average temperatures overall.
Precip Pattern Not Promising
The long range precipitation probability forecasts aren't the best considering the ongoing drought. The latest 6-10 day forecast has Chicago favored for below average precipitation from June 6th through June 10th. The longer range 8-14 day forecast has us favored for about average precipitation overall from June 8th through June 14th.
Here is my 7 day forecast:
Today: Partly to mostly sunny, milder High: 76 (66 lakeside)
Wednesday: Partly/mostly cloudy, pm sct. shower/t-storm possible Low: 58 High: 75 (67 lakeside)
Thursday: Partly to sunny, sct. shower/t-storm possible Low: 58 High: 81 (68 lakeside)
Friday: Mostly sunny Low: 62 High: 85
Saturday: Mostly sunny Low: 69 High: 90
Sunday: Partly to mostly sunny Low: 69 High: 89
Monday: Partly to mostly sunny, sct. t-storm possible Low: 70 High: 88