Will Coming Rain Stop The Deepening Drought?
Mostly Dry Today
Most of this Friday will be dry but a few spotty showers (especially south late this afternoon) can't be ruled out. We need more than spotty showers though to hold off a deepening drought. More on that coming up.
Thursday was the fourth day in a row with temperatures below average. We should be about average today and then at least a bit below average through the weekend but a big warm up is still scheduled for early next week.
Average highs for today's date are around 62°. Today's highs should reach into the lower 60s. An early taste of summer arrives next week. More on that below.
Drought Deepens Slightly For Some
There are at least three rounds of rain in the forecast over the next ten days and it may come just in time to head off an expanding drought in northern Illinois. The GFS model brings the first round of rain in late today into early Saturday. The middle of next week could be wet with periods of showers and thunderstorms Tuesday night through Thursday. The last round of rain would be moving in for the following weekend.
We are running well below average in terms of rainfall for both the month of April and for this spring so far. We are running 1.81" below average on rainfall for the month and just over three inches below average since March 1st. The GFS model precipitation forecast through Saturday afternoon has a range of rainfall from as little as around a tenth of an inch north of the city to nearly a half inch south of Chicago.
More significant rain could come during the middle of the week. Showers and thunderstorms look likely from Tuesday afternoon and continuing at times through Thursday. The GFS model shows total rainfall (including this weekend's too) through Friday morning ranging from around 2.5" to over three inches in total.
The U.S. Drought Monitor's latest update shows a deepening drought in northern Illinois. It has expanded in the past week from mostly Lake County to now include much of Cook County, all of DuPage county and portions of McHenry, Kane and Will county. The portion of our state in a moderate drought is now more than six times bigger compared to last week. 3.8% of the state is in a moderate drought compared to just .57% last week. The portion of Illinois that is now considered "abnormally dry" or just one level below a moderate drought, has increased from 16.26% last week to 22.47% this week.
Indiana has not seen any change in the portion of their state that is in a moderate drought (2.27%) but the "abnormally dry" area has expanded from 17.74% last week to 29.4% this week.
The western U.S. is in much worse shape and facing its first-ever water shortage declaration. The drought situation there is dire. Nearly every category of drought has deepened there compared to last week. Almost 83% of the west is in at least a moderate drought and over 40% is in an extreme drought.
Just Like June By Tuesday
The hourly temperature meteogram compares many different forecast models. Highs today will be right around average then we dip below for Saturday and Sunday. We spike well above average with 70° or warmer highs by Monday and 80° or warmer by Tuesday.
Southwesterly winds along with some sunshine will help to push those highs to near 80° by Tuesday. Those are typical temperatures for the middle of June.
The temperature anomaly forecast shows the eastern half of the country basking in unseasonable warmth Tuesday afternoon. The biggest jump in temperatures on the warmer side of average will occur in and around Chicago that day.
Moving Back To About Average
April started off above average and then dipped below towards the middle of the month. The long range temperature probability forecasts favor us to settle back to about average for the end of April into the start of May. The latest 6-10 day forecast has us outlooked for around average temperatures overall from April 28th through May 2nd. The 8-14 day temperature probability forecast also has us favored for around average temperatures overall from April 30th through May 6th. Average highs for the end of April into the start of May are in the middle 60s.
The even longer range Subseasonal Experiment (SubX) temperature anomaly forecast is signaling a cooler than average pattern for the first couple weeks of May. The temperature anomaly forecast for the week ending May 7th has us outlooked to be a around or a bit below average overall. The forecast for the following week ending on May 14th has Chicago below average overall. Average highs for this period are in the middle to upper 60s.
Drying Out By Start Of May?
The long range precipitation probability forecasts favor us for above average precipitation to close out April and then move us back to about average to start off May. The latest 6-10 day forecast still has Chicago favored for above average precipitation from April 28th through May 2nd. The longer range 8-14 day forecast has us favored for about average precipitation overall from April 30th through May 6th.
Here is my 7 day forecast:
Today: Partly to mostly cloudy, rain possible late mainly south High: 61
Saturday: AM showers, mostly cloudy, spotty pm showers Low: 43 High: 57 (cooler lakeside)
Sunday: Partly to mostly sunny Low: 38 High: 54 (cooler lakeside)
Monday: Partly to mostly sunny Low: 40 High: 72 (cooler lakeside)
Tuesday: Partly to mostly cloudy, windy Low: 59 High: 81
Wednesday: Mostly cloudy, sct. showers/thunderstorms Low: 58 High: 69 (cooler lakeside)
Thursday: Mostly cloudy, on & off showers Low: 48 High: 60 (cooler lakeside)