The Short Term & Long Term Spring Forecast is Mild
Long Term Trend Is Warmer
Meteorological spring started off a bit below average on Monday. Every spring will have its ups and downs in terms of temperatures but the long term trend shows Chicago's springs have gotten warmer. The season is also producing more days above average.
We are not alone. Most of the country has seen an increase in its average spring temperature over the past fifty years. Climate Central's study of 243 cities in the U.S. reveals nearly half of them have seen a bump of 2° or warmer since 1970. 96% of cities have seen an increase in the number of above-average spring days during that fifty year period. The vast majority of those cities (81%) had an increase of at least 5 days.
The study noted some implications from this spring warming:
Warming spring temperatures follow a pattern of warmer seasons encroaching on the cold of winter—shrinking periods of cold that are important for the production of fruit, management of pest populations, and throwing the timing of natural events (known as phenology) into misalignment. Earlier snowmelt can result in changes in water availability and challenges to the breeding of native fish. Earlier spring temperatures can also lengthen the growing season, supporting longer pollen allergy seasons that start earlier and stick around for longer.
Most of Illinois had a bump in the average spring temperature of at least a degree. From the perspective of a day to day weather forecast standpoint that might not seem like much but from a climate standpoint it is significant.
The warm up over the past 50 years for Chicago means a little more than four additional above average spring days over the course of the season.
Some sunshine and a gusty southwest wind should push our highs into the lower to middle 40s today. The average high for this time of the year is 41°.
Even though we do bounce back a bit above average today the wind will make it feel colder. Winds could gust to near or just above 30 mph this afternoon. The combination of temperatures and wind will make it feel like the 20s and 30s.
First 60 Of The Season?
Temperatures for at least the next seven days should be above average. There will be a wind off the lake Thursday through Saturday so temperatures will be noticeably colder near the lake. It's possible we could see our first 60° high of the year early next week.
The temperature anomaly forecast has us nearly 20° above average by Monday. That would mean a high around 60° since average high temperatures this time of the year are around 41°. Most of the country will be enjoying rather mild March weather too. Blues on this map mean areas favored for temperatures below average while reds and browns represent areas where temperatures are forecast to be above average. Next Tuesday and Wednesday's anomaly forecasts look similar.
Quiet Pattern Continues
The latest GFS model's meteogram does not show any measurable rain or snow until next Monday. There is a small chance for some light rain Monday and then more significant rain towards the middle of next week. Notice all the blue depicted in the cloud cover forecast for the next several days. That means plenty of spring sunshine through the weekend.
Relatively Mild Through Middle Of March
The signal remains strong for a mild pattern well into March. This doesn't rule out a few colder than average days but it suggests above average temperatures overall into the middle of the month. The latest 6-10 day temperature probability forecast has us outlooked for above average temperatures overall from March 7th through March 11th. The longer range 8-14 day forecast keeps us favored for above average temperatures overall from March 9th through March 15th. The Midwest has some of the highest probabilities for this mild pattern.
The even longer range Subseasonal Experiment (SubX) forecast has a mild pattern for March continuing right through nearly the end of the month. The forecast for the week ending March 19th keeps us milder than average overall. Chicago and northern Illinois is favored for more above average temperatures overall for the following week ending on March 26th.
Pattern Poised To Become More Active
It's carwash weather this week with little to no precipitation expected for the next several days. This quiet pattern could be ending next week. The 6-10 day forecast favors us for above average precipitation overall from March 7th through March 11th. The longer range 8-14 day forecast has us outlooked for above average precipitation overall from March 9th through March 15th. The risk for spring flooding is above average for many area rivers. More on that below.
The Climate Prediction Center's seasonal forecast for spring suggests a mild and moist pattern overall here. The temperature probability forecast for the months of March, April and May have us outlooked for above average temperatures overall. The precipitation probability forecast for the same period has us outlooked for above average precipitation overall.
Spring Flood Risk Forecast
The National Weather Service considers many risk factors for spring flooding. They include snow cover, soil moisture, and current river conditions.
"A significant snow cover with high water content can increase the chances of flooding once warmer weather melts the snow. Elevated soil moisture conditions reduce the amount of rainfall that is soaked up by the ground and increase the amount of water that then runs off into area streams. Above average river levels reduce the river rise required to reach flood stage, while below average river levels would require an increased amount of river rise to reach flood stage."
Their latest forecast suggests the flood risk is above average for many of our area rivers. The Des Plaines and Fox rivers in particular need to be watched closely.
Here is my 7 day forecast:
Today: Sunny skies, breezy (gusts to 30 mph) High: 43
Wednesday: Partly to mostly sunny Low: 34 High: 45 (cooler near the lake)
Thursday: Partly to mostly sunny Low: 32 High: 40 (cooler near the lake)
Friday: Mostly sunny Low: 28 High: 46 (cooler near the lake)
Saturday: Mostly sunny Low: 29 High: 50 (cooler near the lake)
Sunday: Mostly sunny Low: 29 High: 52
Monday: Partly to mostly cloudy Low: 40 High: 59