Warmest Weekend Of Winter
The skyline was illuminated with sunshine this morning at daybreak. Large chunks of ice are seen floating in Lake Michigan's waters. That ice is fading fairly fast. The ice cover on the lake has dropped dramatically over the past week. As of yesterday the ice concentration on Lake Michigan has fallen to just 14.4%.
Meteorological spring starts in just three days. This will be the last weekend of winter and it should be the warmest of the season. If my forecast verifies, it will be the warmest weekend since late November.
Yesterday was the fourth day in a row with a high of 40° or warmer. This mild stretch has melted quite a bit of snow. Three inches melted away yesterday to drop the snowpack at O'Hare to seven inches. Eleven inches has melted in the last week.
Today will be the fifth day in a row with above average temperatures. Look for some sunshine and a southeast wind to push our highs into the lower to middle 40s. Average highs for this date are around 39°.
Staying Above Freezing
We will stay well above average this weekend then drop a bit below on Monday before bouncing back again next week. Our highs should stay above freezing all the way through at least next Thursday.
The temperature anomaly forecast for this Saturday shows most of Illinois about 10° to 20° above average. Highs should top out around 50°. Nearly everyone east of the Rockies should enjoy a milder than average Saturday.
We should enjoy two relatively mild weekends in a row. The forecast for the first weekend of March is mild too. The temperature anomaly forecast for a week from Sunday has temperatures here around 20° above average that evening. It shows an even greater portion of the country enjoying above average temperatures compared to this Saturday's forecast.
Slim Snow Threat
The latest GFS model's meteogram does not show any significant snow for at least the next ten days. It has some light rain for us early Saturday morning and then another round of light rain late next Friday into the following Saturday.
The accumulated snowfall meteogram for O'Hare shows the range of snowfall predictions from several models. A few models squeeze out some light snow late tonight into early Saturday morning. The model range is between about a tenth of an inch to nearly a half of an inch. Any light snow that falls tonight would be mixed with some light rain and melt quickly early tomorrow.
The GFS model total snowfall accumulation forecast does suggest a light dusting of snow for some spots north of the city tonight. It squeezes out just under a half inch near the Wisconsin border.
The European model also spits out a dusting of snow overnight mainly north and northwest of the city. It lays down a quick tenth to two tenths of an inch in total.
Mild Pattern Marches On
Most of the country might be enjoying a milder than average pattern right into the middle of March. Average highs for this period in Chicago are in the lower 40s. The latest 6-10 day temperature probability forecast has us outlooked for above average temperatures overall from March 3rd through March 5th. The longer range 8-14 day forecast keeps Chicago favored for above average temperatures overall from March 5th through March 11th.
More Moisture By Middle Of March
The long range precipitation probability forecasts bring in more precipitation towards the middle of next month. The 6-10 day forecast favors us for below average precipitation overall from March 3rd through February March 7th. The longer range 8-14 day forecast has us outlooked for near normal precipitation overall from March 5th through March 11th. 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: Partly to mostly sunny High: 45
Saturday: Partly to mostly sunny Low: 33 High: 50
Sunday: Partly to mostly cloudy Low: 35 High: 48
Monday: Mostly sunny Low: 26 High: 38
Tuesday: Partly to mostly sunny Low: 25 High: 45
Wednesday: Partly to mostly sunny Low: 34 High: 48
Thursday: Partly to mostly sunny Low: 38 High: 50