It's Spring Winter's Over*

*just kidding.


A warm-up is coming to the Midwest this weekend that could set a number of record highs in the Chicagoland area. However, a note: this all bears watching because forecasts this far out are subject to change.

"OK Mick, set it up for me."


The unbelievable warmth will be due to a mesoscale ridge of high pressure that will translate over the area and be met with reinforcements. Let me lay it out for you:

Late Thursday a large-scale ridge of high pressure will slide eastward and strengthen as it translates into the Midwest. Here's a map showing 500mb temperatures (25,000 feet above the ground) as warm as -16 degrees Celsius (3 degrees Fahrenheit) stretching all the way up into central Ontario as the main axis of the upper ridge is centered on Minneapolis on Friday:

The ridge will be met with reinforcements on Saturday as it translates slightly eastward, with 500mb temperatures peaking around -12 degrees Celcius (10 degrees Fahrenheit) over Lake Michigan:

By Monday, a surface low pressure will begin to ride up the backside of the powerful ridge and, as it does so, will drag a potent warm front up from the Gulf of Mexico. The strong southerly flow out ahead of the storm should keep temperatures soaring through Tuesday before a weak cold front plows through the area on Wednesday.

PART 2. The important stuff: Beach-weather surface temperatures

So how does it all translate to weather here at the surface? Well, here is Mick's (rough/preliminary) forecast for how these upper-level large-scale features translate to high temperatures (and comparison with the existing record highs at O'Hare airport):

Forecast vs. Record Highs (O'Hare Airport)

Here are the charts from the National Weather Service showing the forecast highs for Friday, Saturday and Sunday:

Warm, warm, warm!


As I stated at the beginning, this all bears watching because forecasts made this far out are always subject to change. That said, the large-scale upper-level features have remained fairly constant in the models for several runs now and there is high likelihood that at least a minor warm-up is in store for the area. Additionally, these forecast highs are liable to change between now and the weekend, with actual conditions being considerably cooler or, even warmer!

Stay tuned.


x Mick

Mika ToscaComment