Don Day: Get Ready for Winter Weather “With a Vengeance”

The cold air will really come in and temperatures will be 25 to as much as 35 degrees below average by Thursday

Annaliese Wiederspahn

March 31, 20205 min read

John mcclain

Wyoming’s weatherman Don Day says enjoy the nice weather while we have it because winter is coming back.

Conjuring John McClain: With a vengeance. Yippee-Ki-Yay.

You can watch the whole forecast in the video (above) or you can follow along here. This is a rushed transcription of Don Day and we added some slides in to make it easier to follow.

“We’ve got a bit of winter I’m afraid to say coming our way.

The last thing you want to hear that it is going to get cold and wintry again but it will in many areas.

We have a strong Pacific cold front coming our way that is going to bring much colder temperatures and some snow.

It is going to be much colder than average and it will be unsettled. But it usually is in the first half of April.

We’ve got some episodes of probably much colder than normal temperatures at times during the first half of the month.

Our patience is going to be tried certainly by the weather over the next two – three weeks.

European model

As for the precipitation thru Friday, the European model shows a lot of blue and yellow. You can see all the yellow up in the Yellowstone National Park, Jackson, and the Wind Rivers.

There’s going to be a big flow of moisture from the northwest. That’s a really good pattern for the Yellowstone plateau to get some late season snowpack as well as the Big Horns here.

European model

You can see it spreading into the central and southern parts of the state too.

There is this axis of heavier moisture that will form along the front here. As the front comes across the state, some upper level moisture and energy will converge in this area and we are expecting to have some fairly decent amounts of snow that I think will cause some travel concerns.

European model

The American model is much more wet than the European model. Both models are showing the same areas will get moisture so that’s good consistency.

But the moisture on the American model is twice as much as the European model. When you see a situation like this, we usually split the difference.

American model

But where will the moisture fall?

There is an axis of light to moderate precipitation in this area here. A bullseye of heavier moisture in Wyoming’s northwest mountains.

American model

If this model ends up being more correct, we will have travel impacts for sure on I-25 and I-80 because temperatures are going to be really cold with this system.

Let’s take a look at the snowfall output.

European model snowfall

This is the European model. This may be under-doing the forecast a bit but the important thing to show you here is how widespread the snowfall is going to be. It also shows you how cold the air will be behind the cold front.

Temperature change

Here is the temperature change as we get on into Thursday afternoon. What you see here aren’t temperatures. This represents the deviation from normal.

You can see along the divide here, the cold air really comes in and temperatures are 25 as much as 35 degrees below average by Thursday with the deepest coldest air along this purple boundary right here.

Map showing temperature deviation from normal

When you are talking 25-30 degrees before normal that is a serious cold wave , no matter what time of year it is.  This will grab your attention for sure.

We could conceivably have some areas in the upper single digits for lows.

Overnight Thursday and Friday it is possible.

This is the forecast for Thursday afternoon. The Pacific front is right along the axis here and here’s the cold air coming right up out of Canada and behind this trough.

There is plenty of cold air that will be funneling in with this system.

By the weekend, we do get into a southwest flow again so this will be the typical roller coaster ride for spring.

Warm air by the weekend

Over the weekend and early next week, it will warm-up but by late Tuesday to Wednesday the trough swings thru and that should bring mountains snow and rain and snow in the plains.

Look at all that blue. That’s a lot of very cold air for this type of year. And look at the jet stream. 

This cold doesn’t have a way to escape this way. It will get driven south first. And if we go out further to 15 days from now, boy look at that. That is cold. This is for April 15.

We think the first half of April while it is going to have some warm periods, but it also will have more opportunities for winter weather to come. 

When we see a pattern like this in the middle of April, we are always concerned with the larger, bigger storm system coming together with people calving in the month of April, stockgrowers pay attention.

Thanks for watching.

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Annaliese Wiederspahn

State Political Reporter