If you want to know what to know what an “extreme weather day” is…look to today.

Today/tomorrow’s mid-latitude cyclone on the Great Plains and Midwest will be a powerful one and one which will provide something for everyone. Blizzards, wind, severe storms, flash flooding, fire…pick your poison, Nature will provide.

In places like Minneapolis and much of Nebraska, this storm threatens to be a historic late-season April heavy snow or blizzard event. In the southern Midwest and South, it threatens heavy rain, flooding and a tornado outbreak. On the southern Plains, strong winds and arid conditions, could further yesterday’s extreme fire behavior. Stay safe out there folks!

A reminder, I will be interviewed on the internet-based program Environmental Coffeehouse at 9 pm EDT/6 pm PDT tonight! A livestream will be available on their public FB page (so you should be able to see it regardless of whether you have a FB page or not). I will discuss abrupt climate change and increasing extreme weather events and how current events (ocean heatwaves, changing jet stream, etc) connect to our rapidly changing climate.

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The beast of an extratropical cyclone over the Great Plains today.
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Progression of the Great Plains/Midwest Cyclone Friday-Saturday.
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Probability of at least 4 inches of snow during the 24 hr period.

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Moderate Risk of severe thunderstorms (Level 4 out of 5) over Central and Southwest Arkansas and extreme northwest Louisiana and small portion of East Texas. Multiple tornadoes possible in the region, with isolated strong tornadoes. Damaging winds and very large hail also possible across a larger region from Iowa southward.

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Moderate Risk (Level 4 out of 5) of Flash Flooding across much of central and southern Arkansas into far northern Louisiana based on possible 1 to 3 inch rainfall rates.

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Extremely Critical Fire Risk (3 out of 3) from southern and Southwest New Mexico into West and North Texas and and western Oklahoma. Conditions exist for extreme fire behavior. Threat is being enhanced by winds associated with today’s cyclone.
If you’re wondering why all this is happening…VERY amplified…or in other words…very wavy jet stream pattern bringing extremely cold air (by April standards) down from from Canada to meet with up with extreme warm air (again by April standards) up from the south. Temps in 20s and 30s to the north with a high of 101 in Western Oklahoma yesterday to the south. Right now Lincoln, NE (where I am) is hitting 80 degrees for the first time this year. Tomorrow, Lincoln will peak in the mid-30s with falling temperatures!

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Massive long wave trough moving over the High Plains from the intermountain West of the US. The trough dips as far south as extreme northern Mexico.
The front end of this trough caused the development of the surface cyclone over Nebraska, intensifying deep moisture movement from the Gulf of Mexico (which, by the way, as a moisture source region, is running well above normal to start the year) and as and providing the deep vertical wind shear (rapidly increasing wind speeds with height) need to generate sustained severe thunderstorms. A recipe for a multi-threat mid-latitude frontal system. And it will not stop anytime soon. Saturday night, the threat will spread eastward, where a significant ice storm event may be possible for portions of upstate New York. In fact, Saturday afternoon, there may be much of Pennsylvania in the 70s while much of Upstate New York may be in the 20s! Incredible temperature contrasts for such a relatively higher latitude location.

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One model depiction (North American Model) show significant temperature contrasts over relatively short distances along a warm front near the PA-NY border Saturday Afternoon. NAM is a colder solution and there are disagreements on where freezing rain line may end up, but any major freezing rain this late in the season in Upstate New York will be quite unusual.

—Meteorologist Nick Humphrey

 

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Author: Meteorologist Nick Humphrey

Meteorologist and geoscientist in Lincoln, NE. Seattle, WA native. Love weather, storm chasing/photography and planetary science.

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