My Interview on ‘Environmental Coffee House’ with Sandy Schoelles (70 min)

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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

 

Stay safe out there today! Severe storms likely and in progress.

Nebraska is in the ice box still…but big storms, including tornadoes and significant straight line wind damage possible in parts of Indiana and Kentucky today.

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Warm, moist air, and lots of vertical wind shear. Good set up for some nasty severe weather.

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Prominent severe weather threat is between the polar and subtropical jets (northerly and southerly branches, respectively). In between, lots of mass is being removed allowing for storms to explode from below, intensify rapidly and maintain themselves in the highly sheared environment (winds rapidly increasingly with height).

There is a lot of speed shear, but not as much change in direction with height, which favors lines of storms. So the threat for damaging winds is quite significant, hence the “moderate risk” (4 out of 5 on the overall scale by the Storm Prediction Center) for a 45% chance of damaging wind reports within 25 miles of a point within the given region, and a 10% or higher chance of winds over 74 mph (hurricane-force). However, a significant tornado risk also exists for storms which do isolated themselves earlier this afternoon. So remain vigilant if you are in these areas and tell anyone you know to remain ready to take cover this afternoon and evening!

My part of Nebraska?

Unseasonably cold. Just straight up…cold. Starting off spring as if it were February with temperatures 25-30 degrees F below normal for highs and 15-20 degrees below normal for lows. Will have some recovery later this week, but near normal conditions (+-5 degrees F) don’t appear consistently likely until early next week. Thursday may give us a one day break with mid-50s (normal is around 60 F). So far our warmest day this year was March 3rd (73 F). The Great Plains have been part of the very wild weather pattern impacting much of the mid to upper mid-latitudes this year thanks to a highly oscillating jet stream with periods of very cold and very warm conditions relative to local norms. Much of Europe has gone through the same with very cold Arctic air mass spells, while the parts of the East Coast had record heat in February, followed by multiple cold and heavy snow periods from damaging nor’easters. All while the Arctic roasted in heat waves in this winter (relative to their norms) has significant heat and moisture moved northward, hitting sea ice hard. Here in my locality, we’ve had the roller-coaster ride of going from a a high of 4 to a high of 56 in ten days (January), a high of 22 to a high of 65 in seven days (February; and actually the high was 58 two days before that high of 22…ha!) to our mid-May days in early March (low-70s). Now after the last 5 days of March in the more seasonable 50s to low-60s, we’re spending the first three days of April barely above freezing. Winter was wild and Spring is starting off confusing weather even by spring standards. At least it’s not record breaking cold, it is unusually cold regardless though. Looking forward to the actual warmth of spring again.