Category: Posts EN

 

Typically by this time in April, cold air has begun to retreat to the wilds of Canada, leaving behind longer, warmer days even across the U.S. northern tier. However, a powerful spring storm is helping to produce heavy precipitation on top of a frigid near-surface air mass. Temperatures this afternoon in Buffalo, NY have hovered around 30 deg (-1 deg C), colder even than the average low temperature this time of year. Significant warming is not expected in the next 18 hours, setting the stage for an unusually late, major icing event.

This same dynamic storm system has been responsible for blizzard conditions in the Central Plains and Midwest as well as big tornadoes in the South. The storm is pushing moisture and warm air into the Northeast, but a stubborn layer of cold air near the surface will cause traffic and power outage headaches. Freezing rain and sleet will lead to ice accumulation up to 0.5 inch (1.25 cm), locally higher, across the Great Lakes, Northeast, and adjacent Canada. As you can see from the models below, there’s still some question about where the heaviest icing will occur. However, there is a general consensus on interior portions of Ontario and New York, especially where mountains can shelter pockets of subfreezing air.

 

 

Many areas will see temps rise above freezing just enough later in the day on Monday to end the icing threat. However, expect hazardous travel conditions tonight through Monday morning at least. Scattered power outages will be a concern as well due to ice accrual and gusty winds felling tree branches and powerlines.

 

A strong, wide-ranging mid-latitude cyclone is spinning across the Plains. On the cold side, bands of heavy snow are combining with high winds to create dangerous blizzard conditions. On the warm side, severe storms are producing high winds, large hail, and even some strong tornadoes (see tweets below). In other areas, heavy icing and wind-driven wildfires threaten large swaths.

 

 

Exactly what NOT to do: Head on with a tornado!

Mountainburg, AR

Credit/Permission: Scott Michaels#ARwx pic.twitter.com/1tqiMYpJo9

— Live Storm Chasers (@LiveStormChaser) April 13, 2018

 

 

Pea to nickel size #hail falling on the east side of Sioux Falls. Time is 7:03 AM CDT. #SDwx @NWSSiouxFalls pic.twitter.com/vRU8j2kJ58

— Derek Thompson (@DerekjT1003) April 13, 2018

 

The storm system will move east and by Saturday, the severe storm threat will shift to the mid-South (see graphic below from the Storm Prediction Center). Meanwhile, heavy snow and mixed precipitation will continue to keep residents across the northern tier in winter’s icy grip.

 

A potent spring storm will spin up across the Central US on Friday and impact much of the country through Sunday.

Severe thunderstorms will develop to the south of the storm track, while heavy snow and blizzard conditions will impact communities to the north of the storm track.

Severe Thunderstorm Outlook:

Severe thunderstorms will erupt in the warm side of the storm along and ahead of a cold front beginning Friday afternoon.

Damaging wind and large hail are expected to accompany the severe storms. Additionally, the risk for several tornadoes will exist Friday afternoon and evening across portions of Iowa and Missouri.

As the cold front marches eastward, so will the risk for severe storms. The Tennessee Valley will be ground-zero for severe weather on Saturday, while the threat will shift to the Southeast coast on Sunday.

Damaging winds and large hail will be the primary concerns with severe storms this weekend.

Winter Weather Outlook

Snow will break out across the northern and central High Plains on Friday as low pressure develops.

The snow will streak eastward into portions of the Midwest and northern Great Lakes Friday night and over the weekend. A significant accumulation of snow is expected from Nebraska to northern Michigan.

As low pressure strengthens across the Plains, strong winds will develop and create blizzard conditions. Farther east, snow will mix with of freezing rain and sleet across southern Wisconsin and central Michigan.

Ground and air travel will be severely impacted by the expected snow, ice, and wind through this weekend.

By Monday the wintry part of this storm will wind down across the Central US, however, snow showers will linger across the Great Lakes.