Tuesday 02 April 2024 - **A strong and dynamic spring storm system impacts a large part of the nation next few days...severe weather in its warm sector…significant accumulating snow up north**

NOAA’s “weather warnings map” is full of colors today…never a good thing. In the northeastern quadrant of the nation there are “Winter Weather Watches and Warnings” (purple, pink, blue) across the Upper Midwest and Northeast US, flash flood watches and warning (green) in the “I-80” states from Illinois to PA, and tornado watches (in yellow) across portions of the Ohio Valley. Map courtesy NOAA/WPC

Overview

A double-barreled storm system will impact a large part of the nation from today through Thursday with an initial (primary) low located over the Upper Midwest and a secondary is to form later tomorrow near the Mid-Atlantic coastline. The initial system is producing severe weather today across the Ohio Valley and there are waves of heavy rain running all along the “I-80” states from Illinois-to-Pennsylvania with “flash flood watches and warnings” issued in most areas. The severe weather threat will shift to the east on Wednesday raising the chances for strong-to-severe thunderstorm activity in the southern Mid-Atlantic and eastern Carolinas.

Farther north, it is cold enough for accumulating snow today across portions of Minnesota and Wisconsin and some spots will get dumped on over the next 24 hours. The accumulating snow threat will shift a bit to the east to Michigan by later tonight and perhaps to the south on Wednesday into Iowa and Illinois. Once the secondary storm gets going near the east coast later tomorrow, the accumulating snow threat will shift from the Upper Midwest to the interior Northeast US and some spots in interior New York State and New England will get dumped on by the time Thursday evening rolls around.

Severe weather is a threat today and tonight across much of the Ohio Valley with a prime area of concern in the states of Ohio and Kentucky. Map courtesy NOAA/SPC

Severe weather threat

Strong low pressure is now centered over the Upper Midwest and it is generating a potpourri of weather conditions including snow to the north (e.g., Minnesota, Wisconsin) and severe weather in its warm sector. A line of strong-to-severe thunderstorms is pushing east at mid-day across southern Ohio and northeastern Kentucky and will soon reach West Virginia. Some of these thunderstorms have the capability of spawning tornadoes and this threat will continue across the Ohio Valley through the rest of the day and into the evening. This particular line of thunderstorms will tend to weaken as it reaches the western part of Virginia later in the day as it encounter some much cooler air; however, they still may produce some heavy downpours and small hail in portions of Virginia. The overall threat of severe weather will shift to the east a bit on Wednesday raising the chance for strong-to-severe thunderstorms in the southern Mid-Atlantic and across the eastern Carolinas.

Accumulating snow will be significant over the next few days with initial storm impacting the Upper Midwest (today and tomorrow) and a secondary storm to impact the interior Northeast US (later tomorrow into Thursday). Map courtesy NOAA, tropicaltidbits.com

Accumulating snow

In the cold sector of the storm, snow is currently falling across portions of Minnesota and Wisconsin and the western/northern parts of Michigan will get in on some of that action as well by tonight. Over the next 24 hours or so, the snowfall can become quite significant; especially, across the state of Wisconsin where a foot or more of heavy, wet snow can pile up by late Wednesday. The snow over the Upper Midwest will be slow to exit on Wednesday as the initial (primary) low will stop in its northward advance and tend to meander around for awhile - even take a southward move - extending the chances of snow into tomorrow night and perhaps a little to the south of today’s action across Iowa and Illinois.

Dynamics will become very impressive over the Northeast US from late tomorrow into Thursday and this raises the chance for quite a thumping of heavy, wet snow in some spots (i..e, heavy snow bands) and there can be “thundersnow” included during this powerful storm. Map courtesy NOAA, tropicaltidbits.com

Meanwhile, low pressure will begin to form on Wednesday near the Mid-Atlantic’s coastline and will then intensify rapidly later tomorrow night. As a result, colder air will begin to filter to the south and east from the Great Lakes and snow is likely to break out across interior New York and New England. As is the case across the Upper Midwest, the accumulating snow in the interior Northeast can be significant from later tomorrow into Thursday with a foot or more on the table in portions of upstate New York and interior New England.

Not exactly the weather wanted by many for the early part of April with snow dominating the scene on Thursday morning, April 4th across the Northeast US (shown in blue). Map courtesy NOAA, tropicaltidbits.com

Upper air dynamics looks to become quite impressive across the northeastern states by later tomorrow night and Thursday raising the chance that some spots in upstate NY and interior New England get absolutely thumped with heavy, wet snow…perhaps even some “thundersnow” to be included in the mix. Farther to the south, snowflakes can mix in with rain late tomorrow night and Thursday across eastern PA, NYC, and New Jersey, and perhaps even as far to the south as northeastern Maryland. The slow-moving storm system will continue to produce unstable atmospheric conditions on Friday in the Mid-Atlantic and Northeast US with lake-effect type snows just downstream of the water and it’ll take part of the upcoming weekend to see a settling down of the overall weather pattern.

Meteorologist Paul Dorian
Arcfield
arcfieldweather.com

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Video discussion on the severe weather and accumulating snow threats of the next few days and also a look ahead to the solar eclipse weather: