April is just about here, but that doesn’t mean Mother Nature will cooperate with the calendar. We’re tracking a new upper-level disturbance that will move into the Northwest coast on Saturday, then will move across the country and off the Northeast coast by Monday. As cold air seeps in from the north due to an incoming Canadian high, the combination of the cold and moisture will allow for a light swath of snow from the Central Plains through the northern Mid-Atlantic region and southern New England between Saturday night and Monday.
So beginning Saturday night, a light snow is expected to break out across much of Wyoming, northern Colorado, and much of Nebraska. Portions of northern Kansas may also experience snow showers. Accumulating snow is likely in this area not only because the snow will be falling at night but temperatures will be in the 20s due to the cold air flowing in from Canada associated with the Polar Vortex.
Then on Sunday, the snow will quickly clear out of Wyoming and Colorado while continuing through the morning hours in parts of Nebraska and Kansas. As the day progresses, snow is expected to move into extreme-southern Iowa, much of Missouri, and the western Ohio Valley, including southern and central Illinois and Indiana. A wintry mix containing sleet and freezing rain is possible in portions of southern and central Missouri. It’s also interesting when looking at the model guidance how where it is expected to snow, temperatures will be cooler than the surrounding areas, as shown below. This is because of cooler air aloft being carried down with the precipitation.
As we get into Sunday night, this will become mainly an Ohio Valley snow event as this upper-level disturbance continues to zoom to the east due to the fast-moving jet stream. Because the jet stream will be in a zonal flow, which is when winds move from west to east, this storm will be on the weaker side as it tracks toward the east as well. Snow is possible throughout the Ohio River Valley, primarily north of the river. Snow will also work into portions of the Mid-Atlantic as the night progresses. This includes much of Pennsylvania, Maryland, New Jersey, and northern West Virginia. Snow should also sneak in by sunrise into the Lower-Hudson River Valley of New York, Long Island, and southwestern New England. Major cities at risk for light snow during this time period include: New York City, Philadelphia, Baltimore, and Pittsburgh. There is the slight chance for snow in Washington, DC, but it is expected to be too mild for snow, so instead rain showers are forecast for the city and to the south. Again, because this snow will be at night, there will be some accumulation. It will be on the mild side during the day Sunday with the sun shining. That will keep ground temperatures above-freezing in many locations overnight. Actual air temperatures Sunday night will also be around freezing, and in many cases just above 32 degrees.
Then on Monday, little to no accumulation is expected due to the sun rising and the increasing temperatures. Light snow and/or a mix of rain and snow is possible Monday morning from eastern Pennsylvania and much of New Jersey and into southern New England and Long Island.