The first winter storm for some in the Northeast is currently shaping up, ready to bring heavy rain and snow to the region Thursday into Friday. This comes as the classic transfer of energy from a weakening low over the Ohio River Valley to a strengthening coastal low pressure takes place, which will end up becoming a nor’easter. It’s not going to be the most robust of nor’easters that we have seen with a forecast minimum pressure in the 990s, especially since winter technically isn’t even here yet, but it will still be strong enough to produce heavy precipitation in addition to gusty winds.
First Low Pressure:
Snow has already broke out Wednesday afternoon in parts of the Mid-Mississippi River Valley, but as temperatures begin to decrease this evening and continue into tonight, that will allow for an increase in the production of snow in the Mid-Mississippi and Ohio River Valleys. The National Weather Service has issued a Winter Storm Warning in and around the St. Louis area, meaning that impactful snowfall is forecast as a light to moderate snow falls in the region tonight into Thursday.
Across the Ohio River Valley, many areas will first see the snow before warmer air invades from the south, allowing for the precipitation to changeover from sleet and/or freezing rain to plain rain between tonight and Thursday. Once you get to the Great Lakes, however, this will be an all-snow event, so cities like Detroit and Cleveland can expect all snow on Thursday. Chicago can also expect snow as the only precipitation from this storm, but it will be very light in terms of intensity and accumulation.
In the Appalachian Mountains, wintry precipitation will also be the story, even as far south as the highest of elevations in South Carolina. Snow and ice are forecast across the southern extent of these mountains on Thursday, mainly in the morning, before the moisture clears out and tracks to the north.
It’s the Northeast where this storm will be the most impactful as the coastal low pressure takes over impacts a greater amount of the eastern population. By Thursday evening, there should be a formidable low pressure just off the Mid-Atlantic coast. Because temperatures will be near to below freezing across much of the Northeast and since the moisture will be extending well away from the center of the low pressure, that will allow for the precipitation to begin as snow on Thursday across most of the I-95 corridor.
I-95 Corridor Forecast:
In the DC metro area and Baltimore, the precipitation will begin around sunrise as you wake up, likely in the form of snow. Along or a few miles east of I-95, this will be an all-rain event. For the major major cities, we’re expecting a few hours of snow before it changes over to a wintry mix for a brief time midday. Then during the afternoon, rain will become the big story.
Farther north into the Philadelphia area, snow will be a bit more long-lasting. Expect the flakes to begin flying during the late-morning, so your morning commute should be smooth-sailing for the most part. Midday will be the worst time to travel since a moderate to heavy snow will be coming down. That will last through the early to mid afternoon before the rain/snow line begins to move inland from central New Jersey. By the evening, we expect rain to be falling in and around Philadelphia while the snow persists across eastern Pennsylvania a couple of hours longer before changing over to a wintry mix or rain. It’s after you get into the western half of the state where this will be an all-snow event.
In the New York City area, several inches of snow is expected, especially in the northern suburbs. Snow will begin at around noon in New York City. Even the Jersey Shore may see some flakes, although we do think this will primarily be a rain event besides a couple of instances when the precipitation type fluctuates. Once this snow begins, it will come down quite heavily thanks to strong banding that will take place in the mid levels of the atmosphere, exactly what the NAM model is highlighting (see model image below). Then during the evening, the rain/snow line will begin to push northward through the city and into southern New England as the center of low pressure tracks closer, ushering in warmer air from the Atlantic Ocean. Therefore, much of Thursday night will just be rain, allowing for slushy roadways.
What makes this forecast tricky is whether the snow will accumulate on the roads. In many of the first snow events of the season, it takes intense snowfall for this to happen. In this case, we do expect many of the roads to become snow-covered because of the heavy snow forecast, especially on secondary roadways, so that is something to keep in mind if you plan on traveling, especially Thursday afternoon.
On our final stop up the I-95 corridor we take you to Boston. This city is always difficult to forecast based on its location and proximity to the relatively warm ocean waters. Based on the current WeatherOptics forecast, we are expecting the precipitation to begin as snow in and around Boston until the late-afternoon or early-evening. Of course this happens to coincide with the evening commute home, so we do suggest you leave work early so you can to avoid the sub-par driving conditions. Even the Cape and southern coast of New England can expect snow to start as well, but that rain/snow line will begin to lift as early as at sunset. It shouldn’t reach the Boston metro area, however, until around midnight. That’s when a wintry mix may take place for a few hours before rain settles in during the wee hours of Friday morning.
In the I-95 corridor Thursday night, most locations can expect rain. Then during Friday morning, a final round of rain, snow, or a mix of the two will move through. Drier air will then sweep through once the precipitation comes to an end midday.
Across the interior of the northeastern US, it will be a different story as snow dominates, allowing for over a foot to fall in various locations. Across Pennsylvania and nearby areas, the precipitation will begin as a moderate to heavy snow, and that snow will start in the morning across southwestern areas or by the early afternoon elsewhere. Many schools will likely close or issue an early dismissal as a result of this timing. Then overnight in Pennsylvania, that snow will actually intensify on the backside of the coastal low pressure, so an area like central Pennsylvania may experience jackpot totals compared to surrounding areas. As mentioned before, most of the eastern half of the state will deal with a changeover from snow during the day to either rain or a wintry mix Thursday night. There is also the concern for significant, or at least dangerous, icing from south-central Pennsylvania southward into the central Appalachian Mountains thanks to the inversion in place.
Most of New York, with the exception of the Lower Hudson River Valley, New York City, and Long Island, will experience solely snow. Snow will begin during either the afternoon or evening across most of the state. Based on the track of the low pressure, central New York favors the heavier totals, and yes, Albany may be in that zone or just south of it.
Across the rest of New England it will be a similar story, with snow beginning during the latter half of the day Thursday with heavy snow overnight. Coastal New Hampshire and Maine can expect snow for the most part, but a wintry mix cannot be ruled out overnight. This snow will persist into much of the day Friday whereas the rest of the Northeast can expect improving conditions by midday, although some lake effect snow will actually develop near Lakes Ontario and Erie.
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