Snow lovers across interior parts of the Northeast who have thus far evaded lake effect snow are anxiously awaiting the first accumulating snow of the winter season. Some residents of upstate New York and northern Pennsylvania will be caught in the cross-hairs of lake effect snow Tuesday, receiving a bonus helping of winter. Closer to the coast, residents will continue to evade winter and instead face the wrath of pounding rain.
A weak wave of low pressure centered over the western Florida Panhandle along a cold front early Monday evening will race up the coast Monday night and spread rain and snow along with it. Though it may still be over the Southeast as of this article, a subtropical moisture connection has helped spread the precipitation all the way to southern Pennsylvania. The low pressure system will race up the coast Monday night, passing just east of New York City by early Tuesday afternoon. By then, this quick hitting storm will already be over for much of the Northeast, with only eastern New England still grappling with the rain and snow.
Precipitation will begin as rain everywhere across the Northeast except for perhaps high elevations of the Adirondacks and northern New England. The rain will quickly changeover to snow in northern Pennsylvania, northern New England, and parts of New York north and west of the Hudson Valley. Some snowflakes may mix overnight well north and west of I-95, but otherwise precipitation will remain in the form of rain throughout the duration of the coastal storm elsewhere in the Northeast.
Torrential rain has already formed ahead of the low’s cold front from New Orleans to Roanoke. The heavy showers and thunderstorms have prompted Flash Flood warnings across the Atlanta metro area and are currently spreading northeastward along the front. Behind the front, temperatures were in the low 40s as far south as Birmingham and Dallas. Ahead of it, temperatures were in the middle 70s along the Gulf Coast. This temperature contrast has helped some of the thunderstorms acquire severe characteristics along the Gulf Coast. One such storm already produced a tornado in Santa Rosa, FL. Additional tornadoes are possible through the evening.
North of the low, a broad region of upward motion was impacting Rush Hour along I-95 from Florence, SC to Baltimore with a shield of light to moderate rain. Precipitation will quickly progress through the Northeast. The rain should spread to Scranton, Albany, and New York City by 10pm before progressing to southern New England cities like Providence, Worcester, and Boston after midnight.
Inland locations in northern Pennsylvania, upstate New York, and northern New England will quickly changeover to snow during the overnight hours. The low will straddle the coast and as such this is where the heaviest precipitation will be confined, but snowfall rates will be high enough to accumulate to a disruptive quantity for areas of high elevation. As the low approaches, warm air will intrude further north and west, changing snow back to rain early Tuesday morning everywhere but the highest elevations of the Allegheny Plateau, the Adirondacks, and northern New England.
Peaks of the Adirondack, Green, White, and Longfellow mountains could receive 6-10″ of snow, with totals decreasing as elevation lowers. Snowfall of 4-8″ is more likely elsewhere in those mountain ranges. The Allegheny Plateau in northern Pennsylvania and New York’s Southern Tier is likely to receive 3-5″ of snow at its highest elevations with 2-4″ likely elsewhere. Low-lying populated areas in the Finger Lakes and Mohawk and Champlain Valleys can also expect accumulations up to 2-4″ including cities like Ithaca, Syracuse, Utica, and Burlington. A coating to two inches is more probable at other southerly and low-lying areas, from northern Pennsylvania northeastward to central Maine. Some cities just outside this range like Albany may pick up a quick coating before changing over to rain.
The heaviest rain will fall along and east of the I-95 corridor in the northern Mid-Atlantic and south of I-84 in southern New England as well as New York’s Hudson Valley. 1-1.5″ of rain is likely to fall for these areas. The rain will be heaviest just after sunrise and during rush hour from Philadelphia to New York City. The downpours should hold off until later in the morning for coastal new England cities like Providence, Boston, and Portland. The rain may instigate localized areas of minor flooding. but otherwise it will be a nuisance. The storm will still be weak as it advances through the Northeast so winds will remain light except along the Jersey Shore, over eastern Long Island, and southeastern New England, where winds could gust to 30-40 mph.
The heavy rain will mark a close to the coastal storm’s impacts for the coastal cities. Dry air will usher in behind the intensifying coastal low just behind the batches of heavy rain. Partial clearing should gradually ensue throughout the afternoon across the Northeast.
As the dry, cold air mass flows southeast across lakes Erie and Ontario, several bands of lake effect snow are likely to add to snowfall for inland areas that received snow Monday night and Tuesday morning. Parts of northwestern Pennsylvania and upstate New York could pick up an additional 3-5″ of snow ,with parts of central New York downwind of Lake Ontario picking up an additional 6-10″.
Besides lake effect snow, the Northeast will experience two frigid but dry days before yet another storm threat late in the week. This second storm could bring wintry precipitation much closer to the coast than this early week storm. Be sure to stick with WeatherOptics as we know more about the possible winter threats later this week.