The region evidently is about to experience a classic Philadelphia early winter storm — a little froth, followed by plenty of ice water. Hold the panic.
Some accumulating snow is possible in the early morning hours well north and west of the city before a changeover to a mix and then rain, forecasters and their computer models say, but Philly’s chances for its first measurable snowfall of the season is minimal or less.
“It’s cut and dried,” said Tyler Roys, senior meteorologist with AccuWeather Inc.
Quite wet, actually.
The National Weather Service in Mount Holly, which has issued a winter-weather advisory for northern and western portions of the Bucks, Chester, and Montgomery Counties for 1 to 3 inches of snow and sleet before the changeover, the region could receive over an inch of precipitation.
That could cause commuting problems for the morning rush.
PennDOT anti-icing crews have been mobilized, said spokesperson Krys Johnson, but they are also clearing leaf-clogged drains to mitigate road-flooding.
The precipitation should shut off well before the peak afternoon commuting period. However, it appears that the meteorological winter, which began officially Monday, is going to get off to a livelier start than last year’s.
“We’re changing the script already,” said Roys, noting another storm threat later in the week. “It’s definitely an active start.”
What time will it start snowing and raining?
Snow is expected to begin sometime between 3 and 5 a.m., and forecasters say that the earlier it arrives, the better the chances that some of it sticks.
Winds will be from the east, and that would import warm air off the ocean, where sea-surfaces temperatures were in the upper 40s on Monday.
Temperatures in the Philly region would be in the upper 20s when the precipitation arrives but forecast to go above freezing by daybreak.
Roys said that it should be all rain across the region by mid-morning.
How much for Philly?
For Philly, Johnson’s reading of the forecast — “A chance of one snowflake” — is essentially correct, meteorologists say.
From King of Prussia eastward, said Roys, “You’re looking at nothing.”
The only thing that could change that would be a surprisingly onset of precipitation, he said.
AccuWeather is less bullish on snow amounts north and west of the city, and Roys said you might have to go to Harrisburg to see an actual inch.
What is the outlook for the rest of the week?
The weather community divides the seasons into tidy three-month increments, which Dec. 1 as opening day.
It will feel like winter, with temperatures several degrees below normal into the weekend, with daytime highs Tuesday and Wednesday mostly in the 30s and lows in the 20s.
A wild card would be the arrival of an Arctic front Thursday morning, said Roys, which might set off snow squalls in parts of the region.
Another significant winter storm is possible on the weekend, however computer guidance has been showing about everything and not much, said Zach Cooper, a weather service meteorologist in the Mount Holly office.
“At this point, all precipitation types are on the table,” he said.
Welcome to winter in Philly.
This is a developing story. Check back later for updates.