Today:
Mostly sunny, with a high near 31. Northwest wind 15 to 20 mph, with gusts as high as 35 mph.

Tonight:
Mostly clear, with a low around 14. Northwest wind 10 to 15 mph.

Sunday:
Sunny, with a high near 25. Northwest wind 5 to 10 mph.

Sunday Night:
Mostly clear, with a low around 4. North wind 0 to 5 mph.

Monday:
Sunny, with a high near 29. Southeast wind 0 to 5 mph.

Monday Night:
A chance of snow after 1am. Mostly cloudy, with a low around 22. Chance of precipitation is 40%. New snow accumulation of less than half an inch possible.

Tuesday:
A chance of snow before 1pm. Partly sunny, with a high near 39. Chance of precipitation is 40%. New snow accumulation of less than half an inch possible.

Tuesday Night:
Partly cloudy, with a low around 25.

Extended Forecast

Christmas Day Mostly Sunny	Wednesday Night Partly Cloudy	Thursday Mostly Sunny	Thursday Night Partly Cloudy then Slight Chance Light Snow	Friday Slight Chance Light Snow then Slight Chance Light Rain	Friday Night Chance Rain And Snow
Hi 39 °F	Lo 27 °F	Hi 41 °F	Lo 29 °F	Hi 43 °F	Lo 32 °F
					PoP 30%

AREA FORECAST DISCUSSION
National Weather Service Mount Holly NJ
653 AM EST Sat Dec 21 2024

Weather Synopsis:
Low pressure southeast of Montauk Point will lift north into the Canadian Maritimes later today and tonight. Meanwhile, Arctic high pressure over central Canada and the Northern Plains will track east this weekend, eventually building over New York State and the Northeast Sunday night into Monday morning. This high departs Monday night, and then weak low pressure passes through the region on Christmas Eve. High pressure returns to close out the week.

Near Term:
THROUGH TONIGHT - Light snow exiting the area early today, then turning much colder, drier, and breezy.

The inverted surface trough that brought widespread light snowfall to the region is beginning to retreat offshore this morning. A widespread 1-4" of snowfall has been reported from around the Philly metro and points north and west. The mid level forcing for ascent and trough axis have moved offshore as well. This is evident at the surface in the lessening coverage and overall intensity of the snow that remains. Some light flurries are possible across eastern NJ for a couple more hours, however the accumulating snowfall has largely ended. The Winter Weather Advisory was allowed to expire.

Following the snow, the story will be the impressive cold advection into tonight. Arctic high pressure will build across southern Ontario today into tonight, advecting a very cold and dry airmass into our region. 850 mb temperatures look to fall to near -15C (give or take a couple degrees). This will translate to much below normal temperatures today, and especially tonight into Sunday. High temperatures today will range from the 20s north of I-78, to the low to mid 30s south of I-78.

In addition to the cold daytime temperatures today, it will also be quite blustery. 925 and 850 mb winds will increase to around 25-30 kts between the strengthening storm offshore and strong high pressure to our northwest today. Expect sustained winds near 15-20 mph with peak gusts around 30-35 mph much of the day. Wind chills will top out only around 15-25 degrees today. Cold advection peaks near 00Z, so the winds should subside some and become less gusty into tonight. However, the modest gradient in place will keep winds elevated around 10-15 mph much of the night.

The persistent breeze tonight combined with temperatures falling to the low to mid 10s across much of the area (single digits in the higher terrain of the southern Poconos and NW NJ) will produce bitterly cold wind chills in the single digits across much of the area, and below zero in the higher terrain. Across the Pocono Plateau, wind chills will be as low as -12 degrees. A Cold Weather Advisory remains in effect there for tonight through Sunday morning.

Short Term:
SUNDAY THROUGH MONDAY NIGHT - 1036+ mb Arctic high pressure will be over the eastern Great Lakes Sunday morning before building to the south and east Sunday night through Monday morning. High pressure moves offshore and departs Monday night.

A bitterly cold airmass will spread into the region during this time with highs only in the teens in the southern Poconos, and otherwise in the mid to upper 20s, which are some 20 degrees below normal for this time of the year. The coldest temperatures in quite some time will be felt Sunday night with lows generally in the single digits to as low as 5 below in the southern Poconos. In fact, the last time the low temperature was less than 10 degrees at Philadelphia International Airport was December 24, 2022 when the low was 7. It will come close to this Sunday night.

Temperatures warm up by about 5 degrees on Monday compared to Sunday, topping off in the upper 20s to low 30s, except for southeast New Jersey and southern Delmarva, where highs will be in the mid to upper 30s.

A clipper system approaches Monday night from the west. Light snow will move into the region from west to east after midnight, and up to a quick quarter of an inch of snow is possible, mainly for the southern Poconos, Lehigh Valley, and northern New Jersey.

Long Term:
TUESDAY THROUGH FRIDAY - Clipper system passes through the region on Christmas Eve, producing minimal snow accumulation, but generally a quarter of an inch or so in the northern areas. Snow mixes with and changes to rain in the southern half of the forecast area before tapering off.

High pressure builds over the area on Christmas Day with highs warming back closer to normal, but still a few degrees shy of normal for this time of the year.

Although high pressure will dominate the area into the end of the week, there may be a few weak mid-level impulses that could produce some light rain or snow on Thursday and Friday. PoPs will be capped at slight chance for both days. Temperatures warm back to normal with highs in the low to mid 40s.

Click for full NWS PHI Office Area Forecast Discussion