Dangerous subfreezing cold in Philadelphia area sets stage for major snowfall. Here's the forecast.
It will be dangerously cold overnight into Saturday, with extreme cold advisories and warnings in effect across the Philadelphia region.
You'll wake up to below zero with temperatures setting the stage for heavy snow on Sunday. Expect temperatures to remain below freezing for the next 10 days, extending into early February. Everyone will receive heavy snow before sleet falls.
We are at the eastern end of winter weather alerts stretching over 34 states from New Mexico to Main. Nearly 200 million people are in the path of this rare, major storm.
NEXT big weather change: snow Sunday morning
A winter storm warning has been issued for the entire Philadelphia area. This alert will take effect at 7 p.m. Saturday and continue through 1 p.m. Monday.
Right now, here's how the timeline is shaping up for Sunday.
- 1 a.m. – 4 a.m.: Snow begins south and east of the city across southern Delaware and far South Jersey.
- 3 a.m. – 6 a.m.: Snow begins across the I-95 corridor, Philly, interior South Jersey, and Chester, Delaware, New Castle, lower Montgomery, and lower Bucks counties.
- 5 a.m. – 8 a.m.: Snow begins for upper Montgomery, Bucks, Berks, Lehigh Valley, and Poconos.
The European Model (ECMWF) has snow beginning around midnight Saturday and lasting through pre-dawn Monday morning. With light snow showers through early Monday morning.
The American Model (GFS) has snow beginning after midnight Sunday morning and lasting through Monday afternoon. With light snow showers into the evening.
Snowfall will be light at the start, very early Sunday morning and increase through the morning.
The storm will intensify by late morning into early afternoon. That is when the heaviest snowfall will occur.
There may be some blowing and drifting snow throughout the day on Monday, complicating travel and snow removal.
How much snow will Philadelphia get?
If storm tracks farther offshore, there will be heavy snow with little or no sleet or freezing rain.
- 10 – 16+ inches: Areas along I-95, including Philly, Wilmington, Trenton, South Jersey, Chester, Delaware, Montgomery, Bucks counties.
- 10 – 12 inches for interior South Jersey, Lehigh Valley, Berks counties.
- 8 – 10 inches for the Shore and southern Delaware.
If storm tracks closer to the Shore, there will be lower snow totals and more sleet and freezing rain.
- 8 inches – 12 inches: Areas along I-95, including Philly, Wilmington, Trenton, and interior South Jersey, and northern Delaware, South Jersey, Delaware, Montgomery, Bucks counties.
- 10 inches – 16 inches: Chester, Delaware, Montgomery, Bucks, Berks, Lehigh Valley, and Poconos
- 4 inches – 8 inches: For the Shore and southern Delaware.
The last time Philadelphia saw a 6-inch+ snowfall was 7.5 inches on January 29, 2022.
The last time Philadelphia saw a 12-inch+ snowfall was 22.4 inches on January 22-23, 2016.
The last time Philadelphia saw more than 24-inch+ of snow was 28.5 inches on February 5 and 6, 2010.
Snow ratios
This weekend will be the coldest air of the season yet and any snow that falls will be at a high snow/water ratio due to the cold. Meaning, the colder the air the more snow is squeezed out.
A 20:1 snow ratio means 20" of snow would be produced from 1" of water. In comparison, so far this season we have seen wet snow with ratios of 6:1 and 8:1.
We will be in a cold enough and dry enough atmosphere to support a 20:1 ratio for light, fluffy snow.
So, if there is 1/2" water in the atmosphere we will see 10", if there is 1/4" water we will get 5", and if there is 3/4" water we will see 15".
Prepare for possible impacts of this storm
There's potential for ice accumulation on power lines and tree limbs with this storm.
Possible impacts could include power outages, airport cancellations, train delays, dangerous roads and downed trees. Be prepared for cancellations to religious services, health appointments, fitness or educational programs Sunday and Monday and possibly beyond.
All School District of Philadelphia schools will be closed on Monday, Jan. 26, Superintendent Tony Watlington said. Students recieved Chromebooks for potenial remote learning days.
Temperatures will plummet Monday through the middle of next week, with highs in the low 20s and overnight lows dipping to single digits and below zero. So, plan on this snow sticking around through the end of the month.
25 mph wind gusts will create blowing and drifting snow throughout the day on Sunday, complicating travel, and snow removal. Downed power lines and branches are likely in areas that receive sleet and freezing rain.
The best advice is to stay with the NEXT Weather team for frequent updates each day to plan and prepare for the weekend. Have the shovels and ice melt ready. This could be the biggest snow of the season.
Sleet and freezing rain possible on top of heavy snow
It may take an hour or so for any snow to hit the ground because the atmosphere is so dry. Between 7 a.m. - 10 a.m. the snow will increase in intensity, and it will continue falling at a rate of 1-2" per hour through early afternoon.
By early afternoon there could be 6-10" of light fluffy snow on the ground. Sleet will develop along the Jersey Shore and southern Delaware between 1 a.m. - 3 a.m. From there it will moves inland, possibly as far as the I-95.
Any sleet could cut snowfall totals, but where the precipitation stays all snow, it will pile up quickly.
At some point Sunday evening, a layer of warm, moist air will be drawn into the storm and there may be a change to sleet and freezing rain from I-95 to the Shore and across Delaware.
This will fall on top of already high amounts of snow. There may even be a period of rain on the beaches.
The question is, how much and for how long there will be any sleet/freezing rain. This could make the difference between 6-8" of snow or 12-16" of snow.
If the storm tracks 50-100 miles farther offshore, we will see mainly all snow and little if any sleet/freezing rain. The snow totals would be the high side of the forecast.
Heavy snow and no sleet will continue north and west of the sleet line from I-95 north Pennsylvania. This is where the highest snow totals will be. The snow will begin tapering off overnight and light snow showers are possible Monday morning.
Where to find warming centers around Philadelphia
Philadelphia has activated an Enhanced Code Blue due to the extremely cold temperatures. The city activates an "enhanced" alert when a Code Blue lasts more than three nights in a row.
Because of the enhanced alert, the Office of Emergency Management has opened multiple warming centers throughout the city. The centers are free and open to the public.
People who need help or see someone in need of help during this cold weather event can also call 215-232-1984.
Bucks County issues a Code Blue whenever temperatures drop below 20 degrees, but could also issue the alert based on other cold-weather factors.
Information about shelter openings can be found on the Housing Link website.
Residents who need temporary shelter, food and clothing during the winter can call 211 or text their zip code to 898-211 for immediate assistance.
During a Code Blue, residents in need of shelter are encouraged to visit one of Delaware County's weather advisory relief centers.
During a Code Blue, the county has additional resources for people experiencing homelessness, including access to temporary warming shelters, food and clothing.
Anyone who needs help with temporary shelter during the cold can call the Your Way Home Call Center at 610-278-3522.
New Jersey
Active Code Blue declarations are listed by county on New Jersey 211's website. The site also includes a list of available warming centers in each county.
Delaware
The Delaware Department of Health and Social Services has opened eight warming centers across the state through Jan. 21. A list of warming centers in each county and their addresses is posted online.
Here's your 7-day forecast:
Saturday: NEXT Weather Alert frigid temps. High 19, Low 11
Sunday: NEXT Weather Alert for snow and ice. High 26, Low 15
Monday: NEXT Weather Alert snow and cold. High 28, Low 24.
Tuesday: Very cold. High 23, Low 11
Wednesday: Very cold. High 24, Low 13
Thursday: Cold but sunny. High 21, Low 10
Friday: Staying cold. High 27, Low 14