Sunday, January 5 2025
The strong winter storm in the middle of the nation today has produced thunder snow, and blizzard conditions in parts of Kansas and Missouri, with a heavy ice storm south of St. Louis. It is moving eastward and will be an all-day event in the Mid-Atlantic on Monday.
In this report, we will take a look at the current setup and use a short-range high-resolution model to plot the timing. I use the NAM 3 Km for the timeline, but it may still need work to resolve the intensity and totals.
This is going to be a southern track storm… Less snow north in Southern Pennsylvania is why there is an advisory in these counties.
Snow will move in on the radar between Midnight and 4 AM (Mid-Atlantic). There may be an hour or two of Virga (sublimation) where the snow does not reach the ground.
Initial Snow Thump:
The dynamics support heavy snow as soon as it breaks through the dry air. In the morning, it could fall at a rate of 1 inch per hour.
Mid-Day Lull?
There may be a brief transition from snow to showers or a pause in precipitation for a few hours. This is part of the transition.
Second Snow Surge Late Day And Evening
As the storm reforms on the coast, it will send moisture back aloft to the old storm circulation, developing a second batch of accumulating snow. It will come to an end for most by midnight.
Tuesday Morning Deep Freeze
Very cold temps and bitter wind chills will be enhanced by fresh snowpack.
DC Mayor Muriel Bowser has declared a Snow Emergency with a forecast of over 6 inches of snow. On my forecast map, they are in the range of 6” to 12”. This emergency lasts through Tuesday evening and affects parking on Snow Emergency Routes to allow the plows to clear the streets.
The storm track favors heavier snow across North Central Virginia, southern Maryland, and even Delaware. One bullseye for heavy snow may focus around DC, Annapolis, and Baltimore.
Less snow will fall to the north, and I may need to revisit the amounts for my final call across the line to Pennsylvania. This is all due to the presence of cold and dry air forcing the storm track on this southern route.
I am sticking with this version for now. There may need to be some adjustment on the north end, but I am confident in the numbers across most of the DMV area and Central Maryland through Delmarva.
I will be updating the model plots in my next report. Below you can see a look at the National Weather Service Regional Office Snow maps.
The storm center was located South of St. Louis and tracking eastward. There is a large dome of very cold and dry air on the East Coast. While it may look like it is racing in on the radar, it will take a few hours to saturate the air layers to support snow.
NAM 3Km Model 3 PM Sun to 7 AM Mon
Notice the path of the heavy snow (dark blue). Also how there is a second cluster of snow that develops in Southern Ohio and passes through Monday evening.
Very cold air in place to support snow moving in…
I’ve noted that the leading edge on the radar might be VIRGA and not reaching the ground. Once it does, it will get heavy in a hurry.
I’ve noted that the leading edge on radar might be VIRGA and not reaching the ground. Once it does, it will get heavy in a hurry.
Timeline snapshots below
This is faster and all of the region will be under snowfall.
This is slower, and snowfall will cover the entire region. The ice part of the storm will affect the southern half of Virginia.
This is when a lull may develop across the mountains and shift eastward.
Southern Maryland into the icy mix.
The Deformation zone is that area in the atmosphere between the Surface Low and the old upper Low inland. The coastal storm will send moisture back to fill in with this second surge of accumulating snow.
Deep Freeze!
I am sticking with this version for now. There may be some adjustment on the north end, but I am confident across most of the DMV area and Central Maryland through Delmarva.
I will be updating the model plots in my next report. Below you can see a look at the National Weather Service Regional Office Snow maps.
They have put out two maps that have some variations but both within my same range.
This has lower numbers along the Pennsylvania line. But central areas still in the heavy snow range between 5 to 10 inches. Much more in the mountains to the west.
This has higher snow along the Pennsylvania Line and most of Central Maryland in the 6″ to 12 inch zone.
Over 6 inches of snow through Delaware and Maryland’s Eastern Shore.
A dramatic range of heavy snow on the Maryland line to the south, much less to the north of I-76.
Faith in the Flakes
I will have my next update and any final snow map this evening. Snow arrives overnight!
This will be our first snow day since January 3 2022.
If you missed it, here is my detailed report from December 30 about why this IS A BIG DEAL!
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I am aware there are some spelling and grammar typos and occasional other glitches. I take responsibility for my mistakes and even the computer glitches I may miss. I have made a few public statements over the years, but if you are new here, you may have missed it: I have dyslexia and found out during my second year at Cornell University. It didn’t stop me from getting my meteorology degree and being the first to get the AMS CBM in the Baltimore/Washington region. One of my professors told me that I had made it that far without knowing and to not let it be a crutch going forward. That was Mark Wysocki, and he was absolutely correct! I do miss my mistakes in my own proofreading. The autocorrect spell check on my computer sometimes does an injustice to make it worse. I also can make mistakes in forecasting. No one is perfect at predicting the future. All of the maps and information are accurate. The ‘wordy’ stuff can get sticky. There has been no editor who can check my work while writing and to have it ready to send out in a newsworthy timeline. Barbara Werner is a member of the web team that helps me maintain this site. She has taken it upon herself to edit typos when she is available. That could be AFTER you read this. I accept this and perhaps proves what you read is really from me… It’s part of my charm. #FITF
