Final Update: 6pm Monday, March 24.
The long advertised major storm still stays too far to our east. Once it takes shape and races northeast, it has a good shot at bringing a genuine blizzard to coastal New England.
But before it forms, one of its component parts will race across our part of the state during the first several hours of Tuesday.
The result will be a few periods of snow, likely starting around 4-5am in the New River Valley and spreading eastward toward the piedmont of Virginia.
But by midday, most of the energy will be transferring to the new offshore storm, allowing some breaks of sun for our part of the state late in the afternoon, and sending highs into the 40s.
As a result, the window of accumulating snow is a small one, between about daybreak and midday Tuesday… again… a little earlier in the New River Valley.
Snow forecast map… ending 2pm Tuesday.
However, with temperatures climbing into the 40s late in the afternoon, melting will take place quickly during the afternoon, so the peak amounts of snow on the ground will be around midday or early in the afternoon.
Then, wind and cold will be issues Tuesday night and Wednesday. Lows in the lower to middle 20s Tuesday night mean that any wet road surfaces will develop icy areas. And while Wednesday will be sunny, highs will hold in the 40s. Fortunately, with the higher March sun angle and the generous winds on Wednesday, all road surfaces should be dry by Wednesday afternoon.
While parts of Greater Richmond could conceivably get a coating, it would not be consistent across the area. Essentially, Richmond is off the hook regarding any substantial snow threat.
Update: 6pm Friday, March 21
Most data indicate the core of this storm bypasses Lynchburg and Danville, well to the east. However, central and western Virginia still may be close enough to see some snow out of it. Earlier, we were tinkering with the idea of a couple or a few inches. And to emphasize, while it is still too too early to ignore this storm, we are feeling better about its most serious effects missing the western half of the state. We now downscale that to an inch or less (which also means there may be nothing at all).
Nonetheless, it is still important to follow the forecast over the weekend, as the storm has not yet formed. The energy for the storm is still in the Canadian Arctic as of Friday evening.
Areas from Richmond to Hampton Roads should follow it most even more closely.
Update: 9am Thursday, March 20
Ironically, today is the first day of astronomical spring. As we like to emphasize, that particular moment does not mean a lot in the real atmosphere. Concern does continue to grow for some accumulating snow in Virginia on Tuesday.
The overnight (00z) simulations hold the core ideas from yesterday afternoon. The Canadian and European simulations essentially hold yesterday’s ideas, while the American simulation (GFS) now looks like it is coming around to those solutions. Additionally, an experimental American simulation (FIM, below) also goes with this idea.
At minimum, we must continue to follow this system closely. All of the simulations discussed above take the center of the storm (area of low pressure) on a general northeast track from the above position. Whether it is a sharper turn to the northeast or a gradual east-by-northeast track is up for discussion.
Even so, this would suggest accumulating snow for most of Virginia, with areas east of Interstate 81 and west of the Chesapeake Bay at greatest risk. This includes Lynchburg and Richmond. However, Hampton Roads and Northern Virginia also should monitor the situation, especially this far in advance.
Regarding the amount of snow, it is still too early to lock in on specific numbers, but the scale of what we are discussing is a couple or a few inches, depending on start time and ground temperatures.
Again, follow the forecast at least 2 times a day through the weekend for updates. Modifications in the forecast are to be expected.
* * * *
Original post Wednesday evening
There is still concern about a storm system that is expected to take shape Tuesday of next week. While there is a legitimate threat of accumulating snow with this system, it is far, far from certain.
This afternoon’s data (especially those coming from the European and Canadian weather simulations/ensembles) do support and strengthen the possibility.
However, we caution that the system is just over 5 days away, its energy still over the North Pacific Ocean.
And although the general pattern (temperature, upper atmosphere steering winds) also supports the possibility, we feel the data need to be more consistent over the next 36-48 hours before ratcheting up the threat.
So for our part of Virginia (all areas), we would put the chance of seeing any snow on Tuesday at about 30%. We would put the chance of seeing plowable snow at about 15%. Not enough to incite panic, but certainly not too little to ignore.
After all, if someone told you there was a 15% chance your dinner would give you food poisoning, would you pay attention? :)
Our suggestion is to be sure to check the forecast at least once a day through this weekend, then again Monday morning and Monday afternoon.
And enjoy the nicer stretch Thursday, Friday, and Saturday.
Astronomical spring starts Thursday at 12:57pm (EDT).