Much buzz has started about a winter storm next week. To emphasize, there is much that needs to come together to produce snow. Many of the classical ingredients will be in the area; it is more a question of getting the ingredients to blend the right way. We still have a lot of time; the energy that will generate this storm is only now moving across the Aleutian Islands of Alaska.
Here’s what we feel good about:
Timing. The simulations we use to help us forecast have been consistent in the timing of this system. The window appears to be Tuesday evening through Wednesday evening, give or take 6 hours or so.
Basic Structure. The general structure and track of the storm suggests rain or snow. Not ice.
Here’s what we do not feel good about… at least not yet:
Precipitation Type. The precise track will determine where the rain/snow line will be. There have been suggestions that the storm goes so far south, that snow could fall all the way to Raleigh.
Amount. That southerly track would also mean less precipitation in Virginia. So, the precise track of the storm center and the upper-level structure of the storm play huge roles regarding moisture transport into the storm, how much precipitation can be generated, and where the rain/snow line moves.
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Many options remain on the table. We could get nothing. Or 12 inches of snow.
Considering the storm is now in the data-sparse North Pacific, we are probably 2-3 days away from having enough good information to start making preparations or decisions.
Another cautionary note. While massive storms can occur in March (remember 1993), to get a big accumulating snow, we need to have high precipitation rates and/or the snow needs to fall at night.
The sun angle in early March is similar to early October, so even on a cloudy day with light snowfall, there is enough energy getting through the clouds to warm the ground more than in mid-January. This heating of the ground, while small, makes snow accumulation more difficult in March (given the same air temperature) versus January.