Winter storm forecast: First call for this weekend
Earlier this afternoon, I posted a synoptic update on the coming winter storm for the Northeast. After holding back on the forecast and basically describing the situation, we have agreed to do a team forecast on our first call for this storm. This is a shared opinion of all of us. It is important to note that these are general forecast amounts – some areas may be locally higher or lower. Some models are showing even higher amounts in some regions even in the bullseye area in the mid-Atlantic, so this may be conservative. This will be fine tuned tomorrow as the event gets closer. In addition, coastal flooding and damaging winds are significant threats as well.
Note that these are general amounts for each region. More specific city-based forecasts cannot be made at this time.
- Northern New England and northern New York: No major impact – little or no snow.
- Coastal southern New England: 2 to 4 inches near Boston; 4 to 6 inches most other areas with locally up to 10 inches in SW Connecticut
- Interior southern New England and Catskills: 1 to 4 inches
- Central valleys (Mohawk, lower Hudson, Susquehanna, Lake Ontario shore, etc.): Little or no impact north, 2 to 6 inches south
- New York City region: 7 to 14 inches, decreasing south to north
- Northern Mid-Atlantic coast (NJ, DE, Philadelphia area): 7 to 12 inches on the Jersey shore, 10 to 16 inches otherwise
- Central New York and northern Pennsylvania highlands: 1 to 4 inches
- Chesapeake and Potomac region (DC, Baltimore): 16 to 26 inches; locally to 30 inches or more especially near and west of DC
- Central Appalachians/Blue Ridge: 16 to 26 inches; locally to 30 inches or more in parts of VA
- Southern Piedmont/valleys (Shenandoah, James, upper Potomac, etc.): 12 to 20 inches in west, 8 to 14 inches in east plus some mixing or ice
- Southern Mid-Atlantic coast (MD, VA): 2 to 6 inches south plus significant mixing, rain or ice, 6 to 12 inches north plus some mixing or ice
- Storm surge/coastal flooding: This is probably the second greatest threat, and for some areas an even greater threat than the heavy snow. The synoptic assessment earlier showed a peak storm surge of 5 to 6 feet possible in the New York City region and part of the Jersey Shore as the storm moves offshore. In addition, waves will create major problems on the open coast and may result in significant erosion. Combined with tidal impacts, it is likely that such would result in a water level of up to 11 feet. That would be higher than Irene in 2011 and comparable to Donna in 1960 and a nor’easter in 1992, with some threat of at least localized subway flooding. For comparison, the peak water level during Sandy in 2012 was near 14 feet in the Battery.
- High winds: Many areas will likely see sustained winds of 25 to 40 mph, with gusts of 40 to 60 mph, as the storm pushes offshore and tracks not far from the coast. Some exposed coastal areas may see even stronger winds, perhaps sustained 50 mph with gusts to 70 mph, and offshore winds will be stronger still. Those winds may result in tree damage and power outages, some of which may be significant. The power outage threat is magnified in areas which experience heavy, wet snow in addition to the very strong winds. Those winds will also lead to widespread blowing and drifting snow with zero visibility in many areas as well.
- Freezing rain: This is primarily a threat in the southern edge of our area, in the southern Virginia valleys and large parts of central North Carolina as warm air tries to rise with the cold air rushing in as a result of the deepening storm. Many areas in those regions will likely see over 1/4 inch of ice accumulation with some areas as much as 3/4 inch to 1 inch. Combined with strong winds, that would likely result in widespread power outages and tree damage. Some freezing rain is also possible to the lower mid-Atlantic coast, which may add to the risk in combination to the winds and snow as well.
Confidence: Moderate to High on the general synoptic setup, Low to Moderate on the amounts and their locations.The previous post mentioned some advice for safety and preparedness. Now is definitely the time to prepare for a dangerous winter storm. As it gets closer, the forecast will be fine-tuned. Safety is paramount!
Forecaster Craig Ceecee – @Ceecee_Wx