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There have been some fluctuations among the model guidance within the last 24 hours since we released our first snowfall forecast. The forecast confidence has gone up and there are some changes from our initial forecast. Please return back to this blog post Wednesday morning, however, for any minor changes on specific impacts, timing, and snowfall amounts.
Alerts:
Winter Storm Warning in effect from 12am Wednesday through 8am Thursday
Coastal Flood Advisory in effect from 1-4am Wednesday and 12-6pm Wednesday
Timing:
Precipitation begins: Either as snow or possible sleet between 6 and 10am Wednesday
Snow peaks in intensity: All of Wednesday afternoon and evening
Snow ends: Between 2 and 5am Thursday
Temperatures:
Tuesday night: Lows between 29 and 34°F
Wednesday: Mainly between 27 and 33°F
Wednesday night: Lows between 28 and 33°F
Winds:
Tuesday night: Peak gusts of 30-40 mph
Wednesday: Peak gusts of 30-50 mph
Wednesday night: Peak gusts of 35-50 mph
Snowfall:
Confidence: Low to Moderate
Most areas to receive 6-12 inches
Some locations, especially at immediate coast and north of I-84 may receive 3-6 inches
Impacts:
Tough travel conditions by Wednesday afternoon
Scattered power outages, mainly at coast
Minor coastal flooding
Snow all day Wednesday
Forecast Discussion:
Again, there are no big changes with this new forecast update. Our nor'easter is beginning to form off the North Carolina coast as energy transfers from the southern Appalachians to the developing coastal low offshore. The low pressure will not become a "bomb cyclone," but it will become a strong storm with pressures nearing 980 millibars on Wednesday as it makes its closest approach to the coast. This storm will move north, hugging the DelMarVa then New Jersey coast, then will take an eastward turn, moving parallel with Long Island. This will be a slow-moving storm compared to the past three nor'easters, so that will allow for a greater potential of snow. The exact track of this storm is still very uncertain, however. There will be a very tight snowfall gradient on the northern edge of this storm. This will make or break the forecast, thus making it very challenging. Notice the difference in precipitation forecast from four different models.
So the precipitation will begin sometime Wednesday morning. It may begin as sleet or even rain, especially at the coast, for a brief time, but the majority of the precipitation will be snow. Expect the precipitation to begin for all locations between 4am and 7am. There will be dry air that the precipitation will have to overcome, so if the precipitation begins a bit later than this time frame, that means the precipitation is taking a longer time to saturate the air. If this happens, it will only have a very slight impact on forecast snow totals.
By the late-morning of Wednesday, however, snow will be falling for all locations, and that dry air will actually help cool temperatures down to the mid to upper 20s for most areas. Then in the afternoon, snowfall intensities will increase as the center of low pressure makes its closest approach to our region while temperatures slightly warm up to near or at freezing due to the peak heating of the day. Since there will already be a layer of snow on the ground, this will not impact accumulations and will only help the snow add up at a fairly fast late. These cooler temperatures compared the the previous March nor'easters will aid in slightly higher snowfall ratios, and this snow will also be fluffier and lighter. The worst of the weather will be in the afternoon and evening as snowfall rates at times reach one to two inches per hour. I recommend you head home from work during the midday hours because road conditions will likely be a mess, especially north of the Merritt Parkway, by the evening. If you can, just stay home all day. Accumulations will begin right away as soon as the snow begins.
Then during the overnight hours, the snow will continue at a moderate intensity through about midnight, then it will taper off to a light snow early-Thursday morning. The snow will then end by the time the sun rises but the damage is already done. The models have been inconsistent with the forecast snowfall totals, so that makes for a challenging snowfall forecast, especially because of the tight northern snowfall gradient. Based on all the model data, factoring in temperatures, snowfall rates, and snowfall ratios, below is my best estimate in terms of snowfall. Most locations can expect 6-12 inches of snow. The best chance for these snowfall totals will be between I-95 and Interstate 84. I can see some locations, especially at the immediate coast and north of Interstate 84, experiencing totals of 3-6 inches.
There is a higher than normal bust potential with this forecast, so I want to show you the best and worse case scenarios because snowfall forecasts are based on probability. The forecast above shows the most likely solution, but if the track shifts, lighter or heavier totals will fall:
Worst-case scenario:
Coastal towns: 12-14 inches
Central towns: 12-14 inches
Northern towns: 10-12 inches
Best-case scenario:
Coastal towns: 2-4 inches
Central towns: 2-4 inches
Northern towns: 1-3 inches
There is also the risk for scattered power outages, mainly at the coast, based on the combination of wind gusts up to 50 mph, a wet snow, and already weekend trees.
We lastly want to note, you're probably wondering how does this snowy March compare to the past. In Bridgeport, we're currently at the 9th snowiest March, but if at least 7.1 inches of snow falls with Winter Storm Toby, which is likely, that would make it the top snowy March on record!
Again, continue to monitor the forecast from Jackson's Weather. I am displaying the best forecast, but please check in Wednesday morning to this blog post for any minor changes, especially with the snowfall forecast.
For the latest developments on Winter Storm Toby, be sure to stay updated with Jackson's Weather. We'll have LIVE updates as new model guidance comes in on our Twitter feed, which you can view below.