GOOD Morning Wilton’s weather contributor Jackson Dill shares his latest update on Winter Storm Grayson from his Jackson’s Weather website. 

Thanks to an offshore storm that’s likely be as strong as Hurricane Sandy, the biggest snowstorm so far this season will likely dump several inches of snow on Wilton Wednesday night through Thursday night. Here’s everything you need to know about this storm’s forecast for now–and keep reading to find out about whether or not schools will likely close…

Timing

  • Snow starts between 10 p.m. Wednesday and 2 a.m. Thursday
  • Heaviest snow between 6 a.m. and 2 p.m. Thursday
  • Snow ends between 4 p.m. and 8 p.m. Thursday

Winds

  • Highest gusts Thursday morning through Thursday evening
  • Wind gusts as high as 50 mph while snow falls
  • Brief blizzard conditions are possible
  • Isolated power outages are expected

Snowfall

  • Uncertainty:  Moderate to High
  • Highest snowfall totals for eastern areas
  • Current Wilton forecast:  3-6 inches (subject to change)

Temperatures

  • Mainly in the 20s while the snow falls
  • Will allow for higher snowfall ratios–up to 15 inches of snow per 1 inch of liquid
  • Temperatures will significantly drop off into single-digits on Thursday night, as new shot of Arctic air arrives.

Detailed Forecast

A broad area of low pressure has been developing near the Bahamas, and it began to organize into a stronger low last night. By today (Wednesday, Jan. 3), it will start deepening, with lowering pressures that will bring snow to portions of the South, including Florida.

This low will continue to move up the coast, and starting Wednesday night, light snow will move into southwestern Connecticut. That’s when the low will undergo bombogenesis–that’s when the pressure drops at least 24 millibars within 24 hours. This storm will definitely exceed this criteria by 7 p.m. tonight with a pressure of 981 mb; it will continue to fall, all the way down to 944 mb by 7 p.m. Thursday, according to the European model.

That is an insanely fast pressure drop, and this storm will likely be as strong as Hurricane Sandy. Thankfully, it will remain off the coast. The main question that remains is, how will it track? Throughout the day Tuesday, the models continued to trend the center of the storm closer to the coast, and all of the models now take it pretty close to the 40/70 Benchmark, as shown below. When storms move over these coordinates (40°N, 70°W), they maximize their impact.

Jet stream dynamics are also very favorable, hinting at a large area of precipitation, so impacts will span hundreds of miles away from the center of the storm. While the storm is still off the coast of North Carolina Wednesday night, we’ll already be seeing snow falling in our area.

The storm will make its closest approach during the day on Thursday; that’s also when it will near the “Benchmark.” As a result, a moderate-to-heavy snow is likely during much of Thursday. Right now I think the heavy snow band will set up to the east of us closer to Boston, but if the track of the storm continues to shift west, then we could be talking about heavier snow and thus heavier snowfall totals.

The track of the low will also help determine how strong the winds will be. This storm is going to be unusually strong, so winds will likely gust as high as 50 mph. Blizzard conditions cannot be ruled out, and spotty power outages are likely. This is a huge concern because of the extreme cold that will follow this storm. Temperatures Thursday night will be in the single-digits while the snow comes to an end, and during the weekend, low temperatures will be even lower, below zero.

Temperatures will definitely be cold enough during the storm, so I’m not concerned about any mixing. We’ll only hit the mid 20s during the day on Thursday, so snowfall ratios will be higher–you’ll get more snow out of the same amount of liquid. In fact, I am leaning toward the higher totals within the range of 3-6 inches for our area.

Of course, if there are any more shifts in the track of this storm, which is certainly possible, I’ll either have to increase or decrease these snowfall amounts–if anything, I’ll likely have to increase them. Based on timing and predicted snowfall totals, travel will be difficult on Thursday and school closures are likely. To keep up with the latest, check the School Predictions page on Jackson’s Weather.

Jackson Dill is a Wilton High School senior who started the website, Jackson’s Weather. His 7-day forecast will appear each Monday on GOOD Morning Wilton. Visit Jackson’s Weather to find out any changes in the forecast. You can also follow him on Facebook, Twitter, and Instagram @JacksonsWeather for around-the-clock updates.