This is one frustrating forecast. A complex winter storm has been traversing the country, and its final act will arrive in New England later this afternoon and evening. This is a multi-hazard event that will bring snow, sleet, freezing rain, and rain to the state. Despite our best efforts, this is looking like a low confidence forecast, the last thing you want as we head toward gametime.
Let's jump right in.
The icing threat remains, but this is by far the lowest confidence piece of a low confidence forecast. I think that there will be a zone of freezing rain inside the main zone that may see higher end freezing rain, and in that zone there may be significant power issues.
Do not look at this map as anticipating widespread .5+ ice accretion. It does not envision that.
It is best to be prepared if you are in central and south (western) Connecticut as just a few degrees can make the difference between freezing rain and sleet.
The trend has clearly been toward more warming, even at the surface.
That could make this storm a less impactful event, but my guess is that the surface will be colder, leaving the door open for freezing rain.
Mid-Late Evening (5pm to 12am)
Everyone should start out as snow. That's where our best chance is for accumulation. Snow will move into the state between 5-9pm, and when it hits it will be a thump. We should see snow quickly go from light at onset to moderate/heavy during the late evening hours. Travel will quickly become hazardous.
This is the critical period as things begin to get tricky. A warm nose punches north and cuts off the snow, and we transition to mixed precipitation. Heavy precipitation will still be falling, and we could see a period of heavy sleet. One critical question is how long sleet lasts. If our snow is slow to transition to sleet, that would increase the snow totals on the front end. It's also possible we quickly change to sleet and then quickly change to freezing rain, which will increase the icing threat and reduce snow totals.
Make sure you're out measuring your snow before the changeover because once the sleet/freezing rain starts, it will quickly consolidate your snow!
As we get closer to sunrise, the guidance is now showing more significant plain rain for parts of the state. I think it's overdone, but along coastal and especially SE CT, it's possible we get above freezing and most down there wake up to a glaze of ice and not a whole lot of snow.
The mixed precipitation and rain should dominate the early portion of this period, but as the storm departs colder air will rush in. That will change our rain and/or mixed precipitation to snow, but I doubt it adds much to our overall totals. Temperatures will drop like a rock during the day, and what hasn't been cleared or salted will freeze solid. We're looking at flash freeze potential here, so even if you end up with rain, you need to be careful on the roads in the afternoon as the temperatures crash.
Monday is going to be frigid. We expect lows near zero statewide and wind chills that are well below zero. Take note.
- With the combination of snow, mixed precipitation, and a flash freeze on Sunday, we are expecting a significant winter weather event for all of Connecticut.
- There is high uncertainty over the amount of icing that we will receive. Higher confidence in snow and icing occurs the further north you are in the state, but everyone should be prepared for some level of icing Sunday morning. A prolonged freezing rain period may cause power issues.
- Even in places that receive plain rain, sharp temperature drops on Sunday and early Monday will cause a freeze that will create hazardous road conditions.
This is one of those storms that's going to require close monitoring in real-time. This is where we need your help! Please send us your photos and observations during the event as we try to provide forecast updates.
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Thank you for reading and trusting SCW.