The questions are coming in fast and furious about best plans for travel with the Thanksgiving holiday fast approaching. Let me start with a summary before I dig in...
- Travel Tuesday is fine until dusk within New England and Upstate New York. Thereafter, conditions deteriorate from southwest to northeast.
- Snow falls from Upstate New York to Western and Northern New England Tuesday night, then changes to rain from south to north by dawn Wednesday.
- Rochester to Buffalo, NY, to Erie, PA, corridor is likely to stay mostly snow.
- Heavy rains fall through New England, New Jersey, Eastern NY and Eastern PA, Wednesday, with over 4" of rain in highest amounts - widespread river flooding is not anticipated given dry antecedent conditions, but urban street flooding and ponding of water in poor drainage areas is likely
- Winds may gust to or over 60 mph from the south on Wednesday across portions of New England - particularly eastern New England - as warm air rushes northward. This wind would result in some power outages and damage.
- Conditions will improve dramatically from late afternoon through dinnertime Wednesday onward, throughout the Northeast corridor, from southwest to northeast
Travel Bottom Line: In the Northeast, travel will be best during the day Tuesday, or from Wednesday evening onward. If you have a flexible schedule, these times will be your best bet. Of course, it's entirely possible that the weather Tuesday night into Wednesday will result in increased traffic both Tuesday daytime, Wednesday night, and Thanksgiving Day.
Some images of note:
Tuesday 10 PM Precipitation Type forecast: This forecast image is from the NAM computer guidance, which looks to be holding onto the cold air appropriately in the climatologically favored locations of the Northeast. The rain/snow line will progress quickly northward over time, reaching the Canadian border before dawn Wednesday, though snow will continue in Western New York, on the cold side of the storm.
Total Expected Snowfall Tuesday night: The initial burst of snow on the leading edge of the precipitation shield will add up for Northern and Western New England into Upstate New York. This forecast is prior to a change to rain by dawn Wednesday.
Storm Total Snowfall for the Northeast: Significant snow is expected on the west side of the storm track. Higher amounts in Northern New England at first seem to contradict the map above, but remember the map above is for snow on the front side of the storm...some "upslope" snow as the system departs is likely in the mountains of Northern New England.
Wednesday 10 AM Precipitation Intensity Forecast (precipitation type not indicated): Rain will fall torrentially in New England Wednesday morning through mid-afternoon, before tapering late in the day. Travel by road will become very difficult with substantial ponding of water, high wind and areas of fog. Travel by air will be delayed by the combination of low visibility for pilots, and strong winds at airfields through the Northeast.
Wednesday 4 PM Surface Wind Gust Forecast: This is the surface wind gust forecast from the NAM computer guidance product for late afternoon Wednesday. As the storm strengthens while pulling into Canada, a strong southerly wind will develop ahead of the storm center, and that results in strong gusts at the surface. Though these forecast gusts of up to 78 mph at exposed south-facing coastal locales may be overdone, surely the potential for damaging gusts of 55 mph or greater is evident. These gusts will result in some power outages and damage Wednesday. Winds let up Wednesday night as they start to blow in colder air from the northwest.
Storm Total Rainfall forecast: I expect a large area of 2" to 4" of rainfall from this storm. Localized amounts of greater than four inches are likely. Given dry conditions preceding the storm, widespread river flooding seems unlikely, though some faster-responding rivers (smaller ones) may come into minor flood stage by storm's end.
This energetic and moisture-laden system will exit the Northeast by Thanksgiving Day, and cold air will spill in behind it, bringing a cold holiday for the Northeast US. One issue to watch is how strong the wind will be Thursday, as this will impact which floats can fly without impediment at the Macy's Thanksgiving Day Parade, and other parades in the Northeast, though right now I'm optimistic winds Thursday won't exceed 30-35 mph gusts...I'll keep you posted.