General Overview
Thursday's storm largely was born out of the Southern branch of the jet stream. Energy consolidated near the Carolina's and rapidly strengthened as it passed south and east of New England. Tomorrow's storm will originate out of the Northern Jet Stream. The storm will lack a storm low center as it gets close to the New Jersey coast Sunday afternoon. Overnight Sunday into Monday the low will deepen and slow as it is near the Eastern MA coast.
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| NWS/NOAA/NCEP Water Vapor Satellit through 915 AM |
It's not impressive on satellite at the moment. One piece of energy is leaving the Rockies and is emerging in the Great Plains. A second piece is up in Alberta/Saskatchewan. We can see these features better on the surface analysis. Here is the 1 PM forecast surface fronts and precipitation.
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| WPC Surface Fronts/Precipitation Saturday 1 PM |
The Canadian feature will drive the overall development of this low. It won't even begin to explode until it is east of the region. Here is the upper air pattern Sunday at 7 PM and Monday at 7 PM
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| click to enlarge images via Weatherbell |
Here is what it will look like at the surface Sunday at 7 AM and Monday 7 AM. Clicking these images and opening in another browser makes it make easier to see.
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| Click to enlarge |
Timing/Impacts
Precipitation begins between 10 AM and 1 PM from SW to NE across Southern New England. That said be careful Saturday night. Some light freezing drizzle is possible in Eastern MA including Worcester County. Keep the speeds down. Max temps will get into the low 30's this afternoon before dropping below freezing again tonight. Temperatures will be in the low 30s when snow/freezing rain begins. Here are the 1 PM tomorrow forecast temps.
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| 12z NAM 3km hires 2 m temps Sunday 1 PM (image Weatherbell) |
With that temperature profile, precipitation will be as rain, sleet, and freezing rain in Eastern MA. The heaviest snow for Central MA does appear to be during the first part of the storm on Sunday. By 7 PM temperatures are near 32-33 across much of Southern New England.
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| 12z NAM 3km hires 2 m temps Sunday 7 PM (image Weatherbell) |
That means that most of our snow will be like cement. It will be hard to move and it will likely stick to everything. The rain/snow line will also make a run towards Boston, Worcester, Hartford, and Providence. Usually, the heaviest snow falls just to the left/north of the rain/snow line. At 7 PM that would put Southern Worcester County, Norfolk County, and Suffolk County in the prime zone.
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| 12z NAM 3km hires precip type Sun 7 PM (image Weatherbell) |
I think Boston may go over to rain thanks to an east wind. Worcester will be safely all snow. After midnight the heaviest snow transfers towards NE MA and NH/ME. Around 5-7 AM cold air will return so any snow at the end of the event will be of the powder variety. Winds will pick up overnight Sunday into Monday which will blow the poweder around. Here are the 7 AM temperatures Monday.
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| 12z NAM 3km hires 2 m temps Monday 7 AM (image Weatherbell) |
Snow may hang on into Monday AM which is a trend to watch tonight and tomorrow. So here is what I am thinking,
The wind will gust 35-45 mph on Monday in the interior and 55-65 MPH at the coast. Keep the electronics fully charged tomorrow. North facing beaches on the Cape could see some coastal flooding. This means all of Cape Cod Bay including Sandwich and Dennis who will be at risk for storm surge Monday afternoon. Periods of snow showers will continue Monday early afternoon before conditions clear. Schools should be ready open Tuesday.
I'll post another update tomorrow morning.
-Zack Green
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