Good morning, 

Following is an update on potential weather-related hazards from an area of low pressure that is expected to move from the mid-Atlantic through southeastern Massachusetts. This system is expected to produce a wintry mix of freezing rain and snow across the Berkshires into northern Worcester County Sunday, with mainly rain elsewhere in Southern New England. It will also bring a period of gusty winds Sunday night to the coastal waters, along with the potential for minor coastal flooding in parts of eastern Massachusetts during Sunday's high tides.

Changes with this update:
  • Gale Watch Issued [Sunday into Sunday Night]: Coastal and offshore waters. 
  • Updated Snow and Ice Accumulations. Note: Portions of the Berkshires into northern Worcester County may need winter weather advisories for parts of Sunday in forthcoming updates.

Details below:

Interior Light Icing and Light Snow (See Attached Images):
Locations: Mainly the northern Worcester Hills and the Berkshires.
Timing: Begins as light freezing rain into the pre-dawn hours Sunday morning, changing to rain by late morning or early afternoon. Ending as a period of light accumulating wet snow Sunday night.
Expected Amounts: A light glaze of ice (up to 1/10"), with up to 2 inches of snow at the highest elevations. 
Impact: Slippery travel.  
Uncertainty: Timing of the exact changeover may affect snow and ice accumulations. To convey this uncertainty and its effect on snowfall amounts, a reasonable worst-case snow accumulation is also attached (if precipitation to change over to snow sooner); in addition to the expected snow amounts.

Marine Impacts: Gale Force Winds [Sunday Night]
Locations: Massachusetts and Rhode Island coastal & offshore waters.
Timing: Onset of Gales between 2 and 4 PM Sunday, ending between 4 and 8 AM Monday. 
Wind Gusts: Northwest 35 to 42 knots, peaking between 6 PM Sunday and 2 AM Monday.
Seas: 4 to 6 feet on the inner bays and sounds; 7 to 11 ft offshore.
Impact: Hazardous conditions for mariners.
Uncertainty: High confidence in occurrence, though uncertainty on exact start and ending times.

Minor Coastal Flooding: Sunday Morning High Tide
Locations: Eastern Massachusetts coast (including Martha's Vineyard and Nantucket) and the South Coast
Timing: Sunday morning high tide (5:41 AM at Providence, 8:45 AM at Boston, and 9:46 AM on Nantucket)
Storm Surge: 1.0 to 1.5 feet 
Inundation: Less than 1 foot above ground level
Impact: Some vulnerable shoreline roads may become temporarily impassable around high tide. 
Uncertainty: High. Timing of highest surge may not coincide with high tide, which would lead to little or no impact. Minor coastal flooding would be the worst case scenario.

Minor Coastal Flooding: Sunday Evening High Tide
Locations: Eastern Massachusetts coast including Martha's Vineyard and Nantucket
Timing: Sunday evening high tide (9:17 PM at Boston and 10:24 PM on Nantucket)
Storm Surge: Around 2.0 feet 
Inundation: Up to 1 foot above ground level
Impact: Some vulnerable shoreline roads may become temporarily impassable around high tide. 
Uncertainty: Lower than with the morning high tide. Locations along the Bay side of Cape Cod, Plymouth County, and Nantucket are most vulnerable.

Thank You!

Meteorologist: Andrew Loconto

If you have any questions or would like more information, don't hesitate to contact us via this email address, on NWSChat, or at the following:

National Weather Service Boston/Norton, MA

46 Commerce Way
Norton, MA 02766
508.622.3280
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