Storm Coordination Message #2 – Late Thursday Night 12/20/18-Late Friday Night 12/21/18

Hello to all…

..Very strong and unusually warm storm system for December is on track to impact the region with the potential for very heavy rainfall and the potential for urban and poor drainage flooding to possibly even small river and stream flooding, strong to damaging winds and possibly even isolated strong to severe thunderstorms that will have the potential to bring stronger winds to the surface with the strong to severe thunderstorm potential highest in Southeast New England..
..A Flood Watch remains in effect for the entire NWS Boston/Norton coverage area from late Thursday Night through late Friday Night for at least 1-3″ of rain with higher amounts possible to likely and the potential for urban and poor drainage flooding to possibly small river and stream flooding..
..A High Wind Watch is now in effect from Friday Morning to Friday Evening for South Coastal Massachusetts and Rhode Island and Cape Cod and the Islands for sustained winds of 25-35 MPH with gusts to 50-60 MPH possible along with isolated higher gusts. Wind Advisories will likely be required for other portions of at least Central and Eastern New England in future updates..
..Minor coastal flooding is possible at the time of the Friday and possibly Saturday Morning high tide cycles for south and east facing coastal locations and will be monitored..
..SKYWARN Activation with Ops at NWS Boston/Norton will commence by around 7-8 AM Friday Morning lasting through Friday Evening..

An unusually strong and warm storm system for December is on track to impact the region late Thursday Night into late Friday Night. The headlines depict current thinking including an expansion of the High Wind Watch through South Coastal Massachusetts and Rhode Island. The headlines will likely undergo further adjustments as we get closer to the storm event. Key factors for this storm system remains as follows:

1.) Rainfall amounts of 1-3″ are likely but its quite possible higher amounts of greater than 3″ could occur as it will be an unusually warm and moist atmosphere for December over the area. As amounts approach or exceed 3″ and depending on the aerial coverage of those rainfall amounts, the risk for flooding increases and this will be watched closely.
2.) There will be very strong winds aloft out of the south and southeast direction. Typically, these winds struggle to reach the surface however given the storm setup and particularly over Southeast New England where temperatures could potentially be as high as 60 degrees or possibly above 60 degrees, that could potentially allow these winds to mix to the surface more prevalently than normal. Also, any thunderstorm activity or heavy convective downpours would also be a mechanism to bring stronger winds down to the surface. These aspects will bear watching as we get closer to the storm event.
3.) While very unusual, we will have to monitor the potential for even isolated severe thunderstorms in this environment and even the very low possibility that an isolated waterspout or tornado could occur particularly in Southeast New England. The unusual warm, moist atmosphere, very strong wind fields aloft and the potential for low-level instability would make this possible with the key conditional component the low-level instability. This will bear close watching.
4.) Minor coastal flooding is also possible at high tide cycles on Friday and possibly the Saturday Morning high tide cycle. This will depend on how the strong winds are and how they are timed at the high tide cycles.

SKYWARN Activation with Ops at NWS Boston/Norton will commence by around 7-8 AM Friday Morning lasting through Friday Evening. Another coordination message will be posted by 1000 PM Thursday Evening. Below is the NWS Boston/Norton Flood Watch Statement, High Wind Watch Statement, Hazardous Weather Outlook and Enhanced Hazardous Weather Outlook:

NWS Boston/Norton Flood Watch Statement:
https://kamala.cod.edu/ma/latest.wgus61.KBOX.html

NWS Boston/Norton High Wind Watch Statement:
https://kamala.cod.edu/ma/latest.wwus71.KBOX.html

NWS Boston/Norton Hazardous Weather Outlook:
https://kamala.cod.edu/ma/latest.flus41.KBOX.html

NWS Boston/Norton Enhanced Hazardous Weather Outlook:
https://www.weather.gov/box/ehwo

Respectfully Submitted,

Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Section Emergency Coordinator
Home Phone #: (508) 994-1875 (After 6 PM)
Home/Data #: (508) 997-4503 (After 6 PM)
Work Phone #: 508-346-2929 (8 AM-5 PM)
Email Address: rmacedo@rcn.com
http://ares.ema.arrl.org
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