Storm Coordination Message #4 – Saturday Evening 1/19/19-Sunday Evening 1/20/19 Winter Storm Potential

Hello to all…

..Major winter storm expected and on track for much of Southern New England late Saturday Afternoon into Sunday Night with heavy snow and significant icing both possible with snow and ice changing to heavy rain and strong winds along coastal areas then changing back to snow with a flash freeze before ending and the potential for minor to moderate coastal flooding at the time of high tide as we get into the Sunday Morning high tide cycle in East Coastal Massachusetts..
..A Winter Storm Warning is now in effect from 4 PM Saturday Afternoon to 7 PM Sunday Evening for Franklin, Northern Worcester, Middlesex, Essex and Hampshire Counties of Massachusetts for 8-18″ of snow with the highest amounts from the route 2 corridor north and west..
..A Winter Storm Watch remains in effect from Saturday Afternoon through Sunday Night for the rest of the NWS Boston/Norton Coverage Area except for Cape Cod and the Islands for 3-9″ or more of snow and sleet with ice accumulations of a trace to 0.20″ of an inch with amounts up to 0.50″ of ice in a band within the Winter Storm Warning area..
..A Coastal Flood Warning is now in effect from 8 AM-Noon for Eastern Essex, Suffolk, Eastern Norfolk and Eastern Plymouth Counties of Massachusetts for flooding of vulnerable shore roads and possibly isolated pockets of minor property damage at the time of high tide Sunday Morning..
..A Coastal Flood Advisory is now in effect from 8 AM-Noon for for Cape Cod and the Islands for flooding of vulnerable shore roads at the time of high tide..
..A Coastal Flood Advisory is now in effect from 5 AM-10 AM for South Coastal Massachusetts and Rhode Island for flooding of vulnerable shore roads at the time of high tide..
..SKYWARN Activation with Ops at NWS Boston/Norton are likely at some point Saturday Evening into Sunday Morning lasting through Sunday Evening. Activation plan will be updated as we get closer to the storm event..

The long quiet period of winter weather with only some strong wind, heavy rainfall events and a few very light snow and ice events is on track to come to an end. The headlines discuss the current potential and first cut at snow and ice totals. Some key factors still remain for the upcoming storm include the following and have not changed much since the last update:

1.) The storm track will determine the area of all snow and where it will be a very heavy snow accumulation, where precipitation mixes with sleet and/or freezing rain with potential sleet and/or ice accumulations and where a changeover to rain occurs. Locations that changeover to rain or sleet and freezing rain will see a changeover to snow before ending with a potential for a flash freeze condition where all wet surfaces will become iced over. At this time the trend has been for more sleet and freezing rain particularly along and south of the Mass Pike and potentially from I-495 west. While this may lower snowfall amounts, the icing will have the potential to cause worse conditions including potential for pockets of tree and wire damage and power outages. Further snow and ice total adjustments will be made before the storm and possibly during the storm as required.
2.) Strong winds will be possible to likely in coastal areas but currently expected to be wind gusts up to 50 MPH. Inland areas could see wind gusts to 40 MPH. Some of this could change based on the intensity of the storm system and the track. That could affect both wind speed intensity and duration of strong winds. There will also be strong winds as the storm departs Sunday Night into Monday Morning.
3.) The snow could be heavy and wet along with the potential for sleet and freezing rain. The weight of the snow and ice coupled with the winds to some extent may cause the potential for isolated to scattered pockets of tree and wire damage and power outages. This aspect will be monitored closely and as mentioned previously, if snow amounts are lowered, ice amounts increase in most areas which could actually lead to greater impact and will be monitored closely.
4.) Minor to moderate coastal flooding is possible on the Sunday Morning high tide cycle in East Coastal Massachusetts where a Coastal Flood Warnings and Advisories are now in effect. While winds are not expected to be as strong as some past nor’easter/coastal storm systems, there is a very high astronomical tide cycle for this weekend which will increase the coastal flood potential.

5.) Spotter reports on snow, ice, amounts, wind measurements of criteria and any damage reports will be critical as well as precipitation type reports when the changeover takes hold. This will factor into forecast adjustments if needed during the storm event.
6.) How these key factors line up and turn into specific outcomes will be better defined after future model runs over the next 12-18 hours.

SKYWARN Activation with Ops at NWS Boston/Norton are likely at some point Saturday Evening into Sunday Morning lasting through Sunday Evening. Activation plan will be updated as we get closer to the storm event. The next coordination message will be posted by 1000 AM Friday Morning. Below is the NWS Boston/Norton Winter Storm Warning/Watch statement, Coastal Flood Warning/Advisory Statement, Hazardous Weather Outlook, Enhanced Hazardous Weather Outlook, Snow and Ice Maps and Facebook Infographics:

NWS Boston/Norton Winter Storm Warning/Watch Statement:
https://kamala.cod.edu/ma/latest.wwus41.KBOX.html

NWS Boston/Norton Coastal Flood Warning/Advisory Statement:
https://kamala.cod.edu/ma/latest.whus41.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

NWS Boston/Norton Snow, Ice and Rain Maps:
https://www.weather.gov/box/winter

NWS Boston/Norton Facebook Infographics:
https://www.facebook.com/NWSBoston/photos/pcb.2050177418409952/2050174001743627/?type=3&theater

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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