Severe Weather Coordination Message #2 – Early Sunday Morning through Early Sunday Evening 7/22/18 Severe Weather/Flash Flood Potential
Hello to all…
..After a beautiful Saturday, heat and humidity will return with a coastal type storm system along with the threat for isolated to scattered strong to severe thunderstorms with strong to damaging winds, frequent lightning, heavy rainfall with the potential of urban and poor drainage flooding to flash flooding and the possibility of an isolated tornado or waterspout. The Storm Prediction Center (SPC) has continued South-Coastal Connecticut, South-Central Rhode Island into portions of Eastern Massachusetts in a Marginal Risk for severe weather..
..SKYWARN Self-Activation is likely to monitor conditions around and after 4 AM Sunday through Sunday Afternoon. Ops at NWS Boston/Norton are also possible but an exact timeframe for Ops needs remains unclear so this will continue to be monitored..
A fairly intense coastal type storm system for July will affect the region Sunday. A strong warm front is still expected to traverse the region and along and behind the warm front, dewpoints will soar from the comfortable upper 50’s to lower 60’s to the sultry low to mid 70s. Based on the track of the low pressure system a bit further west, its possible that the threat for an isolated tornado and waterspout has diminished somewhat as the triple point of the low will be further west, however, that remains uncertain and the wind shear will still be more than sufficient for strong to severe thunderstorms and there will be a level of turning in the atmosphere to support an isolated tornado or waterspout with the warm front. The amount of instability will be more limited and will limit the coverage of the severe weather and it will put much of Southern New England in an environment of a low instability/high shear. That being said, instability does increase as the day wears on Sunday and if there is an overlap with the turning of the atmosphere associated with the warm front with that instability, it would create an environment that can produce isolated to scattered strong to severe thunderstorms with strong to damaging winds and an isolated tornado/waterspout as the main severe weather threats. Heavy rainfall is also possible as thunderstorms may train along and behind the warm front and given its a coastal system it could setup in a band ahead of the low pressure center. This rainfall if it trains over the same areas could bring an urban and poor drainage flooding to flash flood potential that will need to be monitored. The focus areas of where this heaviest rainfall is unclear. It could be over a portion of Southern New England or just south and west of the region. A focus area of monitoring will be the rain moving from southeast to Northwest west of the lower pressure center offshore of southern New England and is moving northward with the coastal low. Also, in any heavier convective showers and as the warm frontal passage occurs, general strong wind gusts of between 35 and 50 MPH are possible particularly in coastal Southeast New England if the heavy convective showers or conditions allow those stronger winds to reach the surface.
SKYWARN Self-Activation is likely to monitor conditions around and after 4 AM Sunday through Sunday Afternoon. Ops at NWS Boston/Norton are also possible but an exact timeframe for Ops needs remains unclear so this will continue to be monitored. If Ops are initiated, a shortened coordination message will be posted if time allows stating Ops are initiated. If ops aren’t initiated and conditions and time allows for it, another complete coordination message may be issued by 10 AM Sunday. Below is the NWS Boston/Norton Hazardous Weather Outlook, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook:
NWS Boston/Norton Hazardous Weather Outlook:
NWS Boston/Norton Experimental Enhanced Hazardous Weather Outlook:
SPC Day-1 Convective Outlook:
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: email@example.com
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