Severe Weather Coordination Message #1 – Late Saturday Night 7/21/18-Sunday 7/22/18 Severe Weather/Flash Flood Potential

Hello to all…

..After one last comfortable day, 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 and the possibility of an isolated tornado or waterspout. The Storm Prediction Center (SPC) has placed 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 late Saturday Night into Sunday. Ops at NWS Boston/Norton are also possible..

A fairly intense coastal type storm system for July will affect the region late Saturday Night into Sunday. A strong warm front will 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. Wind Shear will 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. 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. These environments can produce isolated to scattered strong to severe thunderstorms with strong to damaging winds and an isolated tornado 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. Also, in any heavier convective showers and as the warm frontal passage occurs, general strong winds of between 35 and 50 MPH are possible particularly in coastal Southeast New England.

SKYWARN Self-Activation is likely to monitor conditions late Saturday Night into Sunday. Ops at NWS Boston/Norton are also possible. Another coordination message will be posted by 1000 PM Saturday Evening. Below is the NWS Boston/Norton Hazardous Weather Outlook, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook:

Hello to all…

..After one last comfortable day, 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 and the possibility of an isolated tornado or waterspout. The Storm Prediction Center (SPC) has placed 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 late Saturday Night into Sunday. Ops at NWS Boston/Norton are also possible..

A fairly intense coastal type storm system for July will affect the region late Saturday Night into Sunday. A strong warm front will 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. Wind Shear will 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. 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. These environments can produce isolated to scattered strong to severe thunderstorms with strong to damaging winds and an isolated tornado 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. Also, in any heavier convective showers and as the warm frontal passage occurs, general strong winds of between 35 and 50 MPH are possible particularly in coastal Southeast New England.

SKYWARN Self-Activation is likely to monitor conditions late Saturday Night into Sunday. Ops at NWS Boston/Norton are also possible. Another coordination message will be posted by 1000 PM Saturday Evening. Below is the NWS Boston/Norton Hazardous Weather Outlook, Enhanced Hazardous Weather Outlook and SPC Day-1 Convective Outlook: