Hello to all…
..Scattered to Numerous Strong to Severe Thunderstorms likely late Friday Afternoon into Friday Night across much of Southern New England away from the south coast of Southern New England. Strong to damaging winds, hail, heavy rainfall causing urban and poor drainage flooding and frequent lightning are the main threats. The Storm Prediction Center (SPC) continued much of New England in a Slight Risk for Severe Weather and now extends through South Coastal New England..
..Threat timeframe for strong to severe thunderstorms is after 400 PM EDT Friday. It is noted that this event has the potential to be a potent outbreak for severe weather but like many severe weather events in Southern New England exact details and small mesoscale deviations could drastically alter the potential or the timing of the severe weather..
..SPC has also placed portions of Southern New England in a Marginal Risk for Severe Weather for Saturday, particularly interior Southern New England. This severe weather potential will likely hinge on what occurs late Friday Afternoon through Friday Night..
..SKYWARN Activation with Ops at NWS Taunton will commence at 4 PM EDT Friday through the early portion of the overnight hours. SKYWARN Activation with Ops at NWS Taunton is possible for Saturday..
A rather interesting severe weather setup is shaping up for Southern New England and the Northeast US on Friday. The headlines give current thinking and as stated in the headlines, this event has high severe weather potential but small mesoscale deviations that can be difficult to resolve could alter the outcome. Also, the timing of the severe weather has uncertainty. For Saturday, the severe weather potential is more conditional and will likely hinge on what convection occurs on Friday and positioning and strength of the cold front that moves through the area.
Satellite imagery this morning shows some cloud cover over Southern New England, particularly in western areas, as a line of showers is swinging through Northern New England. There is good clearing behind this in New York State so cloud cover moving out around late morning/midday seems on track and this should allow for intense heating and destabilization with favorable wind shear profiles. This can potentially set the stage for either a cluster or several clusters of scattered strong to severe thunderstorms for the region. There is also the possibility for a larger complex of strong to severe thunderstorms known as a MCS or Mesoscale Convective System to take shape and sweep through much of Southern New England. The timing is a bit uncertain with unstable conditions by mid to late afternoon but weather models showing high levels of instability through the night which could mean severe weather extending into some portion of the overnight hours or not starting until later Friday Evening.
While the setup for severe weather as modeled as high potential, small mesoscale deviations could impact this potential and this includes the following:
1.) There is an insufficient trigger in the atmosphere to set off the favorable levels of instability and shear.
2.) A complex of severe thunderstorms forms but stays up in Northern New England and doesn’t dive southeast into Southern New England. The other possibility is radar this morning is showing a line of thunderstorms forming over Lake Erie, Northeast Ohio, Northeast Pennsylvania and Southwest New York. Does this activity and its movement miss our area with no extension of any strong to severe thunderstorm activity into New York State swinging into Southern New England? Some models show this while others show the extension of the activity in New York State swinging through Southern New England.
3.) The Cloud cover from any leftover upstream convection reducing instability is now less likely based on current satellite and radar trends. Unless something changes, this is least likely to impact the severe weather potential.
For Saturday, SPC has a marginal risk for severe weather over portions of interior Southern New England. There will remain good shear profiles for Saturday and there should be good heating for Saturday depending on how much convection is seen late Friday Afternoon and Friday Night in Southern New England. There is some question as to how much moisture will be available to tap into the good wind shear profiles and how Friday’s convection effects the environment for Saturday. This will be greater detailed in future coordination messages.
SKYWARN Activation with Ops at NWS Taunton will commence at 4 PM EDT. This will be the last coordination message on the Friday severe weather potential. For Saturday’s severe weather potential, the next coordination message will either be posted late Friday Evening or by 1000 AM Saturday Morning depending on how active late Friday Afternoon and Friday Evening is for severe weather. Below is the NWS Taunton Hazardous Weather Outlook, Special Weather Statement, SPC Day-1 Convective Outlook, SPC Day-2 Convective Outlook for Saturday severe weather potential and the latest Friday NWS Taunton Area Forecast Discussion which provides a good technical/meteorological overview of the severe weather potential for Friday for those more advanced spotters who would like that level of detailed info.
NWS Taunton Hazardous Weather Outlook:
NWS Taunton Special Weather Statement:
SPC Day-1 Convective Outlook – Friday July 22nd, 2016 Severe Weather Potential:
SPC Day-2 Convective Outlook – Saturday July 23rd, 2016 Severe Weather Potential:
NWS Taunton Area Forecast Discussion:
Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Assistant Section Emergency Coordinator
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Home/Data #: (508) 997-4503 (After 6 PM)
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