Severe Weather Coordination Message #2 – Tuesday June 23rd 2015 Severe Weather Potential

June 23, 2015 Rob Macedo Leave a comment

Hello to all..

..Potential major severe weather outbreak with scattered to numerous strong to severe thunderstorms likely across much of Southern New England particularly north and west of a Boston to Providence line but potentially affecting an area as far south and east as the Cape Cod Canal. Damaging winds, large hail and urban and poor drainage flooding are the main threats but an isolated tornado or two is also possible. The main caveat to this potential will be evolution of overnight convection and amount of clearing over the region by the midday Tuesday timeframe..
..The Storm Prediction Center (SPC) has placed the area of Central and Southern New Hampshire, Western and Central and interior Northeast Massachusetts and Northern Connecticut in an enhanced risk of severe weather. Surrounding the enhanced risk of severe weather, there is a slight risk for severe weather for Rhode Island and Eastern Massachusetts north and west of the Cape Cod Canal and a marginal risk for severe weather for Cape Cod and the Islands. NWS Taunton is in agreement with this assessment..
..SKYWARN Activation with Ops at NWS Taunton will commence no later than 1 PM for this potentially significant severe weather event and SKYWARN Self-Activation will monitor any convection that could organize ahead of the warm front. ARES/RACES Groups should closely monitor the situation and seek advice from local leadership. Severe Weather Safety Rules should be reviewed ahead of any severe weather activity..

At 900 PM Monday Evening, Doppler Radar shows a line of showers in the West-Central New York State area. This activity is moving eastward and has been on a weakening trend. Behind this activity, a line of convection is organizing in the state of Michigan. The evolution of this overnight activity and any cloud cover is the main uncertainty that could affect the severe weather potential for Tuesday. A review of radar and satellite imagery at this time shows a more than sufficient level of clearing between the activity in Michigan and the Western New York activity to set the stage for the severe weather outbreak but we are still more than 18 hours from the event and convective activity in Michigan and its track and timing will ultimately determine the extent of the severe weather potential on Tuesday for Southern New England. At this time, the consensus of model runs and current trends support a scenario where sufficient heating and destabilization will allow for a potent severe weather outbreak for Southern New England. Factors that are confirmed to be in place for the potential for a severe weather outbreak include very strong winds aloft, a strong cold front and triggering mechanism.

The extent of destabilization as well as the wind profiles will determine if there is a large complex of severe thunderstorms enhancing the damaging wind potential or if there will be discreet supercells that would allow for the isolated tornado threat to materialize that would then evolve into a complex of severe thunderstorms or occur out ahead of any complex severe thunderstorms. If cloud cover does not sufficiently break by noon or 1 PM, the severe weather potential would be marginalized to a more isolated, typical Southern New England severe weather event with isolated to scattered severe thunderstorms and would likely be confined to Western New England but this currently appears to be the least likely scenario.

The threat timeframe for severe weather potential is between 2-8 PM though could go as long as 10 or 11 PM particularly in eastern areas of Southern New England. The Storm Prediction Center (SPC) has placed the area of Central and Southern New Hampshire, Western and Central and interior Northeast Massachusetts and Northern Connecticut in an enhanced risk of severe weather. Surrounding the enhanced risk of severe weather, there is a slight risk for severe weather for Rhode Island and Eastern Massachusetts north and west of the Cape Cod Canal and a marginal risk for severe weather for Cape Cod and the Islands. NWS Taunton is in agreement with this assessment. Damaging winds, large hail and urban and poor drainage flooding are the main threats but an isolated tornado or two remain possible as a secondary threat.

SKYWARN Activation with Ops at NWS Taunton will commence no later than 1 PM for this potentially significant severe weather event and SKYWARN Self-Activation will monitor any convection that could organize ahead of the warm front. ARES/RACES Groups should closely monitor the situation and seek advice from local leadership. Severe Weather Safety Rules should be reviewed ahead of any severe weather activity. The next coordination message will be posted by 9 AM Tuesday. Below is the NWS Taunton Hazardous Weather Outlook, Area Forecast Discussion, SPC Day-2 Convective Outlook and NWS Taunton Severe Weather Preparedness Week Information to review severe weather safety rules:

NWS Taunton Hazardous Weather Outlook:
http://kamala.cod.edu/ma/latest.flus41.KBOX.html

NWS Taunton Area Forecast Discussion:
http://kamala.cod.edu/ma/latest.fxus61.KBOX.html

SPC Day-2 Convective Outlook and Graphics:
http://kamala.cod.edu/offs/KWNS/1506221732.acus02.html
http://weather.cod.edu/text/products/spc/conOutlookGraphic.php?load=d2-graphic
http://weather.cod.edu/text/products/spc/conOutlookGraphic.php?load=d2-prob

NWS Taunton Public Information Statements – Severe Weather Preparedness Week:
http://beta.wx1box.org/local/severe_weather_awareness_2015.txt

NWS Taunton Severe Weather Preparedness Week Web Page:
http://www.weather.gov/box/SevereWeatherPreparednessWeek

Respectfully Submitted,

Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Assistant 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
http://beta.wx1box.org
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