Severe Weather and Hurricane Arthur Coordination Message #5 – Thursday 7/3/14-Saturday Morning 7/5/14 Severe Weather/Flash Flood Potential

July 3, 2014 Rob Macedo Leave a comment

Hello to all..

..Weather Pattern will remain active Thursday through Friday and possibly into Saturday Morning with several days of severe weather and flood to flash flood potential and the potential for some possible impacts from Hurricane Arthur or Arthur’s interaction with a cold front that will move through the region..
..Isolated to Scattered Strong to Severe Thunderstorms are possible to likely Thursday Afternoon and Evening across much of Southern New England. Strong to Damaging Winds, Hail, and heavy rainfall with the potential for urban and poor drainage flooding or flash flooding are the main threats. The Storm Prediction Center (SPC) has now placed Southwest New Hampshire, Western Massachusetts and Western Connecticut in a Slight Risk for severe weather for Thursday with much of the rest of Southern New England in a 5% probability for severe weather Thursday. As we get into late Thursday Night and Friday, possibly extending into Saturday Morning, impacts from Hurricane Arthur and his interaction with a cold front, could cause additional heavy rainfall and flood to flash flood potential across portions of Southern New England with exact locations for impact uncertain..
..A Flash Flood Watch is now in effect for Cheshire County New Hampshire and Franklin, Hampshire and Hampden Counties of Massachusetts from Noon today trough this evening for thunderstorms and heavy downpours producing localized flash flooding where thunderstorms train or track over the same area producing locally heavy rainfall amounts..
..SKYWARN Activation with Ops at NWS Taunton will commence at 11 AM Thursday lasting through this evening. It appears that SKYWARN Activation will be needed Friday for the potential of heavy rainfall and flooding to flash flooding with a cold front moving through the area and potential of moisture from Hurricane Arthur interacting with this cold front. Detail on potential activation for Friday will be determined in the next coordination messages. Interests in the region, particularly Southeast New England, should closely monitor the progress of Hurricane Arthur as there remains some uncertainties in his specific track..
..WX4NHC, the Amateur Radio Station at the National Hurricane Center and the VoIP Hurricane Net are activating at 6 PM EDT/2200 UTC Thursday Evening through Friday Morning for Hurricane Arthur’s impacts on Eastern North Carolina and Northeast South Carolina. The Hurricane Watch Net will be activating at Noon EDT/1600 UTC Thursday for Hurricane Arthur..

After a relatively quiet stretch of weather over the past few weeks, isolated to scattered strong to severe thunderstorms affected portions of Southern New Hampshire, Western Massachusetts and Western Connecticut Wednesday Afternoon. Below is the NWS Taunton Local Storm Report detailing the events from Wednesday Afternoon:

NWS Taunton Local Storm Report – Wednesday Afternoon 7/2/14 Severe Weather Event:
http://kamala.cod.edu/offs/KBOX/1407022217.nwus51.html

The weather will remain active Thursday through Friday and possibly into the Saturday Morning timeframe. Hot and humid conditions will prevail over the region over the next few days. A Cold Front continues to gradually approach Southern New England from the west and will continue to affect our region Thursday. Isolated to Scattered Strong to Severe Thunderstorms will likely refire by late morning/early afternoon in Southwest New Hampshire, Western Massachusetts and Western Connecticut and will likely have a better chance to extend eastward across much of Southern New England. Strong to Damaging Winds, Hail, and heavy rainfall with the potential for urban and poor drainage flooding or flash flooding are the main threats. The Storm Prediction Center (SPC) has now placed Southwest New Hampshire, Western Massachusetts and Western Connecticut in a Slight Risk for severe weather for Thursday with much of the rest of Southern New England in a 5% probability for severe weather Thursday. The extent of the severe weather threat will be contingent on any potential thunderstorms overnight given activity in Eastern New York late this evening and any cloud cover. If sufficient heating and destabilization can occur, wind fields would be sufficient for at least isolated to scattered strong to severe thunderstorm activity across much of Southern New England.

Thunderstorms will have the potential to produce very heavy rainfall and localized flash flooding where thunderstorms train over the same area. A Flash Flood Watch is now in effect for Cheshire County New Hampshire and Franklin, Hampshire and Hampden Counties of Massachusetts from Noon today through this evening for thunderstorms and heavy downpours producing localized flash flooding where thunderstorms train or track over the same area producing locally heavy rainfall amounts.

As we get into late Thursday Night and Friday, possibly extending into early Saturday Morning, impacts from Hurricane Arthur and the interaction of the approaching cold front could potentially lead to what is known as a ‘predecessor rainfall event’ also known as a PRE which could result in the potential for widespread heavy rainfall in the axis of where this event take place. It is unclear where this axis will setup across the region or if it stays south of our area. It is also unclear when this event will occur but it is looking more like the late Thursday Night into Friday timeframe.

In terms of the exact track of Hurricane Arthur, the track currently brings Arthur around the 40 North/70 West Benchmark. While this track would keep the strongest winds south and east of Southern New England, the interaction of this system with the cold front and its transition to a post tropical system could change the impacts of this system on the region. In addition, the cone of uncertainty on the track guidance extends as far north as Southeast New England. Overnight, models appear to be in a bit better agreement on a track closer to or perhaps just south of the 40 North/70 West Benchmark. This would keep most of the strongest winds away from Southern New England though a few stronger wind gusts could affect the Outer Cape and Nantucket Island. With the closest pass of Arthur to Southern New England likely taking place late Friday Night into Saturday Morning which is still approximately 3 days away, there remains some uncertainty. As the system continues to organize and moves north-northeastward and begins to turn northeast, model tracks should become more certain as we get into the Thursday Afternoon to Friday Morning timeframe. Interests in Southern New England, particularly Southeast New England, should monitor the track of Hurricane Arthur as well as how this system interacts with the cold front as we get into the timeframe of impact late this week.

WX4NHC, the Amateur Radio Station at the National Hurricane Center and the VoIP Hurricane Net are activating at 6 PM EDT/2200 UTC Thursday Evening through Friday Morning for Hurricane Arthur’s impacts on Eastern North Carolina and Northeast South Carolina. The Hurricane Watch Net will be activating at Noon EDT/1600 UTC Thursday for Hurricane Arthur. See their respective web links for details:

WX4NHC, the Amateur Radio Station at the National Hurricane Center:
http://www.wx4nhc.org

VoIP Hurricane Net:
http://www.voipwx.net

Hurricane Watch Net:
http://www.hwn.org

SKYWARN Activation with Ops at NWS Taunton will commence at 11 AM Thursday lasting through this evening. It appears that SKYWARN Activation will be needed Friday for the potential of heavy rainfall and flooding to flash flooding with a cold front moving through the area and potential of moisture from Hurricane Arthur interacting with this cold front. Detail on potential activation for Friday will be determined in the next coordination messages. The next complete coordination message will be posted by 1130 PM Thursday Evening regarding severe weather and flood potential for Friday and any impacts directly or indirectly from Hurricane Arthur. Below is the NWS Taunton Hazardous Weather Outlook, Marine Weather Statement, SPC Day-1 Convective Outlook and links to latest National Hurricane Center products on Hurricane Arthur:

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

NWS Taunton Marine Weather Statement:
http://kamala.cod.edu/ma/latest.fzus71.KBOX.html

SPC Day-1 Convective Outlook:
http://www.spc.noaa.gov/products/outlook/day1otlk.html

National Hurricane Center – Miami Florida Information:

Hurricane Arthur NHC Advisory and Graphical Information:
http://www.nhc.noaa.gov

Hurricane Arthur Public Advisory Information:
http://kamala.cod.edu/TPC/latest.wtnt31.KNHC.html

Hurricane Arthur Technical Discussion Information:
http://kamala.cod.edu/TPC/latest.wtnt41.KNHC.html

Hurricane Arthur Forecast/Advisory Information:
http://kamala.cod.edu/TPC/latest.wtnt21.KNHC.html

Hurricane Arthur Wind Speed Probabilities:
http://kamala.cod.edu/TPC/latest.font11.KNHC.html

Respectfully Submitted,

Robert Macedo (KD1CY)
ARES SKYWARN Coordinator
Eastern Massachusetts ARES Section Emergency Coordinator
Pager #: (508) 354-3142
Home Phone #: (508) 994-1875 (After 6 PM)
Home/Data #: (508) 997-4503 (After 6 PM)
Work Phone #: 1-800-445-2588 Ext.: 72929 (8 AM-5 PM)
Email Address: rmacedo@rcn.com
http://ares.ema.arrl.org
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