Severe Weather Coordination Message #5 – Tuesday 7/15/14-Wednesday 7/16/14 – Severe Weather/Flash Flood Potential

July 15, 2014 Rob Macedo Leave a comment

Hello to all..

..The Storm Prediction Center (SPC) has continued a Slight Risk of Severe Weather and expanded it eastward into Southern New Hampshire, Western and Central Massachusetts and most of Connecticut with 5% severe weather probabilities for the rest of Southern New England except for Cape Cod and the Islands for Tuesday. The highest risk with thunderstorms at this time is heavy rainfall and flash flooding of urban and poor drainage areas and possibly smaller rivers and streams, however, strong to Damaging winds, and hail are also threats with an isolated weak tornado also possible depending on the timing of the front and amount of cloud cover over the area for today..
..A Flash Flood Watch remains in effect from today through Wednesday afternoon for all of the NWS Taunton coverage area of Massachusetts, Rhode Island, Northern Connecticut and Southern New Hampshire except for Cape Cod and the Islands.
..SKYWARN Activation with Ops at NWS Taunton will commence at 1 PM Tuesday Afternoon lasting through late Tuesday Evening. SKYWARN Activation with Ops at NWS Taunton are possible Wednesday Morning for flash flood potential especially in Eastern New England..

On Monday, the severe weather threat stayed south of the NWS Taunton coverage area. Heavy downpours during the evening commute caused some minor street flooding issues in the Boston area. Overnight, heavy rainfall and urban and poor drainage flooding and flash flooding remain confined to Southern Connecticut.

As we move into Tuesday, the slow moving cold front will continue to approach Eastern New York and New England. There will continue to be warm and humid conditions over the area. The extent of the severe weather potential will be determined by the following:

1.) Amount of cloud cover over the area for today. Overnight showers and thunderstorms have largely moved out of the area.
2.) Position of the cold front and its forcing mechanism and the timing of the front over the area.

At 1040 AM, satellite imagery showed breaks in the clouds over portions of Eastern New York and Western New England. There was no rapid, solid clearing occurring over the area but some sun is getting through the clouds offering some level of instability and destabilization. Moisture profiles and wind shear profiles are quite favorable for severe weather but the level of instability remains in question. Doppler Radar at 1040 AM showed an area of showers and thunderstorms over Central New York and Central Pennsylvania moving east-northeastwards and as this gradually gets closer to Eastern New York and Western New England, that could be a focal point for convection depending on its movement and timing into our coverage area. At this time, isolated to scattered strong to severe thunderstorms are the most likely coverage we will see versus a widespread outbreak but if more clearing occurs, that could change the situation rapidly. At this time, the main threat for thunderstorms is the flash flood threat and heavy rainfall with flash flooding of urban areas and possibly small rivers and streams, however, noting the breaks in the clouds in the slight risk area, there is a secondary threat for strong to damaging winds, hail and possibly a weak tornado over localized areas. This will continue to be monitored closely.

As noted above, regardless of these two factors, thunderstorms with the potential for heavy rainfall and flash flooding of poor drainage and urban areas and smaller rivers and streams are the highest potential weather hazard in localized areas over the NWS Taunton coverage area. The Flash Flood Watch has been expanded to include the entire NWS Taunton coverage area except for Cape Cod and the Islands through Wednesday Afternoon. Heavy rainfall of 1-3″ with localized higher amounts where thunderstorms back build or train over the same area are possible. The flash flood threat will linger through early Wednesday Afternoon particularly over Eastern New England as the slow moving cold front finally pushes through Southern New England. Any severe weather potential Tuesday Afternoon through Evening will evolve into more of a heavy rainfall threat overnight Tuesday into Wednesday Morning but an isolated strong to severe thunderstorm can not be ruled out over this time period either.

SKYWARN Activation with Ops at NWS Taunton will commence at 1 PM Tuesday Afternoon lasting through late Tuesday Evening. SKYWARN Activation with Ops at NWS Taunton are possible Wednesday Morning for flash flood potential especially in Eastern New England. The next coordination message will be issued by 1100 PM Tuesday Evening pending the evolution of SKYWARN Operations over the course of Tuesday. Below is the NWS Taunton Hazardous Weather Outlook, NWS Taunton Special Weather Statement, NWS Taunton Flash Flood Watch Statement, NWS Taunton Facebook Graphic and SPC Day-1 Convective Outlook:

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

NWS Taunton Special Weather Statement:
http://kamala.cod.edu/offs/KBOX/1407151446.wwus81.html

NWS Taunton Flash Flood Watch Statement:
http://kamala.cod.edu/ma/latest.wgus61.KBOX.html

NWS Taunton Facebook Graphic:
http://beta.wx1box.org/local/7_15_14_am_graphic.jpg

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