Wednesday, May 29, 2013

Rain to Clear, Severe Thunderstorms Possible Later

A warm front is moving northeast toward New England and ahead of this boundary moderate rainfall is falling in portions of Southern New England.  This afternoon the boundary lifts into Northern New England and if enough sun breaks out then severe thunderstorms will break out.  A ridge is building in the east so temperatures will be on the rise for the next several days.

Observations/Short Range Forecast
A decaying band of showers is located in Eastern MA and Northern RI
NWS Boston radar 602 am
This complex will be offshore by 8 am.  Temperatures this morning
2 m temps 5 am (image weatherbell)
Most areas are in the mid to upper 50's.  By 8 am the warm front is on the doorstep of SW CT
WPC Surface forecast 8 am
At noon all of Southern New England is into the 70's
06z NAM hires 2 m temps 12 pm (image weatherbell)
Dew points will also be on the increase, first in CT then into MA and Northern RI.  At noon dew points are in the low to mid 60's.  The dew points will continue to increase as the warm front surges north.  At 2 PM
WPC Surface Analysis 2 pm
A wave of low pressure in Canada with an associated surface trough will act as the "trigger" this afternoon to fire these thunderstorms.  Several factors will need to come into play.  The sun has to shine or else convection will be limited.  Temperatures at 5 PM
06z NAM hires 2 m temp 5 PM (image weatherbell)
An hour later here are the dew points.   Many are in the upper 60's or low 70's
06z NAM hires 2 m dew points 6 PM (image weatherbell)
Severe Weather Threat
As of 2 am, the Storm Prediction Center has much of Central/Western MA, Northern RI, and all of CT in a slight risk for severe storms
SPC Day 1 Outlook
The main threat with any thunderstorms will be damaging wind.  A "severe" wind is one in excess of 58 mph.  
There is a 15% chance of a severe wind occurring within 25 miles of any given point in the yellow below
SPC Day 1 Severe Wind Outlook
Although not as likely, severe hail will be possible as well.  Severe hail is at least an inch in diameter 
SPC Day 1 Severe Hail Outlook
Finally if a few super cell thunderstorms indeed develop, there is a low chance for a tornado in Eastern NY state and Western/Central Southern New England
SPC Day 1 Tornado Outlook
The threat for thunderstorms appears to be between 4-8 PM tonight.  Any thunderstorms will have frequent lightning and heavy downpours.
WPC Day 1 Precipitation Outlook

Tonight lows drop into the mid 60's so it will be a mild night.  Summer sends its first true wave into New England tomorrow.  Most see high temps in the upper 80's/low 90's.  Friday looks to be even warmer, low to mid 90's.  Have a good one, I will be out this afternoon but will try to update as needed.












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