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Area forecast discussion 
National Weather Service Taunton Massachusetts
157 am EDT Monday Jul 25 2016

Summer heat will continue into much of the upcoming week. A weak
front will bring an increased risk of showers and thunderstorms
Monday afternoon and evening and again late next week.


Near term /until 6 am this morning/...
10pm update...
forecast mainly on track. Convection riding best instability well
to the SW. Even cloud debris not as widespread as initially
thought. This may lead to better warming tomorrow, but this will
need to be watched as new guidance comes in.

Previous discussion...

Quiet night tonight with just a few mid/high clouds expected.
Weak shortwave triggering convective complex over Ohio Valley will
track to the mid Atlc region toward 12z with any convective
activity remaining to the SW of new eng. Lows will be mainly in
the 60s with increasing dewpoints after midnight.


Short term /6 am this morning through 6 PM Tuesday/...
*** potential for strong to severe thunderstorms Mon afternoon and
evening along with hot and very humid conditions ***

Weak shortwave will be tracking south of new eng in the morning
with any convection likely remaining to the south. However, models
indicate good influx of moisture as higher Theta-E air moves into
the region during the morning and this will be accompanied by
some clouds and possibly even a few showers. These clouds may
affect temps and instability but confidence in the extent of cloud
cover is not high. We do expect at least partial sunshine and with
850 mb temps climbing to near 20c potential exists for a very hot
day. If we had full sunshine potential for upper 90s to around 100
degrees but due to expectation of cloud cover we will not go quite
this high, with high temps low to mid 90s away from the South
Coast. It will become rather humid with dewpoints climbing into
the lower 70s. We will keep heat advisory for CT valley where heat
indices expected to approach 100 degrees, but confidence not high
enough to expand further east due to uncertainty in amount of

Other concern is the potential for severe weather Mon afternoon
and evening as mid level trof/shortwave approaches from the gt
lakes. MLCAPES expected to peak around 1000-1500 j/kg during the
afternoon. Initially, mid level lapse rates will not be ideal but
pre-frontal trof will likely serve as a focus for developing
convection and 0-6 km shear increasing to 35 kt which will result
in an increased risk for severe weather.

Severe threat likely to continue into the first half of Mon night
as weakening remnant eml moves into the region. Mid level lapse
rates increase to 6.5 c/km aided by subtle cooling aloft which
will help to sustain convection as models indicate sbcapes
500-1000 j/kg with deep layer shear above 30 kt during 00-06z.
Damaging winds will be the primary threat of severe weather,
especially with inverted v profile during the late afternoon.
Heavy rainfall and localized flooding will be a secondary concern
with precipitable waters increasing to near 2 inches.

Front moves through overnight Mon night with notable drying in the
column which will result in clearing skies and lower dewpoints
moving into the region.


Long term /Tuesday night through Sunday/...

* hot temperatures continue through the middle of the week, away
from the coast
* should be a little less humid Tuesday and Wednesday
* showers and thunderstorms are possible again late in the week

Overview...models are in fairly good agreement throughout the long
term portion of the forecast. Minor timing differences as well as
mesoscale differences show up, especially towards the end of the
forecast period. Low pressure in the Maritimes will bring the cold
front through southern New England Tuesday, drying out the low
levels. High pressure is the rule for Wednesday. Then Thursday and
Friday, the European model (ecmwf) has a front with a series of low pressures along
the front from the Delmarva Peninsula to the Maritimes. The GFS is
similar but less detailed with the areas of low pressure. This
could bring periods of showers and possibly thunderstorms to
southern New England. The front may push south of southern New
England Friday with the low pressure over the Delmarva Peninsula
traveling along the front south of the area. Question for Thursday
and Friday is how far south the front pushes, as a move too far
south may shut US out from any rain. High pressure starts to build
back in again on Saturday and possibly on Sunday, though low
pressure south of the region may bring another possibility of
showers Sunday.

Tuesday and Wednesday...drier weather but still hot afternoon
temperatures with highs in the 90s likely, especially away from the
coast. Sea breezes are more likely Wednesday, with temperatures a
bit cooler along the coasts that day. Otherwise, sunny skies and
typical July weather.

Thursday and Friday...this is the period of greatest uncertainty.
Temperatures will cool a few degrees Thursday as clouds increase and
a cold front starts to move through southern New England. The front
moves the rest of the way through and offshore on Friday. This
could result in temperatures down into the low to mid 80s Friday,
quite a relief after the last week.

Showers and thunderstorms will be possible with this frontal
passage, particularly on Thursday when more instability is expected
with both diurnal heating and partial sun. They may linger into
Friday, but as mentioned above, that will largely depend on how far
off the South Coast the front pushes. Regardless, Friday is likely
to be cloudy and cooler, though more humid than previous days.

Saturday and Sunday...high pressure will build in Saturday behind
the front with mostly sunny skies and temperatures in the low to mid
80s once again. Sunday becomes a bit more uncertain with the
possibility of a low pressure system developing or passing quite
close to the Rhode Island/Massachusetts South Coast. This could bring clouds, fog, and
rain to the area, particularly near the South Coast. Models
disagree on how close to the coast this system gets, so quite a bit
of uncertainty here. Still, confident enough to have chance pops in
the forecast for Sunday.


Aviation /06z Monday through Friday/...
forecaster confidence levels.

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short term /through Tuesday/...

Through today...moderate confidence.
Mainly VFR through the afternoon. Between 20z and 02z, a risk for
thunderstorms and rain and rain showers is expected with some strong winds and heavy
rainfall. Localized IFR conditions likely in any thunderstorms and rain.

Tonight...moderate confidence.
Most thunderstorms/showers end between 02z and 04z with VFR
developing initially then late night fog especially at typically
prone airports. Stratus also possible along the cape/islands
especially. Mix of IFR/MVFR conditions.

Tomorrow...high confidence.
Mainly VFR after early morning fog/stratus dissipates. Winds
mainly northwest with gusts 15-20 kt.

Kbos taf...moderate confidence in taf. Timing of afternoon
shra/thunderstorms and rain may be off.

Kbdl taf...moderate confidence in taf. Timing of afternoon
shra/thunderstorms and rain may be off.

Outlook /Tuesday night through Friday/...

Tuesday and Wednesday...high confidence. VFR. Sea breezes likely
to develop on both coasts Wednesday.

Thursday...low confidence. Mainly VFR. Periods of MVFR/IFR in scattered
rain showers/thunderstorms and rain Thursday afternoon and evening.

Friday...low confidence. Increasing clouds should lead to MVFR/IFR
conditions in low clouds/fog and possibly additional rain showers.


forecaster confidence levels.

Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.

Short term /through Tuesday/...high confidence.

Light winds tonight, then pre-frontal southerly winds increasing
to 10-20 kt Mon. Winds diminishing and becoming west later Mon
night. Seas remaining below Small Craft Advisory. There is a risk for late day and
evening thunderstorms Monday which will need to be watched.

Outlook /Tuesday night through Friday/...moderate to high confidence.

Quiet boating weather is expected through this time. The exception
will be Thursday and Friday when winds and seas will remain below
Small Craft Advisory criteria, but low clouds, fog, and periodic showers and
thunderstorms will limit visibilities.


here are the record high Max and min temperatures for July 25:

Boston - 96 (1882)/78 (2001)
Hartford - 98 (2001)/75 (2001)
Providence - 96 (2001)/75 (2001)
Worcester - 93 (1941)/73 (2001)


Box watches/warnings/advisories...
CT...heat advisory from 11 am this morning to 6 PM EDT this evening
for ctz002.
Massachusetts...heat advisory from 11 am this morning to 6 PM EDT this evening
for maz010-011.
Rhode Island...none.


near term...kjc/doody
short term...kjc
long term...rlg

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