Area Forecast Discussion
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FXUS61 KBOX 011401
Area Forecast Discussion
National Weather Service Taunton MA
1001 AM EDT FRI JUL 1 2016
An approaching cold front will bring numerous showers and scattered
thunderstorms this evening, and a few of them may become strong to
severe with locally heavy rainfall. High pressure builds in
behind the front and prevails through much of next week, resulting
in warming temperatures and dry weather.
.NEAR TERM /UNTIL 5 PM THIS AFTERNOON/...
10 AM update...
SPC mesoanalysis shows environment is destabilizing with SBCAPES
500-1000 J/kg south of the Pike. However, deep layer moisture is
lacking as shown by lower KI values and MLCAPES are still nil. As
deeper moisture increases this afternoon, expect a few widely
scattered showers and thunderstorms to develop across SNE per hi-
res guidance, but do not expect much organization. Main show will
occur this evening as mid level trof and increasing shear move
in from the west and some of the hi-res guidance is suggesting an
organized line of showers/t-storms will move across the region.
With sunshine through early afternoon, temps will reach the low to
mid 80s away from the south coast. It will be humid as dewpoints
rise well into the 60s by later this afternoon.
.SHORT TERM /5 PM THIS AFTERNOON THROUGH 6 AM SATURDAY/...
***High confidence in numerous showers and scattered thunderstorms
with locally heavy rainfall roughly between 5 pm this evening
and 2 am Saturday morning***
***Low confidence on whether some storms become strong to severe***
Shortwave and impressive height falls will sweep across New England
this evening. Strong forcing noted as 0 to 6 km shear values
increase to between 35 and 45 knots. Despite the loss of daytime
heating, instability may actually increase during the evening as mid
level lapse rates steepen with the height falls. Models show 500 to
1000 J/kg of CAPE persisting through 06z tonight. As a result we
are fairly confident in numerous showers and scattered
thunderstorms, with locally heavy rainfall this evening. Brief
poor drainage street flooding is possible. In addition, dangerous
cloud to ground lightning is a big concern given its the start of
the holiday weekend.
The biggest uncertainty is if some of these storms become strong
to severe. As usual this is not clear cut since instability is
marginal, but strong forcing will try to make up for it. It is a
very delicate balance, but there certainly is some potential for
some strong to severe thunderstorms. Highest risk is across
western MA/northern CT where better instability is expected, but
cannot be ruled out across the rest of the region given the
strong dynamics. If any storms are able to become strong to
severe, biggest threat will be for localized wind damage, but
there is a secondary concern for hail given cooling aloft. Lastly,
a low risk exists for an isolated tornado given SREF/NCAR ensembles
showing pretty good probabilities for 0 to 1 km helicity of 150+
and LCL/s below 800 meters.
So to summarize, high confidence in showers and scattered t-storms
this evening with localized heavy rainfall and dangerous cloud to
ground lightning. Confidence is low on whether some storms become
strong to severe since instability is marginal, but it is certainly
something to watch closely given strong dynamics.
.LONG TERM /SATURDAY THROUGH THURSDAY/...
* Cooler temps Saturday, then increasing temps through next week
* High pressure brings dry weather for much of next week
Overview...Quiet pattern continues through next week starting with
upper level ridging in the center of the country and an upper trough
in the NE. The upper level pattern flattens out a bit by Monday with
weak ridging continuing across the middle of the country. Models are
in good agreement on the synoptic pattern and will use a blend of
available guidance for this forecast. High pressure builds into the
region Sunday and continues through much of next week.
Temperatures...Aside from slightly cooler temperatures Saturday,
behind the cold front, temperatures will gradually warm into next
week. By the middle of next week, temperatures will be in the upper
80s to lower 90s.
Precipitation...Dry weather continues throughout southern New
England through next week. No precipitation is expected from
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT
MODERATE...30 PERCENT TO 60 PERCENT
HIGH...GREATER THAN 60 PERCENT
Short Term /through Tonight/...
Mainly VFR conditions expected through mid afternoon. MVFR to IFR
conditions in low clouds/fog patches will likely develop late this
afternoon/early this evening south of the MA pike and may affect
all areas for a time this evening.
Otherwise, main concern will be scattered thunderstorms mainly
between 21z and 06z, resulting in briefly lower conditions. A few
may become strong to severe. Low cigs/vsbys may linger across
southeast New England after 06z, with patchy fog possible
elsewhere. Improvement expected by 12z in most locations.
KBOS TAF...Moderate confidence in TAF. Main thunderstorm risk
between 01z and 06z.
KBDL TAF...Moderate confidence in TAF. Main thunderstorm risk
between 22z and 04z.
Outlook /Saturday through Tuesday/...
Saturday...High confidence. Any lingering MVFR conditions will
improve to VFR quickly Saturday morning.
Sunday through Tuesday...High confidence. VFR. Low probability of
sea breezes developing each afternoon.
Low level jet will result in southerly wind gusts increasing to
between 20 and 25 knots this afternoon and evening. We did issue a
small craft advisory for our northeastern waters, where 4 to 5
foot seas should develop. Across the rest of the region, think
wind gusts will be just below criteria but close enough to
Biggest concern for mariners is the risk for a few strong
thunderstorms this evening, with 40+ knot wind gusts possible.
Outlook /Saturday through Tuesday/...
High confidence. Mainly quiet boating weather expected. Winds and
seas remain below SCA criteria throughout the period.
Hit or miss showers and thunderstorms are possible this afternoon
and tonight. However, widespread precipitation looks to be nil over
the next 7 days.
High pressure and dry conditions appear to take hold of the region
Saturday, lasting through the much of next week. Much of this time
will be less humid with RH values dropping close to 30 percent for
much of this time. Winds overall appear to be light during this
MARINE...Small Craft Advisory from 2 PM this afternoon to 4 AM EDT
Saturday for ANZ250.