Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 231431
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
1031 AM EDT SAT JUL 23 2016

.SYNOPSIS...
Hot conditions continue today, along with another risk for
thunderstorms this afternoon, some of which may become severe. An
approaching cold front will bring another round of scattered
showers and thunderstorms from Monday into early Tuesday. More
warm weather follows midweek.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1030 am update...
Another hot day today with highs reaching the low to mid 90s
across eastern MA/CT/RI although a bit cooler along immediate
south coast where sw winds expected. Some of the hi-res guidance
also hinting at a weak seabreeze across the immediate coast in
eastern MA. Dewpoints to mix out this afternoon and likely drop
into the upper 50s to lower 60s away from the immediate south
coast.

Main concern for this afternoon is the potential for another
round of strong to possibly severe t-storms as rather potent
shortwave moves into New Eng later today. Very good mid level
cooling with this shortwave as 500 mb temps drop to -12 to -14C
by evening which is impressive with temps into the 90s. Mid level
lapse rates expected to increase to around 6.5 C/km associated
with the cooling temps aloft which will allow MLCAPES to increase
to around 1000 J/kg. The instability will be tempered by the
decreasing dewpoints this afternoon so do not expect MLCAPES to
get much higher. Hi-res guidance suggesting showers and t-storms
will develop in northern New Eng and spill south into the region
after 3 pm with focus across northern and eastern MA where core
of cold pool moves.

Currently, 0-6km shear is around 40 kt which is more than enough
to support organized severe convection. However, guidance is
indicating deep layer shear decreasing from the north mid to late
afternoon and may drop below 30 kt which would limit organization
of storms. However, very large T/Td spread and inverted V sounding
profile support gusty winds and cant rule out isolated wind damage
with the stronger storms. Hail is also a concern with cooling
temps aloft.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SUNDAY/...
Thunderstorms/showers should end earlier than Friday night thanks
to faster movement of the forcing shortwave. Drier air will lead
to some drying during the overnight but leftover convective debris
cloudiness will likely keep temps from dropping too far. Expect
mins mainly in the 60s. A few spots of fog possible, especially
where late day rainfall is observed.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Overview...

Not much change from the previous model cycle. High pressure
covers much of the southern USA for most of next week. This will
mean any fronts will struggle to get very far south of our region
next week. Mid level flow transitions to a near zonal flow by
early next week, then to a broad trough by mid week. Temperatures
should generally be above seasonable levels most of this portion
of the forecast.

Details...

Sunday...

High pressure in place through the day. Winds appear to be light
enough where seabreezes may develop along both coasts. Moderate
confidence in seabreezes. Above normal temperatures continue for
most of southern New England.

Monday...

A mid level shortwave moves across our region late Monday into
Monday night. Most of the day should be rain-free. Some signs of
marginal instability crossing during the morning, which may be a
warm front with a couple of light showers. Greater instability
moves in from the west during the afternoon and evening, in the
warm sector ahead of a cold front. Precipitable water values
remain high, so locally heavy rainfall is still possible in
stronger thunderstorms. Scattered showers and thunderstorms should
continue into Monday night as a cold front passes by.

Tuesday and Wednesday...

High pressure takes control and brings fair weather. Above normal
temperatures continue.

Thursday and Friday...

Latest operational guidance continues to indicate some potential
for showers, largely due to a stalled front to our south, and
another cold front approaching from the north. Still have low
confidence in the details. Will continue to mention a chance of
showers and thunderstorms due to the presence of these boundaries.

&&

.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels.

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

Short Term /through Tonight/...

Today...moderate confidence.
VFR through at least 18Z. Then another risk for sct TSRA possible
mainly E of a line from kEEN-kORH-kWST. Some strong winds possible
once again in some of these storms. Otherwise, winds mainly W-SW
10-15 kt.

Tonight...High confidence.
Mainly VFR after any storms/showers end through the overnight
hours.

KBOS TAF...Moderate confidence. Another round of thunderstorms is
likely this afternoon to early evening. Some of those storms could
produce strong wind gusts. Low prob of a brief seabreeze
developing this afternoon but it will likely remain just to the
east.

KBDL TAF...High confidence of VFR prevailing. There could be some
patchy fog with MVFR visibility through 12Z.

Outlook /Sunday through Wednesday/...

Sunday...High confidence mostly VFR. Possible areas of IFR in
early morning fog.

Monday...Moderate confidence. Mostly VFR. Possible IFR in early
morning fog. Brief MVFR/IFR cigs/vsbys in afternoon and early
night showers/thunderstorms.

Tuesday and Wednesday...High confidence VFR.

&&

.MARINE...
Forecaster Confidence Levels.

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

Short Term /through Tonight/...High confidence.

Seas will continue to dissipate through the morning as winds
outside of thunderstorms have already dropped to or below 20 kt.
Seas will also gradually dissipate this morning allowing the
remaining small craft advisories to be dropped.

Otherwise, another round of showers and thunderstorms are possible
over the waters this afternoon and evening which could contain
localized strong wind gusts.

Outlook /Sunday through Wednesday/...Moderate confidence.

Winds less than 20 knots and seas less than 5 feet through this
period. A cold front will bring scattered showers/thunderstorms
Monday afternoon and night, with potential for strong wind gusts
and brief poor vsbys in heavy downpours.

&&

.EQUIPMENT...
The KBOX radar is down for maintenance. Technicians will try to
return the radar into service by no later than 3 PM this
afternoon.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 PM EDT this afternoon for ANZ255-
     256.

&&

$$
SYNOPSIS...Belk/Doody
NEAR TERM...KJC
SHORT TERM...Doody
LONG TERM...Belk
AVIATION...Belk/Doody
MARINE...Belk/Doody
EQUIPMENT...



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