FXUS61 KBOX 232009

Area Forecast Discussion
National Weather Service Taunton MA
409 PM EDT Wed Aug 23 2017

A cold front will move offshore this evening. High pressure
brings dry weather with very comfortable humidity levels through
early next week.


Brought the forecast back in line with observed trends this

Not much to talk about tonight. A cold front will finally move
offshore this evening. Drier air will overspread our region
overnight. Dry weather and mainly clear skies prevail. Patchy
fog may develop late in the typically prone locations, but not
expecting anything widespread.

Near normal minimum temperatures.


A large high pressure over central Canada will move slowly east
Thursday and Thursday night. A mid level trough and shortwave
should pass by our region before this high pressure really takes
control of our weather. The lower level of the atmosphere are so
dry, not expecting more than some clouds at times during this

Near to slightly below normal temperatures expected through this


Not too much change with the 23.12Z models particularly with
the synoptic pattern across the CONUS through mid next week.
Reinforced Alaskan vortex is the driver for enhanced warm
advection downstream, even as the pattern across the W becomes
more zonal. Ridging amplifies through the N CONUS and central
Canada as a result, and while this maintains a longwave trof
across New England, the mean flow into New England is a cool and
dry CP draw. Mean SW-NE oriented jet remains entrenched
directly over New England within confluent flow, E of the trof
baseline. This will help to maintain the slow passage of a
1025+hPa high pres, which will lead to generally dry conditions
through mid week.

There are two opportunities for spot showers. The first is
Friday when a relatively robust shortwave rotates through the
region coincident with a slight uptick in PWATs to just shy of
1.00 inches. Mid lvl lapse rates are high enough to enhance the
risk. Will continue to time some slight chance POPs through the
afternoon. The second is Sunday with a similar situation, but
overall weaker dynamics and actually less moisture. Each day
will feature only hit-or-miss showers as even at its peak near
1.00 inches, PWATs remain very low through the period.

Seasonably cool temperatures will accompany this nearly week
long dry period. H85 temps drop to between +5C and +8C at their
coolest point following the Friday wave passage and then remain
generally within this range through mid next week. Full mixing
suggests mid-upper 70s for highs, however as the high pres
shifts into the Maritimes Sun-Tue, flow will shift toward the E,
drawing air off the Gulf of Maine and leading to cooler highs as
a result. Mins will be comfortable thanks to dewpoints holding
in the upper 40s and low-mid 50s through the period, suggesting
the lows will drop into the 50s most night. All-in-all, temps
will remain below normal throughout.


Forecaster Confidence Levels...

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

Short Term /through Thursday Night/...

Tonight...High confidence. Mostly VFR, however a risk of MVFR-
IFR for Nantucket during the evening hours. Clear conditions
across the interior. May see some patchy MVFR-IFR ground fog
develop at the typically prone locations toward daybreak, but
nothing widespread is expected.

Thursday and Thursday night...High confidence. VFR.

KBOS Terminal...High confidence in TAF. Moderate risk for a
seabreeze Thursday, mainly from mid morning into the afternoon.
It is possible the seabreeze stalls just east of the terminal.

KBDL Terminal...High confidence in TAF.

Outlook /Friday through Monday/...

VFR. Light flow generally NW through Sunday, then shifting
toward the E Monday. Sea breezes possible all days.


Forecaster Confidence Levels...

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

Short Term /through Thursday Night/...High confidence.

Allowed the Small Craft Advisory across the southern outer MA
coastal waters to expire at 4 PM. Trend is clearly for
diminishing seas. Still a risk for a gust up to 20 kt ahead of a
cold front as it moves across the waters this evening.

Relatively light winds and seas through this period. Local
seabreezes possible Thursday from mid morning into the evening.

Outlook /Friday through Monday/...

Good boating weather. Weak N-NW winds will shift to the E by
Monday but with gusts generally remaining below 20 kt.
Seas/waves remain below 4 ft through the period.




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