Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 181930
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
330 PM EDT Wed Oct 18 2017

.SYNOPSIS...
High pressure will maintain dry weather and warmer than normal
temperatures through the weekend.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Another beautiful October afternoon/evening. Plenty of sunshine
through sunset of course with dry dwpts in the 40s as upper lvl
ridge crests over the region this evening.

Overnight, similar setup to previous nights, however noting a
slight increase in S gradient flow which suggests a minimal
increase in sfc dwpts. This may limit overnight cooling a bit
compared to previous nights, suggesting lows mainly remain in
the mid 40s to low 50s in the heat islands, a few degrees
warmer.

Otherwise, given increased S gradient and low lvl moisture will
need to also watch for a bit more patchy frost or even low
stratus development inland of the CT coast/RI especially.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Tomorrow...
Upper lvl shortwave continues opening trend as it moves across S
New England during the late afternoon/evening hours. The
attendant cold front loses its baroclinicity and is associated
with little to no moisture increase so aside from a few more SCT
clouds are possible, but this fropa passes with little fanfare.
SFC pres gradient response yields an increase, so S-SW flow will
be breezy with a few wind gusts around 25 mph during the
afternoon. Temps a bit milder in spite of the SCT clouds thanks
to weak warm advection aloft ahead of the wave. Looking at
widespread low 70s.

Tomorrow night...
Weak front shifts E. Gradient winds shift to the W but weaken
inland as pres gradient weakens rapidly with the core of a
stronger high pres shifting E. Winds may remain elevated near
shore. The slight increase in moisture thanks to S gradient flow
during the day will limit overnight mins further still,
suggesting more widespread upper 40s to low 50s.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...

* Above average temps and dry conditions lasting into Monday
* Precipitation chances are increasing for mid-next week.

Pattern Overview/Confidence...

12z guidance is in good agreement for the long term. Passing frontal
system an associated trough will push offshore by Friday morning.
Anomalous ridging will develop across the East Coast pushing heights
and temperatures 2 STD above normal. This strong ridge will last
into early next week before a pattern change appears to take hold of
the area. Digging trough will dip into the Gulf states with the
potential for a closed low peeling off. Another wave will begin to
dive into the Ohio Valley which could result in phasing to a
negatively tilted trough putting much of the East Coast near 3-4 STD
below normal in heights fields. This pattern change will result in
cooler conditions and unsettled weather.

Details...

Temperature Forecast...

Overall trend in the forecast is for above average temperatures
through the period. Cool front will sweep through the region
Thursday night leading to a cooler day on Friday, but still above
average. Anomalous ridge will begin to build for the weekend into
Monday resulting in high temps into the mid 70s. Tuesday`s and even
Wednesday`s temperature forecast is a bit trickier as it is
dependent on the timing of the front. Thus will trend towards a
model consensus until guidance gets a better handling on the FROPA.

Precipitation Forecast...

High pressure will take over the area on Friday through Monday
leading to dry weather. Next chance or precipitation will be around
the Tuesday timeframe when a potent trough will dig into the Ohio
Valley and towards the East Coast. Ensemble guidance is trending
towards a very wet pattern with high PWAT values and strong
southerly LLJ. This is in conjunction with the several waves of low
pressure that will ride along the trough both Tuesday and Wednesday.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

Short Term /through Thursday Night/...Generally high
confidence.

Mainly VFR. A few IFR SCT-BKN CIGS possible mainly E CT into
RI, including PVD after 06Z tonight through 12Z. Confidence too
low for TAF at this time, but will hint at it. VFR then returns
tomorrow and most of tomorrow night.

SW flow expected today through the daylight tomorrow, then
gradual shift to the W is expected tomorrow evening/overnight.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...Moderate confidence in TAF. Although VFR
dominates there is a low risk for some low CIGS around IFR late
tonight into early tomorrow morning.

Outlook /Friday through Sunday/...

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 Thursday Night/...High confidence.

Overnight...
Winds and seas continue to diminish overnight. Quiet boating
weather into tomorrow morning.

Tomorrow and tomorrow night...
S-SW winds increase tomorrow afternoon with gusts to around 25
kt likely over all waters by late afternoon and a slight
increase in outer seas to near 5 ft. These winds persist into
the overnight but slowly diminish as they shift to the W late
tomorrow night. Small Craft Advisories will be issued for all
waters.

Outlook /Friday through Sunday/...High confidence.

Great boating weather as high pressure prevails through the
upcoming weekend with sub SCA conditions.

&&

.FIRE WEATHER...
Ahead of a very weak cold front tomorrow (with which no
precipitation is expected) S-SW winds will gust 20-25 mph across
much of the region. Relatively mild conditions (highs in the
low-mid 70s) and continued dry dewpoints in the mid 40s to low
50s will yield min RH values near 30 percent. With an overall
lack of precipitation of late this suggests elevated fire
weather for the day tomorrow.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 2 PM Thursday to 6 AM EDT Friday for
     ANZ231>234.
     Small Craft Advisory from 2 PM Thursday to midnight EDT
     Thursday night for ANZ230-236.
     Small Craft Advisory from 4 PM Thursday to 6 AM EDT Friday for
     ANZ235-237-255-256.
     Small Craft Advisory from 2 PM Thursday to 8 AM EDT Friday for
     ANZ250-251-254.

&&

$$
SYNOPSIS...Doody/Dunten
NEAR TERM...Doody
SHORT TERM...Doody
LONG TERM...Dunten
AVIATION...Doody/Dunten
MARINE...Doody/Dunten



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