Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 200803
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
403 AM EDT Fri Oct 20 2017

.SYNOPSIS...
High pressure will move from the Appalachians today to a
position east of New England on Sunday. It will provide dry
and much warmer than normal temperatures through the weekend.
The risk of showers will increase by the middle of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
3 AM update...

Satellite imagery shows that the upper level trough axis has
shifted east of the region. A band of thick cirrus clouds over
southern New England was beginning to pull out to the east.
It should be mainly off the coast by daybreak, leaving mostly
sunny skies across our area. At the surface, a weak, dry cold
front will move through as a wind shift, with winds shifting to
west toward daybreak and then to the northwest during the day
today. Wind gusts to 20 mph are expected for a time late this
morning and into the mid afternoon hours.

Mixing during the day will reach 925 mb or a little higher,
similar to yesterday, with temperatures at that level supporting
max sfc temps around 70, except mid 60s in the slopes of the
Berkshires and on Nantucket.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Tonight...
Skies will be clear and winds will be light. It will be on the
chilly side with lows in the upper 30s to mid 40s, except mid 40s
to lower 50s Cape Cod and the islands.

Saturday...

* Very warm weather, but may fall short of record highs

High pressure will become centered just south of southern New
England. An upper level ridge along the east coast will build
into the region. 925 mb temperatures will reach +17C during the
afternoon. With full sunshine, am expecting highs in the mid to
upper 70s, but cannot rule out a high near 80 in Hartford
County. Should be cooler...in the 60s to lower 70s...along the
south coast, Cape Cod, and the islands with southwest flow.

Record highs are 80 at Worcester, 81 at Providence, and 82 at
Hartford and Boston...all set back in 1920.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Highlights...

* Warm and dry weather lasting into Monday
* Unsettled weather pattern with showers at times Tue into Thu

20/00Z guidance coming into better agreement on the upcoming
pattern change later next week. Still some detail differences,
with the CMC remaining the odd model out after Tuesday. Will
continue to favor a consensus blend approach to smooth over the
less predictable details. Have high confidence in the forecast
through Monday, dropping to low confidence in the details after
Tuesday.

Strong mid level ridge along the Eastern Seaboard will finally
be replaced by a deep trough during the middle of next week.
Still expecting temperatures to be above normal for late
October, but the trend will be downward after Monday.

Our prolonged dry spell also appears it will come to an end
during the middle of next week. Depending upon how quickly a
cold front can move east, which is not a given with a strong
high pressure over the North Atlantic, we could see periods of
showers lingering from Monday night through the end of next
week. This would be a greater possibility if a low pressure
develops along this front by Wednesday.

Still thinking the greatest risk for widespread showers
will be ahead of a cold front Tuesday into Wednesday.

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

Short Term /through Saturday/...Generally high confidence.

3 AM update...

Any isolated fog patches, especially in the CT River Valley,
will dissipate first thing after sunrise. Otherwise VFR
conditions through Saturday. Just an isolated fog patch or two
late tonight in the normally colder spots. Northwest winds will
pick up a little, with late morning and afternoon gusts near 20
knots today. Winds then diminish with sunset and will be light
through Saturday.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Saturday Night through Tuesday/...

Saturday Night through Sunday Night: VFR.
Monday: VFR. Slight chance SHRA.
Monday Night: Mainly VFR, with local MVFR possible. Chance
SHRA.
Tuesday: Mainly MVFR, with local IFR possible. Breezy. SHRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Saturday/...High confidence.

3 AM update...

Today...Northwest winds will gust to around 20 knots during the
day. Seas will be near 5 ft early this morning on the southern
outer waters but seas will subside to 3 to 4 ft throughout all
outer waters during the day. Have kept a Small Craft Advisory
posted for the southern outer waters through 10 AM this morning.

Tonight and Saturday...Ideal boating weather. Winds remain 15
knots or less, and seas mainly 2 ft or less. Wind direction will
shift from the north tonight to the southwest on Saturday.

Outlook /Saturday Night through Tuesday/...High confidence.

Saturday Night through Sunday Night: Winds less than 25 kt.
Monday: Winds less than 25 kt. Seas locally approaching 5 ft.
Monday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers.
Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Local rough seas. Chance of rain showers.

&&

.FIRE WEATHER...
Will reissue the Special Weather Statement highlighting a
risk of only marginally elevated fire weather potential for
today. Northwest winds may gust up to 20 mph at times late this
morning through the mid-afternoon hours. We are not expecting 25
mph or higher gusts. Minimum RH values will reach 30-35 percent
across much of the region. These values, combined with the lack
of recent rainfall will lead to a marginally elevated fire
weather potential for today.

&&

.CLIMATE...
Record high temperatures for Saturday, October 21:
BOS 82 in 1920
BDL 82 in 1920
PVD 81 in 1920
ORH 80 in 1920

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 AM EDT this morning for ANZ255-
     256.

&&

$$
SYNOPSIS...Belk/Field
NEAR TERM...Field
SHORT TERM...Field
LONG TERM...Belk
AVIATION...Belk/Field
MARINE...Belk/Field
FIRE WEATHER...Field
CLIMATE...Field



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