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Area forecast discussion 
National Weather Service Taunton Massachusetts
245 am EDT Sat Oct 1 2016

Synopsis...
a low pressure passes by to our south today. Meanwhile, a high
pressure remains over the Maritimes. This combination will mean
cool and damp conditions through most of this weekend. Another low
pressure moves east across New England Monday and Tuesday. High
pressure builds over New England Wednesday and Thursday. Still
watching Hurricane Matthew, but uncertain information whether it
affects New England, or not.

&&

Near term /through today/...
radar continues to show bands of showers moving north across
southern New England. Lift is rather weak, and mainly the result
of a low pressure passing by to our south. As this low pressure
moves offshore, we should start to start to get into a dry slot
later today.

Looking very much like a low quantitative precipitation forecast/high pop kind of forecast. Most
rainfall rates were less then one tenth inch per hour. Will
continue categorical pops through this morning, before slowly
diminishing them this afternoon. In any case, not expecting a
total washout.

A large high pressure over the Maritimes will maintain persistent
northeast winds. Besides keeping southern New England below normal
temperature-wise, this will also keep the low level humidity
higher, particularly across Rhode Island and southeast Massachusetts. Max temperatures
today are not expected to be more than 10 degrees higher than the
low temperatures this morning.

&&

Short term /tonight through 6 PM Sunday/...
our region will still be in range of a potent mid-level cutoff low
late tonight into Sunday. This should be close enough to maintain
meager convective instability across our region. Despite a period
of lower precipitable water values, there should still be enough
moisture around for at least a continued chance of showers.

Temperatures still below normal thanks to flow off the Gulf of
Maine and continued cloud cover.

&&

Long term /Sunday night through Friday/...
big picture...

Longwave pattern continues to show west Atlantic high in place, but
shifting south over the weekend. Closed upper low over the Ohio
Valley shifts north, then moves east as the Atlantic high moves out
of the way. This upper low moves over New England Monday and
Tuesday. High pressure then moves over the northeast USA Wednesday
and Thursday. Upper low along the British Columbia coast swings
across the USA during the week, then lifts northeast across eastern
Canada Friday.

And then there is Matthew. There is a great difference in how the
models handle the storm, especially north of the Bahamas. The GFS
continues to outrun the European model (ecmwf) in bringing the storm up the coast,
but reacts to the building midweek upper high by dancing and
spinning east of our area. The difference continues to be the GFS
showing a greater phasing of Matthew with a southern stream
shortwave, while the European model (ecmwf) shows either no phasing or greatly
delayed phasing...and thus a much slower movement north.

We favored a model blend for most of the long term. The GFS has been
trending slower on Matthew, so a movement away from either extreme
seems a good thing.

Details...

Monday-Tuesday...

Upper low and cold pool move overhead Monday and Tuesday. Monday
will feature the most instability with GFS-ECMWF-NAM-ggem showing
totals in the upper 40s and lower 50s. This looks mainly to be
scattered showers Monday but with enough instability to mention a
widely scattered tstm. Less coverage Tuesday, but enough for
scattered or widely scattered showers. Surface wind flow will
continue from the northeast keeping temps below normal especially in
eastern Massachusetts and Rhode Island. Mildest temps will be in the CT valley.

Wednesday through Friday...

High pressure actually starts building south from Canada on Tuesday,
but is most notable starting Tuesday night with temps and dew points
cooling into the 40s. The high brings fair and dry weather Wednesday
and Thursday with partly sunny skies. Northeast flow continues.

Friday currently looks to maintain the dry weather as high pressure
moves off through the Maritimes. If Matthew moves close enough,
then we could see some showers well out ahead of the system. But
very low confidence in such a scenario so we have indicated only
slight chance pops in eastern and central sections. Otherwise dry
weather.

&&

Aviation /06z Saturday through Wednesday/...
forecaster confidence levels.

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

Short term /through Sunday/...

Today...moderate confidence. Low-end MVFR or IFR cigs linger
through the day with on-and-off rain showers lowering vsbys.

Tonight...moderate confidence. May see some minimal improvement
during the overnight hours. However, low ceilings will remain an
issue. At least MVFR for most of southern New England, with IFR
ceilings toward the South Coast.

Sunday...moderate confidence. MVFR/IFR cigs and vsbys in showers and
fog. Diminishing northeast flow.

Kbos taf...high confidence in trends, moderate confidence in
timing.

Kbdl taf...high confidence in trends, moderate confidence in
timing.

Outlook /Sunday night through Wednesday/...

Monday-Tuesday... low confidence. VFR with areas of MVFR in
scattered showers.

Wednesday...moderate confidence. VFR.

&&

Marine...
forecaster confidence levels.

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

Short term /through Sunday/...

High confidence.

It will likely take until into Sunday for seas to drop below 5 ft
across the eastern, outer coastal waters. With northeast winds
gradually diminishing today and tonight, expecting seas to subside
as well. Small craft advisories will continue for at least a while
today. Will likely be able to convert the remaining gale warnings
to small craft advisories later this morning. Still evaluating the
trends.

Outlook /Sunday night through Wednesday/...

Diminishing northeast wind Sunday night and Monday with gusts 20
knots or less. Northeast winds increase again Tuesday and
Wednesday on the southern and southeast waters with frequent gusts
20-25 knots. Seas 5-6 feet on the eastern waters Sunday but
diminishing. Seas build again Tuesday and Wednesday with 5-7 foot
seas on the outer waters. Small Craft Advisory will be needed for
much of this time period.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory until 5 PM EDT this afternoon for anz232.
Small Craft Advisory until noon EDT today for anz233-234.
Small Craft Advisory until 8 PM EDT this evening for anz230-
231-235-237.
Small Craft Advisory until 11 am EDT this morning for anz236.
Small Craft Advisory until 8 am EDT Sunday for anz250-251-254-
255.
Gale Warning until 5 am EDT early this morning for anz256.

&&

$$
Synopsis...wtb/Belk
near term...Belk
short term...Belk
long term...wtb
aviation...wtb/Belk
marine...wtb/Belk

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