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Area forecast discussion 
National Weather Service Taunton Massachusetts
710 am EST Sat Nov 22 2014

Synopsis...
temperatures moderate today on gusty southwest winds. This will
be followed by a significant warm up Sunday and especially
Monday...but with a period of rain Sunday night and Monday. Dry
and cooler Tuesday...then a coastal storm may affect southern New
England Wednesday and Wednesday night but the track is still
uncertain. Turning colder into the end of the week.

&&

Near term /until 6 PM this evening/...
7 am update...
only minor adjustments this morning as the forecast is on track
for the most part. Main issue is to expect increasing clouds late
this morning and this afternoon.

Previous discussion...

High pressure off the middle Atlantic coast will result in decent warm
advection to develop today. Sunshine will give way to increasing
middle/high clouds in the afternoon as middle level moisture
increases...but no precipitation expected as low levels remain quite dry.
After a cold start to the day temperatures will recover nicely but still
several degrees below normal. Maxes will range from the middle 30s to
lower 40s with middle 40s over the cape/islands. Low level jet
develops across the region in the afternoon which will lead to
gusty SW winds developing with gusts to 25-35 miles per hour...mainly in the
coastal plain. Strongest winds will be on the cape/islands.

&&

Short term /6 PM this evening through 6 PM Sunday/...
tonight...
a weak shortwave will be moving into the region and while moisture
in the column deepens it is still somewhat dry in the low levels.
A few showers are possible...especially north zones where low level
moisture is greater but any precipitation will be spotty and very light.
The main concern is for isolated pockets of light freezing rain in
central/west Massachusetts and SW New Hampshire if any precipitation develops as temperatures expected to
cool to near freezing tonight while temperatures aloft warm well above
freezing. This is not a certainty as it could remain mostly dry
and we will have only chance probability of precipitation. Temperatures will hold nearly steady in
the 30s tonight across much of the region and near 30 degrees
northwest...but rising into the 40s S coast as gusty SW winds continue.
In fact...could see gusts to 40 miles per hour on cape/islands.

Sunday...
weak surface ridging develops across southern New England as moisture gradually
decreases. Expect a dry and mild day with morning clouds giving
way to partial sunshine. Used a blend of available guidance for
temperatures with maxes in the low to middle 50s...except upper 40s northwest
higher terrain.

&&

Long term /Sunday night through Friday/...
*/ highlights...

- turning warmer and wet Monday
- a possible midweek storm...especially for southeast New England
- looking colder into late week

Overview and model preferences...
22.00z model guidance continues to exhibit good agreement in the
synoptic pattern through about middle week. The key is a developing
longwave trough...which axis remains well to the west across the Great
Lakes and into the Ohio Valley. This yields continues stacked SW
flow through the period...keeping the bulk of the colder air to
the west. The one primary issue still within the most uncertain
portion...from Wednesday Onward...is a northern stream shortwave ejecting out
of the Pacific to the S of the alleutian islands. It is this
feature which is still generating a wave of low pressure along a
stalled frontal boundary from the middle Atlantic. This low pressure
would then pass somewhere from the S coast to well southeast of the 40/70
benchmark. The envelop of potential tracks start late Wednesday into Wednesday
night...and range from near the Cape Cod canal to well offshore
with little to no impact. The ensembles all fall in this envelop
while the GFS is near the east edge and the European model (ecmwf) near the west edge.
Therefore...feel that a blend of guidance will convey both the
uncertainty and take into account the potential solutions. This
includes thermal profiles as the European model (ecmwf) is significantly warmer
than the GFS.

Details...

Sun night into Monday...
warm occlusion will be moving through early Monday morning...this is
associated with precipitable waters between 1.0-1.25 inches...moderate southerly low level jet
around 65 knots and k-values above 30. Essentially all ingredients for
widespread rainfall with embedded heavier rain and convective
elements. Ts would be isolated...but not out of the question. Will
need to monitor for this heavy rain threat until it moves through
by about middle morning-middle day Monday. Will also need to monitor for
strong winds thanks to precipitation drag or convective forcing to the
surface as the 65 knots low level jet core is only at about h92. Note modest
inversion initially...but some mixing of this momentum is not out
of the question. Showers may linger into the Monday night hours...but
will be lighter and less widespread as the upper level impulse moves
through and low-middle level moisture remains in place.

Tuesday and Tuesday night...
brief ridge of high pressure moves over from the SW and crests across
the region. Middle level temperatures still relatively high...so expect temperatures
mainly above normal.

Wednesday and Thursday...
as mentioned above confidence is low in this portion of the
forecast but will need to monitor a coastal low pressure system moving
NE from the middle Atlantic. Depending on the track...could see just
some rain for east Massachusetts and Rhode Island with the possibility of a bit of light
mixed precipitation to the interior CT/MA/SW New Hampshire...this is the east edge of
the envelop represented by the GFS. The European model (ecmwf) is much warmer and
passes near the canal..but also is more dynamic with more
precipitation. At this time...given the lack of a blocking Arctic
high and slightly positive ao/nao as the previous forecaster
noted...feel that there will be enough warm air in place for
rain/mixed precipitation rather than snow outright even if the GFS or east
tracking ensembles verify. Will need to monitor this
however...given that warm air could come in faster aloft and there
will be significant travel for the Holiday.

Late next week-early weekend...
Thursday-Friday could see brief shot of light precipitation as the upper
shortwave ejects east-northeast...but by this point drier air is already
moving in behind the coastal low. In any case expect cooler air
to begin to filter in toward the end of the week.

&&

Aviation /11z 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/...high confidence.

No major changes with the 12z update.

Today...
VFR. Middle level ceilings developing in the afternoon. Increasing SW
winds in the afternoon with gusts to 25-30 knots in the coastal
plain.

Tonight...mainly low-end VFR ceilings developing but low probability for MVFR
with a few showers expected. Isolated pockets of -fzra possible
in west Massachusetts and SW New Hampshire. Any icing will be very light. SW wind gusts to
25-30 knots near the coast...possibly up to 35 knots cape/islands.

Sunday...VFR ceilings. SW gusts to 25 knots cape/islands in the
morning...then diminishing wind.

Kbos terminal...high confidence. Expect VFR ceilings tonight but a
few showers possible. SW gusts 25-30 knots developing this
afternoon.

Kbdl terminal...high confidence. A few showers possible tonight
but do not anticipate any -fzra. Low probability for brief MVFR ceilings
tonight.

Outlook...Sunday night through Wednesday.

Sunday night into Monday...moderate confidence.

Conditions deteriorate MVFR-LIFR Sunday night into Monday morning
with +ra and strong S-winds with gusts around 30 kts possible...
otherwise low level wind shear impacts with 50 knots S-winds 2 kft above ground level. Conditions
improve by midday...but could see continued SW-winds around 25 kts.

Monday night through Tuesday...moderate confidence.

West-southwest-flow with mainly VFR.

Wednesday...low confidence.

An offshore storm system could bring significant impacts especially
to the se-terminals.

&&

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.

Low level jet develops across the region this afternoon into
tonight. With still cool air over warmer SST...mixing over the
water will be sufficient for gusts to 35-40 knots developing this
afternoon into tonight...with strongest winds east and S of Cape
Cod. We converted the gale watch to warnings...with Small Craft Advisory for bos
Harbor...Narragansett Bay and mass Bay. Seas build to 10 feet
tonight over southern waters.

Sunday...gusty SW winds 25-30 knots in the morning will be
diminishing through the afternoon and dropping below 20 knots.

Outlook...Sunday night through Wednesday.

Sunday night into Monday...moderate confidence.

Conditions deteriorate into Monday morning with rain over the waters
and embedded heavier showers. Visibility impacts possible. Winds
increasing out of the S. Southerly winds gust to around 30
knots...with seas building to about 10+ feet on the southern ocean waters.
Small craft advisories at least needed.

Monday night through Tuesday...moderate confidence.

Winds turning SW remaining blustery with gusts exceeding 25 kts.
Waves maintained with heights of 8 to 10 feet on the outer waters.

Wednesday...low confidence.

An offshore storm system could bring significant impacts to the
waters yet details uncertain at this time.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
New Hampshire...none.
Rhode Island...none.
Marine...Gale Warning from 3 PM this afternoon to 4 am EST Sunday for
anz231-232.
Gale Warning from 3 PM this afternoon to 1 am EST Sunday for
anz233>235-237-256.
Small Craft Advisory until 6 am EST Sunday for anz230-236-251.
Gale Warning from 3 PM this afternoon to 6 am EST Sunday for
anz250-254-255.

&&

$$
Synopsis...kjc/doody
near term...kjc/doody
short term...kjc
long term...doody
aviation...kjc/doody
marine...kjc/doody

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