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Area forecast discussion 
National Weather Service Taunton Massachusetts
1001 PM EDT Friday Aug 22 2014

Synopsis...
the risk for a few showers will linger into Saturday...otherwise
dry this weekend as high pressure builds south into New England
late Saturday into Sunday. Dry weather with a warming trend is
likely during the early and middle portions of next week. A front
may approach from Quebec late next week with a low chance of
unsettled weather.

&&

Near term /until 6 am Saturday morning/...
10 PM update...
bulk of the -shra activity continues to wain this evening thanks
to both a loss of diurnal heat support and the fact that shortwave
energy begins to move offshore. Not out of the question an
isolated -shra moves through central portions of the box
County Warning Area...but will only highlight isolated chances with this update.
Otherwise. Continue to note low clouds moving in from the east and
interior clouds lowering thanks to onshore flow. This will likely
mitigate fog development somewhat as it will limit radiative
processes. Will still need to monitor for fog/dz moving in
offshore although soundings do still have a dry layer just above
the surface at 00z...which would have to be overcome for dz.
Therefore...will continue to hold off on dz mention for the time
being. Otherwise...forecast on track for the most part. Will
maintain the probability of precipitation through the overnight as yet one last shortwave
will be diving S during the morning hours.

Previous discussion...
the column begins to dry from the north as noted by decreasing
precipitable waters and much lower ki values approaching from the NE. Best
chance of any showers will be before midnight.

Stratus will likely redevelop tonight with plentiful low level
moisture in light easterly flow. Some fog likely as well but we
are not expecting it to be widespread. Can not rule out some
patchy drizzle in eastern new eng as middle level drying moves in
over low level moisture.

&&

Short term /6 am Saturday morning through Saturday night/...
Saturday...
middle level trough axis and last shortwave swings south across the
region...but at the same time middle level drying is moving in so
expect less coverage of showers. Best chance will be in north/northwest zones
as a secondary area of higher moisture and ki values moves in from
the north. However...improvement and partial clearing expected
by middle/late afternoon as the trough shifts S of the region. Temperatures
expected to be similar to today...perhaps a few degrees warmer in
some interior locations but still below normal.

Saturday night...
surface high builds into southern New England which will bring mostly clear skies and
light winds. However...patchy dense radiation fog expected in
normal fog prone locations. A cool night with mins mostly in the
50s.

&&

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

* dry weather expected for most of the period
* warmer...more humid conditions move in around early to middle
portions of next week
* uncertainty continues as a cold front approaches from Quebec
late next week

Overview and model preferences...
medium range models remain in pretty good agreement into early
next week...then start to diverge around the Thursday into early
Friday timeframe due to the approach of a cold front out of
Quebec. Also noting models are trying to bring a system around
the western periphery of the Bermuda high out of the tropics.

Used a blend of available models through Wednesday...then
transitioned over to the ensembles with lesser emphasis placed on
the 00z/12z op runs late next week. 00z/12z European model (ecmwf) runs seem a bit
too fast in bringing the front across the region on Thursday...while
the 12z GFS brings the front across late Thursday night/Fri...kind of
catching up to the ec. Agree with previous forecaster with regards
to the strength of the developing ridge over the region...which
may slow things down further.

Details...

Sunday...high pressure at surface and aloft will build down the coast
out of eastern Canada. Onshore flow will hold temperatures in the lower
70s along the coast...ranging up to the upper 70s across the CT
valley.

Monday through Wednesday...high pressure ridge builds from the
Maritimes to the Middle Atlantic States over time...with the ridge axis
over the top of the region on Monday that slowly sinks S. This
will cause winds to shift to S-SW...bringing milder and more
humid air into the region. Expect to see highs mainly in the
Lower-Middle 80s during this timeframe. With light pressure gradient on
Monday and Tuesday...sea breezes will likely develop keeping it a bit
cooler along the shoreline. Once the S-SW flow is established...
temperatures along the S coast may also be a bit cooler on Wednesday. Some
clouds may start to move in Wednesday night...but timing in question.

Thursday-Friday...lower confidence on this portion of the
forecast. For now...may see frontal system try to work S out of
Quebec around late Thursday/Thursday night timeframe. Question will also be
how much available moisture will be associated with this system.
Did keep only low chance probability of precipitation mainly for the interior for Thursday
afternoon/evening. Very little instability with this...but can
not rule out an isolated thunderstorm so did mention this. Current forecast
suggests a drier and cooler day on Friday.

&&

Aviation /02z Saturday through Wednesday/...
forecaster confidence levels...

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

Short term...through Saturday night...moderate confidence.

Tonight...mainly VFR conditions through 03z-04z...then expect
lowering ceilings back to MVFR-IFR overnight. Scattered showers lingering
into the evening...especially west...which will tend to dissipate
overnight. Fairly confident of trend...but timing is less
certain. Also lower confidence on extent of fog development
tonight. At this time...best chance for fog appears to be in the
CT valley...and could see some along immediate East Coast.

Saturday...conditions improve to VFR by midday with at least
partial clearing developing during the afternoon from the north
and east. A few showers still possible...mainly northwest.

Saturday night...mainly VFR...but patchy late night fog
developing in normal fog prone locations.

Kbos terminal...moderate confidence. Expect ceilings to lower to MVFR
this evening. Timing uncertain and could be a few hours earlier or
later than forecast indicates.

Kbdl terminal...moderate confidence. Expect ceilings to lower to MVFR
tonight. Timing uncertain and could be a few hours earlier or
later than forecast indicates.

Outlook...Sunday through Wednesday...

High confidence VFR. Low probability of patchy MVFR/IFR fog each
night. Sea breezes possible Monday and Tuesday.

&&

Marine...
forecaster confidence levels...

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

Short-term...through Saturday night...high confidence.

East/NE flow will persist through the period. Winds could gust to
15-20 knots tonight into Sat given modest gradient in place...but a
decrease in wind expected late Sat and especially Sat night as
the surface high builds into region.

Outlook...Sunday through Wednesday...

High confidence.

High confidence. Quiet boating weather is expected for much of
this period with high pressure across the region. Low probability
of patchy overnight fog limiting visibilities.

Seas may approach 5 feet across the outermost southern coastal
waters on Wednesday with increasing S swell.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
New Hampshire...none.
Rhode Island...none.
Marine...none.

&&

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

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