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Area forecast discussion 
National Weather Service Taunton Massachusetts
1026 PM EDT sun may 24 2015

Synopsis...
a warm front will move across the region Monday followed by warm
and humid conditions which will likely last into next weekend.
The threat for scattered showers and thunderstorms will increase
from Wednesday afternoon into the weekend.

&&

Near term /until 6 am Monday morning/...
1020 PM update... high cloudiness continue to move across southern
New England tonight. Thicker middle cloud shield will arrive late
tonight into Monday morning. Winds have diminished to below Small
Craft Advisory levels along the coast and all advisories have been
discontinued. Low level winds remain strong enough for some
gustiness to continue overnight.

Temperatures have cooled to the middle and upper 50s on the Outer
Cape and islands...where some patchy fog may form overnight. The
steamship authority reported hazy conditions over Nantucket Sound.
Elsewhere temperatures were in the 60s with dry dewpoint
readings mainly in the 40s. Dewpoints were higher...in the 50s to
near 60 in the vicinity of a warm front which was from West
Virginia to Delaware-Maryland-Virginia as of 10 PM.

&&

Short term /6 am Monday morning through Monday night/...
Monday and Monday night...
Bermuda high sets up along eastern Seaboard. Warm front develops
as it shifts east across New York state during Monday. However...with
strong subsidence in place as well as continued SW surface winds
and 500 mb ridging building across western New England...better
moisture and lift will remain north and west of the region. While there
will be no precipitation with this front...will see a lot of cloudiness
streaming across the region. Expect the warm front to push NE
across northern New England Monday night.

May see some leftover patchy fog along the S coast early Monday
morning...then again near the S coast as well as Outer Cape cod
and the islands late Monday night as dewpoints/relative humidity values increase.

Even with the clouds...it will still be warm on Monday with highs
around 80 except in the upper 60s and 70s across S coastal areas.
Readings will only fall back to the upper 50s to lower 60s Monday
night...and it will be muggy as dewpoints continue to rise through
the 50s.

&&

Long term /Tuesday through Sunday/...
highlights...

* warm and humid into the weekend
* increasing shower/thunderstorm potential Wednesday into Thursday
* more showers and thunderstorms possible this weekend

Overview...
middle level ridging along the East Coast will be the dominant
feature through much of the week...although northern stream energy
riding over the top will deamplify the ridge allowing for a weak
frontal passage around Thursday timeframe. Above normal temperatures with increasing
humidity will be the theme through the week with the warmest temperatures
Tue/Wed...with potential for near 90 degrees interior valleys.
Best chance for showers/thunderstorms will be Thursday with the frontal passage...but
nearby instability axis suggests potential for scattered convection for
interior locations on Wed/Fri. Looking ahead to the weekend...a
more robust middle level trough will be sliding east across southeast Canada
but models differ on timing which will affect timing of a cold
front and sensible weather. We leaned toward wpc guidance which is
closer to slower European model (ecmwf).

Tuesday into Wednesday...
southern New England in the warm sector airmass with SW flow bringing warm and
increasingly humid conditions. 850 mb temperatures 15-16c suggest
potential for near 90 degrees in some of the interior
valleys...but SW winds off cooler ocean will keep temperatures in the 70s
near the South Coast. Dewpoints climbing to 60+ so it will start
to feel a bit humid compared to recent days.

Regarding thunderstorm potential...think Tuesday will be mostly dry with
possible exception of far west new eng as models generate some
marginal instability during the afternoon with sbcapes around 500
j/kg and ki climbing to 30+. Cant rule out an isolated thunderstorm across west
zones during the afternoon/evening...otherwise mainly dry Tuesday.
More instability is forecast on Wednesday with convective available potential energy exceeding
1000 j/kg so expect scattered afternoon showers/thunderstorms
developing...mainly confined to west zones where best instability.
0-6km shear is weak...less than 25 knots so main threat is locally
heavy rainfall given high precipitable waters .

Thursday and Friday...
not much change in airmass with continued threat of
showers/tstms...mainly interior. It appears best chance of
convection will be Thursday as shortwave passes to the north with
subtle middle level cooling and weak frontal passage moving into the region.
Convective available potential energy 1000+ j/kg and some convergence suggests a more active day
and 0-6km shear is a bit stronger as well but still less than 30
knots. Heavy rain is main threat but a few strong to severe storms
possible Thursday. Temperatures above normal...warmest 80s in the interior.

Saturday and Sunday...
GFS is considerably faster than European model (ecmwf) with cold front with
showers/thunderstorms Sat then drying out Sunday as high pressure builds to
the north. European model (ecmwf) has front moving through Sun afternoon/evening with
best chance of convection during this time. Wpc consensus favored
lower solution. A low confidence forecast at this time range and
timing of front will dictate which weekend day has better chance
of convection.

&&

Aviation /02z Monday through Friday/...
forecaster confidence levels...

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

Short term /through Monday night/...high confidence.

Through tonight...VFR. Ceilings at or above 8kft through the night. May see
patchy fog with MVFR to local IFR visibilities after 06z mainly across
the islands...possibly up to the immediate S coast.

Monday and Monday night...VFR. May see patchy fog with MVFR visibilities
early Monday morning and again after midnight Monday night...mainly near
the S coast and Outer Cape cod/Nantucket. SW winds increase Monday
night...gusting to 20-25 knots.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook...Tuesday through Friday...moderate confidence.

Mostly VFR ceilings. But brief MVFR/IFR in any showers/thunderstorms Wednesday
through Friday. Low confidence on duration and areal extent of any
IFR stratus and fog during the late night and morning periods. SW
gusts to 25 knots along southeast new eng coast Tue/Wed.

&&

Marine...
forecaster confidence levels...

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

Short term /through Monday night/...high confidence.

Overnight...have discontinued small craft advisories over all
coastal waters. Winds had diminished to below 25 knots and seas were
now below 5 feet. May see patchy fog develop late tonight across
portions of the southern waters with reduced visibilities.

Monday-Monday night...SW winds continue...gusting up to 20 knots
during Monday. Seas should remain below 5 feet during the day. Expect
SW wind gusts to pick up to 20-25 knots Monday night. Seas also build
to 5-6 feet on the southern waters as well as the eastern outer
waters.

Outlook...Tuesday through Friday...moderate confidence.

Persistent SW flow with gusts around 20-25 kts at times. Strongest
winds over the nearshore waters. Increasing swell and wind wave
will result in seas building to 5-6 feet over S coastal waters. Fog
anticipated during the overnight and morning lending to visibility
restrictions.

&&

Fire weather...
4 PM update...
expect dewpoints to slowly but steadily rise overnight and Monday
with persistent SW winds in place. Forecasted minimum relative humidity values
will be from 35 to 60 percent on Monday...lowest across interior
areas. With the increasing humidity...expect lowered fire weather
risk so will not be issuing a statement at this time.

&&

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

&&

$$
Synopsis...kjc/evt/gaf
near term..gaf
short term...evt
long term...kjc
aviation...kjc/evt/gaf
marine...kjc/evt/gaf
fire weather...staff

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