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Area forecast discussion 
National Weather Service Taunton Massachusetts
336 PM EDT Monday may 25 2015

Synopsis...
warm and muggy conditions start to build in along with an increasing
chance of showers and thunderstorms through the end of the week. The
threat for scattered showers and thunderstorms will increase from
late Wednesday through Thursday and again over the weekend.

&&

Near term /until 6 am Tuesday morning/...
temperatures have climbed into the upper 70s to lower 80s this
afternoon despite the thickening cloud cover. Expect clouds to
linger as the atmosphere moistens up behind the warm front. The
warm front is currently in the Hudson Valley in New York and will
move into southern New England this evening and then north of the
area after midnight tonight.

The front will keep dewpoints in the 50s overnight which in turn
will keep overnight temperatures in the upper 50s to lower 60s.

There is a low probability of showers and sprinkles along the Massachusetts/New Hampshire
border late tonight as the warm front moves through. However...most
of the energy available to produce showers remains farther north.

&&

Short term /6 am Tuesday morning through Tuesday night/...
Tuesday...a real Summer-like day is expected with the warm front
through the area. Expect warm...muggy conditions with temperatures
climbing into the middle to upper 80s across much of southern New
England. Southwesterly winds will keep the South Coast of Rhode Island and Massachusetts
as well as the southern side of Cape Ann significantly cooler with
highs in the upper 60s to lower 70s. Models are indicating some
instability in the afternoon. This may be enough to pop a few
scattered thunderstorms in northwest CT and western Massachusetts. So kept the
slight chance to chance probability of precipitation there. Not expecting anything in the
way of precipitation across eastern MA/RI.

Tuesday night...the upper ridge that has been in place along the
eastern Seaboard starts to break down...shifting to the east. This
will allow better instability to slowly filter into southern New
England. Showers and thunderstorms that develop over New York state could move
into the western portions of southern New England overnight. Have
slight chance to chance probability of precipitation in place for these areas during the
overnight period.

Continued southwesterly flow will keep things warm and muggy. It/ll
be another night with lows in the 60s.

&&

Long term /Wednesday through Monday/...
*/ highlights...

- warm and muggy conditions
- threat of marine stratus / fog along the S coast
- shower / thunderstorm chances beginning late Wednesday
- threat of heavy rain and possible severe weather
- potential lull in activity Friday
- another round of showers / thunderstorms for the weekend

*/ discussion...

Tuesday night - Wednesday night: ridge of high pressure gradually
deamplifies allowing middle-level energy along with low- to middle-level
SW-convergent flow and rrq of an upper-level jet to slink southeast towards
southern New England. Showers/thunderstorms chances increase. Initial activity looks
to develop across PA / upstate New York by afternoon with daytime heating.
Focus appears to be along a pre-frontal boundary parallel with low-
level Theta-E/instability axes pressing east with the west-southwest steering flow
into north/west New England late into Thursday morning. Likely some severe
to the west. Outcomes uncertain for here. Per BUFKIT capping inversion
along with low- to middle-level dry air lingers. H925-85 SW-flow is
divergent. Shower activity likely pushes east into the forecast area
but loses its punch as it does so. Showers potentially lingering
into the following morning. With anticipated elevated instability
thunderstorm activity not out of the question. Otherwise... warm /
muggy conditions with S-flow of higher dewpoint air north...though middle-
to high-level cloud decks may limit heating. Marine stratus / fog
likely to be an issue for much of the forecast period for S/se-
coastal communities as moisture pools beneath a Stout warm-dry-
subsidence inversion.

Thursday - Thursday night: main driving force of middle-level energy
and attendant jet-streak lifts NE resulting in a cool front pushing
southeast out of Canada to become diffuse into the overnight hours. This in
addition to possible cloud cover left-over from Wednesday puts into
question of shower/thunderstorm development. Though the boundary-
layer may not destabilize...mid-level cooling lending to increased
elevated instability and the suggestion of perhaps some middle- to
upper-level forcing /in addition to the consensus of decent Theta-E
and instability axis across southern New England/ yields continued chance shower /
thunderstorm threat. Decent shear so a severe threat is possible but
have greater confidence towards a heavy rain threat. Precipitable waters in excess
of 1.5-inches with freezing level heights of 11-12 kft. Continuing
with a warm-muggy theme with respect to conditions as well as marine
stratus / fog being an issue along the S/se-coast.

Friday - Friday night: discrepancies among forecast guidance. While
the environment looks prime for shower/thunderstorm development...
not a lot of forcing apparent. Offshore high pressure looks to be
influential as ridging enhances aloft ever slightly ahead of a
weekend disturbance. Biggest discrepancy centers around moisture
availability to which GFS BUFKIT profiles suggest can destabilize.
Will keep with slight chance probability of precipitation for the period.

Weekend - early next week: agreed upon that energy diving S round
the north Canadian vortex meets up with energy out of the central Continental U.S.
Pushing a surface frontal boundary S across the NE Continental U.S.. unclear as
to its evolution...whether it stalls. Forecast into early next week
becomes complicated. Of certainty is that a primed environment looks
to exist ahead of the frontal boundary beneath deep-layer forcing.
This should yield likely shower/thunderstorm activity. But with
timing and longevity uncertain will keep with chance probability of precipitation.

&&

Aviation /20z Monday through Saturday/...
forecaster confidence levels...

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

Short term /through Tuesday/...high confidence.

18z update...

Through 00z...VFR. Scattered-broken middle-high level ceilings. Scattered sprinkles
across the north-half of S New England. SW winds 10-15 kts may gust
to 25 knots into this afternoon.

Tonight...VFR. May see patchy fog with MVFR visibilities late S coast/
Cape Cod/islands. SW winds will be up to 40 knots at 1000-2000 feet
above the surface. Not quite strong enough for low level wind
shear to be inserted into terminals...but important to be aware
of.

Tuesday...VFR. Could still have some patchy MVFR visibilities in fog near
the S coast...mainly early. Chance of a thunderstorm with MVFR visibilities in
northwest CT and western Massachusetts...including bdl/baf and in the Berkshires
late in the afternoon.

Tuesday night...VFR deteriorating to MVFR/IFR in areas of fog
particularly along the South Coast...cape...and islands.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook...Wednesday through Saturday...moderate confidence.

Breezy SW-flow with 20 knots gusts at times. IFR stratus / fog possible
across the S/se-coast. Increasing chances for -shra/thunderstorms and rain beginning
late Wednesday to west...most everywhere Thursday...concluding early
Friday. Tempo MVFR-IFR with any activity.

&&

Marine...
forecaster confidence levels...

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

Short term /through Tuesday/...high confidence.

Small craft advisories are up for tonight through Tuesday
night...mainly on the outer waters for increasing seas and
southwesterly winds. While the winds may only reach criteria
briefly...seas will climb to 5 feet and remain there through the
period. In addition...areas of fog are likely to develop Tuesday
night...reducing visibilities.

Outlook...Wednesday through Saturday...moderate confidence.

Persistent SW-fetch with gusts around 20-25 kts at times.
Strongest winds along the near-shore waters. Wave heights in
excess of 5-feet with swell and wind-wave mostly on the outer
waters but getting into the S inner sounds. Dense fog anticipated
lending to visibility restrictions.

&&

Fire weather...
expect dewpoints to slowly but steadily rise into the 50s towards
the end of today. SW winds of 10-20 miles per hour with gusts of 20 to 25 miles per hour
expected...up to 30 miles per hour possible. Forecasted minimum relative humidity values
will be just above 30-percent across the interior...45 to 55 percent
on the South Coast/Cape Cod/islands.

With the increasing humidity...there is a decreased fire weather
risk so will not be issuing a statement at this time.

Although it will be warmer on Tuesday...dewpoints will also be
rising keeping minimum relative humidities from 40 to 50 percent.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory from 2 am Tuesday to 6 am EDT Wednesday
for anz250-254-255.
Small Craft Advisory from 10 PM this evening to 6 am EDT
Wednesday for anz235-256.

&&

$$
Synopsis...rlg/sipprell
near term...rlg
short term...rlg
long term...
aviation...rlg/sipprell
marine...rlg/sipprell
fire weather...

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