Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Taunton Massachusetts
137 PM EDT Tuesday may 5 2015

Synopsis...
a weak cold front may bring a few brief showers today...but dry
weather and mild temperatures will dominate. Little change is
expected through the weekend...with mild to warm afternoon/S and
mainly dry weather persist. A slow moving front may bring a few
showers late this weekend into early next week.

&&

Near term /through tonight/...
137 PM update...

Weak cold front was along the South Coast of New England. There is
not much of a pressure gradient...so expecting light seabreezes to
develop in its wake. Most of the precipitation associated with
this front is done. There could be a stray shower...but it will
not amount to much.

Weak high pressure continues to arrive tonight...maintaining quiet
weather.

&&

Short term /Wednesday through Wednesday night/...

A moisture-starved shortwave will pass by Wednesday morning. Not
sure if it will track far enough northwest to result in a brief
period of scattered showers across any portion of our region. Best
shot is northern CT...and perhaps even into part of Rhode Island and
southeast Massachusetts for a short time. Kept the forecast mainly dry across
our region.

Weak surface high pressure still in place. So once the sunshine
breaks out...we should see temperatures recover into the 60s and
70s...with the lowest temperatures toward Cape Cod and the
islands. While it will be colder than the past couple of days..
these temperatures will still be well above normal.

&&

Long term /Thursday through Monday/...
highlights...

* Spring to Summer-like temperatures through early next week
* high pressure will keep mainly dry conditions into this weekend
* a slow moving front may bring scattered showers sun into Monday

Overview and model preferences...

00z gefs/12z ecens remain in good agreement with overall upper
level steering flow in keeping amplified pattern across the lower
48 through most of this forecast period. Noting long wave
troughing with a few cutoff short waves dive S into the base of
the trough into this weekend while long wave ridge slowly builds east
as it noses north through eastern Quebec to Labrador. Also noting
nearly stationary cutoff low off the southeast U.S. Coast with surface
low/possible subtropical system late in the week or this weekend.
While this system will not directly affect the region...it could
cause the ridge to hold in place and slow an approaching cold
front for late this weekend into next Monday.

00z model suite also in fairly good agreement into this weekend...
then the GFS looks to break down ridging faster than ggem/ECMWF...
mainly due to short wave trying to work out of central Canada
which flattens out the ridge. With overall blocking pattern in
place across North America and further east across the Atlantic...feel
this will be slow to break down so think the slower guidance is
the way to go for sun-Mon. However...with the wide model
solutions...have low confidence from Saturday into early next
week.

Leaned toward a blend of model guidance into this weekend...then
blended toward the ensembles for sun-Monday which was close to the
HPC guidance. This yielded good continuity to the previous
forecast.

Details...

Thursday-Friday...ridging builds east across New England into eastern
Canada during this timeframe. Expect light/variable winds early Thursday to
become S-SW. This will keep mild temperatures in place except along the S
coast where they will be tempered with the general onshore wind
flow. May also see brief sea breezes along the East Coast mainly on
Friday. Also...due to sea surface temperatures running in the middle-upper
40s and mild temperatures during the nighttime hours...may see overnight
patchy fog develop mainly along the coast while increasing dewpoints
may also mean brief patchy fog across the normally susceptible
inland locations each night.

Highs both days away from the S coast will be in the 70s...
possibly up to around 80 across portions of the CT valley both
days.

Saturday through Monday...as mentioned above...model solutions
Widen. Have mentioned only slight chance probability of precipitation mainly north of the Mass
Pike Sat afternoon/night. Increased probability of precipitation to only low chance for
sun/Monday for most areas...but will depend upon timing of the
approaching front. Expect mild temperatures to remain in place through
this weekend with highs in the 70s /except cooler along immediate
S coast/.

&&

Aviation /18z Tuesday through Sunday/...
forecaster confidence levels...

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

Short term /today through Wednesday night/...

High confidence. VFR through the period. Light and variable winds
will lead to local seabreezes later today...and again Wednesday.
Low probability for MVFR conditions in scattered showers late
tonight into Wednesday morning. Low confidence in fog and marine
stratus Wednesday night across southeast Massachusetts. That will need to be
monitored

Kbos taf...high confidence in taf. Sea breezes expected to develop
this afternoon as a result of a weakening pressure gradient behind a
cold front.

Kbdl taf...high confidence in taf.

Outlook...Thursday through Saturday...

High confidence through the period. VFR and dry conditions. Low
risk for patchy fog each night from around midnight through sunrise
with local MVFR-IFR cigs/vsbys.

&&

Marine...
forecaster confidence levels...

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

Short term /today through Wednesday night/...

Through Wednesday...high confidence. Marginal small craft seas
will continue to diminish across the outer coastal waters into
this afternoon. Winds/seas will remain below Small Craft Advisory
thresholds through Wednesday night under a weak ridge of high
pressure.

Outlook...Thursday through Saturday...high confidence through the
period.

Thursday...W-SW winds up to 15 knots across the open waters during
the afternoon. Seas remain below 5 feet.

Thursday night through Saturday...SW winds 15 knots or less with seas
2-4 feet. Low chance of 5 feet seas on the eastern outer waters Sat
afternoon/night.

&&

Fire weather...
mainly dry weather with little appreciable rainfall will continue
through at least Saturday if not into Sunday/Monday. While winds
for the rest of the work week will probably not be strong enough
for fire weather headlines...we may have to be more concerned by
Saturday. There will be at least a bit more potential for some
marginal fire weather headline wind gusts.

&&

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

&&

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

National Weather Service Glossary of Abbreviations