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Area forecast discussion 
National Weather Service Taunton Massachusetts
1018 PM EDT sun Apr 26 2015

Synopsis...
unsettled weather and below normal temperatures will continue into
Tuesday. Weak high pressure will briefly visit the area during
midweek...with temperatures near or slightly above normal. Below
normal temperatures and unsettled weather return Thursday night into
Friday...with improvements for the weekend.

&&

Near term /until 6 am Monday morning/...
1018 PM update...

Middle level clouds blanketed southern New England once again.
Tweaked the next several hours of the ongoing forecast to reflect
the latest observed trends. The main changes were to sky cover and
temperatures. Winds remain light an somewhat variable. With the
loss of daytime heating...sea breezes have ended. A northwest to
north flow will establish itself overnight as a result.

Cannot rule out a stray sprinkle or two...but most areas will
remain dry overnight. The overcast skies are expected to continue
through the night...insulating US and keeping low temperatures in
the upper 30s to lower 40s.

&&

Short term /6 am Monday morning through Monday night/...
Monday and Monday night..upper low moves even farther to the
west...residing just east of southern New England. This will bring
the better dynamics and moisture into the region allowing for a
better chance of showers. Showers will be more diurnally driven
through the day then a shortwave moves through southern New
England overnight...allowing showers to continue.

Despite a warmer start to the day...temperatures will once again
stay in the 50s with cool northerly winds and overcast skies. Then
will have warmer temperatures overnight with lows in the 40s.

&&

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

* lingering showers possible on Tuesday
* sunshine and mild on Wednesday
* digging trough returns on Thursday/Friday
* improvements for the weekend

Details...

Tuesday...moderate confidence.

Center of closed low moves a bit further offshore during
Tuesday...with overall decreasing moisture over our area. The
lingering cold pool aloft may still allow for some scattered
showers in eastern Massachusetts and Rhode Island. Otherwise expecting skies to
become partly cloudy with near normal or slightly below normal
highs in the upper 50s to low 60s for much of the region. With
light flow seabreeze is expected to develop along east and south
shorelines.

Wednesday...high confidence.

Digging trough across the central Continental U.S. Will allow surface/upper
level ridging to make a brief visit to our area. This is expected
to allow for a mostly sunny and mild Spring day...with some
diurnal stratocu. Looking at highs mostly in the 60s...potentially
around 70 in the lower CT River Valley Springfield to Hartford
areas. With anticipated light surface flow...seabreeze is expected
to kick in and will knock temperatures back down into...or keep temperatures
in...the 50s nearshore.

Thursday and beyond...low confidence.

Uncertainty in the forecast continues for this timeframe. Initially
expecting Thursday daytime to be mainly dry...but upper ridge and
weak surface high will be moving east of our area during this
timeframe.

A deep trough will be push eastward into the Atlantic
Seaboard...allowing for a surface low to emerge out of the Gulf
Coast states on Wednesday...and track across the Carolina coastline
during Thursday. The big question for our area is where this low
tracks afterwards. 12z GFS takes the low center over 40n/70w
during Thursday night...close enough to bring a widespread rain to
our area. In contrast...the 00z and 12z European model (ecmwf) take the low out to
sea...giving our area some isolated showers at best.

With this level of uncertainty will be following HPC guidance and
previous box forecast for this timeframe...mainly dry conditions
Thursday but increasing clouds...and chance probability of precipitation Thursday night into Friday
night. Temperatures should be close to seasonable on Thursday but then below
normal during Friday.

Next weekend...moderate confidence.

Outcome for next weekend is in part dependent on evolution of deep
cutoff low/surface low track. For Sat models are showing the upper
low moving further offshore...but for GFS it may be just close
enough to our area to bring some light showers. At this time will
go with a slight chance pop. Then may need to watch quick moving
northern stream energy...where a short wave could bring light
showers to our area on Sunday...but not a washout with it being more
probable that much of the day is dry.

&&

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

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

Tonight...high confidence. VFR with light winds.

Monday...high confidence. VFR most of the time. Areas of MVFR
ceilings/visibilities in scattered showers...especially in the afternoon.

Monday night...high confidence. VFR most of the time. Areas of
MVFR ceilings/visibilities possible in scattered showers.

Kbos taf...high confidence in overall taf.

Kbdl taf...high confidence in overall taf.

Outlook...Tuesday through Friday...

Tuesday...moderate confidence. VFR with MVFR conditions in
isolated showers. Sea breeze development is possible along the
East Coast.

Wednesday into Thursday...moderate confidence. VFR conditions. Sea
breeze development probable on Wednesday...with light onshore flow
expected during Thursday.

Thursday night and Friday...low confidence. VFR conditions with
MVFR in scattered showers. Ceilings/visibilities could be lower dependent on the
track of a low pressure system.

&&

Marine...
forecaster confidence levels...

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

High confidence. Quiet boating weather expected. Very late Monday
night into early Tuesday morning winds and seas start to creep up
as low pressure moves closer to the waters.

Outlook...Tuesday through Wednesday...moderate confidence.
Thursday and Friday...low confidence.

Enough northerly gradient anticipated Tuesday that Small Craft Advisory conditions
are probable for most of the coastal waters...especially east of
the Massachusetts shoreline. Seas gradually diminish during
Tuesday...but Small Craft Advisory conditions may linger into Tuesday evening for
some of the outer coastal waters. Light winds/seas expected for
Wednesday.

During the Thursday and Friday timeframe...a low pressure system
emerges from the Carolina coastline and is expected to track
northeastward. There is considerable uncertainty in how close the
center of this system makes it to the southern New England
coastline. If it stays well offshore...swells could bring a
period of rough seas to our coastal waters. A closer approach
would have significant marine impacts for Friday. At this time
have undercut wna wave guidance by 40 to 50 percent.

&&

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

&&

$$
Synopsis...rlg/nmb
near term...Belk/rlg/nmb
short term...rlg
long term...nmb
aviation...Belk/rlg/nmb
marine...rlg/nmb

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