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Area forecast discussion 
National Weather Service Taunton Massachusetts
959 am EDT Wed Oct 26 2016

the coldest air of the season so far will bring patchy clouds and
chilly temperatures today. High pressure will push across the region
this afternoon and tonight. Strong low pressure will push across the
region late Thursday into Friday, which will bring a period of
wintry weather well inland at the start, rain heavy at times
elsewhere along with gusty winds at the coast. A drying trend
develops later Fri along with temperatures becoming more
seasonable this weekend and probably into early next.


Near term /until 6 PM this evening/...
10 am update...temperatures have climbed above freezing for most
locations at this time so the freeze warning was allowed to expire
as scheduled at 9 am. Ocean effect clouds continue to stream over
the Outer Cape. Expect this to continue through the day. Made
minor changes to temperature and sky cover forecast to account for
the latest trends. Overall, the forecast was on track.

Large high pressure ridge will build east during the late morning
and afternoon, with north-northwest winds at around 10-15 mph. Some gusts up
to 25-30 mph will linger through midday along east coastal areas.

Short range models continue to signal ocean effect clouds across
the Outer Cape, possibly reaching into Nantucket and portions of
the mid cape this afternoon. With sea surface temps in the upper
50s, noted strong signals on the lake effect parameter on the NAM
4 km and GFS BUFKIT soundings for later this afternoon at kchh for
at least ocean effect clouds and possibly a few showers. Only
question at this point will be whether the wind direction will be
more northerly to bring in the showers. At this point, should
remain mainly northwest through today there.

With cold airmass in place across the region, with 850 mb temps in
the -6c to -8c range, will be tough for temps to climb out of the
40s today. Might see a few readings up to around 50 along the
immediate S coast though.


Short term /6 PM this evening through 6 am Thursday/...

High pressure will slowly build east tonight. This should allow
lighter winds, veering mainly from the north across the eastern
waters. As mentioned above, short range models continue to signal
best shot for any ocean effect clouds and showers to push into the
mid and Outer Cape and well as Nantucket during the overnight
hours. Winds may start to veer to more north-NE toward daybreak, which
could push the clouds closer to the coast from Plymouth to the
Cape Cod canal. If any showers do occur, best chance will be from
Provincetown to Chatham.

In the meantime, the high will build east overnight. Overrunning
well ahead of low pressure across the eastern Great Lakes will
bring clouds into central and western areas mainly after midnight.
The ridge will hold off the precip until during the day Thursday.

Expect temps to fall back to the 20s across most inland areas,
ranging to the mid 30s to around 40 along the immediate coast.
The lows may occur around midnight or so, then may level off or
slowly rise as winds shift to light northeast.


Long term /Thursday through Tuesday/...
updated 427 am...


- a period of snow possible high terrain Thu
- rain heavy at times late Thu into Thu night
- a period of gusty winds possible Thu ngt South Coast


Snow potential...very cold airmass in place early Thu with 850 temps
down to about -4c at 12z. Airmass is very dry as well and this
yields large potential for evaporative cooling. This will support a
deep layer of cold air that will be conducive for ptype of snow.
However models have trended deeper/stronger with parent low moving
from Ohio to western New York. This results in a longer duration of east-southeast low
level winds across the region triple point low development
is delayed until Thu evening somewhere vicinity of phl-NYC-CT coast
corridor. As a result this yields more boundary layer warming with
freezing levels only dropping to about 1500 ft per model soundings.
Heavy qpf would be able to offset this blyr warmth and lower
freezing levels but only the NAM is showing robust qpf Thu. Even the
hi res arw and nmm cores are much lighter than the NAM. Appears the
NAM mid level winds /700 mb/ are much stronger than the remainder of
the guid and this is resulting in the higher NAM qpf. Thus have
followed a non-NAM solution here. This scenario supports precip
beginning as snow across northern CT (esp higher terrain) into
western-central Massachusetts including the Worcester Hills. Given the marginal
blyr and surface temps any minor accumulations would likely be
confined to the highest elevations /esp above 1500 ft/. Also given
precip intensity may be lacking accumulations more likely on non
paved surfaces. As of now not expecting much impact...however still
need to watch this unfold closely because if models trend weaker
with parent low and give way to triple point low quicker...blyr will
be colder across our region and yield a higher snow potential.

Heavy rain potential...

Good trough amplification Thu night along with mid level trough
taking on a negative tilt in concert with dry slot approaching from
the west. This will yield rain heavy at times Thu afternoon and
night with heaviest rain possibly 06z-09z as nose of dry slot
approaches. Any poor drainage flooding should be minor as non-NAM
model consensus on quantitative precipitation forecast is 0.75 to 1.25 inches with isolated higher
amounts given convective potential on nose of dry slot. System is
dynamic but remains progressive which will limit qpf to some extent.

Strong winds potential...

Low level southeast jet strengthening up to 50 kt as it moves across
Rhode Island and southeast Massachusetts Thu night. With triple point low expected to
track along or near the I-95 corridor warm sector likely to
overspread coastal Rhode Island into southeast Massachusetts. This will lessen the low
level convergence and increase the probability of gusty winds aloft
reaching the surface. Model soundings indicate potential up to 40-50
kt gusts at bid/hya/chh and ack. In addition some elevated and
surface based instability in warm sector. So more robust showers or
isolated thunder may increase the risk for strong winds. So
eventually may need a Wind Advisory for this region Thu night.


The day begins with triple pt low over eastern Massachusetts at 12z and
continuing to deepen/strengthen as it tracks northeast to off Cape
Ann midday. However its slow to exit as mid level low captures
surface reflection just offshore late Fri. This results in a
blustery day with northwest winds gusting 30 to 40 mph. Although Post
frontal airmass fairly seasonable so expecting highs in the 50s.
Will feel cooler given the gusty northwest winds. Warmest readings
will be over southeast Massachusetts where warm sector airmass overspreads the
area Thu night with temps rising into the 50s to near 60 late Thu
night into early Fri.

The weekend...

Deterministic and ensemble guid continues to struggle with the
amplitude of northern stream short wave energy moving across the
northeast this weekend. Not expecting a washout but there will be
the risk for a period of showers sometime over the weekend. So
followed a model blend given the uncertainty. More certain on temps
not being as cold as previous days with highs close to normal both
days...55 to 60 with Sunday possibly the milder of the two days.

Next week...

Ridge over the MS valley Mon builds northeast into New England Tue.
This will support dry weather along with near seasonable temps Mon
trending to slightly warmer than normal Tue-Wed.


Aviation /14z Wednesday through Sunday/...
forecaster confidence levels.

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

7 am update...

No change from previous tafs. Marginal MVFR/VFR will be confined
to the higher terrain and Cape Cod/Nantucket. North-northwest winds will gusts
up to 25 kt thru today. Earlier discussion below.


Short term /through tonight/...high confidence.

Through today...VFR. Ocean effect clouds may cause brief periods
of MVFR ceilings across Outer Cape cod through mid morning. Northwest winds
gusting to around 20 kt through midday across the Outer Cape and

Tonight...mainly VFR. North winds 10-15 kt will bring ocean effect
clouds into coastal Plymouth County, Cape Cod and the islands
with MVFR ceilings. Sct -shra move onshore on the Outer Cape
overnight, though visibilities should remain mainly VFR.

Kbos taf...high confidence in taf.

Kbdl taf...high confidence in taf.

Outlook /Thursday through Sunday/...

Updated 427 am...

Thursday into Friday...moderate confidence.

Cigs lowering to IFR-LIFR into Thursday. Initial brief period of
snow is possible across northern CT-western/central MA,
transitioning to -ra/rain with embedded +ra, thunderstorms and rain over S/southeast coastal
terminals along with gusty winds up to 35 kts through around
midnight Friday. Winds back out of the west towards Friday morning,
becoming VFR.

Saturday and Sunday...low confidence.

Mostly VFR. Perhaps a mix of MVFR/VFR to places north of the Mass Pike
in widely scattered showers. West/SW winds throughout. Gusts up to 20


forecaster confidence levels.

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

Short term /through tonight/...high confidence.

Through today...northwest winds gusting up to around 25 kt across the
open waters, but will diminish as high pressure builds east. Seas
up to 5 to 7 ft, but will subside through midday across the near
shore bays and sounds. Small crafts will expire there, but will
continue through the day mainly on the eastern outer waters as
seas remain high.

Tonight...north winds diminish. Small crafts on the eastern outer
waters should end as seas finally subside by midnight. Scattered
ocean effect rain showers mainly east of Cape Cod, but may extend
into eastern Cape Cod Bay and Nantucket Sound overnight.

Outlook /Thursday through Sunday/...moderate confidence.

Updated 427 am...

Thursday into Friday...

Low pres over western New York state Thu gives way to a new low along the
southern New England coast Thu ngt...intensifying into a gale center
as it tracks into the Gulf of ME Fri. Could see a period of southeast gales
Thu night followed by northwest gales Fri. Vsby may drop below 1 mile Thu
afternoon and night in periods of heavy rain and fog...improving
around daybreak Fri.

Saturday into Sunday...

Modest westerly winds Sat ahead of a weak cold front...followed by
modest northwest winds sun behind the front becoming north-northeast Sunday


Box watches/warnings/advisories...
Rhode Island...none.
Marine...gale watch from Thursday evening through Friday morning for
Gale watch from late Thursday night through Friday morning for
Small Craft Advisory until 11 PM EDT this evening for anz250-
Small Craft Advisory until 11 am EDT this morning for anz251.
Small Craft Advisory until 2 PM EDT this afternoon for anz255-


near term...rlg/evt
short term...evt
long term...nocera

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