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Area forecast discussion 
National Weather Service Taunton Massachusetts
310 PM EDT Tuesday Jul 26 2016


* updates to near- and short-term forecast portions only,
including aviation, marine, and fire weather.

High pressure will bring dry but continued hot conditions through
Thursday. A cold front will drag S towards New England into Friday
as an area of low pressure emerges from the mid-Atlantic. A cooler
and wetter pattern is possible through the weekend.


Near term /through 6 am Wednesday/...

High pressure builds into New England resulting in diminishing
winds out of the west/northwest becoming light as conditions remain mostly
clear. Considering the overall dry soils across the region and
observed dewpoints during Max-heating of the day falling into and
around the mid-50s, leaning lowest forecast guidance for overnight
lows with the expectation of radiational cooling.

Looking at lows around the upper-50s to low-60s, warmer along the
coast and within urban centers. Would not be surprised to hear a
few isolated locations falling into the mid-50s for lows by
Wednesday morning. A low risk of patchy fog, mainly in sheltered
low lying locations with bodies of water (i.E., CT river valley).


Short term /6 am Wednesday through 6 am Thursday/...


High pressure remains in control. With a 850 mb airmass aloft around
+16-18c and abundant sunshine, in addition to dry-air subsidence,
expect temperatures to warm easily back into the 90s. With light
and variable winds, expect sea-breezes to develop along the shores
around late morning into midday. Likely mix-down of drier air,
another day of 50 degree dewpoints and the absence of muggy air.

Wednesday night...

Continued high pressure, light winds, mostly clear conditions.
Expect another opportunity of radiational cooling to push
temperatures lower overnight. Leaning once again with lowest
guidance advertising upper-50s to low-60s. Focus on dewpoints
during Max-heating of the day which will indicate the depth at
which temperatures can drop. Perhaps a fly in the ointment is
some mid-level clouds drifting into west New England late which could
put a lid on radiational cooling. Winds perhaps begin to turn S
towards morning resulting in rising dewpoints. This in addition to
some patchy fog issues but thinking a low risk.


Long term /Thursday through Tuesday/...


* cold front approaches the region during Thursday
* showers and isolated thunderstorms remain possible Friday into
the weekend

Overview and model preferences...

00z model suite remains in pretty good agreement through
Thursday, then continue to show wide model spread from Thursday
night Onward. This appears to be dependent upon development of
short waves in the nearly zonal 500 mb flow across the northeast,
which will start to back to SW as broad mid level troughing
develops across the Great Lakes into the weekend. The big
differences come into play as models handling the slow movement of
the front out of northern New England differently, along with any
low pressure waves that move along it.

One thing that is in somewhat good agreement is that the front
should push into the region around Friday, then will stall in the
west-SW mid level flow through most if not all weekend.

Used a blend of available guidance through Thursday, then went
with mainly ensemble approach beyond that.


Thursday...models begin their solution variance during this
timeframe, but in fair agreement. Will see another hot and humid
day, especially along the South Coast.

Timing of slow moving front remains in question, but does appear
scattered showers/isold thunderstorms may push into north central and
west mass into north central CT during the afternoon/evening hours ahead
of the front. Have carried low chance pops there, with isold
showers possible further S and east. Kept isold convection going, can
not rule out entirely with marginal instability in place. Decent
850 mb-500 mb lapse rates of 6-6.5c/km, with best shot during Max heating
of the day.

Expect highs in the lower-mid 90s away from the coast, warmest
across the CT valley, ranging to the upper 70s-mid 80s near the
coast possibly touching 90 in Boston and on the North Shore.

Thursday night and Friday...model solutions continue to Widen
during this timeframe with the movement, or lack thereof, of the
front out of S VT/NH. Also questions on development of low
pressure along this front, with the GFS being most robust. Have
kept chance pops going, as models do generally bring in scattered
showers, and kept isold thunder as well. With more clouds around,
will see high temps on Friday 5-10 degrees cooler than Thursday,
mainly in the 80s.

Saturday and Sunday...high uncertainty remains during this
portion of the forecast, with a continued low confidence forecast.
Both the European model (ecmwf) and Canadian ggem models move low pressure off the
mid Atlantic coast during Saturday, with precip working into the
region, while the GFS remains the outlier. More questions on
timing of short wave in the 500 mb flow on Sunday, so kept low chance
pops going there as well.

Monday...low confidence continues. Do have low chance pops going
inland into the afternoon, then have trended drier. Expect
temperatures to run close to seasonal normals.


Aviation /19z Tuesday through Sunday/...

Forecaster confidence levels.

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

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

Rest of today...
VFR. West/northwest winds with gusts 15-20 knots. Sea-breeze hanging along
the immediate East Shore of Essex and Plymouth County Massachusetts.

VFR. Low risk of MVFR-IFR cigs/vsbys with fog towards Wednesday
morning, mainly focused in the CT River Valley. Sea-breeze washes
out. Vrb winds developing.

VFR. Vrb wind becoming onshore along the coastline towards late
morning. If any fog during the morning period, it will quickly
burn off.

Wednesday night...
VFR. Vrb winds becoming S but remaining light towards morning. Low
risk of MVFR-IFR patchy fog developing, mainly focused again in
the CT River Valley and possibly along the S-coast of Rhode Island and Massachusetts.

Kbos taf...W/NW winds diminishing as a sea-breeze washes out off-
shore. With vrb winds more likely Wednesday, expect a sea-breeze
to develop close to mid-morning (15z) with potential gusts up to
15 kts out of the east into midday and afternoon.

Kbdl taf...W/NW winds diminishing. Vrb into Wednesday. VFR and sky clear.

Outlook /Thursday through Sunday/...

Thursday through Saturday...moderate confidence.
Mainly VFR, except MVFR ceilings/visibilities possible in scattered showers
and thunderstorms. Potential for local MVFR-IFR in patchy fog and
low ceilings each night.



Forecaster confidence levels.

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

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

West/northwest winds diminishing overnight. High pressure settling over the
waters which will make for good boating weather. Sea-breezes
developing along the shores around mid- morning Wednesday, so
watch out for some gusts out of the S/east around 15 kts. Low risk
for patchy fog along the S-coast of Rhode Island and Massachusetts towards Thursday

Outlook /Thursday through Sunday/...high confidence.

Wednesday-Thursday...winds and seas below small craft criteria.
Patchy late night/early morning fog with reduced visibilities.
Isolated showers/thunderstorms possible late Thursday/Thursday

Friday-Saturday...winds shift to S-southeast but remain below small
craft levels. Swells will build to around 5 ft on the southern
outer waters Friday night into Saturday, then should subside.
Patchy fog and scattered showers/thunderstorms will reduce


Fire weather...

Drier conditions are expected to persist through Thursday across
S New England as much of the region is in drought with significant
year-to-date rainfall deficits.

An elevated fire weather potential is forecast as minimum relative
humidity values range from 30 to 40 percent. While overall winds
are anticipated light and variable, sea-breezes are expected to
develop around mid-morning into midday behind which S/east wind gusts
up around 15 mph are possible. Some moderation in relative humidity
is expected with marine-layer air coming ashore.


Box watches/warnings/advisories...

Rhode Island...none.



near term...sipprell
short term...sipprell
long term...evt
fire forecast office box staff

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