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Area forecast discussion 
National Weather Service Taunton Massachusetts
426 PM EDT Thursday Aug 27 2015

Synopsis...

High pressure will be in control bringing dry and seasonable
weather through Friday. Temperatures will increase as the high
strengthens as it moves offshore. Hazy...hot and humid conditions
return for a good portion of next week.

&&

Near term /until 6 am Friday morning/...
4 PM update...

Early this evening...

Cold air advection/Post frontal strato-cumulus continues to obscure the
sun at times across the region. In fact the cold air aloft /about
-1 Standard deviation colder than climatology at 850 mb and 700 mb/ combined
with Great Lakes water temperatures around 70f is yielding a Delta-T of
about 15c from lake/surface to 850 mb. This is sufficient for lake
induced rain showers over the Mohawk Valley of New York state into the
Albany/capital region of New York this afternoon. So not out of the
question for a stray sprinkle across the Berkshires into the I-91
corridor of western Massachusetts.

Otherwise dry weather prevails with a mix of sun and clouds...
then clearing toward sunset as daytime heating wanes.

Overnight...

Temperatures will fall modestly after sunset with winds decoupling...
clouds eroding and a dry airmass with dew points in the 50s. So quite
comfortable tonight with most locations dipping into the 50s! The
exception will be in the urban areas and along the coast with
temperatures in the low to middle 60s. Given the radiational cooling
conditions leaned toward the cooler met and mav MOS temperature data
sets. Patchy late night radiation fog possible across west Massachusetts.

&&

Short term /6 am Friday morning through Friday night/...
Friday...

Another Gem of a day as high pressure moves into new eng with
sunshine and light winds. Weak cyclonic flow aloft and steep middle
level lapse rates may yield some decorative scattered diurnal cumulus
but should still yield partly to mostly sunny conditions. Maximum
temperatures upper 70s to lower 80s with seabreezes developing along the
coast. Dewpoints remain in the 50s...so remaining very
comfortable. Enjoy!

Friday night...

Another comfortably cool night with high pressure overhead yielding
light winds/mainly clear skies along with a dry airmass with dew
points in the 50s. This will result in another round of min temperatures in
the 50s...with low to middle 60s in the urban areas and along the
coast. Patchy fog possible late in the typically prone low lying
areas and valleys.

&&

Long term /Saturday through Thursday/...

Highlights...

* high pressure will remain across the region through this
weekend
* anomalously high amplitude ridge builds east across the northern
tier during the work week

Overview...

Overall good agreement seen with the general surface and upper
level pattern across the northeast U.S. Through the long term
period. Continue to note some passing short waves in the general
flow mainly around the Sunday-Tuesday timeframe...though timing is
in question due to how each individual models handles them. With
high pressure and subsidence in place...especially as anomalous upper
level ridging for early September builds across central and
eastern Canada...will see return to Summer and triple h conditions
for most if not all of next week as most areas begin their school
years.

Strong surface high also moves across Quebec late in the period
/Wed and Thursday/ so...in combination with Bermuda-Azores high across
the western and central Atlantic...may see a weak backdoor cold front
try to work down the coast out of Maine. Noted this feature on
Wednesday/S op model runs...and rather good consistency seen on
today/S runs as well especially this far out. However...appears
this front washes out quickly...while the overall high amplitude
ridging looks to remain in place into next weekend.

Details...

Saturday...high confidence.

Large high pressure across most of the eastern half of the country
will remain in place. Winds begin to shift to S-SW during the day
and will pick up a bit mainly along the S coast. Weak sea breezes
look to kick in along the east coastal beaches. Temperatures will rise to
the Lower- Middle 80s but dewpoints remain comfortable away from the
coast...mainly in the middle-upper 50s. Overnight lows will be in the
60s with a few upper 50s across the interior valleys of north central
and west Massachusetts.

Might see some late night patchy fog develop across the normally
prone interior valleys as well as near the coast as dewpoints slowly
increase.

Sunday through Tuesday...low to moderate confidence.

Divergence in model guidance works in during this timeframe with
timing issues amongst individual model runs on how they handle
weak short waves moving along in the upper flow. Do note that the
500 mb cutoff progressive low has flattened out on the 12z model
suite. However...GFS and NAM both rather robust in bringing some
precipitation into the region during sun/Monday timeframe...while the European model (ecmwf)
and ggem remain mainly dry. With strong ridging and subsidence in
place... stuck with a dry forecast.

As S-SW winds become established...will see a return of higher
humidities as well as temperatures well above normal. Expect highs both
Monday and Tuesday running as much as 10 to 15 degrees above normal for
early September with readings mainly in the 80s. A few spots may
see readings into the lower 90s.

Wednesday-Thursday...low confidence.

Noting the 12z ggem has become an outlier as it tries to bring ts
Erika up the eastern Seaboard...while both the GFS and European model (ecmwf) keep
a weaker version down around the northern Florida or Georgia
coast. This was similar to model ensembles so went along with
this.

Will remain hazy...hot and humid on Wednesday with highs in the
upper 80s to lower 90s except cooler along the S coast with
onshore winds. Looks to be a very sultry day.

As mentioned above...may see backdoor front try to work southwestward out
of Maine during Thursday. Have put in slight chance probability of precipitation for
Thursday/Thursday night...though timing is in question this far out.

&&

Aviation /21z Thursday through Tuesday/...
forecaster confidence levels...

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

Short term /through Friday night/...

Through 00z...VFR with ceilings bkn035-050. High confidence.

After 00z...VFR with isolated MVFR late in patchy fog in interior
valleys. High confidence except lower in areal coverage of fog.

Friday/Friday night...high confidence. VFR. Isolated MVFR possible
in late night fog interior.

Kbos terminal...high confidence in taf. Sea breeze likely Friday.

Kbdl terminal...high confidence in taf.

Outlook /Saturday through Tuesday/...high confidence.

Expect mainly VFR conditions through the period. May see patchy
MVFR-IFR ceilings/visibilities late Sat night/Sunday morning across normally
prone interior valleys as well as near the coast.

&&

Marine...
forecaster confidence levels...

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

Short term /through Friday/...high confidence.

Quiet boating weather with winds and seas below Small Craft Advisory thresholds.
Generally west/northwest flow but winds becoming locally onshore over
nearshore waters Friday afternoon as sea breezes develop. Only
wrinkle is a leftover easterly swell of 3 to 4 feet across the
waters east of Cape Cod and Nantucket. Otherwise good visibility/light
winds and dry weather provide fabulous late Summer boating
weather.

Outlook /Saturday through Tuesday/...high confidence.

Expect winds and seas below small craft criteria through the
period. SW wind gusts approach 20 knots Sunday afternoon across the
southern outer waters.

&&

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

&&

$$
Synopsis...nocera/evt
near term...nocera
short term...nocera
long term...evt
aviation...nocera/evt
marine...nocera/evt

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