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Area forecast discussion 
National Weather Service Taunton Massachusetts
509 am EDT Tuesday Oct 13 2015

low pressure will cross southeastern New England this morning. A
cold front across western New York state will sweep across the region
tonight. Expect mainly dry and cooler conditions Wednesday into
Thursday. Low pressure and a cold front will cross northern New
England Friday into Friday night. Increasing winds and the
arrival of colder air may lead to localized wind hazards. The
coldest air so far this season follows for Sunday into
Monday...with the possibility of an area wide freeze. A return to
more seasonable conditions is expected beginning Tuesday.


Near term /until 6 PM this evening/...

Low pressure...well defined on latest water vapor satellite
imagery...continues to move north-NE toward the S coast early this
morning. Leading edge of precipitation moving ashore across S and central
Rhode Island as seen on latest NE 88d radar mosaic. Still some isolated c/g
lightning strokes seen offshore as well. Noted marginal elevated
instability /tq values 16 to 17/ moving close to and ahead of the
low as seen on 00z model guidance so can not rule out isolated
thunderstorms through 11z-13z along the S coast to Marthas
Vineyard and the lower cape. Showers will continue to slowly move
across central and eastern areas...pushing offshore by midday.

Expect low clouds and patchy fog...locally dense at times...across
Rhode Island/southeast Massachusetts through middle morning. This should slowly improve as the
precipitation moves in over the next few hours. Elsewhere...mainly middle
and high clouds that will lower as the low passes across eastern
areas. Also noting a few showers moving in the SW flow across
western Massachusetts/north central CT. Will see some spotty light showers there.

Noting dry slot between systems on the water vapor that will work
in with a brief break in the action...then cold front pushes
toward the region this afternoon out of New York state as its 500 mb short
wave shifts steadily east. Most of the moisture and energy looks to
shift into northern New best shot for showers this
afternoon will be across central and western areas especially
along the east slopes of the Berkshires.

With weak gradient between systems...expect light/variable or calm
winds through midday then will pick up from the SW ahead of
approaching cold front this afternoon.

With milder air working in ahead of the front...expect high temperatures
mainly in the upper 60s to lower 70s.


Short term /6 PM this evening through 6 PM Wednesday/...

cold front will steadily move east early tonight. Winds will shift to
west as drier air works in...and may be briefly gusty along the S
coast as the front moves through. Some clouds will linger across
the east slopes of the Berkshires along with a few light showers as
colder air works in. Expect temperatures to fall back to the upper 40s to
middle 50s...except the middle to upper 50s along the immediate coast.

as broad trough aloft sets up west of the region...will remain west
winds will continue to bring cooler air into the region though the
core of it looks to remain across northern New England. Will be
enough instability to cause some diurnal clouds to develop across
most of the region. May still see some widely scattered showers across
the east slopes of the Berkshires as well. Highs will be in the
60s...mildest across east Massachusetts into Rhode Island as well as the middle and lower CT


Long term /Wednesday night through Monday/...
highlights ...

- thursday: a potential lull in the weather and seasonable
- Friday-saturday: cool and wet with potential wind-hazards
- Sunday-monday: coldest air so far...potential freeze

Discussion ...

13/00z guidance is in rather good agreement on the overall
synoptic pattern. Still some differences in the details...which is
not that uncommon for this time range. The most significant
difference is the evolution of a low pressure moving through
southeast Canada and northern New England. 13/00z European model (ecmwf) retains a
single low pressure...while the 13/00z GFS and Canadian split off
some energy and develop a secondary low pressure over southern
Ontario. This will have implications on how long precipitation may
stick around Saturday.

Eastern USA middle level trough gets reinvigorated this weekend as
the coldest air so far this season puts in an appearance. More
seasonable conditions expected to develop next week.

Given the good overall agreement...and the typical predictability
for the details this weekend into early next week...will continue
to follow a consensus approach for now.

Wednesday night into Thursday...

Modest middle level shortwave during this portion of the forecast...
but not a lot of moisture to work with. Thinking we will remain
mainly dry. The greatest risk for a shower would be Thursday
afternoon. Will need to continue to monitor the see if
more moisture can interact with this shortwave.

Friday into Saturday...

As mentioned above...the details are not so clear for this portion
of the forecast. In general...expecting a low pressure to be
nearby to our north...with a strong cold front poised to cross
Friday into Friday night. This front should result in gusty winds
as it moves on by...particularly across Rhode Island and southeast Massachusetts. Not
expecting a washout...but this will probably be the wettest period
in this portion of the forecast. Still need to resolve the
evolution of a secondary low pressure...if it develops at
all..Saturday. For now...will maintain a slight chance of showers
due to uncertainty in available moisture.

Sunday into Monday...

Still looking like the coldest air so far this season arrives
ahead of a strong high pressure. With the clear skies and light
winds...still expecting many locations away from the coast to
likely be dealing with freeze...or frost. Will likely need to
consider frost/freeze headlines as we get closer in time...much
of this driven by cold air advection.

With such cold air aloft...any sunshine could lead to diurnal
clouds and showers. However...the amount of moisture remains in


Aviation /08z Tuesday through Saturday/...
forecaster confidence levels...

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

Near term /through Wednesday/...

Through 12z...moderate confidence.
Occasional IFR-LIFR ceilings/visibilities across southeast New England terminals
with patchy fog...becoming dense at times through 11z-12z then
should improve. Will also see localized rain/+ra and isolated
thunderstorms and rain mainly along S coastal Rhode Island/Massachusetts through 12z-13z. Will also see
local MVFR-IFR ceilings/visibilities in patchy fog across portions of CT
valley through 12z.

Today...moderate confidence.
Through mid-morning...IFR to local LIFR ceilings/visibilities in low
clouds/patchy dense fog should improve by 14z-15z across east Massachusetts...
Cape Cod and islands. Any leftover MVFR-IFR ceilings/visibilities across CT
valley should improve to low end VFR ceilings. Remainder of
day...may see brief local MVFR with scattered showers as cold front
approaches. SW winds will be a bit gusty especially across CT
valley and S coast...gusts up to 20 knots possible.

Tonight...high confidence.
Cold front will push across the region. Leftover MVFR ceilings/local
MVFR visibilities in any showers will move east through 03z-05z. Some -shra
will linger overnight across east slopes of the Berkshires...may see
brief MVFR conditions. Otherwise...VFR. Winds shift to west.

Wednesday...high confidence. Will see diurnal clouds develop at
around 4kft. Expect scattered-broken cloud deck through the day. May also
see brief local sprinkles with cold air chance for
-shra across east slopes of the Berkshires. Expect west-SW winds to gust
to around 20 knots along S coast...Cape Cod and the islands.

Kbos terminal...moderate confidence in taf.
Have brief MVFR conditions from 09z-14z as showers move across.
Low chance for thunderstorms and rain through 14z. Conditions should improve by middle

Kbdl terminal...high confidence in taf.

Outlook /Wednesday night through Saturday/...moderate confidence.

Breezy west winds with scattered rain showers activity Wednesday night
into Thursday. Scattered-broken low-end VFR ceilings. Strong southwest winds
Friday ahead of a cold front with gusts in excess of 30 kts
possible. Greater chance for MVFR-LIFR conditions. Improving
Saturday to MVFR to low-end VFR with sct-bkn. Strong northwest
winds with gusts in excess of 30 kts possible.


forecaster confidence levels...

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

Short term /through tonight/...

Through 12z...moderate confidence. Coastal low will push NE
across the southern waters with showers and isolated thunderstorms.
Visibility restrictions possible in and around the cape and
islands and all waters S and east. S winds remaining below 15 kts and
seas below 5 feet.

Today...moderate confidence. Showers should diminish as low pressure
moves across the east waters by around midday. Continued S-SW winds
will allow for an increased swell 5-7 feet by evening. Small craft
advisories for seas in effect for the outer waters as well as
bi/Rhode Island sounds.

Tonight and Wednesday...high confidence. Cold front from the
Great Lakes sweeps offshore early tonight as winds shift to west.
Will see gusts up to 20 knots late tonight and Wednesday.

Outlook /Wednesday night through Saturday/...moderate overall

May see west winds and waves diminish some into Thursday beneath
a weak area of high pressure.

Friday S/SW gales are possible...but will hold at 30 kts for now.
Seas expected to be quickly building over all waters Friday...but
especially the outer coastal waters. Winds turn northwest behind a cold
front and remain blustery with gale force gusts possible. Gusty
winds and rough seas should linger into Saturday.


Box watches/warnings/advisories...
Rhode Island...none.
Marine...Small Craft Advisory for hazardous seas from 5 PM this
afternoon to 6 PM EDT Wednesday for anz235-237.
Small Craft Advisory for hazardous seas from 6 PM this evening
to noon EDT Wednesday for anz250.
Small Craft Advisory for hazardous seas from 2 PM this
afternoon to 6 PM EDT Wednesday for anz254>256.


near term...evt
short term...evt
long term...Belk

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