Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Taunton Massachusetts
654 PM EST sun Dec 28 2014

a cold front crossing New England will move offshore by evening.
High pressure builds south from Canada and then spreads across the
USA for much of the week. This will mean a dry and cold spell for
New England. A storm moving out of the Southern Plains will move
to the Great Lakes Saturday and bring rain to southern New England
over next weekend.


Near term /until 6 am Monday morning/...
7 PM update...made minor updates to temperatures...dewpoints...
and winds for latest trends. Forecast is on track overall with
overcast skies across the region. Expect skies to clear through
the night.

much of the airmass dries early tonight which would support
clearing skies. Cross sections show lingering moisture /over 70
percent relative humidity/ north of the Mass Pike below 900 mb through 12z Monday.
Areas south of the Pike are less moist but not Bone dry. So will
keep clouds around early night with a clearing trend overnight.
Temperatures in the 20s inland and 30s along the coast.


Short term /6 am Monday morning through Monday night/...
flat flow aloft with surface high pressure building through the
Great Lakes into Canada. This should be a dry period with mostly
clear skies. Mixing during the day is forecast to reach 900 mb.
Winds in this layer will be 15-20 we would expect gusts
up to 20 knots during the day. Temperatures at 900 mb of -3c to -5c
would support maximum surface temperatures of 40-45. But with zonal flow aloft
and cold advection in play we will edge close to seasonal normals
with forecast temperatures in the middle 30s to lower 40s.

Monday night should also be dry with seasonal mins in the upper
teens and 20s.


Long term /Tuesday through Sunday/...
* dry weather through most of the work week
* seasonable to perhaps slightly below normal temperatures expected
* next shot of precipitation potentially Saturday

Models are in good agreement through much of the long term with
light winds and cooler temperatures to start the week off. Surface
flow shifts to the southwest as low pressure moves over Hudson Bay
with moderating temperatures expected Thursday and Friday. Models
start to show some timing discrepancies for Friday into the weekend
with the European model (ecmwf) a bit faster than the GFS with a low pressure system
moving through Quebec and into the Maritimes. At this point...will
use a blend of the models for this time period while the next few
runs shake out.

Tuesday and Wednesday...dry but more seasonable weather is expected
as high pressure builds into the Great Lakes and surface winds allow
colder air to drain from the north.

Thursday and Friday...winds shift to the southwest as low pressure
moves over Hudson Bay and then eastward through Quebec. While there
is a cold front associated with the low...models are forecasting
this to stay well to our north at this time. Therefore...dry
weather will persist but temperatures will moderate a bit.

Late Friday through Sunday...there is a significant amount of
uncertainty for this time period due to complexities with the flow
far upstream of southern New England. This will affect how the
northern and southern stream end up interacting and ultimately how
low pressure ends up evolving over the eastern U.S. And Canada. At
this point the models are going with low pressure moving across the
Great Lakes into Canada...bringing a warm front and then a cold
front over southern New England. This would result in widespread
precipitation over the region...but right now it looks like a warm would be mostly rain. Will use a blend of models for
this time period while we wait and see how the situation evolves


Aviation /23z Sunday through Friday/...
forecaster confidence levels...

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

Tonight...moderate-high confidence. Still lots of clouds upstream
and forecast models suggest clouds will linger through midnight
before clearing. VFR.

Monday and Monday night...high confidence. VFR. Northwest winds
gusting 15-20 knots Monday midday and afternoon.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook...Tuesday through Friday...

Tuesday and Wednesday...high confidence. VFR.

Thursday and Friday...moderate confidence. Mainly VFR. Could see
some MVFR ceilings very late Friday night as warm front approaches.


forecaster confidence levels...

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

Short term /through Monday/...moderate to high confidence.

Tonight...northwest winds gusting 15 to 20 knots nearshore. Five
foot seas on the outer waters. Winds diminish and seas will
subside early tonight. A Small Craft Advisory will remain posted
for the southern and southeast outer waters until Monday morning
because of lingering 5 feet seas.

Monday...northwest winds gusting 20 to 22 knots. Seas generally 3
to 4 feet over the outer waters. No headlines expected.

Monday night...winds and seas remain below small craft thresholds.

Outlook...Tuesday through Friday...

Tuesday through Wednesday...high confidence. Quiet boating
conditions expected. Northerly winds Tuesday will shift to the
west Wednesday.

Wednesday night and Thursday...westerly winds and seas start to
build as high pressure moves away from the waters. Small craft
conditions are likely Wednesday night and there is a low probability
of gale force wind gusts Thursday.

Friday...winds and seas subside as high pressure crests over
southern New England and the waters. Quiet boating conditions are


Box watches/warnings/advisories...
Rhode Island...none.
Marine...Small Craft Advisory until 8 am EST Monday for anz254>256.


near term...wtb/rlg
short term...wtb
long term...rlg

National Weather Service Glossary of Abbreviations