Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Taunton Massachusetts
1251 am EST Sat Dec 27 2014

large high pressure across the Middle Atlantic States will drift
east off the coast of North Carolina later today. West to
southwest winds around this high will bring dry conditions with
above normal temperatures to the region. A cold front is expected
to bring some rain showers on Sunday. Low pressure may pass to our
south early next week. Otherwise mainly dry and near normal to
below normal temperatures are expected for much of next week.


Near term /until 6 am this morning/...
1245 am update... clear skies continued across the region with
light wind or calm conditions...and temperatures in the middle 20s to
lower 30s inland ranging up to the lower 40s at the immediate
coast. Not expecting much more of a drop in temperatures

Am keeping an eye on a solid area of low cloudiness once again
that has been progressing steadily southward across central and
southern Vermont and central New Hampshire. The 925 mb relative
humidity on the NAM again pegs this well...and forecasts it to
nudge into extreme northern Massachusetts...north of Route 2 for the early
morning hours. If this trend continues...will increase the
cloudiness in the grids in that area into the middle-morning hours.


Short term /6 am this morning through 6 PM Sunday/...
Saturday...strong high pressure off the middle Atlantic coast remains
dominant along the eastern Seaboard. Ridge axis crosses New
England during the day. Expect general west winds early to begin to
back to SW during the afternoon. This will allow milder air to
work into the region as h925 temperatures to rise to +3.5c to +6c by late
in the day. Expect SW winds to pick up during the day...up to
10-15 miles per hour. Temperatures will rise to the upper 40s across the higher
inland terrain to the lower 50s along the coastal plain. As the
ridge shifts east during the afternoon...will start to see some high
clouds filter in from the west.

Saturday night...low pressure moves NE into Quebec with its trailing
cold front working across the Great Lakes/west PA and New York during this
timeframe. Clouds will lower and thicken during the night as mild
air continues to move across the region on SW winds. However...may
see some cooler air may be briefly trapped as the precipitation
approaches overnight across northwest Massachusetts. Have carried scattered rain showers
for western areas after midnight. Lows will fall to the
30s...except around 40 along the coast.


Long term /Sunday night through Friday/...
* chance of showers Sunday with a cold front
* a low pressure system may pass south of our area early next
* turning colder during the work week and mainly dry


Sunday through Monday...moderate to high confidence.

Surface low pressure center tracks from eastern Quebec into the
Canadian Maritimes on Sunday. A cold front trailing from the low
will move through southern New England during the day. Not a lot of
moisture associated with the portion of the front to move through
our area...enough for mostly cloudy skies and the chance for rain

There is the potential for an open wave developing to the south of
our area along the cold front...and as a result there may still be
lingering showers over the southeastern zones Sunday night and
Monday. In that area have low to slight chance probability of precipitation...otherwise dry
for most of the area with decreasing clouds expected on Monday.

Temperatures should remain warm enough for the precipitation type to be
mainly rain...although there is a slight chance for snow showers on
Sunday night or Monday if precipitation lingers. Sunday high temperatures
are cooler but still above normal with highs in the 40s. Monday's
highs are close to the 30s to low 40s.

Tuesday and Wednesday...moderate confidence.

There is still some model discrepancies during this period. However
the 12z operational GFS/European model (ecmwf) indicate mainly dry conditions for
midweek. GFS/European model (ecmwf) show the potential for a cold front/short wave
crossing the area next Wednesday...but not a lot of moisture with this
feature so continue to think result will be limited to some clouds.
Otherwise our area is in the periphery of surface high pressure.
Some GFS ensemble members show a low pressure making a pass south of
our area...but confidence continues to be low on whether this
scenario brings precipitation as far north as our area. Continuing
with the consensus drier scenario for this forecast package.

A cooling trend is expected through midweek. Looking for highs in
the middle 20s to middle 30s and lows in the middle teens to middle
20s...normal to a few degrees colder than normal.

Thursday...moderate confidence.

Our area is more under the influence of high pressure centered over
the southeastern U.S. Than a distant low pressure...passing through
Hudson Bay and Newfoundland/Labrador. Tightening pressure gradient
between these two features may make for a breezy day. Otherwise dry
and seasonably cold conditions are expected.

Friday...moderate confidence.

Models continue to indicate high pressure over our area for
Friday...but there is also the continued indication of a low
pressure system approaching from the southwest Friday night. Main
precipitation chances look to hold off until Sat...but since this is 7 days
out timing could easily change. At this time Friday is expected
to be dry...with chance probability of precipitation Friday night in western zones.


Aviation /06z Saturday through Wednesday/...
forecaster confidence levels...

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

Short term /through Saturday night/...

Overnight and Saturday...high confidence. VFR. Clear skies
through midday Saturday then high clouds increase from the
northwest during the afternoon. The only curve Ball could be an area of
low cloudiness sagging southward across southern Vermont and central New Hampshire
which could move into northernmost Massachusetts...north of Route 2 until
about middle-morning with ceilings between 3000 and 4000 feet.

Saturday night...moderate to high confidence. Mainly VFR.
Low probability of MVFR ceilings/local MVFR visibilities in scattered showers across
central-west Massachusetts/north central CT after midnight.

Kbos terminal...high confidence in taf.

Kbdl terminal...high confidence in taf.

Outlook...Sunday through Wednesday...

Sunday...moderate confidence. MVFR possible in scattered rain

Monday through Wednesday...moderate confidence. VFR.


forecaster confidence levels...

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

Short term /through Saturday/...high confidence.

Overnight and later today...winds and seas below Small Craft
Advisory criteria. West winds back to the SW and may gust to around
15 knots across the southern waters this afternoon.

Saturday night...expect SW winds to increase ahead of
approaching cold front. Winds and seas across southern waters
may approach marginal small craft criteria toward daybreak.

Outlook...Sunday through Wednesday...moderate confidence.

Sunday...Small Craft Advisory conditions are possible for Sunday
across much of the coastal waters. A cold front will move across
the waters...prompting SW winds to become northwest. The potential for
gusts to 25 kts exist ahead of and behind the front...and seas up
to 5 feet are possible on the outer coastal waters. Scattered
showers could cause some brief visibility restrictions.

Monday through Wednesday...winds and seas should remain below
Small Craft Advisory thresholds.


Box watches/warnings/advisories...
Rhode Island...none.


near term...gaf
short term...evt
long term...nmb

National Weather Service Glossary of Abbreviations