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Area forecast discussion 
National Weather Service Taunton Massachusetts
409 am EDT sun Mar 29 2015

Synopsis...
high pressure builds over the eastern USA today bringing dry
weather. A cold front sweeps down from Canada and crosses New
England Monday. Fast moving area of low pressure passes south of
New England Tuesday night and Wednesday bringing more light rain
and/or snow showers. A more significant storm may approach late in
the week.

&&

Near term /until 6 PM this evening/...
through 8 am...
back edge of the clouds is moving southeast across southern New
England. Expect a clearing trend during this time with south
coastal areas the last to clear. Some clouds may linger on the
islands and South Coast a little past 8 am.

Today...
high pressure centered over the Middle Atlantic States will bring dry
weather to the eastern USA. Could be some lingering clouds over
the South Coast and islands but these should clear out middle to late
morning. Cold temperatures aloft this morning should moderate during the
afternoon. Mixing to 925 mb would support maximum temperatures in the middle 30s
to around 40.

&&

Short term /6 PM this evening through 6 PM Monday/...
cold front and upper trough move through the Great Lakes tonight
and then swing across New England on Monday. Left exit region of
the supporting upper jet moves in toward sunrise. Surface low
pressure passes to our north and swings the cold front across our
area during the afternoon. The moisture column extends up to 600
mb with about 10 mb/hour of lift.

Expect showers along/ahead of the front. Based on upper
jet...support for showers would start near sunrise in the west and
middle to late morning in the east. The cold frontal passage would be around
midday/early afternoon west and middle to late afternoon east.
Temperature profiles might allow snow initially but expect warming
during the morning that will change this to rain. Any snow
accumulations should be limited to an inch or less.

Cold advection mixing behind the front May Draw upon 35 knot winds
aloft bringing them to the surface in middle to late afternoon gusts.
We will trend forecast gusts higher with this package but stay a
little below this full potential...roughly 25 to 30 knots.

&&

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

* Alberta clipper moves through Tuesday night into Wednesday
* moderating Spring-like temperatures late this week
* increasing chances for precipitation sometime during the Easter weekend

Overview...

Northwest flow to start over the region Monday night lasting into
next weekend. Several shortwaves will be riding through this flow
allowing for the active pattern to continue. 00z model guidance is
in good agreement some discrepancies on the Tuesday night system and
again on the Thursday/Friday timeframe. 00z NAM seems to be the
farthest north on the Alberta clipper moving Tuesday night compared
to the rest of the guidance. Threw the NAM out and did a blend of
the GFS/CMC which gives a good run in the middle. For the end of the
week...the ec becomes more amplified compared to the progressive GFS
and has slowed down by 24 hours. Trended this portion of the
forecast towards wpc as there is to much uncertain still.
Temperatures will remain at or below average for this long term
expect by the Thursday into Sat timeframe where a brief warm-up...may
occur.

Details...

* Monday night into Tuesday...high confidence.

Cold front will push offshore by Monday night allowing for cold air advection to
stream into the region. Expect westerly winds to remain gusty
overnight...near 25-30 miles per hour.

Tuesday will be mostly dry as southern New England is squeezed
between two systems. Winds will continue to gust through the day.
Temperatures will be in the middle to upper 40s but with the wind...it will
feel like the upper 30s. Clouds will be on the increase throughout
the day as next system approaches.

* Tuesday night...moderate confidence.

Next shortwave will quickly dive through the flow from Canada and
move just south of southern New England. The latest ec has trended
towards the GFS in pushing this system farther south impacting the
mid-Atlantic. However the NAM drags the clipper right over southern
New England where the CMC is close to the ec ensembles. Overall
believe that locations along and south of the Pike have the best
chance to see precipitation. Models are similar on the timing bringing
precipitation in overnight and pushing out by late Wednesday morning. This will
allow for temperatures to be cool enough for snow showers. Will need to
continue to watch the trends with this system since it could produce
a quick 1-2 inches of snow across the area.

* Wednesday into Thursday...moderate confidence.

Weak ridge will build behind the clipper system Wednesday into Wednesday night.
This will allow for strong high pressure to build over southern New England. Latest
trends in the guidance is most of the day on Thursday will stay dry
as high pressure is slow to break down. Temperatures will be on the
increase with middle 40s on Wednesday and low 50s on Thursday as warm air advection
increase ahead of approaching system.

* Thursday night into Saturday...low confidence in timing. Moderate
confidence in precipitation occurring.

High pressure will move offshore as a low pressure system moves
across southern Canada. This system will drag a cold front across
the area either Thursday night/GFS or Friday/ec.. appears there
could be a few waves that may develop along this front so decided to
blanket this time frame with chance probability of precipitation and hopefully within the next
24 hours can put better detail into the forecast. Regardless appears
temperatures on Friday will be above average allowing from spots to finally
get about 60f. Temperatures will turn colder behind the frontal passage by
Sat or sun.



&&

Aviation /08z Sunday through Thursday/...
forecaster confidence levels...

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

Short term...tonight through Sunday night

Today...VFR. Patchy 1500 foot ceilings possible along the South Coast
before 12z this morning.

Tonight...VFR. Increasing clouds after midnight but above 3000
feet.

Monday...VFR. Brief MVFR possible in scattered snow showers early
then scattered rain showers. Cold front moves through from west to
east during midday to mid-afternoon. Gusty west winds behind the
front may reach 25-30 knots.

Kbos taf...high confidence.

Kbdl taf...high confidence.

Outlook...Monday night through Thursday...high confidence.

Monday night into Tuesday...lingering MVFR will increase to VFR.
Gusty west wind between 20-30 kts.

Tuesday night...VFR for most of the period. May see MVFR south of
Mass Pike in rain/snow showers.

Wednesday into Thursday...VFR.



&&

Marine...
forecaster confidence levels...

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

Short term...tonight through Sunday night...

High confidence.

High pressure builds over the waters today bringing diminishing
wind. Seas will subside through the day but with 5-8 foot seas
initially on the exposed waters and lingering 5 foot seas on the
outer waters late in the day. Small craft advisories will continue
on most waters this morning but should expire during the afternoon
and evening as the seas subside.

Cold front approaches on Monday...swinging across the waters
during the afternoon and evening. Expect south-southwest winds to
increase during the day Monday with potential frequent gusts
25-30 knots. Seas will also build with 5-8 foot heights possible
by afternoon. Small Craft Advisory may be needed again at that
time.

Outlook...Monday night through Thursday...moderate confidence.

Tuesday...high pressure will be over the area however winds will be
gusty reaching near 30kts. This will keep seas up above Small Craft Advisory.

Tuesday night...quick moving system will move over southern waters.
This will keep both seas and winds above Small Craft Advisory on Tuesday night.

Wednesday into Thursday...high pressure will follow on Wednesday allowing
for seas and winds to relax.

&&

Box watches/warnings/advisories...
CT...none.
Massachusetts...none.
Rhode Island...none.
Marine...Small Craft Advisory until 3 PM EDT this afternoon for anz231-
235-237-251.
Small Craft Advisory until 10 PM EDT this evening for anz250-
254>256.

&&

$$
Synopsis...wtb/dunten
near term...wtb
short term...wtb
long term...dunten
aviation...wtb/dunten
marine...wtb/dunten

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