Area Forecast Discussion
Issued by NWS Boston, MA

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FXUS61 KBOX 251759

Area Forecast Discussion
National Weather Service Taunton MA
1259 PM EST Sat Feb 25 2017

Mild air remains over the region today.  A strong cold front
will cross the region tonight, bringing showers and a low
chance for thunderstorms as this front passes. Blustery
conditions with temperatures close to seasonal normals expected
for Sunday and above average on Monday. A couple of weather
systems will bring periods of wet weather Tuesday into
Thursday. Colder air looks to return late next week.


10 AM update...
Fog is lifting and sunshine developing across portions of E MA
and RI. Further west, stratus lingering across the interior.
Cross sections indicate abundant low level moisture across
western New Eng where clouds should prevail through the
afternoon although some breaks of sun are possible. More
sunshine expected in eastern New Eng. Much of the region will
remain dry as leading edge of showers assocd with the cold front
and lead shortwave not expected to move into western MA until
early evening. Lowered PoPs and have just low chc pops in
western MA for late today. Also slight chc pops Cape/Islands
late today as models indicate some elevated instability moving
up from the ocean so can`t rule out an isold shower here.

Temps already mid 50s to lower 60s and should see maxes top out
65-70 degrees this afternoon, cooler south coast with southerly
flow. Best chance for records today are at BOS and ORH.


The cold front arrives in the Hudson Valley around 6-7 pm and
crosses into western New England around 8-9 pm...Central
sections 9-10 pm...and eastern New England 10 pm to midnight.
This front will be supported by the sharp upper shortwave.
Airmass stability will decrease through the evening...for
example, Totals will climb into the lower 50s. This supports the
concept of sufficiently unstable conditions for a few
thunderstorms as the cold front approaches and moves through.
The greatest risk for tstms would be in Western MA and Western
CT where the low level inflow is least maritime.

Low level southerly winds will increase during the afternoon, so
that by evening we expect a 50-knot jet at or below 5000 feet.
Confidence is not high as to how much of that wind may be
brought to the surface in gusts during showers/tstms, but its
presence suggest a chance of strong wind gusts this
evening...possibly isolated damaging wind. Greatest risk would
again be in western areas early tonight.

Precipitable water fields continue to advertise values a little
over an inch, which is well above normal. But this is a narrow
and fast- moving zone, so while showers may be briefly strong,
total amounts should be 0.50 inches or less.

Colder air rushes in behind a cold front. It will be a race
between the cold air and the departing showers, but a brief
changeover to snow is possible at the end. Any accumulations
should be limited, generally less than an inch and mainly over
the higher terrain of the Berkshires and Worcester Hills.

Finally, the colder air advection behind the front will bring
mixing of strong WNW winds aloft to the surface late at night.
Wind gusts at that time will have a potential of reaching 30-35

Sunday...High confidence.

The shortwave trough moves offshore Sunday morning. The last of
any pcpn should end by that time. So Sunday shapes up to be a
dry day as high pressure builds in from the west.

Cold advection continues during the day. Mixing due to this
advection will tap winds aloft of 25-35 knots and possibly a
few areas of 40 knots. These winds will diminish during the
afternoon as the high pressure area approaches.

Temps aloft chill behind the front, but hover on Sunday at
levels that support sfc max temps around 40 or the lower 40s.
Given the morning temps starting in the 30s, we have forecast
max temps in the upper 30s to mid 40s.



* Above average temperatures for next week
* Widespread showers possible Wednesday/Thursday
* More seasonable conditions return on Friday

Pattern Overview...

The 00z models and their ensembles have been in generally good
agreement through the period with the GFS just a bit displaced.
Therefor used a blend of the ensembles for the bulk of the
forecast. Overall, zonal flow over the region as Bermuda high
begins to build in the mid-levels. By mid-week the western
trough is forecast to transition into the east as a surface
front will move from the Great Lakes towards the Northeast
around Wed/Thurs. Still some issues with the timing of the front
as a surface wave may develop along it, which could slow it
down a bit. This appears to be more inline with the EC/GEFS and
ECENS. Otherwise, northwest flow behind the front could result
in several clippers for next weekend.


Monday... High confidence.

Westerly flow across the region as high pressure builds south of the
region. Developing LLJ of near 40 kts will develop with high
pressure to the south and quick moving wave to the north. This will
make conditions a bit gusty at times. As surface high pressure moves
farther to the east, winds will begin to back resulting in WAA.
Surface temps could reach into the mid 50s on Monday with full
mixing. Otherwise dry weather will prevail.

Tuesday...High confidence.

More of a transition day for Tuesday as high pressure moves eastward
as upper level trough approaches. Southwest flow aloft will help
saturate the profile. Guidance does show a weak wave developing a
coastal low but appears to be just to far east to bring significant
rainfall to the region. Depending on when this occurs, we could see
a few flakes north of the Pike but confidence is low on this
occurring. For now expect a few showers and clouds on Tuesday.

Wednesday into Thursday... Moderate confidence.

Main weather produce for the long term will occur Wed into Thursday
as upper level trough approaches the region. Warm front ahead of the
system will bring some showers to the area as temperatures rise well
above average.

Upper level low will move from the Plains towards northern Maine.
This will drag a potent cold front through the region. Good
agreement amongst the guidance with this system, just some issue`s
with the exact timing of the front. Trended towards the slower side
as there is the potential for a secondary low to develop along the
front. This is more inline with the ensembles.

This is an anomolous system with PWATs 3 STD above normal as Gulf
moisture is tapped out ahead of the frontal passage. Heavy precip is
a possibility if secondary low does develop bringing the better
dynamics over southern New England. Also have noticed that there is
a potent southerly LLJ out ahead of this system with 925 mb LLJ
increasing to near 50-60 kts. If heavy rain does develop then we
could tap into these stronger winds as the system moves through.
Lastly appears that there is some elevated instability so have kept
with iso thunder in the forecast. Still a lot of details to work
out, but a system to watch in the coming days.

High confidence in above average temperatures with a non-diurnal
trend Wednesday night. Went several degrees above guidance and could
still be a bit low.

Friday and beyond... Moderate confidence.

As the cold front passes through, northeast winds take a hold of the
region. Models appear to be inline with a few shortwaves/clipper
systems moving through the flow. So some snow showers are certainly
possible as temps drop back to seasonable.


Forecaster Confidence Levels...

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

Short Term /through Sunday/...

Through 00z...Mix of VFR/MVFR cigs this afternoon, but IFR
stratus and patchy fog expected to develop along the south coast
and Cape/Islands toward 00z.

Tonight...Moderate confidence.
Widespread showers and isold t-storms will move through
western New Eng 00-02z then diminish as it moves into eastern
New Eng 03-06z. Brief heavy rain and gusty winds possible with
any t-storms in western New Eng. Precip may end as brief snow
showers in the Berkshires 03-06z. IFR/MVFR cigs with patchy
fog will improve to VFR after cold fropa and wind shift to W/NW
02-06z. W/NW gusts to 30 kt developing after the wind shift,
with G35 kt possible over higher terrain.

Sunday...High confidence.
VFR with sct-bkn cigs 4-5k ft. W/NW gusts to 30 kt, higher gusts
possible over higher terrain in the morning.

Sunday night...High confidence.
VFR. Diminishing W wind becoming SW overnight.

KBOS TAF...Moderate confidence through this evening, then high
confidence in improving conditions overnight.

KBDL TAF...Moderate confidence through this evening, then high
confidence in improving conditions late this evening.

Outlook /Monday through Wednesday/...

Monday...High confidence. VFR with westerly wind gusts near 20-30

Tuesday...Moderate confidence. Generally VFR with MVFR conditions
possible south of the Pike.

Wednesday...Moderate confidence. MVFR to possible IFR in -SHRA.


Forecaster Confidence Levels...

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

Short Term /through Sunday/...High confidence.

Today...High confidence.

Increasing southerly winds through the day, with gusts to 25
knots mid to late afternoon. Seas will increase through the day
with 5 to 6 foot heights on the southern waters by mid to late

Tonight...Moderate confidence.

A cold front sweeps across the waters the first part of the
night. This will bring showers and a widely scattered
thunderstorm. The showers may tap strong winds at 2000 to 4000
feet above the surface and bring them to the surface in strong
southerly wind gusts. Seas build to 5-8 feet on the exposed
waters of the south and the outer waters of the east.

Behind the front, winds shift from the West or West-Northwest
and bring cooler air. Winds late tonight should gust 30 to 35
knots. Seas will continue at 5 to 8 feet.

Sunday...High confidence.

West-Northwest winds continue to gust 30 to 35 knots during the
morning and early afternoon. Winds may slowly diminish during
the later afternoon. Seas will linger at 5 to 8 feet on the
exposed waters.

Outlook /Sunday Night through Wednesday/...

Monday...High confidence. Improving conditions on Monday with gusts
near 20 kts and seas beginning to relax as high pressure builds over
the southern waters.

Tuesday into Wednesday...Low confidence. Wind and seas will be below
SCA for Tuesday. Approaching system to the west could see lower
vsbys in rain and fog. Seas build late Tuesday night into Wednesday
as low pressure system approaches. There is the potential for
southerly gales across the waters.


We will need to monitor rising water levels across southern New
England into early next week. Much, if not all, of our snowpack
has, or will have, melted. There is still much more snowpack
upstream, over northern new England, that will push into the
headwaters and head downstream. Some river levels could approach
action stage.


BOS 73/2017 - previous record 70/1985
PVD 72/1985 - topped off at 71 degrees (no record)
BDL 73/1985 - topped off at 72 degrees (no record)
ORH 69/2017 - previous record 67/1985

BOS   49/1930 - bottomed out at 46 (no record)
PVD   45/2017 - ties previous record of 45/1984
BDL   43/1981 - bottomed out at 42 (no record)
ORH   48/2017 - previous record 46/1985

BOS 65/1930 * broken 67/2017
PVD 69/1976
BDL 70/1976
ORH 64/1976

BOS   46/1891
PVD   45/1930
BDL   45/1930
ORH   37/1996, 1984, 1976

BOS   Max Dew Point 54 ties highest for date set in 1985
PVD   Max Dew Point 53 is highest for date. Previous high 50/1990
BDL   Max Dew Point 54 is highest for date. Previous high 49/1990
ORH   Max Dew Point 53 is highest for date. Previous high 48/1985


MARINE...Gale Warning from midnight tonight to 7 PM EST Sunday for
     Small Craft Advisory from midnight tonight to 7 PM EST Sunday
     for ANZ230-236.


LONG TERM...Dunten
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