NWS Technical Forecast Discussion


000
FXUS61 KBOX 252142
AFDBOX

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

.SYNOPSIS...
A strong cold front will cross the region tonight, bringing
showers and a low chance for thunderstorms as this front passes.
Blustery conditions with more seasonable temperatures expected
for Sunday. Well above normal temperatures return Monday, and
likely remain through much of next week. A couple of weather
systems will bring periods of wet weather Tuesday into Thursday.
Colder air looks to return late next week.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Fine line of convection along the cold front moving into
eastern NY. Sct to numerous t-storms along this line where
MUCAPES 250-500 J/kg but MUCAPES 1000-1500 J/kg further south
across SE PA where greater severe wx threat exists. Hi-res
guidance indicates this line will move into western MA and
northern CT 00-02z. Strong mid level omega holds together into
W MA along with 40-50 kt LLJ so expect the line to maintain
itself as it moves into W MA early this evening but the line of
convection will begin to outrun better instability to the west
so some weakening is expected. Still expect brief heavy
downpours and gusty winds in western MA and N CT with low risk
of an isold damaging wind gust if convection can mix down
stronger winds aloft. Will have to monitor radar closely as deep
layer shear and 0-1km helicity values are quite robust and
damaging wind or even a brief tornado is favorable in this
environment if instability is greater than forecast.

As the line moves east across central and eastern New Eng
02-06z it will diminish and weaken as mid level omega weakens
rapidly and becomes fragmented. So just a few showers expected
by the time it gets to eastern MA. The rain may end as a brief
period of snow showers in the Berkshires as deeper colder air
rushes in behind the front, but moisture will be exiting as the
cold air moves in. Low risk of a coating to less than an inch in
the Berkshires.

Gusty W/NW winds develop behind the cold front which moves
through SNE 01-06z from west to east. Gusts to 30-40 mph
possible, strongest over higher terrain. Min temps by Sun
morning will range from 35 to 40 degrees, except upper 20s to
lower 30s over the higher terrain in central and western MA

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday...Mid level shortwave moves east of New Eng. Expect
partly to mosunny skies with sct-bkn strato-cu developing in
cold advection pattern. Gusty W/NW winds expected with soundings
supporting gusts to 35 mph with chance of a few gusts over 40
mph across the higher terrain where low prob a wind advisory may
be needed.

Much colder airmass Sun as 850 mb temps drop to -8 to -10C.
However, temps will likely overachieve a bit as soundings
indicate mixing above 850 mb with good downsloping. Expect
maxes ranging from the upper 30s higher elevations to the mid
40s in the coastal plain with a few upper 40s possible.

Sunday night...
Surface high moves off mid Atlc coast with ridge axis moving
east of New Eng. Winds will diminish and shift to SW overnight.
Column is dry except for some increase in mid/high level
moisture. Expect mostly clear to partly cloudy skies with mins
ranging through the 20s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Highlights...

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

Overview...

25/12Z guidance remains in rather good agreement through this
period. Mainly a nearly zonal flow aloft near New England, while
a deeper mid level trough develops over the western USA. This
would favor above normal temperatures, as well as a storm track
to our north and west. Eventually, this mid level trough will
move east, reacquainting our region to winter.

Favored a consensus approach to smooth over the less predictable
details. Timing the arrival of the aforementioned trough is not
yet set in stone, and could change with later forecasts.

Details...

Monday...High confidence.

High pressure remains to our south, maintaining a southwest flow
for our region with dry weather. Expecting another good mixing
day, with strong west winds of 40-50 kt at 925 mb. Gusty winds
should be the result.

Eventually, this high pressure moves off to the east. This
should permit a shortwave passing just south of our region to
bring a chance of showers Monday night towards the south coast.
It`s possible this wave passes even farther south, which would
keep mean drier weather Monday night.

Tuesday...High confidence.

High pressure continues to move east, as a second, more potent,
shortwave arrives later in the day. Southwest flow aloft will
help saturate the profile. Depending on when this occurs, we
could see a few flakes north of the Pike early in the day.
However, confidence remains low on any snow occurring. Will
continue the forecast of clouds and showers.

Wednesday into Thursday...Moderate confidence.

Main weather producer for this portion of the forecast still
anticipated to impact our region sometime between early
Wednesday morning and Thursday afternoon. The low pressure
should stay well to our north and west, so we`re looking at a
more wet than white forecast. South to southwest winds will
maintain temperatures well above average for late February.

Moisture content with this system is above normal for this time
of year. However, this system is progressive, so still not
expecting a large amount of rain. Very strong low level jet may
impact our region, if it comes farther north. Any heavy rainfall
could produce strong gusts. Some weak instability, so
thunderstorms are possible. Still a lot of details to work out,
but a system to watch in the coming days.

Friday and beyond...Moderate confidence.

As the cold front with the mid week low pressure passes
through our region, west to northwest winds take a hold across
our region. Mainly dry weather with a return to more wintry
temperatures. Can see a scenario where ocean-effect clouds and
snow could develop, if temperatures get low enough.

&&

.AVIATION /21Z SATURDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

Short Term /through Sunday Night/...

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 Thursday/...

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

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

Wednesday into Thursday...Moderate confidence. MVFR to possible
IFR in -SHRA/-RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

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

Tonight...Moderate confidence.
Southerly winds shift to W/NW behind a cold front 03-06z.
Increasing post-frontal winds with a few marginal gale force
gusts to 35 kt expected. Will continue gales for most of the
open waters.

Sunday...High confidence.
W/NW gusts to 30-35 kt, especially during the morning with a
gradual diminishing trend during the afternoon.

Sunday night...High confidence.
Diminishing W winds in the evening becoming SW overnight.
Another surge of 25-30 kt gusts expected toward daybreak.

Outlook /Monday through Thursday/...

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

Tuesday...High confidence. Relatively quiet boating weather
during the day. Seas build late Tuesday night

Wednesday into Thursday...Moderate confidence. More widespread
rainfall with lower vsbys possible. Increasing south to
southwest winds with building seas. Small Craft Advisories
likely, with a low risk for gale force gusts.

&&

.HYDROLOGY...
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.

&&

.CLIMATE...
RECORD HIGH TEMPS FOR YESTERDAY
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

RECORD HIGH MIN TEMPS FOR YESTERDAY
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

RECORD HIGH TEMPS FOR TODAY
BOS 65/1930 * broken 69 degrees
PVD 69/1976
BDL 70/1976 * tied 70 degrees
ORH 64/1976 * broken 65 degrees

RECORD HIGH MIN TEMPS FOR TODAY
BOS   46/1891
PVD   45/1930
BDL   45/1930
ORH   37/1996, 1984, 1976

DEW POINTS OF NOTE FOR YESTERDAY
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

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Warning from 2 AM to 11 AM EST Sunday for ANZ231>235-251.
     Small Craft Advisory from 11 PM this evening to 7 PM EST
     Sunday for ANZ230-236.
     Small Craft Advisory from 11 PM this evening to 10 PM EST
     Sunday for ANZ237.
     Gale Warning from 2 AM to 2 PM EST Sunday for ANZ250-254>256.

&&

$$
SYNOPSIS...Belk/KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...Belk
AVIATION...Belk/KJC
MARINE...Belk/KJC
HYDROLOGY...Staff
CLIMATE...Staff

NWS BOX Office Area Forecast Discussion



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