Area Forecast Discussion
Issued by NWS Boston, MA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBOX 191134
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
634 AM EST Fri Jan 19 2018

.SYNOPSIS...
Dry and seasonably cold conditions today, then a warming trend
this weekend with continued dry weather. A storm system will
bring the potential for heavy rain and strong coastal winds late
Monday night into Tuesday, but there is a risk of some wintry
mix/ice across the interior late Monday and Monday night.
Blustery, dry and seasonably cold weather will follow Wednesday
and Thursday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
630 AM update...

Mid level shortwave exits this morning. Few flurries to the
north but this activity moves off the Maine coast. Just an area
of clouds moving across northern MA to contend with this
morning, otherwise mostly sunny skies. Some high clouds move
in from the west later today with lower strato-cu developing
over the Berkshires.

Expect highs mostly in the mid 30s today, cooler higher terrain.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Tonight...

Expect a general W wind flow in place as large high pressure
moves off the mid Atlantic and Carolina coast.

As winds become mainly zonal across the region, low level wind
data indicating a 35-40 kt jet up to H9 which increases to 45-50
kt by around 12Z Sat. However, some question on the low level
lapse rates and whether it will mix down. Noting very good low
level lapse rates at H95 especially across the southern waters
after 06Z Sat. Looks like will see a good gradient in place
which will drive the W winds, which will become gusty along the
immediate coast and especially across the waters after
midnight. Better shot will be across the waters.

Temps will fall to the mid 20s to around 30 early tonight, then
will level off or even rise a bit after midnight on W-SW winds
which will gust up to around 20-25 kt along the S coast, Cape
Cod and the islands.

Saturday...

Still noting strong low level jet crossing the immediate coast
and across the coastal waters during Sat, upwards to 45-50 kt
which could mix down with the good low level gradient in place.
Will see westerly wind gusts up to 20-25 kt across the higher
inland terrain, and up to 25-35 kt along the S coast, Cape Cod
and the islands. May need wind advisories for portions of the S
coast.

Another weak H5 short wave moves across northern New England.
Not expecting any precip with it, but could see mid and high
clouds cross central and northern Mass during the day. Good warm
air advection sets up, with H85 temps up to +5C to +7C across
central and southern areas Sat morning on W-SW winds, though
cooler air may work southward during the afternoon as H85 temps
fall.

Have forecasted highs in the upper 40s to lower 50s across the
lower CT valley to the coastal plain, but will be a bit cooler
along the S coast with the gusty winds off the colder waters as
well as over the higher inland terrain.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...

Highlights...

* Dry and mild Sunday
* Risk of some wintry mix/ice in the interior late Mon/Mon night
* A period of heavy rain and strong coastal winds likely late Mon
  night into Tue
* Blustery and seasonably cold Wed/Thu

Sunday...

Less wind Sunday with NW flow but continued mild with temps in the
40s across much of the region. Expect mostly sunny skies as axis of
mid/high level moisture across northern New Eng. Turning colder Sun
night as cold front drops south across the region with strong high
pres building across Canada and ridging nosing down into New Eng.

Monday into Tuesday...

Developing warm advection pattern ahead of warm front will lead
to some light precip developing Mon afternoon and more likely
Mon night. With high pres to the N/NE and good cold air damming
signature, thermal profiles should be cold enough for some
light snow/mix/ice in the interior with minor accum possible. A
brief mix is also possible at the onset in the coastal plain.

However, the main event will likely be late Mon night and especially
Tue as potent mid level trough/low lifts NE across the Gt Lakes.
Ptype mostly rain but ECMWF has low level cold air lingering into
Tue morning across interior MA where some wintry mix/ice may
continue before precip quickly changes to rain. Models indicate a
strong pre-frontal low level jet which will advect high PWAT airmass
northward into New Eng. PWAT and low level wind anomalies around
+2SD which suggest potential for heavy rainfall and gusty winds. As
previous forecaster noted, some convection also possible given steep
mid level lapse rates. However, system is progressive which should
limit excessive rainfall potential. Still, deterministic
GFS/ECMWF/GGEM all indicate potential for 1"+ QPF and EPS has
moderate probs of 1 inch rainfall. Temps may reach into the 50s in
the coastal plain with 40s elsewhere.

Wednesday and Thursday...

Blustery and colder weather expected but dry conditions with NW
flow. GEFS and EPS mean 850 mb temps around -8C Wed and -10C Thu so
near seasonable temps expected, perhaps a bit below normal Thu.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

Short Term /through Saturday/...High confidence.

Today...Mainly VFR. Some low end VFR/MVFR cigs developing over
the Berkshires.

Tonight and Saturday...VFR. W-SW winds increase late tonight
and Saturday morning. May see sustained winds up to 20-25 kt and
gusts up to 30-35 kt, with best chance along the S coast, Cape
Cod and the islands as well as the inland higher terrain.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...High confidence in TAF.

Outlook /Saturday Night through Tuesday/...

Saturday Night: VFR. Breezy.

Sunday through Sunday Night: VFR.

Monday: Mainly VFR, with local MVFR/IFR possible. Chance RA,
chance SN in the afternoon.

Monday Night: Mainly MVFR, with areas IFR possible. Breezy. RA
likely. Chance SN, FZRA, PL interior.

Tuesday: Mainly MVFR, with local IFR possible. Windy with gusts
to 30 kt. RA.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Saturday/...High confidence.

Winds have diminished briefly early this morning across the
waters so have ended Small Crafts through the morning.

Strong low level wind jets will cross the waters starting
around midday today through Saturday. With the W-SW winds in
place, will see winds increase especially late tonight and
Saturday.

Have issued Small Craft Advisories from this afternoon through
around midnight tonight, which will transition to Gale Watches
for the outer waters as well as the southern bays and sounds
late tonight and Saturday. Could see gusts up to 35-40 kt in
the gale watch areas. Seas may build as high as 6-9 ft, highest
across the southern waters during Saturday.

Outlook /Saturday Night through Tuesday/...

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Local rough seas.

Sunday through Monday: Winds less than 25 kt. Seas locally
approaching 5 ft.

Monday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Rain likely.

Tuesday: Low risk for gale force winds with gusts up to 35 kt.
Rough seas up to 12 ft. Rain.

&&

.HYDROLOGY...
A Flood Warning remains in effect for the Connecticut River at
Middle Haddam, where ice jams are causing river fluctuations.

For details on specific area rivers, including observed and
forecast river stages, please visit the Advanced Hydrologic
Prediction Service (AHPS) graphs on our website.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Watch from Saturday morning through Saturday afternoon
     for ANZ232>235-237-250.
     Small Craft Advisory from 1 AM to 8 AM EST Saturday for
     ANZ232>234.
     Small Craft Advisory from 7 AM to 4 PM EST Saturday for ANZ230.
     Small Craft Advisory from 1 AM to 5 PM EST Saturday for ANZ231.
     Small Craft Advisory from 2 AM to 4 PM EST Saturday for ANZ236.
     Small Craft Advisory from 10 PM this evening to 8 AM EST
     Saturday for ANZ235-237.
     Small Craft Advisory from midnight tonight to 8 AM EST
     Saturday for ANZ250.
     Small Craft Advisory from 2 AM to 7 PM EST Saturday for ANZ251.
     Gale Watch from late tonight through Saturday evening for
     ANZ254.
     Small Craft Advisory from noon today to 5 AM EST Saturday for
     ANZ254.
     Gale Watch from late tonight through Saturday evening for
     ANZ255-256.
     Small Craft Advisory from noon today to 3 AM EST Saturday for
     ANZ255-256.

&&

$$
SYNOPSIS...KJC/EVT
NEAR TERM...KJC/EVT
SHORT TERM...EVT
LONG TERM...KJC
AVIATION...KJC/EVT
MARINE...KJC/EVT
HYDROLOGY...


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.