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 261101
AFDBOX

Area Forecast Discussion
National Weather Service Taunton MA
601 AM EST Sun Feb 26 2017

.SYNOPSIS...
High pressure centered south of New England brings dry weather
today and Monday. Cold air briefly visits for today, then milder
air moves back in on Monday. A couple of weather systems will
bring periods of wet weather Tuesday into Thursday. Colder air
returns late next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

6 AM Update...

Overall trend in the forecast remains on track for today. Good
mixing across the area with strong LLJ over the region. Some
spots have reached about 35 mph with higher elevations closer to
40 mph. Anticipate these gusty winds to continue through the
morning hours as CAA continues to poor into the region.

Northwest flow aloft with meager moisture in the low levels.
Cannot rule out a few flakes across western MA in lake effect
snow plume. Low level moisture does increase over CT later in
the day, but have low confidence at this time if anything will
materialize.


Previous Discussion...

Upper shortwave moves east of our area this morning. Colder
drier air moves in on northwest winds. There is sufficient cold
advection to support mixing up to 850 mb. Winds in this layer
reach 30 knots, so expect gusts of 25-30 knots during the day.
The mixing diminishes toward sunset, by which point winds will
diminish.

Dry air through most of the airmass today. Cross sections do
show lingering moisture 850-900 mb, which should be enough to
form some diurnal clouds. Expect partly to mostly sunny skies.

Temperatures at 850 mb cool to -8C over the Southeast and -10C
over northern and western MA. This supports max sfc temps in the
upper 30s to mid 40s. With enough sunshine, mixing may extend a
little higher than 850 mb and allow sfc temps to reach the upper
40s in some spots.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
Tonight...High Confidence.

Surface ridge remains in place to our south. A shortwave moving
across Canada pushes a weak cold front to the Canadian border
and tightens the pressure gradient over New England, especially
northern New England. The gradient over Southern New England
will be lighter, and more conductive to radiational cooling.
With dew points in the teens, min temps in the coldest spots
will likely nudge into the teens, while the remaining areas
will have mins in the 20s.

Monday...High Confidence.

High pressure remains to our south, with surface winds trending
west-southwest. Diurnal heating will again create a mixed layer
to around 850 mb. Winds in this layer reach 30 knots, and GFS
suggests some potential for 35 knots just above the layer.
Expect gusty WSW winds. Temperatures at 850 mb are forecast at
-3C to -5C, which would support max sfc temps in the 50s. The
WSW wind may keep temps a little cooler at the south coast.

&&

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

* Above average temperatures for next week
* Widespread showers possible Tuesday through late Wednesday
* More seasonable conditions return on Friday

Pattern Overview...

00z models and ensembles remain in generally good agreement and a
consensus approach was used. Overall, frontal boundary is forecast
to progress through the East during the Wed-Thur timeframe. Upper
level trough will remain over the region into next weekend resulting
in seasonable conditions. Guidance continues to struggle with
strengthen and timing of each wave so an average solution was
preferred given the jumpiness in timing/track over the past several
days.

Details...

Tuesday...High confidence.

Bermuda high will build south of the region on Tuesday as upper
level trough moves over the Plains, putting the region in
southwesterly flow. Upper level warm front will approach from the
south during the day resulting in showery weather. Still some issues
on surface temps and how far north the warm front will lift, so
cannot rule some wet flakes north of the Pike, but confidence is low
on this occurring. Guidance continues to show the higher theta-e
plume moving to the region during the latter half of the day and
with an approaching upper level jet, could see some heavy rain late
Tuesday as surface low develops. Still timing issues with this
system but something to keep an eye on.

Temperatures will be above normal with highs rebounding back into
the low to mid 50s.

Wednesday into Thursday... Moderate confidence.

Main weather producer will occur Wednesday into Thursday. Still some
uncertainty on the timing and location of the surface low.

Southern New England will remain in the warm sector starting
Wednesday as upper level trough approaches from the west. This
system will drag a cold front across the region by Thursday. Stout
southwesterly LLJ near 60 kts will develop ahead of the system. This
will tap into Gulf moisture, pushing PWAT values 2-3 STD above
normal for this time of year. Moisture flux will be on the increase
as the frontal system approaches so anticipate a period of moderate
to perhaps heavy rain on Wednesday into Wednesday night. Lapse rates
will also steepen to 7 c/km as well as LI dropping below 0 resulting
in the potential for thunder. While the whole period don`t be wet,
as dry air intrudes in the mid-levels at times, appears that a good
slug of rain can fall. Will need to monitor this system as stout mid-
level ridge to the south could either slow the system down or push
the better dynamics to the north and west of southern New England.
Regardless have high confidence that precipitation will fall and
temperatures will be above average on Wednesday into Wednesday
night.

Cold front will sweep through during the the day on Thursday
resulting in temperatures falling throughout the day. Still timing
issues on FROPA but appears that gusty winds will follow suite as
model sounding indicating good mixing.

Friday and beyond... Moderate confidence.

As the cold front passes through, northwest winds take a hold of the
region. Models continue to indicate the potential for a clipper
system on Friday/Saturday. This will bring reinforcing cold air to
the region allowing temperatures to fall back towards seasonable.
Good mixing and cold air over the ocean may result in ocean effect
snow showers over the weekend before another clipper system comes
through towards the end of the weekend.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels...

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

Short Term /through Monday/...

Today... High Confidence.

VFR through the period. Enough moisture at 4000-5000 feet to
support scattered to broken cigs at that level. Winds up to this
level will reach 30 to 35 knots, supporting surface gusts to
those speeds during the day. Expect winds to diminish by late in
the day.

Tonight... High Confidence.

VFR with diminishing wind. Trend to light winds in the interior
overnight.

Monday... High Confidence.

VFR with WSW winds gusting to 30 knots.

KBOS TAF...VFR. Gusty NW winds to 30 knots. High confidence in
TAF.

KBDL TAF...VFR. Gusty NW winds to 25 knots. High confidence in
TAF.

Outlook /Monday Night through Thursday/...

Tuesday into Wednesday...Moderate confidence. Periods of -RA through
the period will result in MVFR/IFR conditions. Cannot rule out LIFR
in fog during the overnight hours.

Thursday...Moderate confidence. Improving conditions from west to
east during the latter half of the day. Blustery westerly winds
are possible.

&&

.MARINE...
Forecaster Confidence Levels...

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

Short Term /through Monday/...High confidence.

Went ahead and added Boston Harbor into the gale warning as
gusts have been between 33-36kts over the past hour. Model
soundings continue to show these types of gusts into the mid-
morning.

Today...NW winds gusting 30-35 knots, slowly diminishing in the
afternoon. Seas linger at 5 to 8 feet on the exposed waters most
of the day. A Gale Warning is in effect for most of the waters,
and we will maintain this. Small Craft Advisory in effect for
Boston Harbor, Narragansett Bay, and Block Island Sound.

Tonight...
Diminishing winds turning West and possibly SW overnight. Gusts
near 20 knots. Diminishing seas overnight with lingering 5 foot
heights on the outer waters.

Monday...

WSW winds with gusts 25 to 30 knots. A Small Craft Advisory will
be needed on at least some of the waters.

Outlook /Monday Night through Thursday/...

Tuesday...Moderate confidence. Improving conditions across the
waters as high pressure passes southward. Warm frontal passage late
Tuesday could drop vsbys in rain and fog.

Wednesday into Thursday...Moderate confidence.  Approaching system
from the west will push a cold front through on Thursday, increasing
both seas and winds during the period. Heavy rain and thunder is
possible lowering vsbys. There is the potential for southerly gales
across the waters Wed night and northwesterly gales on Thursday
behind the cold front.

&&

.HYDROLOGY...
Rising water levels, partly from rain overnight but also from
snowmelt in Northern New England. A couple of rivers in the CT
River Valley rose above alert stage during the night, but
crested below warning stage. Others crested below alert stage.

There is still plenty of water moving downriver from the
snowpack. We will need to monitor water levels across southern
New England for a while this week.

&&

.CLIMATE...
RECORD HIGH TEMPS FOR YESTERDAY
BOS  69 * breaks old record 65/1930
PVD  63 * no record
BDL  70 * tied old record 70/1976
ORH  65 * breaks old record 64/1976

RECORD HIGH MIN TEMPS FOR YESTERDAY
BOS  49 * breaks old record 46/1891
PVD  47 * breaks old record 45/1930
BDL  41 * no record
ORH  40 * breaks old record 37/1996, 1984, 1976

DEW POINTS OF NOTE FOR YESTERDAY
BOS   Max Dew Point 56 is highest for date. Previous high 52/1985
PVD   Max Dew Point 54 is highest for date. Previous high 51/1965
BDL   Max Dew Point 58 is highest for date. Previous high 48/1984
ORH   Max Dew Point 55 is highest for date. Previous high 47/1985

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Warning until 11 AM EST this morning for ANZ230>235-251.
     Small Craft Advisory until 7 PM EST this evening for ANZ236.
     Small Craft Advisory until 10 PM EST this evening for ANZ237.
     Gale Warning until 2 PM EST this afternoon for ANZ250-254>256.

&&

$$
SYNOPSIS...WTB/Dunten
NEAR TERM...WTB/Dunten
SHORT TERM...WTB
LONG TERM...Dunten
AVIATION...WTB/Dunten
MARINE...WTB/Dunten
HYDROLOGY...Staff
CLIMATE...Staff



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