Somerville, Massachusetts 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

906
FXUS61 KBOX 100824
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
324 AM EST Sun Nov 10 2024

.SYNOPSIS...

Increasing clouds today ahead of a cold front that brings light
accumulations of rain to the region overnight tonight. Warm on
Monday. Another Cold front brings cool and gusty winds again on
Tuesday. Less windy with seasonable temps Wednesday. Trending
drier for Thursday into the weekend.

&&

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

High pressure centered over southern New England overnight shifts to
the east today as brief period of mid level ridging builds over the
region. Surface flow shifts to the southwest today thanks to surface
high pressure to our southeast, which will yield a modest increase
in high temperatures compared to Saturday; widespread highs in the
50s are expected with a few areas across SE MA reaching for 60F this
afternoon. Dewpoints will exhibit a marked increase after 21Z as
PWATs jump from less than 0.5" to over an inch prior to 00Z tonight.
While high cloud cover will increase steadily through the day as
cold front approaches from the west, don`t expect any shower
activity associated with the front to occur prior to 00Z as any
early returns on radar will be up against substantial initial
dewpoint depressions; particularly north of the MA Turnpike
where these depressions will be as high as 20F.

Given dry airmass in place for much of the day and breezy southwest
winds, again, a Red Flag warning is once again in place due to
elevated fire weather concerns. Several new fires started on
Saturday, and residents of southern New England should exercise
extreme caution as any fires that do start have the potential to
spread very quickly.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...

Tonight...

Our first chance for a modest accumulation of rainfall comes
overnight tonight as cold front sweeps across the region. As
mentioned in the short term, it will take some time for the column
to saturate enough for rain to actually fall, but with dewpoints
climbing into the 50s by daybreak across the south coast, do expect
a solid period of light rain overnight, particularly south of the MA
Turnpike. Unfortunately, models continue a downward trend with
expected QPF with several members of the HREF ensemble forecasting
just a few hundredths of an inch of rain across central and
northeastern MA, with amounts closer to 0.3" along the South Coast.
At this point, any rain is good rain, but widespread rain totals of
0.25" or less will do little to quell the fire weather concerns
southern New England has faced over the last several weeks.

Strong 925mb jet develops across southeastern SNE overnight, with
45kt to 50kt winds aloft draped along and south of the I-95
corridor. Winds are expected to be greatest, gusting to as high as
30-35kt, across the waters and the Cape where better mixing is
expected thanks to dewpoints approaching 60F, but a developing
inversion over much of interior SNE should keep the worst of the
winds isolated to the South Coast/Cape/Islands.

Monday...

Precipitation wraps up around 12Z Monday morning save for a few
showers across the Cape through 15Z. Synoptically, its a transient
day as we remain on the western edge of slight mid level ridging,
This pattern wont stick around for long as another shortwave looks
moves into Upstate NY by Monday afternoon.

Monday looks to be the warmest day of the week as cooler air aloft
lags behind departing precipitation. Most guidance depicts 18Z 850mb
temps between 7-9C, which will mix efficiently to the surface thanks
to developing downsloping, westerly flow. Overall expect temps to
climb into the 60s outside the high terrain with readings closer to
70F not out of the question in portions of the CT River
Valley, eastern MA and RI.

Same downsloping flow that aids in warming temperatures will lead to
another breezy afternoon for SNE with wind gusts between 20-25mph
expected.

&&

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

Tuesday

Another shortwave and cold front pass through the region on Tuesday,
but PWATS by this time will have dropped below 0.5 inches, and no
precipitation is expected.  Winds behind the front turn northwest
and become very gusty.  Bufkit soundings show winds at the top of
the mixed layer around 40mph.  Frequent gusts of 25-35 mph, with
some gusts of 40mph possible Tuesday afternoon.  High temperatures
drop into the upper 40s to low 50s behind the cold front.

Wednesday

High pressure moves overhead, allowing the pressure gradient to
relax and the gusty winds to end.  Skies turn mostly sunny, but
highs remain in the upper 40s with the cold airmass overhead.

Thursday

Guidance has trended drier for Thursday, even as a shortwave trough
exits the Great Lakes.  The EURO and Canadian now push all of that
shortwave energy well south of SNE, even keeping a ridge overhead.
The GFS still brings a weak surface low through SNE but has also
trended drier.  There is still tons of time for guidance to work
this system out, but its less likely that the region will see
beneficial rain to help the drought conditions.  Much of the same
airmass remains in place, keeping temps in the mid to upper 40s.

Friday and Beyond.

There is still quite a bit of uncertainty in this period as guidance
remains inconsistent on the Thursday system, but signs are pointing
to returning to a ridging pattern with continued dry weather.  The
latest 12z cluster analysis now shows that 65% of ensemble members
favor a ridge heading into next weekend.  Even the other 35% that
favor troughing over the east have a growing ridge to the west.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

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

06Z Update...

Tonight...High Confidence

VFR. Light and variable winds

Tomorrow...High Confidence

VFR. Southwest winds around 10 knots, with gusts possible around
20 knots.

Tomorrow Night...High Confidence

SHRA/-SHRA overspreads southern New England between 02Z and
04Z. Ceilings falling to MVFR category with pockets of IFR, but
confidence in IFR is low due to the dry conditions. MVFR vsybs
possible in showers. Steady 10-12 knot southwest winds with some
higher gusts greater than 20 knots over The Cape/Islands.

KBOS TAF...High Confidence in TAF.

VFR with SW winds around 10 knots Sunday. Light rain showers
move in around 04-05z Monday.

KBDL TAF... High Confidence in TAF.

VFR with SW winds around 10 knots Sunday. Light rain showers
move in around 01-02z Monday.

Outlook/Monday through Wednesday/

Monday Night: VFR. Breezy.

Tuesday through Tuesday Night: VFR. Windy with local gusts up
to 30 kt.

Wednesday through Wednesday Night: VFR. Breezy.

Thursday: VFR. Slight chance RA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Today...

Relatively calm conditions expected for much of the day today
but southwest wind gusts increase to 15-20kt this evening. Seas
less than 5ft.

Tonight...

Cold front crosses the waters late tonight and early Monday
morning. Strong jet develops across the southern waters which
will support wind gusts to as high as 35kt south of Cape Cod.
Seas will build to 5-6 feet in this region. Winds over the
eastern waters will be less than 25kt, with seas less than 5 ft.
SCA has been issued for the southern waters including Nantucket
sound starting between 03 and 06 this morning and persisting
through much of Monday. SCA across the outer waters will
continue into Monday night.

Outlook /Monday Night through Thursday/...

Monday Night: Winds less than 25 kt. Local rough seas.

Tuesday: Strong winds with gusts up to 30 kt. Areas of rough
seas. Slight chance of rain.

Tuesday Night: Strong winds with gusts up to 30 kt. Rough seas
up to 10 ft. Slight chance of rain.

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of rough seas.

Wednesday Night: Winds less than 25 kt. Local rough seas.

Thursday: Winds less than 25 kt. Areas of seas approaching
5 ft. Chance of rain.

&&

.FIRE WEATHER...
The prolonged period of dry weather coupled with a very dry
ground will continue to result in elevated fire weather concerns
through Sunday afternoon. Chilly night expected for tonight, with
light northerly winds. For Sunday, full sun should begin the
day but with increased cloud cover by the afternoon. Southwest
winds on Sunday will pick up to around 20 mph in gusts.

A frontal system brings welcomed light rain overnight Sunday night
ending by Monday morning. Rain amounts are expected to be no greater
than a quarter inch.

Minimum relative humidities on Sunday are expected to be as low as
30 to 40 percent, and around 50 percent for the Cape and Islands.
On Monday, expect relative humidities to be around 50 to 60
percent.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Red Flag Warning from 9 AM this morning to 6 PM EST this
     evening for CTZ002>004.
MA...Red Flag Warning from 9 AM this morning to 6 PM EST this
     evening for MAZ002>024-026.
RI...Red Flag Warning from 9 AM this morning to 6 PM EST this
     evening for RIZ001>008.
MARINE...Small Craft Advisory from 1 AM to 4 PM EST Monday for ANZ232.
     Small Craft Advisory from 10 PM this evening to 7 PM EST
     Monday for ANZ235-237.
     Small Craft Advisory from 10 PM this evening to 1 AM EST
     Tuesday for ANZ254>256.

&&

$$

SYNOPSIS...KP/KS
NEAR TERM...KS
SHORT TERM...KS
LONG TERM...BW/Dooley/KP
AVIATION...KP/KS
MARINE...KS
FIRE WEATHER...KP/KS