❰ Current Conditions
Special Weather Statement
PATCHY BLACK ICE ACROSS MUCH OF SOUTHERN NEW ENGLAND EARLY THIS MORNING
Special Weather Statement issued October 31 at 4:35AM EDT by NWS Boston/Norton MA
Patchy black ice is likely early this morning as temperatures in the 20s results in moisture freezing on untreated roads. This is especially true on bridges and overpasses. Motorists should exercise caution if traveling early this morning. Any pavement that looks damp may be icy. Temperatures will rise above freezing around mid to late morning which will alleviate any problems.
Area Forecast Discussion
National Weather Service Boston/Norton MA
358 AM EDT Sat Oct 31 2020
Large high pressure will build over the region today with
sunshine and cool temperatures. The high moves offshore tonight
and a weak disturbance moving up from the south may bring a
a few showers to southeast New England late tonight and Sunday
morning. Milder temperatures return Sunday with another period
of widespread rainfall late Sunday and Sunday evening ahead of
a strong cold front. Blustery and cold conditions are expected
Monday and Tuesday. Turning milder with above normal
temperatures for the end the week.
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Strong high pres builds over New Eng today with dry conditions
and light winds. Soundings show very dry column through the mid
levels with PWATs down to near 0.1". Expect full sunshine
today, although some shallow low level moisture below the
subsidence inversion will result in some strato-cu at times.
925 mb temps -2 to -3C supports highs in the upper 30s over
interior high terrain and low/mid 40s elsewhere.
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
High pres moves east of New Eng. The evening starts out clear.
Developing low level southerly flow and increasing low level
moisture will result in lower clouds developing and
overspreading SNE from the south overnight. Additionally there
is a weak mid level shortwave which tracks south of New Eng late
tonight which may bring a few showers to the south coast and
Cape/Islands toward daybreak.
Good radiational cooling in the evening will allow temps to fall
sharply after sunset. Lows will likely occur in the evening with
temps dropping into the 20s away from the coast. Then as winds
turn southerly and cloud cover increases expect rising temps
overnight. In fact temps will rise through the 40s late tonight
along the south coast and Cape/Islands and possibly reach 50
Area of deeper moisture moving up from the south and weak low
level convergence assocd with a developing low level jet will
likely bring a period of showers to Cape/Islands and possibly
into eastern MA in the morning before showers exit during the
afternoon. The exact location where this the axis of rainfall
sets up is not certain and it is possible it could shift
further west or to the east.
Meanwhile, deep closed low and amplifying mid level trough moves
across the Gt Lakes during the day. The attendant strong cold
front will approach New Eng by late in the day. Deepening
moisture moving in from the west with increasing forcing from
left exit region of the approaching upper jet will bring
numerous showers into SNE from the south and west during
mid/late afternoon. It will be a considerably milder day with
highs ranging from upper 40s in NW MA to mid/upper 50s along
the south coast.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
* Starting off the week cool, warming up into the 60s by
* Rain, heavy at times overnight Sunday with some snow on the tail
end in the higher elevations
* Chances of snow showers Monday into early Tuesday morning before
drying out the rest of the week
The wettest period of the whole week will kick off the extended
forecast Sunday night into early Monday morning. A surge of
subtropical moisture which overspreads the region Sunday will
encounter the strongest forcing of the day ahead of a potent cold
front Sunday night. It enters western MA/CT after 8pm and should be
offshore by sunrise on Monday taking most of the precip with it. One
fly in the ointment is the potential or lack thereof of snow in the
highest elevations. At the moment significant snowfall (more than an
inch or so in the Berkshires) isn't likely. The NAM is the outlier,
showing a stronger, slower moving low pressure which wraps in colder
air before the heavy QPF is out, bringing more widespread snowfall
to the interior overnight. Something to keep an eye on, but we're in
the far reaches of the NAM's guidance range, so not taking it into
more consideration until we see some consistency.
By Monday the bulk of the precip exits as a drier and colder post
frontal airmass moves in. 850 mb temps drop to at least -8C Mon/Tue,
potentially even colder on Tuesday. This will keep high temperatures
in the 30s and 40s, with very cold nights in the 20s Monday and
Tuesday night (away from the coast). Additionally, given mid level
cold air advection, the boundary layer will be very well mixed,
pulling down some gusty winds, 20 to 40 kts on Monday, even higher
over the ocean, 40-50 kts. As such, it will feel about 10 degrees
colder than it actually is.
Precipitation won't be widespread on Monday but snow showers are
possible beneath a deep cold pool aloft, even a few snow squalls
given the decent low level lapse rates, mid level trough, and gusty
winds. In any case, the better chance of additional light snow
showers comes Monday night and Tuesday morning as a final shortwave
rounds the base of the broader trough.
By Tuesday into the late week, high pressure expands into New
England keeping precipitation out of the forecast. Additionally,
flow around the high becomes S/SW on Wednesday which will begin a
period of rising temperatures. At 850 mb temps once again rise above
+10C. This will allow for highs well into the 60s by Thu/Fri.
.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through 12z...High confidence.
VFR, but patchy ground fog in the CT valley and interior
VFR with light winds.
Low end VFR/MVFR cigs developing from the south and
overspreading the region overnight. A few showers possible
late tonight across southern RI and SE MA.
Mix of VFR/MVFR cigs. A period of showers likely in the morning
over Cape/Islands and possibly eastern MA before exiting in the
afternoon. More showers developing and moving into SNE from the
south and west late in the day with more widespread MVFR cigs.
KBOS TAF...High confidence in the TAF.
KBDL TAF...High confidence in the TAF.
Outlook /Sunday Night through Wednesday/...
Sunday Night: Mainly VFR, with local IFR possible. Windy with
gusts up to 35 kt. Chance SHRA.
Monday: Mainly VFR, with local MVFR possible. Strong winds with
gusts up to 45 kt. Chance SHSN, slight chance SHRA.
Monday Night: VFR. Strong winds with gusts up to 45 kt. Slight
Tuesday: VFR. Strong winds with local gusts up to 40 kt.
Tuesday Night through Wednesday: VFR. Breezy.
Today...Diminishing N winds becoming light southerly late in the
day. SCA for hazardous seas will continue for the outer waters
although seas will be subsiding.
Tonight and Sunday...Increasing southerly winds with gusts to
25 kt developing over eastern waters late tonight spreading to
rest of waters during Sunday. Building seas. Another SCA will
likely be needed. Vsbys may be reduced in showers and fog at
times late tonight and Sunday.
Outlook /Sunday Night through Wednesday/...
Sunday Night: Low risk for gale force winds with gusts up to
35 kt. Rough seas up to 10 ft. Chance of rain showers.
Monday: gale force winds with gusts up to 45 kt. Rough seas up
to 13 ft. Chance of rain showers.
Monday Night: Moderate risk for gale force winds with gusts up
to 45 kt. Rough seas up to 13 ft. Chance of rain showers.
Tuesday: Low risk for gale force winds with gusts up to 40 kt.
Rough seas up to 11 ft. Slight chance of rain showers.
Tuesday Night: Winds less than 25 kt. Local rough seas.
Wednesday: Winds less than 25 kt. Areas of seas approaching
MARINE...Small Craft Advisory until 8 AM EDT this morning for ANZ235-
Small Craft Advisory until 8 PM EDT this evening for ANZ250-
Small Craft Advisory until 2 PM EDT this afternoon for ANZ256.