Lexington Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 191940
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
240 PM EST Thu Feb 19 2026

.WHAT HAS CHANGED...
Winter Weather Advisories posted from 10 AM Friday to 7 AM 
Saturday due to accumulating snow and ice leading to slippery 
road conditions. There continues to be uncertainty with regard 
to the coastal storm late Sunday into Monday, but we are 
favoring a less impactful offshore track at this time. 

&&

.KEY MESSAGES...

- Mix of accumulating snow, sleet, freezing rain and plain
  rain Friday, changing over and ending as a period of light-
  accumulating snow in many areas Friday evening. Slippery road
  conditions are expected, with Winter Weather Advisories for
  interior Southern New England to just east of the I-95
  corridor Friday into Friday night.

- Cloudy and chilly Saturday with periods of flurries or light 
  snow showers, but very limited if any accumulation.

- Coastal storm late Sunday-Monday more than likely to miss or
  just brush southern New England but too soon to rule out a 
  more high impact outcome. 

- Another round of unsettled weather mid week. 

&&

.DISCUSSION...
Key Message 1...Mix of accumulating snow, sleet, freezing rain 
and plain rain Friday, changing over and ending as a period of 
light- accumulating snow in many areas Friday evening. Slippery 
road conditions expected. Winter Weather Advisories for interior
Southern New England to just east of the I-95 corridor Friday 
into Friday night.

Surface low pressure located as of Thursday afternoon in 
vicinity of northeast MO is expected to lift northward into the 
Great Lakes region on Friday, spreading a shield of warm-frontal
precipitation into the Northeast states on Friday. A secondary 
area of low pressure also looks poised to develop off the NJ 
coast on Friday, which will maintain a "milder" marine-
influenced airmass for much of the eastern coast of 
Massachusetts. Meanwhile, warmer air aloft will at least make an
attempt to lift northward, but the majority of model forecasts 
suggests that nose of warmer air aloft won't make it much 
further northward than the Mass Pike; it becomes stonewalled and
eventually shifts southward into Friday night as the secondary 
low pulls away and cold advection/cold air damming in NH/ME 
shifts southward. 

This combination of a warm nose aloft struggling to make much 
northward inroads and above-freezing temps on easterly winds 
makes for a challenging precipitation-type/precipitation-type 
changeover forecast. The whole potpourri of precipitation types 
(snow, sleet/freezing rain, and plain rain) are anticipated, 
eventually transitioning to a period of light snow in all areas 
Friday night as colder air returns southward. Winter Weather 
Advisories have been posted for most of interior Southern New 
England to just west of the Boston-Providence I-95 corridor from
mid-morning Friday to the early Saturday morning period. 

Felt the 12z HREF precipitation types looked reasonable and 
were used for weather types/changeovers. Precipitation breaks 
out in far western New England after the Friday morning commute,
and gradually spreads east-northeast into the afternoon. Areas 
near and north of the Mass Pike and into the Merrimack 
Valley/North Shore should remain as mostly snow for the duration
of the event, where the greatest accumulations of wet snow are 
forecast (3-5" with spot 6" amounts along the NH border). Areas 
along and south of the Mass Pike southward into Northern 
Connecticut and northwest Rhode Island are more likely to see a 
mix of precip types, with accreting freezing rain (up to two-
tenths of an inch), sleet and minor wet snow (C-3"). 

For the Greater Boston/South Shore area, the persistent onshore
flow should lead to rain mixed with ice pellets, with any 
wintry precip that falls from the sky struggling to accumulate 
during the daytime; as colder northerly flow drives southward 
Friday evening (more likely after the PM commute), a transition 
over from wintry mix of rain/sleet over to a minor-accumulating 
but greasy light snow with a couple inches of snow accumulation 
forecast. Subsequent forecast updates may need to consider 
expanding the Advisory into Boston and eastern RI/southeast MA 
mainly for Friday night, due to deteriorating weather conditions
affecting travel. Even in interior Southern New England, expect
any wintry mix to change/end as light snow as the colder air 
returns back southward. 

Plain rain is expected for most of southeast New England, 
ending as a coating to an inch of wet snow Friday evening. 

Key Message 2...Cloudy and chilly Saturday with periods of 
flurries or light snow showers, but very limited to no 
accumulation.

Developing secondary low takes hold and races east early 
Saturday, but what is left behind for us is this cloudy, 
raw/chilly airmass with a lot of shallow RH with drier air aloft
for much of Saturday. Models show really light QPF ( < 0.05), 
and forecast temp/moisture profiles reflect that any light snows
that develop would have really poor snowgrowth. Because of 
that, accumulations if any would be limited to an inch or less. 
Highs may only range around 30-32 for northeast MA, and in the 
mid to upper 30s for RI, northern CT and southeast MA.

Key Message 3...Coastal storm late Sunday-Monday more than 
likely to miss or just brush southern New England but too soon 
to rule out a more high impact outcome. 

We continue to monitor a deep mid level trough that digs into 
the eastern seaboard on Sunday and Monday generating a deepening
surface low off the mid Atlantic coast that then tracks north 
and east. While all possibilities remain on the table, the 
latest GFS runs continue to be a NW outlier to other global 
guidance and ensemble guidance (which shows a much less 
impactful track missing or brushing SNE). Some of the closer 
tracks are a result of modeling depicting a deeper trough with a
stronger downstream ridge. However, the bulk of the guidance 
including the mean of the EPS, GEFS, and Canadian are more 
progressive with a positively tilted trough and a flatter 
downstream ridge, allowing a track further offshore. For that 
reason, we continue to expect a better chance of a low impact 
storm. Even with a further offshore pass, it will likely lead to
gusty winds and increased waves on the waters, as well as 
potential for ocean enhanced snow showers over southeast MA. As 
we get into the range of high resolution guidance we should have
a better idea over the next 24 to 36 hours. 

Key Message 4... Another round of unsettled weather mid week. 

Zonal flow and a surface ridge of high pressure then move 
overhead briefly on Tuesday bringing a period of quiet weather 
into mid week, but another frontal system approaches late 
Wednesday bringing once again the return of wet weather. 
However, with the trend toward warmer low/mid level temperatures
(925 mb temps approaching 0C) much of the warm frontal 
precipitation likely falls as rain outside of the high terrain.

&&

.AVIATION /19Z THURSDAY THROUGH TUESDAY/...
Forecaster Confidence Levels...

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

Through Tonight...High Confidence.

VFR. Light winds gradually shift from ENE to SE this afternoon.

Friday and Friday Night... High Confidence in trends. Moderate 
Confidence in timing.

VFR conditions gradually lower to MVFR, primarily with the 
CIGS, by late morning. By midday, -RA showers begin to 
overspread the region west to east, but some uncertainty on the 
exact timing. Light snow will mix into the rain generally by 
mid-afternoon for western terminals, later in the evening for 
eastern terminals. It's also possibly some -FZRA may mix into 
showers later Friday afternoon across interior terminals as 
temperatures gradually drop below freezing, but uncertainty 
remains high on when that would occur.

KBOS Terminal...High confidence in TAF.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Saturday through Tuesday/...

Saturday: MVFR/IFR conditions possible. Breezy. Chance SN.

Saturday Night: VFR. Slight chance SN.

Sunday: Mainly VFR, with areas MVFR possible. Breezy. Slight
chance SN.

Sunday Night: Mainly VFR, with local IFR possible. Strong winds
with local gusts up to 40 kt. Chance SN.

Monday: Mainly VFR, with local IFR possible. Strong winds with
gusts up to 50 kt. Chance SN.

Monday Night: Mainly VFR, with local MVFR possible. Windy with
local gusts up to 35 kt. Slight chance SN.

Tuesday: VFR. Breezy. 

&&

.MARINE...
Forecaster Confidence Levels...

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

High confidence through the end of this week.

Small Craft Advisories remain in effect for seas up to 5 feet 
through this evening. Waves begin to build over the southern 
waters again Friday afternoon as a winter storm moves through, 
reaching SCA levels again by Friday evening. Winds remain calm 
until Friday, where gusts 25-27 knots begin to pick up over the 
southern waters.

.Outlook /Saturday through Tuesday/...

Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of
snow. Local visibility 1 to 3 nm.

Saturday Night through Sunday: Winds less than 25 kt. Areas of
seas approaching 5 ft. Slight chance of snow. 

Sunday Night: Moderate risk for gale force winds with gusts up
to 45 kt. Rough seas up to 14 ft. Chance of snow. 

Monday: gale force winds with gusts up to 45 kt. Rough seas up
to 22 ft. Chance of snow. 

Monday Night: Low risk for gale force winds with gusts up to
45 kt. Rough seas up to 22 ft. Chance of snow. 

Tuesday: Winds less than 25 kt. Rough seas up to 15 ft. 

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Winter Weather Advisory from 10 AM Friday to 7 AM EST Saturday 
     for CTZ002>004.
MA...Winter Weather Advisory from 10 AM Friday to 7 AM EST Saturday 
     for MAZ002>014-026.
RI...Winter Weather Advisory from 10 AM Friday to 7 AM EST Saturday 
     for RIZ001-003.
MARINE...Small Craft Advisory until 7 PM EST this evening for 
     ANZ254>256.

&&

$$

DISCUSSION...Loconto/BW
AVIATION...McMinn
MARINE...McMinn