Lexington, Massachusetts, USA
000
FXUS61 KBOX 170524
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
1224 AM EST Tue Feb 17 2026
.WHAT HAS CHANGED...
Will issue a special weather statement to cover possible
freezing drizzle for early Tuesday morning but impact should be
minimal if any develops at all. Otherwise, there are no
significant changes with a more active period of weather for the
latter part of the workweek into the weekend, but with quite a
bit of uncertainty on the details.
&&
.KEY MESSAGES...
- Weak low pressure moving in early Tuesday to Tuesday afternoon
could produce patchy freezing drizzle or flurries, but little
if any impact given spotty anticipated coverage.
- Accumulating snow expected across portions of southern New
England Wednesday afternoon into Wednesday evening.
- Weather pattern remains quite unsettled for late in the week
into next Monday with multiple periods of wintry precip
possible. Low confidence on timing and details.
&&
.DISCUSSION...
Key Message 1...Weak low pressure moving in early Tuesday to
Tuesday afternoon could produce patchy freezing drizzle or
flurries, but little if any impact given spotty anticipated
coverage.
Partly to mostly cloudy conditions continue early tonight, but
cloud cover will again be on the increase tonight and overnight.
This is in response to a weak-amplitude mid-level shortwave
disturbance and associated poorly-organized sfc low pressure
currently over the U.P. of MI, a feature which treks ESE through
interior northern/north- central New England on Tue. Model
point soundings show a pretty dense layer of low-level RH, but
the issue is that the top of this layer extends up to around the
-8 to -10C isotherm, then dries out entirely, thus opening the
door for potential incomplete saturation of the snow-crystal
nucleating layer. With that in mind, and that there's some very
spotty/light/mottled-looking QPF in some of the guidance, it
might be enough to wring out scattered flurries or very spotty
freezing drizzle ("snizzle") as this wave moves through during
the pre-dawn hours to the eastern MA coast by the aftn.
Although we only need a trace of ice to trigger winter weather
advisories, given that the majority of road surfaces have been
treated to the point they're white, and the spotty anticipated
coverage, will instead turn to messaging via special weather
statement. Even then, any impact would be on unpaved roads or
elevated bridges; given with what's to come later this week
(more on that to follow), this very light event doesn't really
fit the bill as being necessarily impactful. If trends in QPF
were to increase, then later shift(s) could consider an
Advisory, but that doesn't seem like a likely outcome when
looking at the probabilistic datasets. Otherwise, Tue is a
cloudy and pretty dreary/raw day despite southwest winds, and
undercut NBM 4.3 highs which were in the mid 40s by about 5
degrees, for values in the mid 30s/around 40.
Key Message 2...Accumulating snow expected across portions of
southern New England Wednesday afternoon into Wednesday evening.
Difficult snow forecast as there is still uncertainty with axis
of heaviest precip and how far south accumulating snow will get
across SNE. International guidance (ECMWF, Canadian RDPS and
UKMET) remain the warmest solutions and furthest north, while
GFS and NAM are colder and further south. Mid level shortwave
lifts NE from the Gt Lakes but it will be encountering a closed
low over the Maritimes which maintains confluent flow across
northern New Eng. This should suppress the shortwave further
south and likely keep the surface boundary south of New Eng. As
a result leaning toward a somewhat colder solution across SNE
which is supportive of more snow than rain north of the MA Pike,
while to the south rain may flip to snow late day and evening
as colder air filters southward. Precip looks to begin sometime
late morning into the afternoon from SW to NE. It could start as
rain even for northern MA as BL warms ahead of the precip but
wet bulb cooling should result in a quick rain to snow
transition north of the Pike with any changeover occurring late
day or evening to the south.
Decent overrunning situation develops north of the warm front
with relatively narrow band of deep moisture and forcing for
ascent oriented WNW to ESE across SNE. Where the axis of
heaviest precip sets up remains somewhat uncertain and it is
possible it could be displaced to the south of the coldest air
which adds a level of complexity. We are relying on ensemble
guidance and and staying in a probabilistic space until we can
gain more confidence. GEFS and EPS ensemble guidance indicates
highest probs (40-70%) of 3+ inches of snow across interior
northern and NW MA. This is where we think there could be 2-4
inches of snow accum with generally an inch of less south of the
MA Pike. However, if guidance trends further south more snow
could fall south of the Pike as suggested by GFS and NAM.
This system pulls away Wed night and we have high confidence of
dry conditions Thu with temps mostly in the 30s as high pres
builds in from the north.
Key Message 3...Weather pattern remains quite unsettled for
late in the week into next Monday with multiple periods of
wintry precip possible. Low confidence on timing and details.
A very complex and chaotic pattern for the end of the week into
early next week as there are numerous shortwaves within an
active Pacific jet in this highly charged -PNA/-NAO pattern.
Global guidance is struggling with how these shortwaves
interact with each other and with northern stream energy to the
north resulting in a low predictability pattern. It does appear
there will be another wintry event sometime Fri into Sat with
potential for snow and/or mixed precip but this doesn't appear
to be a significant event. Then we will have to watch the
Sunday-Monday period. GFS, AIGFS and ECMWF AIFS all show
something potentially significant during this period, but there
is a lot of spread among the individual ensemble members. Stay
tuned.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
06z TAF Update:
Rest of Tonight and Tuesday: Moderate confidence.
BKN/OVC VFR thru 06-09z then deteriorating to at least
widespread MVFR 09-12z as weak wave of low pressure passes to
our north. MVFR to borderline IFR ceilings for Tue, which could
be accompanied by scattered flurries or patchy freezing
drizzle/sprinkles, but either type too spotty to mention in TAF
given expected nil accums. Best chance would be between 11-18z
west to east. It remains uncertain if ceilings improve
thereafter, and MVFR-IFR ceilings could linger into Tue night.
Winds become S/SW 5-10 kt.
KBOS Terminal...Moderate confidence in TAF. VFR/MVFR ceilings
thru tonight, then increasing clouds with ceilings dropping to
widespread MVFR/borderline IFR. Low chance of flurries or
freezing drizzle but accums are nil given spotty coverage.
KBDL Terminal...Moderate confidence in TAF. VFR ceilings thru
tonight, then increasing clouds with ceilings dropping to
widespread MVFR/borderline IFR. Low chance of flurries or
freezing drizzle but accums are nil given spotty coverage.
Outlook /Wednesday through Saturday/...
Wednesday: MVFR/IFR conditions possible. RA, SN, slight chance
FZRA.
Wednesday Night: Mainly IFR, with local MVFR possible. RA,
chance SN.
Thursday through Thursday Night: VFR.
Friday: Mainly VFR, with local IFR possible. Breezy. SN likely,
chance RA.
Friday Night: MVFR/IFR conditions possible. Breezy. Chance SN,
chance RA.
Saturday: Mainly VFR, with local IFR possible. Breezy. Chance
SN, chance RA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Tuesday Night: High confidence.
Low pressure continues to pull away from the southeast waters,
with decreasing NE to N wind speeds down to 10-15 kt by
tonight. Light winds Seas will remain elevated over the outer
waters to around 4-6 ft through Tue night, which has prompted
extension of the small craft advisory through 12z Wed. Mainly
dry weather should prevail, though can't rule out a flurry or
sprinkle Tue aftn but not enough to restrict visbys.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain. Visibility 1 to 3 nm.
Wednesday Night: Winds less than 25 kt. Seas up to 5 ft. Rain
likely, slight chance of snow. Visibility 1 to 3 nm.
Thursday: Winds less than 25 kt. Seas up to 5 ft.
Thursday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Friday: Winds less than 25 kt. Chance of rain, chance of snow.
Local visibility 1 to 3 nm.
Friday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of seas approaching 5 ft. Chance of
rain, chance of snow. Areas of visibility 1 to 3 nm.
Saturday: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain, chance of snow.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory from 4 AM early this morning to 7 AM EST
Wednesday for ANZ250-254.
Small Craft Advisory until 7 AM EST Wednesday for ANZ255-256.
&&
$$
DISCUSSION...KJC/Loconto
AVIATION...FT
MARINE...KJC/Loconto
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https://api.weather.gov/products/types/AFD/locations/BOX