Lexington Weather

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 161907
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
207 PM EST Mon Feb 16 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 /19Z MONDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...

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

18z TAF Update:

Through 00z Tuesday: High confidence in trends but moderate on
timing of any improvement in MVFR ceilings.

BKN/OVC VFR ceilings for most, though some low-end VFR/MVFR 
ceilings for eastern and southeast MA and part of eastern RI.
Categories not expected to drop any lower, but it is uncertain
how soon any improvement in the MVFR ceilings occurs. Expect
there to be a lot of BKN/OVC025-040 bases around, potentially
into the evening. N to NE winds around 5-10 kt, on the higher
end of that range near the east coast.

Tonight and Tuesday: Moderate confidence. 

BKN/OVC VFR (possibly continued MVFR) early but conditions
deteriorate to at least widespread MVFR 06-12z 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 /Tuesday Night 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 /Tuesday Night 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 Tuesday to 7 AM EST Wednesday 
     for ANZ250-254.
     Small Craft Advisory from 10 PM this evening to 7 AM EST 
     Wednesday for ANZ255-256.

&&

$$

DISCUSSION...KJC/Loconto
AVIATION...KJC/Loconto
MARINE...KJC/Loconto