Lexington, Massachusetts, USA
35.1°F
1.7°C
Cold
Overcast
Today: Hi 86 °F
Tonight: Lo 66 °F
Dew Point:
32.4°F
Humidity: 90%
UV Index: 0.0 None
Barometer:
mb
Rain Rate: 0.00 in/hr
Rain Today: 0.01 in
Rain Tuesday: 0.00 in
Visibility: 8 miles
Wind:
Now: Calm
Avg: Calm
Gusts: 0 mph
Issued by:
National Weather Service Boston / Norton, MA
Point Forecast Updated Wed Aug 19, 2026 2:58am EDT
- Dry today through tonight.
- Unsettled weather returning Thursday with a front passing through, followed by a brief tranquil period Friday.
- Another round of unsettled weather possible for the weekend.
Patchy Fog then Mostly Sunny
Hi 86 °F
Patchy fog before 7am. Mostly sunny, with a high near 86. West wind 2 to 8 mph.
Mostly Clear
Lo 66 °F
Mostly clear, with a low around 66. Southwest wind 3 to 8 mph.
Chance Rain Showers
Hi 84 °F
A chance of rain showers after 10am. Partly sunny, with a high near 84. West wind around 6 mph. Chance of precipitation is 40%. New rainfall amounts less than a tenth of an inch possible.
Slight Chance Rain Showers then Mostly Cloudy
Lo 62 °F
A slight chance of rain showers before 10pm. Mostly cloudy, with a low around 62. Northwest wind around 5 mph. Chance of precipitation is 20%.
Mostly Sunny
Hi 81 °F
Mostly sunny, with a high near 81. Northeast wind around 7 mph.
Partly Cloudy
Lo 60 °F
Partly cloudy, with a low around 60. Southeast wind 2 to 6 mph.
Chance Rain Showers
Hi 77 °F
A chance of rain showers after 8am. Partly sunny, with a high near 77. Northeast wind 3 to 9 mph. Chance of precipitation is 40%.
Chance Rain Showers
Lo 61 °F
A chance of rain showers. Mostly cloudy, with a low around 61. East wind 3 to 7 mph. Chance of precipitation is 40%.
Chance Rain Showers
Hi 79 °F
A chance of rain showers. Mostly cloudy, with a high near 79. Southeast wind 3 to 7 mph. Chance of precipitation is 40%.
Chance Rain Showers
Lo 62 °F
A chance of rain showers before 3am. Mostly cloudy, with a low around 62. Southwest wind around 5 mph. Chance of precipitation is 40%.
Mostly Sunny
Hi 82 °F
Mostly sunny, with a high near 82. West wind 5 to 9 mph.
Mostly Clear
Lo 59 °F
Mostly clear, with a low around 59. West wind around 7 mph.
Sunny
Hi 81 °F
Sunny, with a high near 81. West wind 5 to 8 mph.
Mostly Clear
Lo 59 °F
Mostly clear, with a low around 59. West wind 3 to 7 mph.
Issued by:
National Weather Service Boston / Norton, MA
Updated Wed Aug 19, 2026 2:58am EDT

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000
FXUS61 KBOX 190744
AFDBOX
Area Forecast Discussion
National Weather Service Boston/Norton MA
344 AM EDT Wed Aug 19 2026
.WHAT HAS CHANGED...
No significant changes.
&&
.KEY MESSAGES...
- Dry today through tonight.
- Unsettled weather returning Thursday with a front passing
through, followed by a brief tranquil period Friday.
- Another round of unsettled weather possible for the weekend.
&&
.DISCUSSION...
KEY MESSAGE 1...Dry today through tonight.
With the low earlier this week now off the coast of Nova Scotia,
high pressure has been able to build in over southern New England in
its place. Notably aloft, a trough well to our north and west in
Canada continues shifting eastward over the southern portion of the
Hudson Bay. With where we are in context of this trough, strong SW-
ly flow aloft develops today through the column. Diurnal mixing
should also aid in mixing down this SW flow, which may inhibit sea
breeze development despite the presence of high pressure centered
just off to our east. Any early morning fog and lower clouds will
diminish shortly after sunrise. 925 mb temperatures will likely
remain in the 20-23C range for the afternoon, encouraging highs into
the mid to upper 80s.
KEY MESSAGE 2...Unsettled weather returning Thursday with a front
passing through, followed by a brief tranquil period Friday.
A shortwave within this slightly SW flow makes its way towards
southern New England heading into tomorrow, bringing with it more
favorable dynamics and moisture for showers as the jet aloft also
becomes more SW and cyclonic. With better ascent and forcing, will
need to keep an eye on where the best moisture tracks. The
differences between the CAMs and the global guidance remain quite
significant, with the NAM showing greater moisture through the
column across the whole region, while the Canadian, ECMWF, and GFS
all indicate layers of dry air in the lower to mid levels that would
greatly affect precipitation. Given the signal for dry air limiting
rainfall, I kept the chances for precipitation to around 30% or less
and total QPF to up to 0.15". This is in line with what most of the
ensemble guidance is indicating as well, as the greater
concentration of moisture is shown in this guidance to remain just
to our southwest.
Following the passage of this front, much drier air files in behind
it. Dew points are expected to drop into the 50s across the region
and remain generally in the upper 50s and low 60s Thursday night
into Friday. High pressure makes its return Friday as a brief
respite from this unsettled pattern, with onshore breezes and highs
in the low 80s and upper 70s, with mid 70s along the immediate
coastal areas.
KEY MESSAGE 3...Another round of unsettled weather possible for the
weekend.
A much larger shortwave moves in from the Great Lakes Saturday into
Sunday, greatly amplifying the SW flow aloft. Guidance signals at
the possibility of a series of waves tracking NE along within this
SW flow, and a surface low may pass along the east coast up into
southern New England. Track is still somewhat uncertain, but this
would likely bring the return of showers. Depending on the timing of
these waves and low pressure, thunderstorms could be possible if
they can take advantage of daytime heat.
Heading into the start of next week, it's also worth noting that the
troughing associated with the leading shortwave cutting south
through the Great Lakes could end up more as a closed off low aloft.
Deterministic guidance keys in more on this possibility, but the
Canadian ensemble notes the possibility along with the ECMWF
ensemble hinting at it slightly; the GEFS keeps it a bit more open
as of the 00z run. We may find ourselves in the low's post-frontal
airmass for Monday with more W-ly flow keeping the region slightly
cooler; 850 mb temps may fall to near 10C. Will be something to
continue monitoring in future updates.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
06z TAF Update
Through 12z...Moderate confidence.
MVFR for most with some areas of IFR. Some patchy fog remains
possible between 08z-11z. Light to calm winds through the rest
of tonight before more SW winds pick up after sunrise.
Today...High confidence.
MVFR to start, becoming VFR within a few hours after sunrise. SW
winds between 5-10 kt, with gusts to just under 20 kt a
possibility for the Cape and Island terminals. Seabreezes not
expected given the strength of SW flow and forecast soundings
indicating good diurnal mixing, though some models do continue
to hint at it for BOS.
Tonight...High confidence.
VFR, with the exception of possibly the Cape and Islands, far
SE MA, and coastal RI. Winds remaining light SW below 10 kt with
calm winds possible over the interior.
Thursday...Moderate confidence.
VFR with chances for SHRA. TSRA not expected.
KBOS Terminal...Moderate confidence in TAF. Low chance for a
seabreeze in the 16-21z timeframe. Only a few models indicate it
and keep it short-lived, so opted to hint at it with a S wind at
17z. Would not be surprised if this does not happen though,
given the strong SW flow over the region.
KBDL Terminal...High confidence in TAF.
Outlook /Thursday Night through Sunday/...
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR.
Friday Night: VFR. Slight chance SHRA.
Saturday: VFR. Chance SHRA.
Saturday Night: Mainly VFR, with local IFR possible. Chance
SHRA.
Sunday: VFR. Chance SHRA, slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
Through Thursday...High confidence.
Light winds generally from the SW, though gusts nearing 20 kt
are possible for this afternoon in the eastern waters. Showers
possible over the waters Thursday into Thursday night. Patchy
fog also a possible tonight, particularly for the southern
waters. Seas to 2-3 ft.
Outlook /Thursday Night through Sunday/...
Thursday Night: Winds less than 25 kt. Slight chance of rain
showers.
Friday through Friday Night: Winds less than 25 kt. Chance of
rain showers.
Saturday: Winds less than 25 kt. Chance of rain showers, slight
chance of thunderstorms.
Saturday Night: Winds less than 25 kt. Rain showers likely,
slight chance of thunderstorms.
Sunday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers, slight chance of thunderstorms.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
DISCUSSION...Hrencecin
AVIATION...Hrencecin
MARINE...Hrencecin
Radar images courtesy Weather Underground / Intellicast.
UV Index forecast high for today: 4 Medium
Current (Measured): 0.0 None
Note: Rain measured automatically by weather station. Rain totals do not necessarily include melted frozen precipitation.
For more accurate, manually measured rain data, see the Local Precip Data page.
0.00 in
Rain Rate (/hr):
0.00 in
Rain Last 60 min:
0.01 in
Rain Today:
0.00 in
Tuesday:
0.01 in
August:
1.26 in
2026
1:17pm
36.1°F
High today:
12:00am
25.2°F
Low today:
2:28pm
30.4°F
High Tuesday:
7:11am
16.2°F
Low Tuesday:
12:00am
25.2°F
Low wind chill today:
7:11am
16.2°F
Low wind chill Tuesday:
1:17pm
33.3°F
High dew pt today:
11:56pm
20.7°F
High dew pt Tuesday:
None
Wind gust today:
None
Wind gust Tuesday:
No alerts/warnings active for Southeast Middlesex County.
First Light:
6:11am
Sunrise:
6:39am
Sunset:
5:19pm
Twilight ends:
5:47pm
Daylight length:
10 hours 39 minutes
Phase:
Waxing Crescent (82%)
Moon set:
8:18am
Moon rise:
9:38pm