Lexington Weather

Lexington, Massachusetts, USA

10/17/2021 9:33pm 
  • Lexington Conditions: Partly cloudy
  • Temperature: 52.3°F / 11.3°CColder 0.9°F than last hour.
  • Dew Point: 46.9°FDecreased 0.6°Fsince last hour.
  • Relative Humidity: 82%Increased 1.0% since last hour.
  • Wind: Calm, 10-min avg: Calm, gust: 3 mph
  • Barometer: 29.67 in Steady
  • Visibility: 10 miles
  • Rain Today: 0.35 in

Area Forecast Discussion
for Boston, MA

FXUS61 KBOX 111403

Area Forecast Discussion
National Weather Service Boston/Norton MA
1003 AM EDT Mon Oct 11 2021

High pressure remains in control through late this week with 
warmer than normal temperatures. Widespread precipitation 
chances return to the forecast for either Saturday or Sunday, 
but timing is uncertain at this time.



Mostly clear skies along the South Coast, but mostly clouds over
the remainder of Southern New England. Additional marine clouds
east of Massachusetts. Clouds over land will slowly break, and
some spots may go mostly sunny. Will need to monitor the clouds
to our east...will they dissipate or move ashore?

In general, no changes planned to the forecast. Expect partial
clearing through the afternoon. Late morning temps in the upper
50s to mid 60s should continue to warm. Morning soundings
support mixing up to between 900-mb and 925-mb. Temps at that
level suggest sfc max temps in the upper 60s and low 70s.

In addition, a Rip Current Statement continues for the eastern 
MA coast due to persistent easterly swells. With beaches being 
unguarded this time of the year, people should exercise caution 
if going out into the waters.




With high pressure building in as well as decreasing clouds and
winds, it should be a decent night for radiational cooling.
Leaned towards the MOS guidance for overnight lows. Expect lows
to fall into the mid 40s to low 60s, except for mid 50s in the 
urban centers and near the coast.


High pressure moves overhead with winds turning to the southeast
and south. Expect more sun than clouds and with 925mb
temperatures +13 to +15C, expect highs in the low to mid 70s.
These forecast highs are about 10 degrees warmer than the
climatological normals for the second week of October.



* Above normal temperatures with quiet weather through much of the 
  week. Cannot rule out a few isolated showers across the interior 
  on Wednesday, but the next opportunity for widespread rain showers 
  is this weekend. 

Tuesday night through Friday...

Ridge axis will be situated over New England into Quebec Tuesday 
night. A trough will lift across the Great Lakes. The ridge will 
build offshore and into Nova Scotia by late Wednesday, while the 
deamplifying trough lifts into northern New England/southern Quebec. 
Another ridge builds in from the Great Lakes on Thursday and over 
the region on Friday. The trough lifts offshore Wednesday night into 
early Thursday. High pressure generally in place over the region 
through this period, though on Wednesday into early Thursday a weak 
surface trough swings through. High pressure builds back in on 
Thursday and Friday. 

Not anticipating any major concerns through this timeframe. High 
pressure generally in control through the period bringing dry and 
quiet weather. Above normal temperatures are expected with a gradual 
upward trend with southerly/westerly flow. Will have 925 hPa temps 
on Wednesday increasing to 14-17 degrees Celsius. For 
Thursday/Friday will have W/NW flow keeping 15-18 degree Celsius air 
overhead at 925 hPa. For all day time highs during this period went 
with a blend of the NBM 75th percentile and 90th percentile of 
guidance to bump up highs. High temperatures ranging from the upper 
60s to mid 70s for most days. Not out of the question there could be 
some upper 70 degree readings late in the week depending on cloud 
cover. Low temps generally in the 50s, but did lower temperatures 
for Tuesday night into early Wednesday to the 10th percentile of 
guidance. Expecting a strong radiational cooling night with clear 
skies and light winds. Should see lows in the mid to upper 40s in 
the typical strong radiator spots, elsewhere readings will be in the 

Did an isolated shower mention on Wednesday as a surface trough 
swings through. The risk of a shower is highest across western 
portions of the CWA. Think that most areas will be dry, but could 
see an isolated shower or two across parts of the interior. This 
coincides with a moisture surge of PWATs approaching 1 inch. 
Uncertain if there will be enough mid level moisture in place. This 
also still matches up well with the highest probabilities of 
EPS/GEFS measurable precipitation. 

Saturday through Sunday...

Ridge axis builds offshore and a trough lifts in from the 
Mississippi River Valley on Saturday or Sunday. A deep low should be 
situated to the northwest of the region, which will slide a warm and 
cold front through New England. This far out timing and intensity is 
uncertain due to model differences, but this brings a shot for more 
widespread precipitation. 

Pretty good agreement in a trough lifting into and through the 
region, but the specific details are uncertain at this time. Due to 
this have just kept the NBM guidance which keeps slight chance to 
chances of precipitation. Still looks like above normal temps 
persist into Saturday, but will depend on how quickly/when the cold 
front moves through. Think there could potentially be some rumbles 
of thunder given K index values increasing to around 30 and a few 
hundred J/kg of MUCAPE, but have held off from including a thunder 
mention in the latest forecast.


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

This afternoon...High confidence in trends, moderate in timing.

Clouds lingered over most of Srn New England. Most ceilings 
mid morning ranged from 500 feet to 1500 feet. Patchy fog was
still around, most of it near Worcester Airport. 

Expect a gradual improvement through the afternoon, but it will
take some time. Ceilings will lift to VFR this afternoon, with 
clearing in some spots. Winds generally out of the NE/ENE at 
5-10 kts. Gusts of 20-25 kts along and south of the south coast.

Tonight...High confidence in trends, moderate in timing. 

VFR for most especially earlier in the evening. May see some
LIFR to MVFR fog developing. Have hinted at for the majority of
terminals with low cloud bases and some visby reduction. Winds
light and variable and generally less than 5 kts.

Tuesday...High confidence. 

Any patchy fog burns off quickly and conditions improve to VFR.
Light winds out of the southeast/south generally less than 5

KBOS Terminal...High confidence in TAF. 

KBDL Terminal...High confidence in TAF.

Outlook /Tuesday Night through Friday/...

Tuesday Night through Thursday: VFR. 

Thursday Night: VFR. Slight chance SHRA.

Friday: VFR.


Forecaster Confidence Levels.

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

Small Craft Advisories remain in effect for the outer waters and
the RI coastal waters for gusts up to 25 knots and seas over 5 
foot. Winds will diminish and become variable tonight and 
Tuesday as high pressure builds fair weather over the waters.

Outlook /Tuesday Night through Friday/...

Tuesday Night: Winds less than 25 kt. Areas of seas approaching
5 ft. 

Wednesday: Winds less than 25 kt. Seas locally approaching
5 ft. 

Wednesday Night through Friday: Winds less than 25 kt.


A Coastal Flood Statement continues for this afternoon's high 
tide cycle across eastern MA coast. Any impacts will be 
restricted to very marginal and localized splashovers. 
Nonetheless, given that it is a public holiday and the continued
nice stretch of weather, decided to hoist a statement for 
awareness purposes.


MA...High Rip Current Risk until 8 PM EDT this evening for MAZ007-
RI...High Rip Current Risk until 8 PM EDT this evening for RIZ008.
MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ235-237.
     Small Craft Advisory until 8 AM EDT Tuesday for ANZ250.
     Small Craft Advisory until 11 AM EDT Tuesday for ANZ254.
     Small Craft Advisory until 2 PM EDT Tuesday for ANZ255-256.



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