Lexington Weather

Lexington, Massachusetts, USA

52°F

5/11/2024 5:24pm

Lexington Conditions: Mostly cloudy
Temperature: 52.3°F / 11.3°C
Dew Point: 42.8°F
Relative Humidity: 70%
Wind: Calm, 10-min avg: Calm, gust: 2 mph
Barometer: 29.82 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 091045
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
645 AM EDT Thu May 9 2024

.SYNOPSIS...
High pressure to the north will bring mainly dry and mild conditions 
today. Some showers are possible tonight into early Friday as low 
pressure tracks to the south, otherwise drier and cooler for much of 
Friday as NE winds develop. Cooler than normal this weekend with 
rain chances increasing Saturday night and Sunday, then milder 
temperatures return early next week but an unsettled weather pattern 
will continue.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Weak shortwave ridging develops today between departing shortwave to 
the east and upstream shortwave across Gt Lakes. Somewhat drier air 
in the column will be present today which will yield mainly dry 
conditions, although moisture will begin to increase from the south 
later today as low pres moves to mid Atlc region. This increase in 
moisture will lead to low risk for a few showers late today near the 
south coast, otherwise mainly dry. 

Fog and stratus in eastern MA should erode by daybreak with a brief 
period of partial sunshine this morning before clouds return. Highs 
should reach mid-upper 60s and near 70 Hartford to Springfield, but 
cooler across east coastal MA as winds turn NE. In fact, expect 
temps falling through the 50s during the afternoon along the eastern 
MA coast.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Tonight...

As mid level trough amplifies over the Gt Lakes, backing flow aloft 
will bring increasing moisture northward into SNE. However, there is 
uncertainty regarding how far north and east showers will get across 
SNE as best moisture will remain to the SW. Best chance for a period 
of rain tonight will be from western MA to RI closest to best 
moisture, with decreasing probs further NE into portions of eastern 
and NE MA.  

Lows will be in the 40s tonight, with increasing NE winds along the 
south coast and Cape/Islands as low pres moves off the mid Atlc 
coast. 

Friday...

Some lingering showers are possible Fri, especially across SW 
portions of SNE, but drier air will gradually move in from the north 
during the day as high pres builds south into eastern New Eng. This 
may lead to partial sunshine developing across portions of northern 
and eastern MA. NE flow will result in cooler temps Fri with highs 
mostly in the 50s, with some lower 60s possible in the CT valley.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Key Points...

* Trending drier this weekend with some sun possible

* Below average temperatures continue through the weekend

* More seasonable temps return next week

Weekend

Shortwave trough passes to the south of the region, as the 
associated surface low passes well offshore to the east. Another 
weaker shortwave follows quickly behind leaving the region in 
cyclonic flow for much of the weekend. With the best moisture and 
forcing to the south with the leading shortwave, models have trended 
drier with even some breaks in cloud cover possible. High temps over 
the weekend have also trended slightly warmer with the possibility 
for breaks of sun, however, onshore flow and 850mb temps below 0C 
will likely keep high temps below 60F in the east, and below 65F in 
the west. Overnight lows also stay on the cool side with the cool 
airmass in place staying in the low to mid 40s.

Next week

The pesky upper level low and mid level cold pool finally moves east 
as a upper level ridge builds in. Surface flow turns SSW with WAA 
bringing 850mb temps back above 0C to even +10C by mid week. High 
temps begin to moderate back into the low to mid 70s. As for rain 
chances, high pressure to the south should keep things dry early in 
the week. Rain chances look to increase again mid to late week as a 
shortwave approaches the region, but uncertainty remains high at 
this time.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

12Z TAF Update:

Seeing fog and low status burn off quickly this morning 
including across the Cape and Islands. Should see those 
terminals go and remain VFR by 13z. Otherwise VFR across the 
region. There is a low chance for an isolated shower later this 
afternoon, but confidence was not high enough to include in TAFs
at this hour. 

Today...Moderate confidence. 

Mainly VFR cigs, but areas of MVFR cigs across east coastal MA.
N wind around 10 kt turning NE during the afternoon.

Tonight...Moderate confidence. 

MVFR cigs expanding westward across SNE. Low prob for IFR.
Scattered showers developing, especially across western half New
Eng. NE wind 5-15 kt.

Friday...Moderate confidence. 

Cigs improving to VFR from NE to SW as drier air works in from 
the N. A few showers possible, mainly from SW MA and CT to the 
south coast.

KBOS TAF...Moderate confidence in TAF. IFR-LIFR stratus and fog  
has improved to VFR but cigs may briefly drop down to IFR 
before daybreak. Some uncertainty with cigs today which may vary
between VFR and MVFR but no vsby restrictions. NW winds will 
become NE this afternoon.

KBDL TAF...High confidence in TAF today. VFR through today, then
cigs may lower to MVFR tonight. Scattered showers possible 
tonight.

Outlook /Friday Night through Monday/... 

Friday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

Saturday: Mainly VFR, with local MVFR possible. 

Saturday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

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

Sunday Night: Mainly VFR, with local MVFR possible. 

Monday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Friday...

North winds will become NE this afternoon with speeds below 20 kt, 
but may increase with gusts 20-25 kt tonight into Fri, especially 
over south coastal waters as low pres tracks to the south. Seas 
build to near 5 ft over the eastern outer waters late tonight and 
Fri. A SCA may be needed for eastern MA waters but confidence not 
high enough to issue as conditions look marginal. 

Outlook /Friday Night through Monday/... 

Friday Night through Saturday: Winds less than 25 kt. Seas up
to 5 ft. Slight chance of rain showers. 

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

Sunday Night through Monday: Winds less than 25 kt. Seas
locally approaching 5 ft.

&&

.TIDES/COASTAL FLOODING...
High astronomical tides coupled with onshore flow may result in some 
splashover/very minor coastal flooding during the overnight high 
tide cycle tonight. However, wind/waves do not appear high enough to 
result in a significant issue. The daytime high tides are lower and 
do not pose a threat for coastal flooding.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...KJC/KP
NEAR TERM...KJC/KP
SHORT TERM...KJC
LONG TERM...KP
AVIATION...KJC/KP
MARINE...KJC/KP
TIDES/COASTAL FLOODING...