Lexington Weather

Lexington, Massachusetts, USA

55°F

6/9/2023 9:04pm

Lexington Conditions: Few Clouds
Temperature: 55.2°F / 12.9°C
Dew Point: 53.6°F
Relative Humidity: 94%
Wind: Calm, 10-min avg: Calm, gust: None
Barometer: 29.68 in Steady
Visibility: 10 miles
Rain Today: 0.22 in

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 040000
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
800 PM EDT Sat Jun 3 2023

.SYNOPSIS...
Unseasonably cool weather will prevail this weekend with gusty 
northeast winds and periods of rain or drizzle, especially in
eastern Massachusetts Sunday and Sunday night. Unsettled 
weather may linger into early next week, depending on the 
location of where low pressure sets up. A drying trend with 
moderating temperatures are possible mid to late next week.

&&

.NEAR TERM /THROUGH SUNDAY/...
Not much reason to change the forecast much this evening. Did
tweak temperatures to reflect observed trends into the
overnight. Thinking temperatures remain nearly steady across the 
eastern half of southern New England, with temperatures dropping
about 5-10 degrees farther west. Greatest rainfall chances and 
strongest winds remain across the eastern half of southern New 
England overnight.

Previous Discussion...

Continuing with a persistence forecast. Upper low over northern
New England slowly drops south to Stellwagen Bank overnight, 
keeping our area under moist N/NE flow which will keep 
cloudiness locked in along with patchy rain/drizzle, especially 
closer to coast. Strongest winds should be focused near Cape Cod
and Islands through early tonight where we see steeper lapse 
rates combined with strong winds in lower levels, resulting in 
better mixing. 

Tough to time best window for steadier rainfall but 12z HREF
seems to have a good idea, indicating one area moving down coast
(which can already be seen on radar) toward evening.

High Surf Advisory remains posted for eastern MA through
Sunday. Obviously very poor beach days but dangerous conditions
for anyone observing the rough surf from jetties given large 
breaking waves onto rocks and other nearshore structures. Always
observe from a distance!

&&

.SHORT TERM /SUNDAY NIGHT/...
Upper low slowly drifts south to Cape Cod Sunday and eventually
south of New England Sunday night. Looks like a better chance of
steadier rain by Sunday afternoon, especially near E MA coast, 
as inverted trough rotates westward toward our area and nose of 
northerly LLJ brings additional low level convergence. This LLJ
will also bring potential for another round of 30-40 mph gusts
with focus near Cape Ann.

Farther inland, some uncertainty as to how far west rain will
make it. We followed depiction shown by HREF which keeps most of
activity to east of Worcester, so dry weather is favored in CT 
Valley and east slopes of Berkshires.

Unseasonably cold temperatures will be the big story and we have
the potential to break record cold highs for Sunday (see records
below). Cold air is focused in lower levels with 925 mph temps
cooling to 2-3C across central/eastern MA and RI in heart of
cold pool. We nudged highs downward a bit with lower 50s in
these areas but it's certainly possible that some locations
don't even break 50 degrees! Milder temperatures are expected
farther inland where highs should reach 60 in the CT Valley.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Latest guidance suite remained rather consistent with the
overall synoptic pattern for this portion of the forecast. While 
still some detail differences remain, they have narrowed to some
extent. That said, still favored an ensemble mean/consensus
approach with this update.

The main weather feature will be a mid level cutoff that is
expected to linger between the Maritimes and New England through 
most of next week. This should also keep a surface low pressure 
stuck beneath it to our east as well. The risk for showers will 
wax and wane relative to our proximity to these features. A high
pressure moving into the northern central USA for the second
half of next week may provided just enough dry air, or nudge
that offshore surface low, just far enough east to result in a
drier forecast. For now, decided to only trend the forecast 
drier towards Friday and Saturday.

Despite the prolonged risk for showers and possible
thunderstorms, still not thinking it will be a total washout. 
Showers and thunderstorms would be most favored during the 
afternoon and evening hours most days.

Temperatures should be near to slightly below normal through
most of this period. Slight warmup anticipated to begin Monday, 
then be closer to normal by Tuesday.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Forecaster Confidence Levels:

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

Moderate confidence.

Ceilings should improve to VFR inland tonight but remain MVFR  
closer to coast. Main change with this update was to keep
ceilings mainly MVFR this evening. Thinking there will be a drop 
to IFR towards the east coast near daybreak.

Previous Discussion...

Widespread MVFR cigs Sunday with local IFR and light rain 
across eastern MA, especially in the afternoon, and possibly 
reaching central MA and RI. Mainly VFR CT Valley. Similar 
conditions persist Sunday night.

N/NE winds prevail through Sunday, gusting to 20-30kt with
strongest winds near coast.

KBOS Terminal...Moderate confidence in TAF. Forecast is based
on persistence with ceilings hanging 010-015, but could briefly
drop to IFR at times. 

KBDL Terminal...High confidence in TAF. 

Outlook /Monday through Thursday/...

Sunday Night: Mainly VFR, with areas IFR possible. Windy with
gusts up to 30 kt. Chance RA, chance SHRA, patchy BR.

Monday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA.

Monday Night: VFR. Chance SHRA.

Tuesday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, isolated TSRA.

Tuesday Night: VFR. Breezy. Chance SHRA.

Wednesday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

* Period of gale force winds near and south of Islands 
* Rough seas on MA/RI waters due to strong NE winds this weekend 

Gale Warnings remain posted for waters near and south of
Islands. Expecting frequent gusts just over 35kt through early
tonight before gusts settle back a bit to 25-30 kt and persist
through Sunday night, including the rest of the MA and RI
coastal waters.

Another surge of wind is expected Sunday afternoon on waters off
Cape Ann but at this point it looks marginal to upgrade to Gale 
Warnings. 

Main point is strong N/NE winds will continue to produce rough
seas on coastal waters through weekend which may make conditions
difficult to navigate for less experienced boaters. Seas should
average 3-6 feet nearshore and up to 10 feet offshore.

Patchy light rain/drizzle expected at times tonight with more
widespread light rain Sunday and Sunday night, especially on
eastern MA waters. 

Outlook /Monday through Thursday/...

Monday: Low risk for Small Craft Advisory winds with gusts up 
to 25 kt. Rough seas up to 10 ft. Chance of rain showers. 

Monday Night: Winds less than 25 kt. Local rough seas. Chance
of rain showers. 

Tuesday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Chance of rain showers. 

Tuesday Night through Wednesday: Winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain showers.

&&

.TIDES/COASTAL FLOODING...
Key Points:
 * Splashover possible tonight along E MA coast - little impact
 * Better chance of widespread minor flooding Sunday night and 
   Monday night

Combination of high astro tides (11+ ft MLLW for Boston)
combined with strong NE flow may result in minor coastal
flooding along eastern MA coast. Our main tides of concern are
the Sunday night and possibly Monday night high tide cycles.

For high tide late tonight, we are only expecting a surge of up
to 1 foot which is only expected to result in some splashover of
the most vulnerable shore roads with little impact, mostly as a
result of wave action.

The Sunday night high tide looks to have a higher risk of minor
flooding since the tide is a little higher and the surge may
reach 1.0 to 1.5 feet along with continued wave action. Thus, we
may need to issue a Coastal Flood Advisory in later forecasts
since more of the E MA coastline, including Cape Cod and the
Islands, would be impacted. There is also a risk of minor
flooding during the Mon night high tide.

Along the South Coast, surge values will be lower due to
offshore flow (NE winds). Locations such as Providence are
forecast to remain well below flood stage.

There is also a risk of minor flooding during the Mon night high  
tide.

&&

.CLIMATE...
Record Low Max Temps for Sunday June 4th.

BOS...52/1891 
PVD...55/2012 
BDL...59/2018 
ORH...51/2018

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Surf Advisory until 8 PM EDT Sunday for MAZ007-015-016-
     019-022-024.
RI...None.
MARINE...Small Craft Advisory until 8 AM EDT Monday for ANZ230-231-237-
     250-251-254.
     Gale Warning until midnight EDT tonight for ANZ232>235-255-256.
     Small Craft Advisory until 2 AM EDT Monday for ANZ236.

&&

$$
SYNOPSIS...Belk/JWD
NEAR TERM...Belk/JWD
SHORT TERM...JWD
LONG TERM...Belk
AVIATION...Belk/JWD
MARINE...Belk/JWD
TIDES/COASTAL FLOODING...Staff
CLIMATE...Staff