Lexington Weather

Lexington, Massachusetts, USA

88°F

8/8/2022 6:17pm

Lexington Conditions: Clear
Temperature: 87.8°F / 31.0°C
Dew Point: 73.6°F
Relative Humidity: 63%
Wind: S 3 mph, 10-min avg: 3 mph, gust: 14 mph
Barometer: 29.79 in Steady
Visibility: 10 miles
Rain Today: 0.00 in

Southeast Middlesex County, MA - Heat Advisory
- SEE ALL NEARBY ALERTS -

Area Forecast Discussion
for Boston / Norton, MA

        
000
FXUS61 KBOX 051045
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
645 AM EDT Fri Aug 5 2022

.SYNOPSIS...
Heat and humidity will be the main weather story right into 
early next week. This hot stretch continues today, with even 
higher humidity. The greatest potential for showers and
thunderstorms will be today into Saturday, with localized heavy
rainfall possible at times. It may be Tuesday, or later, before
this heat and oppressive humidity finally breaks in a
significant way.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

645 AM Update

GOES Fog channels continue to show some areas of patchy fog and
low stratus across southern New England. Fog has become less
dense over the last hour and wil continue to lift as the morning
progresses. Forecast remains on track and no changes have been
made with this update. See previous discussion for additional
details.

Previous Discussion

Another round of early morning stratus and fog towards 
southeast MA. 

Expecting more overall cloud cover today, which will result in
slightly lower max temperatures today. However, also expecting 
dew points to be higher, which will keep max heat indices in the
90s across most of southern New England. So, the Heat 
Advisories will continue as posted.

The other concern for today will be the risk for showers and
thunderstorms. Mid level moisture will not be as dry as
yesterday, making it easier to develop and sustain updrafts. An
approaching cold front and mid level shortwave will also provide
some support. However, wind fields are generally weak relative
to the general buoyancy. Thus, not expecting much risk for severe
weather. Any thunderstorms today would pose a lightning and
downpour risk.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/...
With the weak wind fields in place, expecting thunderstorms to
diminish quickly after sunset. The same cannot be said for the
possibility of showers tonight. Showers and thunderstorms
redevelop for Saturday. Have little confidence in trying to time
out the risk for specific locations given the rather soupy
environment. Have greater concern for downpours than severe
weather yet again Saturday.

Above normal temperatures and near oppressive humidity
continues. Will likely need to extend Heat Advisories for some
areas Saturday. These areas could change daily, so will take
any extensions on a daily basis.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
Highlights

* Oppressive heat and humidity continues through Monday.
  Additional heat headlines likely for Sunday, and possibly 
  Monday.

* Slow-moving frontal boundary early next week may support a
  period of unsettled weather

* Temperatures moderate closer to normal mid-week.

Sunday and Monday

Little change in the weather pattern for Sunday and Monday as 
deep southwest flow continues to pump warm moist air into 
southern New England. Dewpoints remain in the low 70s while 
afternoon temperature stop out in the low to mid 90s. This will 
translate to heat indices in the mid to upper 90s for both 
Sunday and Monday. Thus, additional heat headlines are likely 
for some areas on these days. Most areas are expected to stay 
dry during this time frame, but with the unstable atmosphere, we
can't rule out a brief spot shower or thunderstorm during the 
afternoon.

Next Week

Quite a bit of uncertainty beyond Monday as global models are 
struggling to come to a consensus on how to resolve a slow 
moving cold frontal boundary early next week. GFS supports an 
earlier arrival Monday night, while the EURO supports a later 
arrival on Tuesday. Have leaned on NBM on guidance due to the 
uncertainty. The expectation is that this frontal boundary will 
support periods of wet/unsettled weather in the Tuesday to 
Thursday time frame. Additionally as an upper-level trough 
associated with this boundary digs into the Northeast, we should
see temperatures return to something closer to normal. While 
the models are in quite a disagreement early in the week, there 
is better agreement later in the weak for coastal low developing
off the east coast. Perhaps this will introduce an opportunity 
for so much needed rainfall! Check back for more details in the 
coming days.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels:

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

Today...Moderate confidence.

Areas of LIFR to start the day towards SE MA. Local sea breezes 
expected to kick in for BOS around 15-17z time frame. Generally 
VFR elsewhere. Greater risk for showers and thunderstorms, 
especially across the western two-thirds of southern New 
England, which could lead to brief MVFR conditions.

Tonight...Moderate confidence. 

Mainly VFR. MVFR/IFR CIGS possible for some, mainly along the
south coast, Cape, and islands. TSRA come to an end after 
sundown, but SHRA are possible through much of the night.

Saturday...Moderate confidence.

Mainly VFR, with local MVFR in scattered SHRA and TSRA.

KBOS...Moderate confidence in TAF, mainly due to timing of any
SHRA or TSRA impacting the terminal. Timing of seabreeze
development may be off by an hour or so.  

KBDL...High confidence in TAF.

Outlook /Saturday Night through Tuesday/...

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

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

Monday Night: Mainly MVFR, with areas VFR possible. Breezy.
Chance SHRA, isolated TSRA.

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

&&

.MARINE...
Forecaster Confidence Levels:

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

High confidence. 

Areas of fog should dissipate this morning. Winds and seas to 
remain relatively tranquil through Saturday.

Outlook /Saturday Night through Tuesday/... 

Saturday Night: Winds less than 25 kt. Seas locally approaching
5 ft. Slight chance of rain showers. 

Sunday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers. 

Sunday Night: Low risk for Small Craft Advisory winds with
gusts up to 20 kt. Seas up to 5 ft. Slight chance of rain
showers. 

Monday: Winds less than 25 kt. Areas of seas approaching 5 ft.
Slight chance of rain showers. 

Monday Night: Winds less than 25 kt. Seas up to 5 ft. Chance of
rain showers, isolated thunderstorms. 

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

&&

.CLIMATE...
August 5th daily record maximum high temperatures...

BOS - 100F [1955]
ORH - 96F  [1944]
PVD - 100F [1944]
BDL - 101F [1955]

August 5th daily record maximum low temperatures...

BOS - 76F [1938]
ORH - 73F [1938]
PVD - 77F [1938]
BDL - 76F [1938]

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT this evening for CTZ002>004.
MA...Heat Advisory until 8 PM EDT this evening for MAZ002>023-026.
     Air Quality Alert from 11 AM this morning to 11 PM EDT this 
     evening for MAZ007-015-016.
RI...Heat Advisory until 8 PM EDT this evening for RIZ001>007.
MARINE...None.

&&

$$
SYNOPSIS...Belk/RM
NEAR TERM...Belk/RM
SHORT TERM...Belk
LONG TERM...RM
AVIATION...Belk/RM
MARINE...Belk/RM
CLIMATE...