Lexington Weather

Lexington, Massachusetts, USA

90°F

8/8/2022 5:39pm

Lexington Conditions: Partly cloudy
Temperature: 90.1°F / 32.3°C
Dew Point: 74.3°F
Relative Humidity: 60%
Wind: SW Calm, 10-min avg: 2 mph, gust: 17 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 031124
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
724 AM EDT Wed Aug 3 2022

.SYNOPSIS...
Heat and humidity will be the main weather story right through
this weekend into early next week. The heat and humidity will 
peak on Thursday and Friday, with near record high temperatures
and oppressive heat indices as well. The greatest potential for
showers and thunderstorms will be on Friday with even some 
localized heavy rainfall possible.

&&

.NEAR TERM /THROUGH TONIGHT/...
0630 AM Update

Forecast is on track and no changes are needed at this time.

Previous Discussion

High pressure builds across southern New England today. Rather 
quiet day expected weather- wise. Seabreezes expected to develop
along the coasts, which will lead to slightly cooler conditions
across portions of the coastal plain. Farther inland, not 
expecting temperatures to be be much lower than yesterday. What 
should be noticeably lower will be the humidity.

&&

.SHORT TERM /THURSDAY/...
Humidity starts to return late tonight, and continues to build
Thursday. While expecting rain-free conditions through 
Thursday, thinking another round of stratus will overspread
portions of RI and southeast MA. It is possible this stratus
could push farther inland, possibly reaching south central
Massachusetts and northeast Connecticut. However, confidence in
this is lower, especially with a southwest wind. 

Continued excellent agreement for oppressive heat and humidity
Thursday. Still have greatest confidence in reaching Heat
Advisory thresholds, so will continue with that headline for
now. CIPS analogs do indicate about a 20-40 percent chance of
needing an excessive Heat Warning. So, cannot close the door
entirely on that possibility. In either case, it will be very
uncomfortable for most.

&&

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

* Oppressive heat and humidity continues Friday. Heat Advisory 
  in effect.

* Scattered showers and thunderstorms Friday afternoon with
  local heavy rainfall possible

* Hot/humid weather continues trough the weekend and into early
  next week. Additional heat headlines possible

Thursday night and Friday

Pronounced Bermuda high pressure system continues to pump hot
and humid air into the northeast Thursday night into Friday. 
Dewpoints surge overnight Thursday into Friday across southern 
New England, rising into the low to mid 70s. Thus, expect 
Thursday night to consist of very uncomfortable sleeping 
weather.

Current heat advisory extends into Friday as we'll have a 
second consecutive day of 850 temps near 20 Celsius supporting 
surface temps in the mid to upper 90s at the surface across 
southern New England. While temperatures are not expected to be 
as warm as what is expected Thursday (see short term AFD) the 
increased humidity will have heat indices well over 100 degrees 
again on Friday afternoon. Also can't rule out heat indices 
perhaps eclipsing the 105 mark which would warrant excessive 
heat warning headlines. Confidence in reaching that mark is low 
at this time, so we're hanging on to the heat advisory in the 
mean time. Highest heat indices expected to reside across the CT
and Merrimack River valleys.

Some relief will be possible Friday afternoon as a weak surface
cold front drops into southern New England. While the forcing 
associated with this front is expected to be weak, it should be 
enough to initiate scattered convective showers and 
thunderstorms across the northern and western areas of southern 
New England. Weak wind fields will suppress the severe 
thunderstorm threat, but also introduce the possibility for slow
moving storms that will have the ability to produce much needed
locally heavy rainfall. 

This Weekend

Bermuda High holds strong this weekend and continues to support
a deep southwest flow pattern into southern New England. This 
will continue to result in above normal temperatures and 
humidity. Additional heat headlines may be needed this weekend. 
Heat and humidity will also support an unstable atmosphere 
during the afternoon hours which will bring isolated 
shower/thunderstorm chances each afternoon through Monday. May 
see temperatures and humidity moderate early next week with a 
cold frontal passage possible during the Monday to Tuesday time 
frame.

&&

.AVIATION /11Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels:

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

Today: High confidence. 

VFR with expected sea-breezes for the coastlines about 15-17z. 

Tonight: Moderate confidence.

Continued VFR for most, though re-developing mist/fog and
stratus for the evening for at least the Cape and Islands, but
also possible towards south central MA and northeast CT.

Thursday: High confidence. VFR.

KBOS...High confidence in TAF. 

KBDL...High confidence in TAF. 

Outlook /Thursday Night through Sunday/...

Thursday Night: VFR. Breezy. 

Friday through Friday Night: Mainly VFR, with areas MVFR
possible. Chance SHRA, slight chance TSRA.

Saturday: Mainly VFR, with areas MVFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Saturday Night: VFR. Breezy. 

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

&&

.MARINE...
Forecaster Confidence Levels:

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

High confidence. 

Rather tranquil winds and seas through Thursday. Biggest concerns
for tonight are potential for fog, with significant reductions 
in visibility near the south coastal/nearshore waters.

Local nearshore seabreezes today, transitioning to south to
southwest winds tonight into Thursday.

Outlook /Thursday Night through Sunday/... 

Thursday Night: Winds less than 25 kt. 

Friday: Winds less than 25 kt. Chance of rain showers, slight
chance of thunderstorms. 

Friday Night: Winds less than 25 kt. Slight chance of rain
showers, isolated thunderstorms. 

Saturday: Winds less than 25 kt. Slight chance of rain showers.

Saturday Night: Winds less than 25 kt. 

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

&&

.CLIMATE...
August 4th daily record maximum high temperatures...

BOS - 96F [1928]
ORH - 95F [1944]
PVD - 98F [1944]
BDL - 96F [1944]

August 4th daily record maximum low temperatures...

BOS - 76F [1930] 
ORH - 72F [2002] 
PVD - 74F [2010] 
BDL - 74F [2006]

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 from 11 AM Thursday to 8 PM EDT Friday for 
     CTZ002>004.
MA...Heat Advisory from 11 AM Thursday to 8 PM EDT Friday for 
     MAZ002>021-026.
RI...Heat Advisory from 11 AM Thursday to 8 PM EDT Friday 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...