Lexington Weather

Lexington, Massachusetts, USA

91°F

8/8/2022 5:37pm

Lexington Conditions: Partly cloudy
Temperature: 90.7°F / 32.6°C
Dew Point: 74.3°F
Relative Humidity: 59%
Wind: WSW 1 mph, 10-min avg: 2 mph, gust: 12 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 062331
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
731 PM EDT Sat Aug 6 2022

.SYNOPSIS...
Heat and humidity will be the main weather story right into 
early next week. Heat Advisories have been extended through
Monday, and the threat of isolated to scattered thunderstorms 
will remain as well. It may be Tuesday, or later, before this 
heat and oppressive humidity finally breaks in a significant 
way. Will have daily shots for showers and thunderstorms for 
much of next week, but no washouts are anticipated at this time.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
7:30 PM Update:

Diurnal cu has faded away as the sun angle lowers. Showers and 
storms have diminished quickly over the past hour as well. Only 
a few light returns from KBOX over far eastern New York along 
the Massachusetts border. Those widely isolated showers will 
fade over the next hour or two. During this update only a few 
minor changes to the current temperature trend because obs were 
running a few degrees warmer than what was in the forecast 
grids. Otherwise, the forecast remains well on track. 

See previous discussion below...

===================================================================

As of 3 PM temperatures have climbed into the upper 80s and low 90s 
which, with dewpoints in the upper 60s and low 70s, is making it 
feel like 100-105 out there. Of note is the smattering of convection 
that has formed across northern MA in the 1-2 hours. Forcing is very 
limited with a stationary front well removed from our area, in New 
Hampshire. Even so, diurnal heating has been enough to force some 
scattered storms given the extremely unstable environment with CAPE 
values over 2000 J/kg and low level lapse rates ~8.5C/km. Thinking 
continues to be that these will be mostly garden variety pulse 
thunderstorms whose updrafts go up and come back down rather quickly 
thanks to negligible shear and poor mid level lapse rates. 

Tonight any leftover convection loses steam after sunset and sets us 
up for a dry night. Clear skies except for the Cape and islands 
where lingering low level moisture may bring the return of low 
stratus clouds.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Get ready for a repeat of the same weather once again: hot, humid, 
with scattered disorganized showers and thunderstorms in the 
afternoon. While instability once again blossoms thanks to 
temperatures in the 90s and dewpoints in the 70s, lack of shear to 
organize or sustain convection and poor mid level lapse rates will 
limit severe potential. Still thinking there will be a decent amount 
of scattered showers and thunderstorms in the afternoon and early 
evening as a weak trough of low pressure drops into western MA/CT 
providing some weak forcing. This will also tighten the pressure 
gradient making for a breezier day, especially over southeast MA and 
on the southern and eastern waters. Sunday night convection once 
again diminishes with sunset leaving a mostly clear night with lows 
in the 70s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Highlights...

* Oppressive heat and humidity continues through early next week. 
  There is the chance for isolated showers and thunderstorms daily. 
* A slow-moving cold front could bring the chance for some much 
  needed rainfall to portions of the region by later next week, but 
  timing and areal coverage remain uncertain at this time. 
* Turning more seasonable and much less humid late next week. 
  
Details...

No notable air mass change as we enter the new work week so high 
heat and humidity continues with a trend towards somewhat more 
seasonable temps later in the work week. For reference, typical 
highs for the second week of August are in the low to mid 80s. For 
those tired of the heat and humidity, we should get a reprieve 
sometime in the mid to late week time frame. But there remains 
plenty of uncertainty with regards to the timing. CIPS analog 
indicates that there is a somewhat better chance for stronger 
thunderstorms in the Tuesday or Wednesday time frame, but that is 
contingent on the strength and progression of the cold front. Given 
the plenty of uncertainty, mainly stuck to blended guidance for the 
long term forecast.  While there may seem to be no end in sight to 
this heat, the good news is that we are now past the 
climatologically warmest time of the year and cooler days are not 
far away.

&&

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

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

Tonight...High confidence. 

VFR. Threat for IFR/LIFR stratus/fog returns across the south 
coast but confidence is lower. WSW winds 5-10 kts, terminals
along the south coast, Cape, and Islands are WSW 10-15 kts, gust
to 20 kts.

Sunday...Moderate Confidence. 

Mixed bag of conditions. IFR stratus more likely to persist
towards the south coast. Still mainly VFR farther inland, with
brief periods of MVFR in any showers or thunderstorms.

Sunday Night: VFR. SW winds 5-10kt gusting to 20 kt along the
south coast. 

KBOS...Moderate confidence in TAF due to uncertainty as to
whether any TSRA makes it to the terminal this afternoon. 

KBDL...Moderate confidence in TAF due to uncertainty as to
whether any TSRA makes it to the terminal this afternoon. 

Outlook /Monday through Thursday/...

Monday through Monday Night: Mainly VFR, with areas MVFR
possible. Breezy. Slight chance SHRA.

Tuesday: Mainly MVFR, with local VFR possible. Chance SHRA,
slight chance TSRA.

Tuesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA, isolated TSRA.

Wednesday: Mainly MVFR, with local IFR possible. Chance SHRA,
slight chance TSRA.

Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA, isolated TSRA.

Thursday: Mainly MVFR, with areas VFR possible. Chance SHRA,
isolated TSRA.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tonight through Sunday night...High Confidence.

Light winds and seas through early Sunday with late night areas
of fog with reduced visibility. Sunday and Sunday night winds 
gust 15-20 kts with gusts 20-25 kts. Seas increase to 5-6 ft on
the southern waters overnight. 

Outlook /Monday through Thursday/... 

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

Monday Night: Low risk for Small Craft Advisory winds with
gusts up to 20 kt. Areas of seas approaching 5 ft. Slight
chance of rain showers. 

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

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

Wednesday: Winds less than 25 kt. Chance of rain showers. 

Wednesday Night through Thursday: Winds less than 25 kt. Seas
locally approaching 5 ft. Chance of rain showers, isolated
thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...Heat Advisory until 8 PM EDT Monday for CTZ002>004.
MA...Heat Advisory until 8 PM EDT Monday for MAZ002>023-026.
RI...Heat Advisory until 8 PM EDT Monday for RIZ001>007.
MARINE...Small Craft Advisory from noon Sunday to 6 AM EDT Monday for 
     ANZ231>235-237.
     Small Craft Advisory from noon Sunday to 2 PM EDT Monday for 
     ANZ254>256.

&&

$$
SYNOPSIS...BW
NEAR TERM...BW/Gaucher
SHORT TERM...BW
LONG TERM...Chai
AVIATION...BW/Chai/Gaucher
MARINE...BW/Chai