Lexington Weather

Area Forecast Discussion
for Lexington, MA

        
000
FXUS61 KBOX 010812
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
412 AM EDT Wed Apr 1 2020

.SYNOPSIS...
Mainly dry and cool conditions today as northerly flow
continues. A large ocean storm will track well southeast of New
England tonight then stall into Friday. This storm will bring 
occasional rain to eastern and southeast New England, strong 
winds over the Cape/Islands and potential for minor coastal 
flooding along east coastal Massachusetts. High pressure will 
bring dry but continued cool conditions Saturday. Another weak, 
fast moving system will bring unsettled weather on Sunday, then 
dry conditions return early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Strong ocean storm moves east off the NC coast today with deep 
moisture remaining to the south. However, as the storm deepens
the western extent of the deep moisture plume may back into the
Cape/Islands with risk for some light rain here late in the 
day. Otherwise, dry weather. N/NE flow will result in 
increasing low level moisture which will back in across eastern 
New Eng. This will bring lots of clouds to eastern MA into RI 
with more sunshine further to the west, especially into the CT 
valley. Another chilly day with temps several degrees below
normal, ranging from lower 40s across eastern MA to near 50 in
the CT valley. Strengthening N/NE flow as storm deepens to the
south with gusts 25-30 mph developing this afternoon over the
Cape/Islands. 

&&

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

Sub 980 mb low tracks well SE/E of the 40N/70W benchmark.
However, large circulation with developing warm advection and
deep moisture wrapping to the west will result in some light 
rain backing in across the Cape/Islands this evening and 
possibly into eastern MA overnight. Much of the rest of SNE 
expected to remain dry. Increasing N winds along the coast, 
with gusts 35-45 mph developing overnight outer Cape/ACK with
25-30 mph along the immediate coast. 

Thursday...

Ocean storm expected to stall well east of the benchmark in 
response to strong downstream blocking over the north Atlantic. 
Deep moisture plume and a well defined TROWAL will rotate 
westward into New Eng. This will bring periods of rain to
eastern MA which is expected to gradually push west through SNE
in the afternoon. Low level temp profile warm enough to support
rain in the higher elevations. Gusty northerly winds expected 
with gusts 35-45 mph Cape/Islands with a risk for 50 mph over 
ACK where wind advisories may be needed. 25-35 mph gusts 
expected elsewhere. Highs mostly in the 40s, to near 50 in the 
lower CT valley which will be dry into the afternoon. 

&&

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

* Near to below normal temperatures through Saturday night, the
  near to above normal temperatures into early next week

* Periods of showers developing sometime late Wednesday night
  into Friday

* Dry Saturday, then spotty showers with another weak 
  disturbance Sunday

* Mainly dry conditions Saturday through Tuesday, expect for
  some scattered showers possible with a cold front passage 
  Sunday into Sunday night

Details....

Mid level flow not expected to evolve too much through the end
of this week. Still thinking southern New England will be under
the influence of a persistent cutoff meandering between the
Great Lakes and the North Atlantic. This pocket of colder air
aloft will maintain some instability where showers will result
at times. This cutoff should finally move far enough away from
our region towards Saturday. Expecting the weather pattern to be
more progressive as we head into early next week.

At the surface, expecting an offshore low pressure to
retrograde back to the west Thursday night into Friday. While
this low should remain over the North Atlantic, it should get
close enough to produce a period of showers, especially across
eastern MA. Depending upon the exact timing, which is not yet
known, there is a risk for some wet snowflakes across the 
higher terrain of central and western MA Thursday night.

With a high pressure farther to the north, the pressure gradient
increases. Could be quite gusty towards the coasts during this
time, too. 

As this low pressure moves farther away Friday into Saturday,
looking at a drying trend. Winds will diminish Friday night, 
but will remain onshore so could see a few isolated showers 
lingering across Cape Cod and the islands. High pressure then 
passes by Saturday, with another cold front sweeping across our
region Sunday. We should return to the influence of a high
pressure early next week.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

Through 12z...
MVFR cigs Cape/Islands spreading inland across SE MA, otherwise
mainly VFR. 

Today...Moderate confidence due to some uncertainty with how 
far inland MVFR cigs will track.

Expect MVFR cigs developing across much of eastern MA/RI this 
morning with pockets of IFR this afternoon outer Cape/Islands. 
Mainly VFR to the west. Low risk for some light rain developing 
late in the day Cape/Islands. N wind gusts 25-30 kt developing 
in the afternoon over Cape/Islands.

Tonight....Moderate confidence. 
MVFR cigs eastern MA/RI with localized IFR outer Cape/ACK. 
Mainly VFR to the west. Occasional light rain developing over 
the Cape/Islands and possibly spreading across eastern MA 
overnight. N wind gusts to 35 kt over ACK and outer Cape with 25
kt gusts developing along the coast. 

Thursday...Moderate confidence. 
MVFR with occasional rain developing eastern MA/RI gradually 
spreading west and possibly reaching CT valley by late 
afternoon. Areas of IFR Cape/Islands. N wind gusts 35-40 kt 
outer Cape/ACK with 25 kt gusts elsewhere. 

KBOS Terminal...High confidence in trends, but lower confidence
on exact timing. MVFR cigs developing 12-14z.

KBDL Terminal...High confidence.

Outlook /Thursday Night through Sunday/... 

Thursday Night: Mainly MVFR, with areas IFR possible. Windy 
with gusts up to 35 kt. Chance SHRA, patchy FG.

Friday: MVFR/IFR conditions possible. Windy with gusts up to
35 kt. Slight chance SHRA.

Friday Night: Mainly VFR, with local IFR possible. Windy with
local gusts up to 30 kt. Slight chance SHRA.

Saturday: Mainly VFR, with areas MVFR possible. Breezy. 

Saturday Night: VFR. 

Sunday: Mainly VFR, with local MVFR possible. Chance SHRA.

&&

.MARINE...
Gale warnings issued for eastern MA waters as strong ocean storm
to the south results in a strengthening low level jet. N wind
gusts to 35-40 kt develop tonight and continue into Fri. SCA 
for south coastal waters west of Cape Cod with gusts mainly
below 35 kt. Rain developing tonight over eastern MA waters and
moving west through Thu. Some vsby restrictions likely. 

Outlook /Thursday Night through Sunday/...

Thursday Night: Low risk for gale force winds with gusts up to
35 kt. Rough seas up to 18 ft. Rain showers likely, patchy fog.
Local visibility 1 nm or less.

Friday: Strong winds with gusts up to 35 kt. Rough seas up to
19 ft. Chance of rain showers. 

Friday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 30 kt. Rough seas up to 18 ft. Slight chance of
rain showers. 

Saturday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Rough seas up to 16 ft. 

Saturday Night: Winds less than 25 kt. Rough seas up to 13 ft. 

Sunday: Winds less than 25 kt. Rough seas up to 10 ft. Slight
chance of rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Gale Warning from 1 AM Thursday to 8 PM EDT Friday for ANZ231-
     232-250.
     Small Craft Advisory from 11 AM this morning to 8 AM EDT 
     Friday for ANZ233>235-237.
     Small Craft Advisory from 1 AM Thursday to 8 AM EDT Friday for 
     ANZ230-236.
     Small Craft Advisory until 8 PM EDT Thursday for ANZ251-256.
     Gale Warning from 7 PM this evening to 8 PM EDT Friday for 
     ANZ254-255.

&&

$$
SYNOPSIS...KJC
NEAR TERM...KJC
SHORT TERM...KJC
LONG TERM...Belk
AVIATION...Belk/KJC
MARINE...Belk/KJC