351
FXUS61 KBOX 240437
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
1237 AM EDT Tue Sep 24 2024

.SYNOPSIS...
Weak high pressure will build over our region into Tuesday, but
continued onshore winds should keep cloudiness in place,
especially near the coast. Rain chances return late Wednesday
into Thursday as a front moves through the area. Dry and warmer
weather looks to follow through the weekend.

&&

.NEAR TERM /THROUGH TODAY/...
10 PM Update

Forecast looks to be on track. Only made some minor tweaks to
reflect new guidance. Clouds will persist across the area with
weaker winds overnight.

Previous discussion...

Area of light showers assocd with a weak
shortwave are moving into SE NY and SW CT and will remain mostly
south and west of Hartford county this afternoon where deeper
moisture present. Further E across CT drier air in low-mid
levels should prevail. Meanwhile a few very light showers
continue to back in from the ocean across eastern MA into RI so
can`t rule out a spot light shower or sprinkle into this
evening.

Weak upper trough moves east of New Eng tonight followed by mid
level ridging moving in from the west. Meanwhile, surface ridging
will build south into SNE. Surface and deeper layer ridging will
promote large scale subsidence with wedge of drier air from the
north resulting in dry conditions. Varying amounts of cloud
cover expected and patchy late night fog possible in the CT
valley. Lows will range from the upper 40s interior to low-mid
50s coastal plain. Still a bit breezy over the Cape/Islands with
gusts to 20 mph at times.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
Tuesday...

Very little change in the pattern with surface and upper level
ridging in place. Wedge of somewhat drier air in the column
persists with deeper moisture remaining to the west. Expect
another mainly dry day, although considerable cloudiness again
with a low risk for a few light showers or sprinkles from
persistent easterly flow and low level moisture. Very similar
low level temps to today will lead to highs mid-upper 60s to
around 70 in parts of the CT valley, with E-NE winds 10-15 mph.

Tuesday night...

Upper level ridge axis shifts to the east as a weak shortwave
moves to the north and west. Deep moisture plume assocd with the
shortwave approaches but bulk of showers will remain to the
west where best moisture and forcing is located. Just a low
risk for a shower spilling into western MA late at night. Lows
will range from the upper 40s to mid 50s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Key Points:

 * Showers possible late Wed-Thu with passing front
 * Dry and warmer pattern follows through early next week

Main focus is on Wed-Thu time frame as deepening upper trough and
its associated fronts cross region bringing our next chance at any
appreciable rainfall which is certainly needed despite parts of SNE
receiving a good dose of rain over weekend. Not seeing a lot of
parameters that suggest much in way of rainfall, more like 0.25 to
0.50 inch this time, and even convective indices are not overly
impressive or favorable for thunderstorms, though a few cannot be
ruled out due to decent lapse rates and limited surface-based CAPE.

Once this system departs Thu, it appears we`re in for another
stretch  of dry and seasonably warm weather into  at least early
next week. Broad upper ridge builds from Great Lakes into New
England which takes appearance of an omega block, meaning ridge
doesn`t go anywhere for several days and maintains troughing over
middle of country and over north Atlantic.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Forecast Confidence Levels:

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


Tuesday...High Confidence.

Mainly VFR with pockets of MVFR possible as stato cumulus form
again in the late morning to early afternoon. Winds stay onshore
out the East at 5-10 knots, higher over Cape Cod and the Islands
at 10-20 knots.

Tuesday Night...Moderate Confidence.

MVFR with pockets of IFR possible esspically closer to the
higher terrian. Winds remain east at 5-10 knots.

Wednesday... Moderate Confidence

MVFR possibly improving to VFR. Winds remain east at 5-10 knots.
Rain chances increase across western MA and CT late in the day.


BOS TAF...High Confidence in TAF.

Mainly VFR with periods of MVFR possible. Winds remain east at
10-15 knots for entire TAF period.

BDL TAF... High Confidence in TAF.

Mainly VFR today, turning MVFR tonight. Winds remain ENE at
5-10 knots for entire TAF period

Outlook /Wednesday Night through Saturday/...

Wednesday: Mainly VFR, with areas MVFR possible.

Wednesday Night: Mainly VFR, with local IFR possible. Chance
SHRA.

Thursday: Mainly VFR, with areas IFR possible. Slight chance
SHRA.

Thursday Night through Friday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Tonight through Tuesday night...High Confidence.

NE flow will gradually weaken through tonight. Gusts to 25 kt
over SE waters will diminish below SCA tonight with E-NE wind
10-20 kt Tue and Tue night. Rough seas, up to 9 ft, over outer
waters will slowly subside Tue into Tue night but remain above 5
ft through the period. SCA for outer waters extended through Tue
night.

High rip current risk for Tuesday. Seas are slowly subsiding
but leftover easterly swell will support dangerous rip currents.

Outlook /Wednesday Night through Saturday/...

Wednesday: Winds less than 25 kt. Areas of rough seas.

Wednesday Night: Winds less than 25 kt. Areas of rough seas.
Slight chance of rain showers.

Thursday: Winds less than 25 kt. Local rough seas. Slight
chance of rain showers.

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Slight
chance of rain showers.

Friday: Winds less than 25 kt. Areas of seas approaching 5 ft.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents from 8 AM EDT this morning through this
     evening for MAZ007-019-020-022>024.
RI...High Risk for Rip Currents from 8 AM EDT this morning through this
     evening for RIZ006>008.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for ANZ250-251-
     254>256.

&&

$$

SYNOPSIS...KJC/JWD
NEAR TERM...KJC/Hrencecin
SHORT TERM...KJC
LONG TERM...JWD
AVIATION...KP
MARINE...KJC/JWD