-- Discussion containing changed information from previous version are highlighted. --
903
FXUS61 KBOX 091045
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
645 AM EDT Thu May 9 2024

.SYNOPSIS...
High pressure to the north will bring mainly dry and mild conditions
today. Some showers are possible tonight into early Friday as low
pressure tracks to the south, otherwise drier and cooler for much of
Friday as NE winds develop. Cooler than normal this weekend with
rain chances increasing Saturday night and Sunday, then milder
temperatures return early next week but an unsettled weather pattern
will continue.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Weak shortwave ridging develops today between departing shortwave to
the east and upstream shortwave across Gt Lakes. Somewhat drier air
in the column will be present today which will yield mainly dry
conditions, although moisture will begin to increase from the south
later today as low pres moves to mid Atlc region. This increase in
moisture will lead to low risk for a few showers late today near the
south coast, otherwise mainly dry.

Fog and stratus in eastern MA should erode by daybreak with a brief
period of partial sunshine this morning before clouds return. Highs
should reach mid-upper 60s and near 70 Hartford to Springfield, but
cooler across east coastal MA as winds turn NE. In fact, expect
temps falling through the 50s during the afternoon along the eastern
MA coast.

&&

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

As mid level trough amplifies over the Gt Lakes, backing flow aloft
will bring increasing moisture northward into SNE. However, there is
uncertainty regarding how far north and east showers will get across
SNE as best moisture will remain to the SW. Best chance for a period
of rain tonight will be from western MA to RI closest to best
moisture, with decreasing probs further NE into portions of eastern
and NE MA.

Lows will be in the 40s tonight, with increasing NE winds along the
south coast and Cape/Islands as low pres moves off the mid Atlc
coast.

Friday...

Some lingering showers are possible Fri, especially across SW
portions of SNE, but drier air will gradually move in from the north
during the day as high pres builds south into eastern New Eng. This
may lead to partial sunshine developing across portions of northern
and eastern MA. NE flow will result in cooler temps Fri with highs
mostly in the 50s, with some lower 60s possible in the CT valley.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Key Points...

* Trending drier this weekend with some sun possible

* Below average temperatures continue through the weekend

* More seasonable temps return next week

Weekend

Shortwave trough passes to the south of the region, as the
associated surface low passes well offshore to the east. Another
weaker shortwave follows quickly behind leaving the region in
cyclonic flow for much of the weekend. With the best moisture and
forcing to the south with the leading shortwave, models have trended
drier with even some breaks in cloud cover possible. High temps over
the weekend have also trended slightly warmer with the possibility
for breaks of sun, however, onshore flow and 850mb temps below 0C
will likely keep high temps below 60F in the east, and below 65F in
the west. Overnight lows also stay on the cool side with the cool
airmass in place staying in the low to mid 40s.

Next week

The pesky upper level low and mid level cold pool finally moves east
as a upper level ridge builds in. Surface flow turns SSW with WAA
bringing 850mb temps back above 0C to even +10C by mid week. High
temps begin to moderate back into the low to mid 70s. As for rain
chances, high pressure to the south should keep things dry early in
the week. Rain chances look to increase again mid to late week as a
shortwave approaches the region, but uncertainty remains high at
this time.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
Forecast Confidence Levels:

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

12Z TAF Update:

Seeing fog and low status burn off quickly this morning
including across the Cape and Islands. Should see those
terminals go and remain VFR by 13z. Otherwise VFR across the
region. There is a low chance for an isolated shower later this
afternoon, but confidence was not high enough to include in TAFs
at this hour.

Today...Moderate confidence.

Mainly VFR cigs, but areas of MVFR cigs across east coastal MA.
N wind around 10 kt turning NE during the afternoon.

Tonight...Moderate confidence.

MVFR cigs expanding westward across SNE. Low prob for IFR.
Scattered showers developing, especially across western half New
Eng. NE wind 5-15 kt.

Friday...Moderate confidence.

Cigs improving to VFR from NE to SW as drier air works in from
the N. A few showers possible, mainly from SW MA and CT to the
south coast.

KBOS TAF...Moderate confidence in TAF. IFR-LIFR stratus and fog
has improved to VFR but cigs may briefly drop down to IFR
before daybreak. Some uncertainty with cigs today which may vary
between VFR and MVFR but no vsby restrictions. NW winds will
become NE this afternoon.

KBDL TAF...High confidence in TAF today. VFR through today, then
cigs may lower to MVFR tonight. Scattered showers possible
tonight.

Outlook /Friday Night through Monday/...

Friday Night: Mainly VFR, with local MVFR possible. Slight
chance SHRA.

Saturday: Mainly VFR, with local MVFR possible.

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

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

Sunday Night: Mainly VFR, with local MVFR possible.

Monday: VFR.
-- End Changed Discussion --

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Friday...

North winds will become NE this afternoon with speeds below 20 kt,
but may increase with gusts 20-25 kt tonight into Fri, especially
over south coastal waters as low pres tracks to the south. Seas
build to near 5 ft over the eastern outer waters late tonight and
Fri. A SCA may be needed for eastern MA waters but confidence not
high enough to issue as conditions look marginal.

Outlook /Friday Night through Monday/...

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

Saturday Night through Sunday: Winds less than 25 kt. Areas of
seas approaching 5 ft.

Sunday Night through Monday: Winds less than 25 kt. Seas
locally approaching 5 ft.

&&

.TIDES/COASTAL FLOODING...
High astronomical tides coupled with onshore flow may result in some
splashover/very minor coastal flooding during the overnight high
tide cycle tonight. However, wind/waves do not appear high enough to
result in a significant issue. The daytime high tides are lower and
do not pose a threat for coastal flooding.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.

&&

$$

SYNOPSIS...KJC/KP
NEAR TERM...KJC/KP
SHORT TERM...KJC
LONG TERM...KP
AVIATION...KJC/KP
MARINE...KJC/KP
TIDES/COASTAL FLOODING...