095
FXUS61 KBOX 131058
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
658 AM EDT Mon May 13 2024

.SYNOPSIS...
Mainly dry conditions today and turning milder with more
seasonable temperatures as high pressure builds to the south. A
warm front will bring scattered showers tonight followed by
warm weather Tuesday, but a few showers are possible in the
interior during the afternoon. A coastal storm lifting NE from
the middle Atlantic coast may bring showers and cooler
temperatures Wednesday, and unsettled weather could linger into
Thursday as the low pressure is slow to depart. High pressure
returns Friday then another system may bring more rain next
Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Shortwave ridging moves into New Eng today with surface high
pres south of New Eng. Dry air in the column to start the day
will result in lots of sunshine this morning, then clouds will
increase during the afternoon as warm advection increases ahead
of an approaching warm front. A modest low level jet transports
higher PWATs into New Eng from the west during the afternoon
which may lead to a few showers in western MA mid-late
afternoon, otherwise dry weather today. The S-SW flow will bring
a milder airmass into SNE as 925 mb temps increase to 10-12C.
Highs should reach the upper 60s to lower 70s, but cooler along
the immediate coast where sea-breezes develop.

&&

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

Warm front will be moving into SNE tonight with PWATs
increasing to 1-1.25". Deepening moisture plume ahead of the
front moves across the region 00-06z which will bring scattered
showers, especially north of the Pike where best forcing sets
up. Then dry slot moves in behind the front 06-12z so shower
activity will exit to the north and east overnight. S-SW winds
and higher dewpoints advecting into the region will result in a
milder night with lows upper 40s to lower 50s.

Tuesday...

Warm sector airmass overspreads SNE on Tue with warm and somewhat
more humid airmass. Some stratus is possible across northern MA to
start the day, otherwise expect partly to mostly sunny skies with
clouds increasing later in the afternoon. 925 mb temps increase to
15-17C supporting highs 75-80, perhaps a few lower 80s in the
interior valleys, but 60s near the south coast due to increasing S-
SW flow. Dewpoints will be climbing through the 50s. It will become
breezy with soundings suggesting gusts to 20-30 mph in the
afternoon.

Marginal instability across the interior which may lead to a few
convective showers developing mid-late afternoon, but better chance
of showers and t-storms will be to the north and west where better
moisture and instability closer to a frontal boundary.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Key Points

* Rain possible Wednesday with showers lingering into Thursday

* Mainly dry Friday, then unsettled wet weather returns for the
  weekend.

* High temps remain seasonable with onshore flow

Wednesday

Shortwave trough exits out of the Ohio River Valley and passes just
south of SNE.  With the best forcing to the south, this has caused
models to trend the associated surface low further south. This shift
south has been a trend with guidance over this time range in the
last week. Wouldn`t be surprised if models keep shifting the low and
QPF south over the coming days. With the shift south, Ensemble QPF
probs have decreased significantly. Probs for 1 inch of rain is now
less then 10% and for 0.5 inches less then 30%.  High temps drop
back into the mid to upper 60s with 850mb temps dropping back to +7C
along with showers and thick cloud cover around much of the day.

Thursday and Friday

Guidance has trended slower kicking out the shortwave as it tries to
cutoff over the mid Atlantic coast due to downstream blocking. This
has resulted in rain chances lingering into Thursday before an
abnormally dry airmass and NW flow kicks in for Thursday afternoon
into Friday. High temps both days should reach the upper 60s to mid
70s with mainly sunny conditions and onshore flow. The only wrench
in a nice pleasant end to the week is if the cutoff stalls just
south of the region which would bring cooler temps, cloudy skies,
and more rain. Winds Thursday could become gusty up to 35mph
esspically near the coasts as the surface low passes offshore to the
east.

Next Weekend

Another shortwave trough exits the Great Lakes Saturday into Sunday.
Guidance remains quite spread on the timing and amplitude of this
shortwave. There will likely be rain sometime over the weekend, but
its too early to pin down exact timing and how much will fall. Highs
over the weekend look to remain seasonable in the upper 60s to mid
70s with onshore flow.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
Forecast Confidence Levels:

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


Today...High confidence.

VFR with 5-10k ft cigs developing in the afternoon. A few
showers possible in western MA after 18z. S-SW wind 10-15 kt
with sea-breezes developing along the coast.

Tonight...High confidence.

VFR cigs with scattered showers moving through the region,
especially north of the Pike. Lower MVFR cigs may develop across
northern MA overnight. S-SW wind 5-10 kt

Tuesday...High confidence.

VFR. A few convective showers possible across interior MA and
northern CT during the afternoon. SW gusts to 20-25 kt
developing.

KBOS TAF...High confidence in TAF.

VFR. Sea breeze develops around 14z. Low chance for a shower
tonight

KBDL TAF...High confidence in TAF.

VFR.  SSW winds.

Outlook /Tuesday Night through Friday/...

Tuesday Night: MVFR/IFR conditions possible. Breezy. Chance
SHRA.

Wednesday: Mainly MVFR, with areas IFR possible. Breezy. SHRA
likely.

Wednesday Night: MVFR/IFR conditions possible. Breezy. Chance
SHRA.

Thursday through Thursday Night: Mainly VFR, with local MVFR
possible. Breezy. Slight chance SHRA.

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

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Tuesday...

Increasing S-SW winds this afternoon into tonight with gusts to 20
kt at times over nearshore waters. SW gusts to 25 kt Tue,
especially eastern MA waters where SCA will likely be needed.

Outlook /Tuesday Night through Friday/...

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

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

Wednesday Night: Low risk for Small Craft Advisory winds with
gusts up to 30 kt. Areas of rough seas. Chance of rain showers.

Thursday: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Areas of rough seas. 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. Seas up to 5 ft.

&&

.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