000
FXUS61 KBOX 281742
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
142 PM EDT Sun Apr 28 2024

.SYNOPSIS...
Warm but unsettled conditions today with a few chances of
widely scattered showers through early Monday. Mainly dry and
warm temperatures on tap for Monday, except it`s considerably
cooler along portions of the immediate coast. A backdoor cold
front will bring cooler temperatures Tuesday and Wednesday
before it warms up again by late in the week. The greatest risk
for a period of showers will be later Tuesday into Wednesday.
Next period of unsettled weather arrives around Saturday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
9 AM Update...

Variable cloud cover exists across the region this morning
ranging from clearing skies out in northwestern MA to overcast
ceilings at just 1000ft in several areas, leading to a slow
start to daytime heating. Most localities remain in the mid 40s
to low 50s at this hour, but sunnier skies developing late this
morning and early afternoon will lead to quick jump in temps
into the mid 60s and low 70s. As mentioned by the previous
forecaster, will continue to monitor the chance for scattered
showers this afternoon and again late tonight.


Previous Update...

Numerous showers across southern New England into northern New
York early this morning, in northern New York there is enough
instability for rumbles of thunder. These showers are associated
with a warm front that is slowly making its way across the
northeast states. Would not be shocked if a couple make it to
western Massachusetts or northwestern Connecticut. Otherwise,
showers east of the CT River will diminish shortly after
sunrise.

Surface high pressure which gave us wonderful conditions over the
past couple of days is shifting south along with surface pressure
falls. Today features more clouds than sunshine. WAA increases PWATs
across southern New England, well above an inch in most cases.
Aloft, mid-level ridge with pulses of energy provides enough lift to
keep the clouds about and a few hit-and-miss showers. An isolated
rumble of thunder is not out of the question for areas furtherest
north and west where a some breaks in the clouds may allow for a few
hundreds units of CAPE. Window for these showers are between 22z and
03z, does look to be more sct`d in nature. Will say there are some
discrepancies in the CAMs this morning, most notably the ARW, which
shows more widespread light to moderate rains with potential for
embedded thunder into southern Connecticut.

Given higher PWATs, higher humidity is on tap today, dewpoints are
increasing through the 40s and 50s. This is most noticeable since the
previous two days have featured dewpoints in the 20s and 30s. Highs
this afternoon climb into the upper 60s and lower 70s away from the
coast. Perhaps a few mid 70s in the mid CT River Valley. The coastal
plain, areas south of Boston to Providence area in the mid 60s. The
immediate south coast will be the coolest do to the onshore winds,
from the southwest, keep temperatures in the mid 50s to 60
degrees.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
A mild night ahead, many locations are in the lower and mid 50s, at
the coast temperatures are slightly cooler in the upper 40s and low
50s. Deep southwest flow and overcast sky cover helps maintain these
temperatures. Any lingering showers exit the region between 03z and
06z. Do think there will be areas of coastal fog that develops, many
VSBY guidance show potential of widespread fog and/or low stratus. A
wind shift to the north-northwest around dawn should help to advect
lower dewpoints, this should help to cut down on the duration of the
fog. That said, a later shift in the wind could prolong the fog
across southeast Massachusetts and Rhode Island.

Clouds to start Monday, mid-level ridging is nearly over New England
by afternoon should promote cloud cover to gradually thin. Otherwise
a warm afternoon away from the coast. While coastal towns are in the
upper 50s and lower 60s, just a few miles inland temperatures
quickly climb into the 70s! Further inland, mid and upper 70s are a
good possibility. In fact, NBM has 20-30 percent probabilities of
80F across the lower CT River Valley, Springfield to Hartford. What
will be tricky, how far inland does the sea breeze make it. If the
guidance shows the sea breeze to be a bit strong it could mean the
forecast highs will need to be lowered. In addition, if clouds
remain stubborn and don`t thin out enough, it could lead to cooler
temperatures as well. Something to keep in mind heading into
Monday.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Key Points...

* Periodic rain chances through the week, first late Tue/Wed then
  again on Friday.

* After a warm start to the week temps cool Tue/Wed before warming
  back up late week.

Details...

Tuesday and Wednesday...

Tuesday a weak surface low pressure moves into SNE and this in
conjunction with the high to the north will push a backdoor cold
front through the region taking those 70s we enjoyed on Monday out
of the forecast for two days. Highs will be limited to the 60s
(inland) and 50s (along the coast) each day. A mid level shortwave
moves out of the Great Lakes Tuesday night bringing a round of light
rain to the region overnight into Wednesday. The best forcing from
divergence at 300 mb and upslope orographics will place the
bullseye for the largest rainfall totals over northern/central
MA and areas further to our north and west.

Thursday through Saturday...

Mid level ridging then builds in for the latter half of the week
leading to a warming airmass (highs back into the 70s!) and dry
weather. The trend in the guidance over the last 24 hours has been
to slow the advancement of our next disturbance, now looking more
likely to bring unsettled weather for sometime over the weekend but
as early as Friday night. GEFS ensemble guidance is more excited
about the possibility of measurable rain Friday night than the EPS;
for now sticking with a blend and low POPs.

&&

.AVIATION /18Z SUNDAY THROUGH THURSDAY/...
Forecast Confidence Levels:

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

18Z Update...

Through tonight... Moderate confidence in fog formation

Scattered showers and an isolated rumble of thunder possible
this evening, between 22-03Z. Generally VFR conditions through
03Z with low end VFR to MVFR cigs developing behind departing
showers away from the Cape and Islands. IFR with localized LIFR
likely as fog forms on the Cape/MVY/ACK after 06Z tonight.

Winds SW becoming NW overnight. Gusts to 15kt possible through
early evening, generally less than 10kt thereafter.

Tomorrow... High Confidence in Trends

MVFR/IFR may persist through ~15/16Z but will
eventually improve to VFR at all terminals by mid day. Winds NW
across the interior but a seabreeze will develop along the
coast, from the E/ESE along the eastern MA coast and from the
ESE/SE around Narragansett Bay. Winds around 10kt expected.

Tomorrow Night..

Mainly VFR with localized MVFR in widely scattered shower
activity. Winds generally light and variable in direction.

KBOS TAF...High confidence in TAF.

VFR to MVFR behind scattered showers this evening, between
23-03Z. Expecting fog to stay well south of the terminal as the
winds shift from the SW to the NW overnight. Seabreeze tomorrow
with NE winds by 13Z and ESE winds by 16Z. VFR redevelops
quickly tomorrow morning.

KBDL TAF...High confidence in TAF. Scattered showers this
evening between 22Z and 03Z, an isolated rumble of thunder is
possible but confidence is much too low to include in the TAF.
Winds SW becoming NW overnight and maintaining direction through
Monday. VFR through the period with a chance for MVFR late
Monday evening.


Outlook /Monday Night through Thursday/...

Tuesday: Mainly MVFR, with areas VFR possible. Chance RA.

Tuesday Night: Mainly MVFR, with local IFR possible. Chance RA.

Wednesday: Mainly VFR, with local IFR possible. Chance RA.

Wednesday Night: Mainly VFR, with local MVFR possible.

Thursday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through Monday... High confidence.

Generally tranquil boating conditions expected through Sunday
outside of a few rounds of widely scattered showers overnight
tonight and tomorrow evening. Onshore breeze across the eastern
waters will subside quickly this evening giving way to primarily
south/southwest winds for Sunday. Some patchy fog possible
Sunday night into early Monday morning. Dry conditions with mix
of clouds Monday afternoon along with northerly winds 10 to 15
knots. Seas mainly 3ft or less all waters.

Outlook /Monday Night through Thursday/...

Monday: Winds less than 25 kt.

Monday Night: Winds less than 25 kt. Slight chance of rain.

Tuesday through Wednesday: Winds less than 25 kt. Chance of
rain.

Wednesday Night through Thursday: Winds less than 25 kt.

&&

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

&&

$$

SYNOPSIS...BW/Dooley
NEAR TERM...BW/Dooley/KS
SHORT TERM...Dooley
LONG TERM...BW
AVIATION...KS
MARINE...BW/Dooley