268
FXUS61 KBOX 180646
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
246 AM EDT Thu Jul 18 2024

.SYNOPSIS...

A cold front moves into southern New England today bringing lower
humidity away from the south coast. The front moves offshore tonight
with high pressure in control Friday through the weekend. This
brings seasonable temperatures and comfortable humidity levels.
Dry and pleasant weather this weekend. The pattern turns more
active again next week with increasing humidity.

&&

.NEAR TERM /THROUGH TODAY/...

A cold front will slowly make its way across the region through the
day before stalling along the south coast. This means that relief
from the humidity won`t arrive for most until later today, and
overnight for far southeast MA. We`ve still got dewpoints in the low
70s in northern MA and mid 70s in southern MA/RI at 3 AM. Drier air
will be filtering in on northwest flow today dropping those
dewpoints into the 50s for northwest MA by late morning/early
afternoon. That dry air finally pushes over the Cape and islands by
tonight. In the mean time, that moist airmass will be conducive to
scattered showers and even some thunderstorms along and off the
south coast this morning before pushing off by afternoon. Clouds
will become increasingly sparse through the day by the same token.
Temperatures will be warm but not as warm as days past, with cooler
air filtering in in the low and mid levels. Highs max out in the mid
to upper 80s.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM FRIDAY/...

The real difference will be felt overnight as those lower dewpoints
allow for much cooler temperatures than we`ve felt recently, in the
50s and 60s. Friday is the pick of the week as high pressure moves
overhead and rising heights aloft allowing for clear skies, cooler
temperatures (upper 70s to mid 80s), and a much less humid airmass.
Dry and quiet weather to take us into the weekend.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
High pressure over the Great Lakes will extend eastward into SNE.
This will leave the region with dry and pleasant conditions through
Sunday. High temperatures slowly climb from the mid 80s on Friday
and Saturday to the upper 80s on Sunday. Dewpoints Friday start out
in the low 60s, but climb into the mid to upper 60s for Saturday and
Sunday. Global guidance does show roughly 100-300 J/kg of MUCAPE
will be available in western portions of SNE Saturday afternoon.
With a little bit of cyclonic vorticity aloft, this could lead to
some isolated low topped showers. Saturday will likely be the most
cloudy day of the weekend with a rather thick deck of cirrus clouds
aloft associated with the weak cyclonic vorticity impulse.

Next Week

A more active pattern looks to set in again for next week as deep SW
flow aloft kicks back in bringing increased moisture back and
several weak shortwaves towards SNE. Temperatures through the week
look to stay in the mid 80s, but dewpoints will be on the rise again
reaching the 70s by Tuesday staying there through the end of the
week. Timing these features this far out is difficult given the
spread in deterministic and ensemble guidance. Will need to monitor
trends in the coming days for severe convection with CSU ML probs
showing 5% severe on days 7 & 8.

&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
Forecast Confidence Levels:

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

06z TAF update...

Today...Moderate confidence.

Weakening convection this morning is exiting the east coast of
MA with patchy SHRA behind. Areas of MVFR-IFR stratus and
patchy fog will impact the south coast and Cape and Islands. But
rest of area should remain VFR outside of any convection. Areas
of MVFR-IFR cigs likely impacting portions of RI and eastern MA
in the morning, but improving to VFR 14-16z except a bit later
over the Cape/Islands. VFR interior. A few showers or a t-storm
possible over Cape/Islands in the morning. NW wind around 10 kt
interior, with winds turning SW along the south coast.

Tonight...High confidence.

VFR. Light NW winds.

Friday and Friday night...High confidence.

VFR. Light W winds with onshore flow at coasts. Overnight winds
become west at all terminals.

KBOS TAF...Moderate confidence in TAF.

Line of t-storms expected to impact the terminal 00-01z. Brief
gusts to 40 kt possible if storms hold together. A period of
MVFR cigs possible late tonight and Thu morning, otherwise VFR.

KBDL TAF...Moderate confidence in TAF.

A few additional showers or a t-storm may impact the terminal
through 03z.

Outlook /Friday Night through Monday/...

Friday Night: VFR.

Saturday: VFR. Slight chance SHRA.

Saturday Night through Monday: VFR.

&&

.MARINE...
Forecaster Confidence Levels:

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

Through tonight: High confidence.

Winds diminishing, SW becoming NW then N Thu night behind the
front. Seas over south coastal waters will be 5-6 feet today,
diminishing overnight. Showers and a few t-storms continue
into the early afternoon, especially southern waters.

Friday: High confidence.

Winds 5-10 kts. Seas 2-4 feet.

Rip Currents...

A rip current statement is in effect into this evening along
south coastal beaches due to high risk for rip currents. Leftover
5-6 ft southerly swell will result in dangerous rip currents.

Outlook /Friday Night through Monday/...

Winds less than 25 kt.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...High Risk for Rip Currents from 8 AM EDT this morning through this
     evening for MAZ020-021-023-024.
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 this morning for ANZ232.
     Small Craft Advisory until 8 PM EDT this evening for ANZ235-
     237.
     Small Craft Advisory until 2 PM EDT Friday for ANZ254>256.

&&

$$

SYNOPSIS...BW/KP
NEAR TERM...BW
SHORT TERM...BW
LONG TERM...KP
AVIATION...BW/KP
MARINE...BW/KP