199
FXUS61 KBOX 301144
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
744 AM EDT Thu Jul 30 2026

.WHAT HAS CHANGED...
No significant changes.

&&

.KEY MESSAGES...

- Showers linger across southern New England today. Friday will
  still see some showers, though more scattered and accompanied
  by increasing breaks of sun.

- Mix of clouds and sun with seasonable temperatures and some
  humidity this weekend. Next chance for showers and t-storms
  return with a frontal boundary moving in late Sunday into
  Sunday evening, possibly lingering into Monday along the
  southeast coast.

&&

.DISCUSSION...
KEY MESSAGE 1...Showers linger across southern New England today.
Friday will still see some showers, though more scattered and
accompanied by increasing breaks of sun.

A more manageable amount of rain expected today compared to Wednesday
as the upper low continues to spin overhead. The surface low shifts
east over the Gulf of Maine today. This will back low level flow to
the north, eliminating the bulk of the orographic enhancement while
the low level jet pivots and lifts out as well. Even so, given the
cold pool aloft (-10 to -12C at 500mb) and mid level PVA combined
with elevated PWATs and a saturated atmospheric column we`re in for
another day of low clouds, accompanied by light to moderate rain
showers. By Friday we finally get some mid level height rises as the
trough lifts into the maritimes and this allows for some drier air
filter in reducing shower coverage and increasing the breaks of sun
on Friday. Friday`s building ridge will also mean a warmer
airmass nudging into the region bringing us upper 70s/low 80s
for the first time in several days.

KEY MESSAGE 2...Mix of clouds and sun with seasonable
temperatures and some humidity this weekend. Next chance for
showers and t-storms return with a frontal boundary moving in
late Sunday into Sunday evening, possibly lingering into Monday
along the southeast coast.

Weekend on the whole looks favorable with high pressure to our south
allowing for modest warming and an increase in humidity level too,
with a mix of clouds and sun. Seasonable highs in the low to mid 80s.

Things turn more unsettled as we move into late Sunday into Sunday
evening, and in some global model ensemble solutions possibly
lingering into part of Monday. Another seasonably-strong upper level
trough moving across Ontario and into Quebec drags a slow-moving
surface cold front through the northern-central Appalachians and the
Northeast. This frontal boundary will draw upon some deeper moisture
with precipitable water values increasing to 1.5-1.7", about 1
standard deviation above early August climatology. This front looks
to offer our next chance for rain/thunderstorms, with most of the
ensemble means offering a timing around late in the day Sunday into
Sunday night. AI-based severe weather progs show very limited
chances for severe weather, which seems reasonable as flow aloft is
not particularly strong and the evening time-of-day putting a limit
to how much destabilization can occur. While nothing like the
lingering slow-moving rainstorm, this front could still produce some
decent rainfall with EPS/GEFS probabilities showing moderately high
(40-70%) probs 24-hr rains over a half inch but low (< 30%) probs of
24-hr rains over an inch. Some spots in interior Southern New
England have seen higher rain totals in the last 24-48 hrs, so these
areas could need to be monitored for heavy rain/flooding but it`s
still viewed as a low risk at the moment. Where there is still some
uncertainty is if a lobe of mid-level energy on the southern end of
the mid-level trough axis can close off until a closed low over the
lower Ohio Valley; if this happens, we`d still clear out
sufficiently enough by early Monday, but there may be some lingering
clouds/showers Monday near the southern waters and perhaps into
southeast New England. That`ll need to be monitored in subsequent
model runs.

&&

.AVIATION /12Z THURSDAY THROUGH MONDAY/...
Forecaster Confidence Levels...

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

12z TAF Update:

Today...Moderate confidence.

LIFR/IFR cigs with MVFR vsbys in areas of lingering light
rain/drizzle and fog, only slowly improve to IFR/MVFR cigs and
MVFR/VFR vsbys. Low risk for a few heavy showers and isolated
TSRA across RI and southeast MA terminals this PM. Light surface
winds with broad area of low pressure over the region.

Thursday Night...Moderate confidence.

Widespread IFR and lower end MVFR in lingering spotty light
showers/drizzle and areas of fog. N winds remaining generally
below 10 kt.

Friday...High confidence.

VFR. Light N winds with coastal sea breezes. Slight chance of
some scattered showers.

KBOS Terminal...Moderate confidence in TAF.

KBDL Terminal...Moderate confidence in TAF.

Outlook /Friday through Monday/...

Thursday Night: Mainly VFR, with local IFR possible. Patchy BR.

Friday: VFR. Slight chance SHRA, slight chance TSRA.

Friday Night: VFR.

Saturday: VFR. Breezy.

Saturday Night: Mainly VFR, with local MVFR possible.

Sunday: Mainly VFR, with local MVFR possible. Breezy. Chance
SHRA, slight chance TSRA.

Sunday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, slight chance TSRA.

Monday: VFR. Chance SHRA, slight chance TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

As the low shifts overhead and begins to move into the maritimes
winds will become N/NE on Thursday then N Thursday night.
Seas will remain rough, 3-5 ft, diminishing to 2-4 ft by Friday.
Rain showers will limit vsby at times. Vsby 1-3NM at times in
areas of fog and showers much of Thursday, improving Thursday
night into Friday.

Outlook /Friday through Monday/...

Thursday Night: Winds less than 25 kt. Seas up to 5 ft. Patchy
fog. Local visibility 1 to 3 nm.

Friday: Winds less than 25 kt. Seas up to 5 ft.

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

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

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

Monday: Winds less than 25 kt. Areas of rough seas. Chance of
rain showers.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ250.
     Small Craft Advisory until 2 PM EDT this afternoon for
     ANZ254>256.

&&

$$

DISCUSSION...Loconto/BW
AVIATION...McMinn
MARINE...Loconto/BW