Harmony, Rhode Island 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

069
FXUS61 KBOX 152318
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
718 PM EDT Fri May 15 2026

.WHAT HAS CHANGED...

Chances for some brief scattered showers late Saturday night
into very early Sunday morning. Confidence increasing in near
record high temperatures possible by Tuesday and/or Wednesday
along with the potential for a round of strong to severe
thunderstorms.

&&

.KEY MESSAGES...

- Fog possible overnight before warm-up kicks off Saturday.

- Unseasonably warm temps Sun through Wed with near record high
  temps into the 90s possible Tue and/or Wed.

- Strong to severe thunderstorms possible by Tue with perhaps a
  better potential by Wed but a lot needs to be sorted out.

- Seasonable temperatures return by next Thu and Fri.

&&

.DISCUSSION...

KEY MESSAGE 1...Fog possible overnight before warm-up kicks off
Saturday.

The closed low aloft will continue shifting offshore through
tonight, being replaced by more zonal flow to kick off the weekend.
The associated surface low currently located off to our east that is
providing the moisture plume around NE MA will also progress east
through tonight and pull away from the region. Latest mesoanalysis
indicates some surface-based CAPE along the south coast that`s
helping fuel some pop-up showers. These will likely continue through
this evening, ending around sunset. Cloud cover will linger before
winds start to shift more NW then SW, and with the moist ground
conditions, patches of fog may develop across southern New
England, extending beyond the usual areas in the river valleys
and other frequently foggy areas. Lows will once again be
mostly in the 40s with dew points not far behind them.

Southwest flow closer to the surface really kicks up Saturday
morning as the quasi-zonal flow aloft takes hold. Skies clear
out and with the full sun along with warmer air aloft, highs
will rise into the 70s across southern New England. Spots in the
CT Valley may also approach 80. Winds may gust between 20-25
MPH in the afternoon. A weak shortwave passing just to our north
overnight may also bring the chance for some light showers late
Saturday night into Sunday, but not much else expected in the
way of precipitation tomorrow. With warmer air remaining aloft
and SW flow starting to shift more W, lows overnight Saturday
will likely only fall into the mid to upper 50s.

KEY MESSAGE 2...Unseasonably warm temps Sun through Wed with near
record high temps into the 90s possible Tue and/or Wed.

High confidence continues in a pattern change to unseasonable warm
temperatures for the first half of next week and potentially
flirting with record highs on Tue/Wed. GEFS/EPS guidance continue to
show a building Bermuda High pressure system resulting in above to
well above normal height fields.

W-SW flow should push high temps into the 80s on Sun away from the
Cape and Islands. A weak backdoor cold front may bring briefly
cooler temps Mon...mainly on the immediate coast. Highs Mon on the
immediate coast probably in the upper 60s and 70s while 80+ risk
will be confined to the interior. The hottest days look to be Tue
and/or Wed depending on the timing of a cold front. 925T near +24C
should result in the potential for high temperatures to climb into
the 90s away from any modified marine influences. This may result in
record high temperatures being challenged at least in areas away
from the south coast.

KEY MESSAGE 3...Strong to severe thunderstorms possible by Tue with
perhaps a better potential by Wed but a lot needs to be sorted out.

Quite the ways out there...especially for a convective forecast.
That being said...there are some signals for potentially strong to
severe thunderstorms later Tue and perhaps a better chance by Wed.
This will be dependent upon the timing of a cold front...but given
anomalous/near record warmth the potential is there. In fact...much
of our machine learning guidance indicates some modest severe
weather probabilities for a Day 4-5 forecast...so this is certainly
something to watch.

KEY MESSAGE 4...Seasonable temperatures return by next Thu and Fri.

The long range guidance is in good agreement in the return of
seasonable temperatures by Thu and Fri behind the mid-week cold
front.

&&

.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...

Forecaster Confidence Levels...

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

00z TAF Update...High confidence in trends with moderate
confidence in timing.

Lingering MVFR with some localized IFR conditions across eastern
MA will continue to improve to VFR as the evening wears along.
Most locations should be VFR by midnight...except across parts
of the Cape and Islands. However...we will need to watch for
localized patchy ground fog developing overnight in the
typically prone locations given light/calm winds and wet
grounds from the recent rain.

Any fog patches quickly burn off by early to mid morning Sat.
Otherwise...VFR with SW wind gusts of 20 to 25 knots developing
by Saturday afternoon. Mainly VFR conditions continue Sat night
with SW winds of 5 to 15 knots and some 20-25 knot gusts
persisting near the coast. Some LLWS possible late Sat night
along with perhaps a brief passing shower or two.

KBOS...High confidence in trends with moderate confidence in
timing.

KBDL...High confidence in TAF.

Outlook /Sunday through Wednesday/...

Sunday: VFR. Breezy.

Sunday Night: VFR.

Monday: VFR. Breezy.

Monday Night: VFR.

Tuesday through Tuesday Night: VFR. Breezy.

Wednesday: Mainly VFR, with local IFR possible. Breezy.
Scattered SHRA, scattered TSRA.

&&

.MARINE...
Forecaster Confidence Levels...

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

SCAs remain in effect on most waters as easterly swell brings
elevated seas in the 4-7 ft range tonight. Winds shift more SW
tonight into Saturday, getting up to around 15 kt sustained
Saturday afternoon. Gusts to 25 kt possible then as well. Fog
possible again tonight over the waters.

Given the continued elevated seas and increase in winds
tomorrow, SCAs have been extended through Saturday into part of
Saturday night. Winds and seas are expected to remain elevated
then, and possibly into Sunday morning.

Outlook /Sunday through Wednesday/...

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

Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 25 kt. Areas of seas approaching 5 ft.

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

Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 25 kt. Areas of seas approaching 5 ft. Scattered rain
showers, isolated thunderstorms.

&&

.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 2 AM EDT Sunday for ANZ235-237-251.
     Small Craft Advisory until 4 AM EDT Sunday for ANZ250-254>256.

&&

$$

DISCUSSION...Frank/Hrencecin
AVIATION...Frank/Hrencecin
MARINE...Frank/Hrencecin