743
FXUS61 KBOX 261834
AFDBOX

Area Forecast Discussion
National Weather Service Boston/Norton MA
234 PM EDT Tue May 26 2026

.WHAT HAS CHANGED...
No significant changes to the forecast.

&&

.KEY MESSAGES...

- Warm and humid on Wednesday with isolated to scattered showers
  and thunderstorms possible Wednesday afternoon


- Trending cooler for the end of the week with chance of showers Thu.

- Below normal temperatures this weekend into early next week with
unsettled conditions.

&&

.DISCUSSION...
KEY MESSAGE 1...Warm and humid on Wednesday with isolated to
scattered showers and thunderstorms possible Wednesday afternoon

An area of surface high pressure positioned to the south will
continue to support southwest flow and low-level WAA into southern
New England on Wednesday. 925 hPa temps rise to 20-22C which will
support surface temperatures in the mid to upper 80sF on Wednesday
afternoon. Dewpoints increase as well to the low 60s. This will
support some diurnal instability with the latest suite of high
resoution model forecasts suggesting 400-800 J/kg of SBCAPE. 0-6km
shear is modest but sufficient between 30-35 knots to support
organized convection as a moisture starved cold front pushes through
the region Wednesday evening. Mid-level dry air and weak mid-level
lapse rates will be the limiting factors for thunderstorm
development, but enough ingredients are in place to warrant some
risk.

The latest 12Z HREF members depict considerable spread across each
of it`s 5 non time-lagged members. NAMNest and FV3 members support
some isolated shower/thunderstorms near the south coast while the
ARW, NSSL-WRF, and HRRR keep things mostly dry. Leaned on a blend of
guidance to place a 20-25 percent chance of showers or storms over
CT, RI, and southeast MA between 2 and 6PM tomorrow. The cold front
then ushers out any remaining showers and cloud cover to support a
quiet/dry Wednesday night.


KEY MESSAGE 2...Trending cooler for the end of the week with chance
of showers Thu.

Cooler temps Thu and Fri in the post frontal airmass, but near
seasonable with highs upper 60s near the eastern MA coast to low-mid
70s further inland. Northern stream shortwave drops south across the
region Thu with increasing moisture which may lead to scattered
showers developing in the afternoon, especially across eastern half
New Eng. Then on Friday there are timing differences with cutoff low
moving south from eastern Canada. GFS is the quickest among the
deterministic guidance and brings increasing risk of shower from the
north during the afternoon while ECMWF and GGEM and slower. GEFS
ensemble probs of 0.1" QPF suggest a drier/slower solution for Fri
as weak shortwave ridging develops between the 2 systems so leaned
toward NBM PoPs which keeps it mainly dry Fri. Then increasing
shower chances during Fri night as the cutoff low approaches.

KEY MESSAGE 3...Below normal temperatures this weekend into early
next week with unsettled conditions.

Timing differences continue with arrival of anomalous cutoff low
which will impact sensible weather Sat. Consensus of the guidance
favors the cutoff low and accompanying cold pool aloft dropping
south across New Eng during Sat which should be the cooler and
wetter of the weekend days. Expect at least scattered showers Sat
with highs in the 60s with some improvement Sunday. However, the
overall pattern features a blocking pattern into early next with
upper trough persisting across the NE. Multiple shortwave passages
are anticipated which will bring the risk for showers at times early
next week with temps averaging a bit below normal, but a washout is
not expected.


&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
Forecaster Confidence Levels...

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

18Z TAF Update:

Through 00Z...High confidence in TAF.

VFR. Sea-breeze diminishes 21-22Z with winds flipping back to
southwest at BOS.

Tonight...High Confidence

VFR. Light southwest winds. Some fog/low stratus possible near
the south coast which could support a brief period of MVFR/IFR
conditions at Cape/Islands terminals.

Tomorrow...High Confidence

VFR. West winds 5-10 knots. Low risk for afternoon -SHRA/-TSRA
mainly over CT, RI, and Cape/Islands terminals. Best chances
would be after 21Z. Confidence not currently high enough to
include PROB30 group in TAF. MVFR/IFR stratus/fog at ACK.

Tomorrow Night... High Confidence.

Winds flip to the north/northwest between 03-06Z Thursday behind
a cold front. This will push out any fog/low stratus over The
Islands termianls. VFR elsewhere with north/northwest wind 5-10
knots.

KBOS...High confidence in TAF.

KBDL...High confidence in TAF.

Localized fog remains possible early this morning, though
confidence in occurrence and exact timing remains moderate.

Outlook /Thursday through Sunday/...

Thursday: VFR. Breezy. Chance SHRA, slight chance TSRA.

Thursday Night: Mainly VFR, with local MVFR possible.

Friday: VFR.

Friday Night: Mainly VFR, with local IFR possible. Chance SHRA.

Saturday: VFR. Breezy. Chance SHRA.

Saturday Night: VFR. Breezy. Slight chance SHRA.

Sunday: VFR.

&&

.MARINE...
Forecaster Confidence Levels...

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

Tonight and Tomorrow

Southwest winds associated with high pressure to the south will
persist over the coastal waters through tomorrow night. Winds stay
at modest speeds around 10-15 knots with some gusts to 20 knots
possible. Seas remain managable and sub-SCY level with significant
wave heights between 1-3 feet.

Tomorrow Night

A moisture-starved cold front moves over the coastal waters tomorrow
night. This may be accompanied by a few showers and possibly a
thunderstorm near the south coast. Winds shift to the northwest
behind the frount around 10 knots.

Outlook /Thursday through Sunday/...

Thursday: Winds less than 25 kt. Chance of rain showers.

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

Friday: Winds less than 25 kt.

Friday Night: Winds less than 25 kt. Chance of rain showers.

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

Saturday Night: Low risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft. Chance of rain showers.

Sunday: Winds less than 25 kt. Seas up to 5 ft. Slight chance
of rain showers.

&&

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

&&

$$

DISCUSSION...KJC/RM
AVIATION...KJC/RM
MARINE...KJC/RM