461
FXUS61 KGYX 290650
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
250 AM EDT Wed Jul 29 2026

.WHAT HAS CHANGED...
A flash flood watch has been issued for today and tonight for
southwestern portions of New Hampshire.

&&

.KEY MESSAGES...
1. A closed low develops over or just west of our region
today and tonight. This will bring multiple rounds of rainfall
with locally heavy rainfall possible resulting in isolated to
scattered flash flooding, especially in southwestern New
Hampshire.

2. The cutoff low is slow to depart, with gradually improving
conditions through the end of the week. A semi-unsettled pattern
remains into next week.

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...

Not much change to earlier forecast philosophies. However, based
on the infusion of latest CAM and ensemble output, we feel a bit
more confidence in at least localized flash flooding across
southwestern NH today and tonight. A flash flood watch has been
issued to cover this possible threat.

Overall, large scale mass fields remain largely unchanged in
latest model output for the next two days or so. The main issue
has been finer scale feature such as where training convection
will take place. Right now the most concern is for the eastern
slopes of the southwestern NH hills and mountains. This is where
the highest PWATs will coincide with instability and an
increasing southeasterly LLJ (helps the upslope process).
Overall, looking like basin averages of 1-2 inches there but
moderate chances for localized amounts up to 5 inches in
persistent convective showers and thunderstorms. This will
likely lead to at least a localized flash flood threat, mainly
this afternoon and evening.

As for the rest of the the forecast area, fog is likely this
morning on the coastal plain. For this afternoon, expect
increasing chances for showers and perhaps a few thunderstorms
with locally heavy rainfall. However, the flood threat is much
lower than southwestern NH. In place, many areas in central and
mountainous ME may be dry for much of the day except the
aforementioned fog and possible drizzle.

KEY MESSAGE 2 DESCRIPTION...

It will be a slow rebound to warmer, drier conditions with the upper
-level low still hanging overhead Thursday, but eventually it is
ejected out to sea by a 500 mb jet streak over the Gulf Stream.
There will at least be a chance for nuisance rain showers until the
low fully exits our region sometime Friday/Friday night, but with
the upper-level forcing collapsing as the surface low
occludes/vertically stacks, the chances for more heavy rain will
decrease as time goes on. Thursday may bring some locally heavy rain
early, especially focused along the coast, but more widespread will
be areas of drizzle/mist, and generally raw conditions for July.
Some mixed signals Friday, as there may be enough cold air and
moisture aloft with the remnants of the trough to fuel some diurnal
showers, but there is also the chance subtle height rises will
result in subsidence and dry conditions prevailing. Cool temperatures
in the 60s on Thursday will increase to more seasonable 70s-low 80s
by Friday.

Saturday looks to generally be a rinse and repeat of Friday, with
only a isolated chance of diurnal/upslope-enhanced showers, and near
seasonable temperatures. The calm weather is short lived, however,
as sizable rain chances return by Sunday, especially for the
interior parts of the forecast area. Model spread begins to increase
by this range, but there is agreement regardless that another slow-
moving, moisture-rich shortwave trough will impact the Northeast
U.S. to start next week. The biggest disparity at this point is the
ECMWF indicating a full cutoff low over the Ohio Valley, while the
GFS shows more of an open wave (but still slow moving) 500 mb
trough. Interests with outdoor activities should plan for rain in
the forecast Sunday-Monday.

&&

.AVIATION /TODAY THROUGH SUNDAY/...
Through tonight...Primary early morning impacts will be
IFR stratus and areas of fog, locally dense.

Ceilings tend to remain IFR this morning, then periods of
RA/TSRA combined with low attendant ceilings and vsbys. Winds
will be primarily out of the SSE at 5-15 kts, gusts to 25 kts.
Locally stronger winds are likely within any thunderstorm. VFR likely
in central and mountainous ME and northern NH. Conditions
deteriorate to IFR or lower most locations tonight.

Thursday: IFR cigs much of the day, with some breaks possible in
the afternoon.

Friday-Sunday: Expect conditions to slowly improve on Friday as
low pressure moves away from the region though scattered showers and
a thunderstorm are possible.  VFR conditions should dominate
Saturday outside of an isolated afternoon shower/storm. Winds at
or below 10kts.

&&

.MARINE...
Broad low pressure moves east into New England. Onshore flow
will result in abundant marine stratus and vis reducing fog
today and tonight.

SCA conditions likely this evening through early Fri with S-SE
wind gusts southwest of Pen Bay up to 25 kts with seas of 3-7
ft.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...Flood Watch from 8 AM EDT this morning through Thursday
     morning for NHZ005-007>009-011-015.
MARINE...Small Craft Advisory from 11 PM this evening to 8 PM EDT
     Thursday for ANZ150-152>154.

&&

$$

DISCUSSION...Barker/Ekster/Schroeter