115
FXUS61 KGYX 171830
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
230 PM EDT Sun May 17 2026

.WHAT HAS CHANGED...
Increased precipitation chances this afternoon to highlight an
isolated convective threat across southwestern New Hampshire.
A more showery Monday appears likely as a system brings light
showers to northern New England. Hot weather remains in the
forecast on Tuesday and Wednesday, with strong thunderstorms
likely in the afternoon on both days.

&&

.KEY MESSAGES...
1. A mostly tranquil evening is expected to wrap up the day
today. However, some isolated thunderstorms this afternoon
across southern NH can not be ruled out. If these storms come to
fruition, they may be strong, with at least some embedded gusty
wind potential.

2. A hot first half of the week is expected, with temperatures
in the 80s. Some 90F readings look to be possible on Tuesday and
Wedensday. Instability on both Tuesday and Wednesday will allow
for strong thunderstorms to develop. The cold front moves
through Wednesday night, with cooler temperatures and dry
conditions through the rest of the week.

&&

.DISCUSSION...
KEY MESSAGE 1 DESCRIPTION...
Dry and mostly clear weather has started the day today. The warm
temperatures and mostly clear skies will allow for an unstable and
mixed environment this afternoon. The mixed environment will allow
for breezy westerly winds through the day. These winds may carry
some more moist and energy-ripe air from upstate New York, into
southern New Hampshire. CAPE within this airmass looks to be near
500-1000J, and very high effective shear. The advection of this
warmer, more unstable airmass may allow for the development of an
isolated strong thunderstorm this afternoon, especially towards
Keene and Cheshire county locations.

Monday will start cloudy, with scattered showers moving in by
daybreak. Light onshore flow and an increased prevalence of dense
clouds from the aforementioned low will allow for temperatures to
stay cooler tomorrow across Maine, but warmer as one moves further
to the west. Western NH is looking at high temperatures in the mid-
80s, with highs in most of Maine struggling to reach 70F. Most of
the showers should be scattered and out of the area by the mid-
afternoon on Monday.

KEY MESSAGE 2 DESCRIPTION...
Heading into the middle of the week, more unsettled, hot and stormy
weather looks to be in the forecast. 850mb temperatures around 15-
17C are likely to mix down into the upper 80s and lower 90s
across southern NH on both Tuesday and Wednesday. Southwesterly
winds are likely to keep any sea breeze confined to coastal
Midcoast areas. It is certainly possible that we could see 90F
readings at the Portland Jetport on Tuesday. Wednesday is only
looking a little cooler for these areas. Across the interior,
highs are likely to be in the upper 80s for Tuesday. However, a
cold front will move through the area on Wednesday, getting past
much of the interior before peak heating kicks in. This will
allow for areas north of the mountains to have a much cooler
Wednesday than areas south of them.

The efficient heating experienced on Tuesday and Wednesday will
allow for the development of thunderstorms on both days. For
Tuesday, dewpoints near 60F will allow for ample moisture to develop
storms. In addition, CAPE between 1000-2000J and at least 30kts of
mean shear will create a favorable environment for organized
thunderstorms to develop. Storms will likely be scattered in nature
and could contain some small hail and damaging winds if they develop.

It will likely be a similar setup on Wednesday, but with a more
defined lifting mechanism as a cold front moves southeastward
through the day. The frontal passage timing will probably prevent
storms from developing north of the mountains, and with the cold
front, its more likely we`ll see a line of storms moving along the
cold front. From this far out, it does seem like Wednesday`s storms
are a little less likely to become strong, but some gusty winds
can`t be ruled out with a developing outflow that forms with the
line of storms that develop. There is likely to be much less CAPE to
work with, and slightly cooler high temperatures will also hinder
the workable energy these storms will have. In addition, the
timeframe of convective storms will most likely be small.
Noticeably cooler temperatures are expected by Wednesday
evening after the cold front passes.

Cooler and drier weather is expected through the remainder of the
week.


&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Through 18z Monday... Daytime cumulus and winds subside this
evening with VFR continuing through Monday. Winds become SE to S
Monday morning with gusts 15 to 20 kts through the afternoon.
SHRA remnants from the eastern Great Lakes may rake across the
western portion of the forecast area through the late morning
and early afternoon, mainly for HIE and terminals near the
US/CAD border.

Outlook:

Monday Night: VFR as winds become light with surface inversion
developing. Marine airmass may invade or approach the Midcoast.
This could result in IFR to LIFR cigs towards RKD with vis
reduction due to fog.

Tuesday: Afternoon SHRA/TS chances near the US/CAN border.
There is uncertainty how far east SHRA/TS develop in the
afternoon.

Tuesday Night: Coverage of SHRA decreases. VFR forecast.

Wednesday: A cold front passes through the region with SHRA/TS
west to east through the day. MVFR possible w/ frontal passage
and in showers/storms.

Wednesday Night: Winds shift NW with VFR behind exiting cold
front.

Thursday and Thursday Night. VFR expected with no sig wx.

&&

.MARINE...
Weak cold front crosses the waters this evening with high
pressure moving overhead into Monday. Expect conditions to fall
below SCA through Tuesday morning. Winds may approach SCA
criteria on the coastal waters Tuesday and Wednesday as
southerly fetch builds. Winds then become offshore behind a
stronger cold front Wed evening. High pressure builds in from
the west mid to late week.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement until 8 PM EDT this evening for
     MEZ023>028.
NH...Beach Hazards Statement until 8 PM EDT this evening for NHZ014.
MARINE...None.

&&

$$

DISCUSSION...Palmer
AVIATION...Cornwell
MARINE...Cornwell