417
FXUS61 KGYX 171450
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1050 AM EDT Sat May 17 2025

.SYNOPSIS...
A slow moving low pressure system will bring rounds of showers
and thunderstorms through the weekend. Today, there is a low
severe thunderstorm risk across New Hampshire as strong winds
and hail will be possible in the afternoon near and south of a
warm front. More showery weather is expected on Sunday with
unsettled weather possibly extending into Monday. Unfortunately,
the outlook for the rest of the week is unsettled and colder
than normal.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1045AM Update...Just a few cosmetic updates to the near-term, but
the overall forecast thinking remains the same. The upstream
convection across VT and Eastern NY has been generally weakening as
it moves eastward into a less favorable environment. CAMs have
initialized pretty poorly and struggled with this morning activity,
but SPC mesoanalysis does have mostly elevated CAPE to work with
should it make into the northern half of NH and into the western ME
mountains over the next few hours. This will bring primarily a heavy
rainfall and small hail potential as models don`t really have any
surface based CAPE until early this afternoon across southern and
western NH (with some clearing seen on satellite just upstream).
Going into this afternoon, the primary threats for potential severe
weather continue to be damaging winds and hail, but should anything
discrete develop, there is enough SRH to support a brief tornado.

620 AM Update...Fog is the main theme this morning with many
observing sites 1SM or less. This will tend to thin as the
morning progresses although it will take longer to do on the
coastal plain. Otherwise, precipitation has ended and has
largely done so until later this afternoon.

Previously...


As of 06z most of the region is dry except for a weakening small
line of thunderstorms in northern NH along with a few showers
and isold thunderstorms east of there into central ME.
Otherwise, there`s areas of fog and drizzle.

The bulk of this morning into the early afternoon looks to be
mainly dry as a warm front begins to sharpen up over southern
NH. However, north of the warm front, which includes most of
Maine, the weather will be cool with low clouds, some fog and
occasional drizzle.

By late afternoon, significant height falls will take place
ahead of an approaching short wave trough. Thunderstorms
ongoing across Upstate NY and VT will move into western NH. The
areas encompassed by the CT Valley as well as southern NH will
be near a warm front and most susceptible to surface based
destabilization this afternoon. Therefore, storms that move into
those areas or develop in those areas will have the chance of
being strong to severe with hail and strong winds through the
evening hours. Heavy rainfall is likely as well in thunderstorms
which could pose a local flooding risk.

Showers and thunderstorms will likely move eastward late this
afternoon and evening across the warm front into Maine where the
air mass will be much less unstable. However, some elevated
instability will be present so thunder is not out of the
question even here late in the day and into the evening.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SUNDAY/...
Upper level low pressure will continue to approach tonight. The
result will be rounds of showers and perhaps a few
thunderstorms, some which may contain heavy rainfall. The upper
low moves overhead on Sunday which will portend to showery
weather with a thunderstorm or two, but mainly just cool showery
weather with highs near or a bit below normal.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
1045 PM Update... Little change in the latest NBM suite of
guidance. The main story of next week will be for below normal
temperatures for mid to late May.

The upper low shifts east of the area early next week to around Nova
Scotia, but broad troughing across the NE and enough residual
moisture will still be sufficient enough for isolated to scattered
showers to develop (lower coverage than Sunday), mainly during the
daytime hours. Temperatures will be in the mid 50s to lower 60s for
the most part on Monday and then a touch cooler on Tuesday.

Another slow-moving, upper low then enters the picture for the
second half of next week with models in good agreement a 500-mb low
closing off near the Great Lakes that will slowly head toward New
England. Shower chances will ramp back up as a result with cloudier
conditions and temperatures staying on the cooler side.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...
Short Term...IFR conditions are expected today north of a warm
front in central NH and ME. Conditions will be MVFR or better
across southern NH by early afternoon but showers and
thunderstorms are expected to fill in this afternoon with some
possibly bringing heavy rainfall, gusty winds, and perhaps some
small hail.

Long Term...LIFR to IFR fog and/or stratus may stick around
12-15Z Sunday, mainly in the RKD-AUG corridor...otherwise
showers will again be likely during the day Sunday into Sunday
and could produce IFR to MVFR conditions. For Monday and
Tuesday...MVFR ceilings possible during the first part of
Monday, but coverage of showers will be lower and mostly during
the daytime hours these days. Chances for showers and and flight
restrictions then increase toward the middle of next week.

&&

.MARINE...
Short Term...Other than fog, no other marine hazards are
expected today through tonight.

Long Term...Winds become westerly Sunday and then northwesterly
Monday into Tuesday as surface low pressure moves east of the
waters. Gusts to 20-25 kt may occur from time to time during
this period, but in general things look to remain under SCA
levels through Wednesday. Winds become east to northeast toward
the second half of next week with developing low pressure to the
south. It`s uncertain what track the low will take, but SCA
conditions are possible toward late week.

&&

.HYDROLOGY...
Multiple rounds of showers and storms are likely during the
afternoon and evening today and could pose another threat of
flash flooding. The threat is highest from the foothills and
points north on Saturday where WPC has highlighted a Slight Risk
of Excessive Rainfall.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$

NEAR TERM...Combs/Ekster
SHORT TERM...Ekster
LONG TERM...Combs