945
FXUS61 KGYX 220625
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
225 AM EDT Mon Jun 22 2026

.WHAT HAS CHANGED...
Convection allowing guidance continues to show the potential
for swaths of heavy rainfall this evening and overnight.
Localized flash flooding remains possible.

&&

.KEY MESSAGES...
1. Soaking rainfall expected this afternoon through tonight.
Some of this rain may be heavy and localized flash flooding is
possible.

2. Temperatures rebound Wednesday and Thursday, but weak
disturbances keep showers possible. A cold front nears the
forecast area Friday.

&&

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

First half of the day is looking okay, but things start
downhill by mid afternoon. Rain will move into the area from the
southwest as a broad area of warm advection precip. Now to
varying degrees CAM guidance is washing this out a bit as it
moves north. There is also some bouncing around of the highest
QPF axis, though you could argue for a subtle southward shift.

What we do know is that this low pressure will be seasonably
strong, something on the order of once a year in early summer.
However the moisture transport is strong, more like once every 5
to 10 years. ECMWF EFI has also highlighted the southern half
of the forecast area for anomalous rainfall totals for this time
of year. That all suggests to me that a widespread soaking rain
is likely, but with higher confidence for areas south of the
mtns. That in and of itself is not a problem, we need the rain
for long term deficits. The hazard will be recent rainfall
coupled with heavy rainfall rates.

21.12z HREF was showing max QPF in the 4 to 5 inch range. The
latest runs of the HRRR have been mimicking those totals,
however bouncing around different points in the forecast area.
Local research has shown that the max QPF totals from CAM
guidance is usually a good guide for what may fall, it is the
location that struggles. So I am on the lookout for those kinds
of high QPF amounts, and if they occur on already saturated
ground from previous day`s rainfall, flash flooding becomes more
likely. Biggest areas of concern there will be the mtns,
especially across western Maine, and into the lower Kennebec
River Valley. There will likely be some thunder with this
rainfall but the threat of severe weather looks to remain
southwest of the forecast area.

Rainfall will clear out pretty quickly Tue morning from west to
east. There may be isolated afternoon showers, but will be
fairly inconsequential compared to the evening and overnight
rains. Given the recent wet weather and high pressure pushing in
Tue night, I expect more valley fog likely.

KEY MESSAGE 2 DESCRIPTION...

Upper trough will be swinging through the Northeast come
Wednesday, with broad cyclonic low level flow overhead. NW flow
remains over the forecast area through the day as this airmass
translates east. It will bring some dry air with it, but think
cloud cover may be a little underdone at this range. Would at
least expect upslope clouds to remain NW of the mountains.
Daytime highs should rebound from a cool start to the week, with
a tight spread on expected highs along the coast and interior.
More variability exists for points NW of the foothills due to
greater cloud cover probability.

Mid level zonal flow continues into late week, and this keeps
the door open for embedded waves to bring short term unsettled
conditions. This may come in the form of diurnal showers
Thursday, before guidance brings a cold front near the region
towards Friday. Current timing isn`t favorable for stronger
storms, but extended machine learning guidance maintains a
signal of possibility for the day.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
Cannot rule out a few showers percolating tonight, but
generally expecting it to be precip free thru midday. VFR
conditions currently, but valley fog is forming quickly.
Especially where it rained today IFR or lower conditions are
expected thru sunrise. Confidence is highest at LEB and HIE, but
it may also include AUG, RKD, PWM, and CON. Conditions return
to VFR around sunrise, with conditions again deteriorating in
the evening. Areas of MVFR or lower are likely as widespread
rainfall moves into the region.

Outlook...

Tuesday: Conditions improving to VFR by midday. Isolated shower
possible across the northern half.

Tuesday Night: VFR conditions expected. Patchy valley fog
possible with local IFR or lower.

Wednesday: Mainly VFR with more clouds than sun for the
mountains.

Thursday-Friday: Diurnal showers bring potential for
restrictions Thursday, with a cold front potentially bringing TS
on Friday.

&&

.MARINE...
South southeast winds will increase today ahead of approaching
low pressure. Some marginal SCA conditions are possible across
the waters, especially north of Cape Elizabeth. Winds and seas
will diminish into Tue. The waters remain under cyclonic flow
Wednesday as low pressure pushes into the Canadian Maritimes.
This should result in conditions below SCA criteria through
Friday morning. A cold front will approach the region Friday.

&&

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

&&

$$

DISCUSSION...Cornwell/Legro
AVIATION...Baron/Cornwell/Legro