Waterville, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

099
FXUS61 KGYX 082305
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
705 PM EDT Fri Aug 8 2025

.SYNOPSIS...
Showers and thunderstorms in and around the mountains this
afternoon will fizzle this evening. High pressure builds back in
over the weekend for fair weather and increasing temperatures.
Temperatures and humidity continue to rise through the first
half of next week as a ridge of high pressure builds over the
Northeast. The ridge starts to break down mid week that will
allow for some chances of showers and thunderstorms.

&&

.NEAR TERM /UNTIL 5 AM SATURDAY MORNING/...
7 PM Update...Isolated showers and thunderstorms in the far
interior will continue to weaken and dissipate with the loss of
daytime heating. Otherwise we expect some patchy valley fog
overnight.

Previously...

Impacts and Key Messages:
* No significant weather impacts expected

A shortwave trough moves through the area today and we have
already seen some isolated showers and storms this afternoon as
a result, mainly in and around the terrain as that has been the
main lifting mechanism. With no real steering flow these are
slow movers. The KALB 12Z RAOB observed PWAT values around 1.25"
and KCAR observed around 0.80, so with us somewhere in the
middle and modeled PWATs around an inch, some brief downpours
are occuring with these. With how dry we have been, there should
be no issues even if a location happens to pick up a quick 1"
or 1.5". This activity is getting its energy from diurnal
heating so it should fizzle heading into the evening hours and
be done not long after sunset.

Mostly clear skies and light winds should lead to a period of
radiational cooling tonight, so went ahead and blended in some
MAV guidance to adjust low temperatures down a couple degrees
from the NBM. Expect low to mid-50s through the mountains,
foothills, and valleys, with mid- to upper 50s along the coastal
plain. This will lead to patchy, locally dense, valley fog.

&&

.SHORT TERM /5 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Impacts and Key Messages:
* No significant weather impacts expected

The shortwave lifts off to the northeast and the resulting
height rises should keep any chances of showers/storms very low.
CAMs are still pegging the International Border as an area
where something could develop off the terrain, but as we have
seen the past couple days anything would be isolated as surface
high pressure and dry air remain in place. PWATS are again
modeled around 1-1.25", so any more robust showers/storms would
contain downpours. High temperatures look to end up similar to
today with the exception of a stronger seabreeze keeping the
coastal areas cooler. Temperatures climb into the low to mid 80s
across the mountains and foot hills, with more in the way of
mid-70s to around 80 in the coastal plain.

It looks like some clouds and maybe even some showers may ride
the ridge into the area from ongoing convection in the Great
Lakes Region, mainly in the north. Even so there should once
again be a good window for radiational cooling before any of
that arrives if it does. Therefore, I used some MAV guidance to
knock low temperatures down a couple degrees. Dewpoints will be
trending up so it still might end up warmer than tonight with
mid to upper 50s across the board. Northern Somerset and
Northern Franklin counties may be the "warm" spot, closer to 60,
if clouds do encroach early.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Key Messages:
* Hot temperatures arrive late this weekend through the middle
  of next week. This could be the longest stretch of upper
  80s/lower 90s of the year so far, but there will be some
  complicating factors
* Daily showers and storms will be possible through early next
  week, mainly across the interior and mountains

Details:
Under high pressure through midweek next week, heat will be the
main point of conversation. Supportive 850mb temps increase to
around 18 to 20 C Monday through Wednesday, with resulting
surface temps in the upper 80s to low 90s across the interior
and foothills. Temperatures jump Sunday, and then further to
start next week. ECMWF Extreme Forecast Index stands out on
Monday and Tuesday, with some SoT contours of 1 to 2 across most
of the forecast area. This is a good signal for temperatures
well above normal, but exact values will continue to refine over
the coming days.

While NBM probs of greater than 90 degrees are fairly consistent
Mon-Wed, there are some items that bring uncertainty to the
forecast: 1) High pressure centered to the south and east will
aid in low level onshore flow. The advecting marine air, while
weak in this environment, could be enough to keep coastal
communities a few degrees cooler than inland. How far inland
this influence make it should be better represented in high res
guidance as next week approaches. This could be defeated by a
more prominent offshore flow, if it develops. 2) Building
instability and moist mid- levels will create a similar
environment to the past week...with daytime showers and
thunderstorms. Rain cooled air and additional cloud could
hamper insolation, albeit locally. So far this is a missing
item from guidance of next week, but the pattern supports these
isolated to scattered showers.

Storms that develop during the daytime next week will be lacking
wind shear through much of the column. Should low and mid-level
lapse rates stay in the 6 to 7 C/km range, would need to watch
for gusty winds from failing updrafts in taller storms.

This pattern looks to finally change into late next week as a
cold front pushes into the region Wednesday night. There remains
many different iterations of this feature to be fully confident
in its timing and placement, but most global solutions bring
the front over the CWA during this overnight period.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
Short Term...Some showers and storms are present in the
mountains, but this activity will fizzle this evening. Patchy
valley fog is likely again tonight with restrictions possible at
LEB and HIE. Fog will clear in the morning and then VFR will
prevail through Saturday. Showers and storms are possible in the
mountains again Saturday afternoon. Increasing low level
moisture may lead to valley and coastal fog Saturday night/early
Sunday morning. Wind gusts near 15kts are possible at coastal
terminals Saturday afternoon.

Long Term...VFR is expected through Tuesday as high pressure
brings mostly dry conditions. Any restrictions are expected to
revolve around coastal fog, mainly along ME Midcoast terminals
in the evening and overnights. Of low coverage will be the
occurrence of SHRA or TS across interior ME/NH during the
afternoon and early evening.

&&

.MARINE...
Short Term...Wind gusts and seas remain below SCA criteria
through Saturday night as high pressure remains over the waters.
Winds will be generally southerly at 10-15kts. Increasing low
level moisture may aid in the development of areas of fog
Saturday night.

Long Term...Under continued high pressure through next
Wednesday, conditions are expected to remain under SCA criteria.
There will be light onshore flow through the period, but only
enough to build wave heights to 2 to 3 ft through Tuesday. A
cold front approaches the waters Thursday morning.

&&

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

&&

$$

SYNOPSIS...
NEAR TERM...Baron/Ekster
SHORT TERM...Baron
LONG TERM...Cornwell
AVIATION...
MARINE...