Lebanon, Maine 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

719
FXUS61 KGYX 070941
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
541 AM EDT Mon Jul 7 2025

.SYNOPSIS...
Another hot and humid day today with high temperatures in the
90s but feeling closer to 100 degree in many areas. A few
showers and thunderstorms will be possible, but they do not look
like they will be widespread enough to provide much relief. So
that means another muggy night tonight before one more very warm
day across the southern parts of the area Tuesday. The front
unfortunately will not make much progress south and will stall
over southern New England. This will keep our area cooler but
continue with threats for afternoon showers through the week.

&&

.NEAR TERM /THROUGH TODAY/...
540 AM Update...Elected to expand the Heat Advisory a few zones
northeastward as areas will warm quickly today with a good
jump start. Otherwise, just the usual minor tweaks to align with
observations. The forecast remains in good shape with another
hot, humid, and breezy day expected.

Previous Discussion...
Warm front remains draped across ME...but is largely confined to
the CAR forecast area. Clouds and showers will continue to skirt
thru northern Franklin Co and thru central Somerset Co...but
otherwise a dry and mostly clear night is expected locally. Some
rain showers did occur in the Lakes Region east thru the ME
Capital Region...so if valley fog occurs overnight these will
be the most likely areas.

This afternoon will again feature twin hazards. First and most
widespread will be the heat. Since the front made little
progress...today will be much like yesterday. Widespread low to
mid 90s are expected along with high dewpoints. The resulting
heat index values will be mid to upper 90s. The current advisory
looks good.

The second but more conditional threat will be thunderstorms
again. ECMWF EFI has a significant number of members with
favorable CAPE/shear overlap during the afternoon...especially
near the warm frontal boundary. This will mainly be across
western ME. SPC HREF also has some low probablilites of rotating
updrafts across parts of western NH and into most of the
northern half of the forecast area. A little more in the way of
shear will introduce a small hail threat despite the very warm
environment. But otherwise the main hazard will be gusty to
damaging winds. This is supported by an SPC Marginal Risk as
well as by CSU machine learning guidance. It would not surprise
me to see a few severe storms...but likewise it could struggle
like yesterday without a more significant forcing mechanism.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
Front will continue to sag south overnight. With the loss of
daytime heating I do not anticipate much in the way of precip
overnight...but with the boundary nearby and WAA still
continuing along and south of it an isolated to widely scattered
shower is possible. I will keep those slight chance to chance
PoP going thru the overnight. Without a strong frontal push thru
the area it should be another warm night. The NBM has lows near
70 for many areas...and based on ECMWF EFI showing a strong
preference for warm temps I think this makes sense.

Tue will be the last of the very warm days for the forecast.
South of the front will remain quite warm and muggy. Highs may
be able to top out around 90 across southern NH...with a very
sticky 80s elsewhere. The precip forecast will be interesting as
the front will be lingering near the coast. If it has not
cleared the coast by afternoon...convection is likely to pop
right along the shore. The shear is forecast to be weaker by
Tue...so the hazards will be more torrential rain and lightning
than severe.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Key Message: Cooler and generally showery thru the extended.

Impacts: No significant weather impacts anticipated.

Forecast Details: Overall I did not adjust the NBM much thru the
extended. The only change was to tweak thunder chances beyond
Tue. There tends to be a high bias in thunder in the
extended...by about a category. So beyond day 4 I capped things
at isolated thunder.

Otherwise the front will stall south of the forecast area while
high pressure builds across to our north. The location of the
high will promote northeast to east winds and a largely onshore
flow pattern. This will keep temps on the cooler side for
July...and at least puts the threat for significant heat behind
us for a little.

Precip looks to be driven mostly by diurnal processes. There
will not be much large scale forcing for ascent...so daytime
heating will allow for scattered convection. Towards the end of
the period a more significant trof will approach and may lead to
more widespread precip locally. Any concern for flooding will
revolve around where rain falls each day. If we end up in a
situation where repeated rounds of convection occur in the same
locations that would elevate the flood risk.

&&

.AVIATION /10Z MONDAY THROUGH FRIDAY/...
Short Term...VFR conditions expected today. There may be some
valley fog south of the cloud deck where precip occurred today.
This would mainly be the NH Lakes Region and around the lower
Kennebec River Valley...which may include AUG. I have a brief
period of IFR conditions there near sunrise. During the
afternoon SHRA/TSRA will develop again...local MVFR conditions
would be possible. However at this time the TAF sites do not
appear particularly likely to see convection. The greatest
chance for an afternoon SHRA/TSRA will be at HIE.

Long Term...VFR conditions expected to prevail much of the
extended. Local MVFR or lower conditions will be
possible...especially during the afternoons...in any SHRA/TSRA
that form. Confidence is quite low in location for highest
chance of precip however. As surface high pressure tries to nose
in...valley fog may develop during the nights...and will be most
likely for areas that do receive rain.

&&

.MARINE...
Short Term...Marginal SCA conditions may diminish this
morning...but southwest winds are expected to freshen again
ahead of a slow moving front during the afternoon. I have
extended the SCA thru the evening. Again this will be mainly for
gusts right around 25 kt and seas building to near 5 ft. The
front will finally reach the coastal waters by Tue...with
showers and thunderstorms possible along it during the
afternoon.

Long Term...The front will hang up over southern New England
into the entrance to the Gulf of ME. This will keep showers and
storms in the forecast for much of the week. Winds and seas are
generally expected to remain below SCA thresholds.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory until 8 PM EDT this evening for MEZ012>014-
     018>021-023-024-033.
NH...Heat Advisory until 8 PM EDT this evening for NHZ006>015.
MARINE...Small Craft Advisory until 11 PM EDT this evening for ANZ150-
     152-154.

&&

$$

NEAR TERM...Baron/Legro
SHORT TERM...Legro
LONG TERM...Legro