061
FXUS61 KGYX 161407
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1007 AM EDT Tue Jul 16 2024

.SYNOPSIS...
Heat and humidity build for the next few days as high pressure
strengthens off the Eastern Seaboard, with chances for
scattered afternoon or evening showers and thunderstorms each
day. A cold front moves through late Wednesday through Thursday,
bringing drier and somewhat cooler conditions for the end of
the week and going into the weekend with high pressure building
in from the west.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
1005 AM...This update mostly reflects adjustments to grids
based on current obs and CAMs, which suggest just a few spotty
showers across the mtns through mid afternoon, before the more
significant convection moves in from the west after 5-6 PM.
Otherwise, no real changes to temps and heat this afternoon,
and the fact it will be a scorcher.

645am Update...Shower activity shifted east overnight, with
mainly light showers. The exception was a rather large storm
that moved through the western ME mountains dropping around an
inch of rain in 45 minutes with plenty of lighting. Still a
couple light sprinkles for the morning, but otherwise turning
dry.

Previous Discussion...
An active couple days ahead considering continuing heat and a
round or two of potentially strong storms.

Mild temps overnight will again allow a quick start to the heat
today. Once morning clouds clear out of regions away from the
coast, temps again boost into the lower to mid 90s, with heat
indices pushing into the mid to upper 90s for many interior and
south coastal regions. No changes to the Heat Adv at this time,
although some trends are weaker with onshore winds towards the
Midcoast today. This could result in a few hours of heat index
values into the mid 90s here. Expect a mostly sunny day outside
of the mountains after mid morning.

Other talking point today will be late day convection. Limited
moisture and warm temperatures aloft will keep a lid on rain
chances for much of the day. This could change when forcing
arrives from the west, perhaps in the way of a mature MCS this
evening. These are notoriously hard to track at this
range...largely dependent on how the wave of energy evolves
over the past 12 hours. Current suite of short range guidance
does bring showers/storms towards the NH/VT border this
evening.

Sfc CAPE remains the most robust across central to southern NH
through mid evening amid ample shear. If this line of storms
forms and continues to progress east, it should lose some punch
as surface inversion will be growing in southern ME. Thus
focused gusty wind wording mainly west of the ME Lakes Region.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Complex of showers and storms will be ongoing this evening and
into the overnight period. Should see a gradual weakening of
thunderstorm intensity and coverage as the night wears on. Kept
the mention of thunder for first half of the night as elevated
CAPE remains amid the added forcing. Still will have plenty of
moisture in the region as the wave passes. PWATs climb above 2in
and warm cloud depth exceeds 12kft along with low associated
LLJ. Thus expect these storms to contain heavy downpours. As
long as storms keep moving amid the strong LLJ and training does
not occur, would expect higher amounts to remain at or below a
localized inch of QPF.

Wednesday will again be hot, but added cloudiness or daytime
showers/storms creates some uncertainty on if another day in the
90s will be achieved. NBM and ensemble guidance keeps the hot
temps in the region, and went with these for now.

Slightly improved lapse rates and earlier moisture could pave
the way for additional strong storms Wed. Widespread deep layer
shear remains in the region, and still won`t be lacking in the
moisture department. Cold front should approach near or just
after peak heating for the day, thus decent chance of seeing
good instability. While Tuesday`s storms will be fresh on mind,
another round may be in store Wednesday packing gusty winds and
heavy rain. 00z HREF does have pockets of heavier QPF with this
round, perhaps with localized values of 2 to 3 inches in these
storms.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Models have been fairly consistent over the last few days for
breaking the heat wave come Wed night and Thursday as a more
localized -NAO sets up over Greenland and the Atlantic poleward
of 50 N. This does help break down the ridge, but there is so
much warm over central and western Canada that there really
isn`t much of source to cool things down, but itll be more
along the lines of less warm, with temps running normal or a
little above. However, once we clear the hot air out, it will be
mainly dry Friday into early next week, with daytime temps
mostly in the 80s, and overnight light in the mid 50s to mid
60s.

Thu will also depend on what happens with the passing front,
but, as we often see with cold fronts in the summer, if it
doesnt get through before dark, it will likely not mix down
until nest morning, and because we may rain overnight into Thu
morning, may not see the drier air mix down until later in the
day, so, while it will not be as hot but itll still be humid.
The good news is, we should see the effect of that cold front by
Thu night with clearing and lower humidity, with mins in the
mid 50s in the mtns to 60 to 65 in the S.

Friday through the weekend will be dry and sunny. More comfortable
RH are expected Fri with highs 75-80 in the mtns and low to mid
80s in the S and lows Sat morning in the mid 50s to low 60s.
Sat and Sunday will be a few degrees warmer, with highs mostly
in the 80, but will start to see the RH creep up a bit by
Sunday. Monday looks dry and warm as well.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Short Term...Some fog along coastal terminals tonight and early
Tue morning. This should retreat to the waters during the day
with VFR conditions. A round of showers or storms could affect
NH terminals this evening, moving east overnight. Could see some
valley fog develop Tues night. Showers and storms again develop
Wed afternoon, perhaps a bit more widespread as a cold front
approaches.

Long Term...Sct TSRA will develop inland during Wed afternoon
as a front approaches and move through Wed night. This is the
best to see several hours or more of flight restrictions as fog
settles in behind any rain that does fall. Flight restrictions
could linger into Thu morning, but should see improvement to VFR
during the afternoon. Thu night through the weekend will be
mainly VFR, the only exception being late night valley fog.

&&

.MARINE...
Short Term...Waves and gusts generally below SCA. There will be
some shower/storm complexes moving through Tue/Wed
afternoon/evening which could bring gusty winds, lightning, and
heavy downpours to the waters. Otherwise, marine fog develops
tonight and may weaken some Tuesday. A cold front approaches the
waters Wed afternoon.

Long Term...Generally winds/seas stay below SCA levels through
the coming week, but could approach SCA gusts/seas Wed night
into early Thu.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Heat Advisory until 8 PM EDT this evening for MEZ012-018>024-
     033.
NH...Heat Advisory until 8 PM EDT this evening for NHZ004-006-
     008>015.
MARINE...None.

&&

$$

SYNOPSIS...
NEAR TERM...Cempa/Cornwell
SHORT TERM...Cornwell
LONG TERM...Cempa
AVIATION...
MARINE...