697
FXUS61 KGYX 190647
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
247 AM EDT Tue May 19 2026

.WHAT HAS CHANGED...
Expanded the Heat Advisory to Coastal Rockingham county, but
the overall forecast remains unchanged for today.

&&

.KEY MESSAGES...
1. Hot, well above normal temperatures move into the region
today and Wednesday. Widespread highs in the upper 80s to lower
90s are expected today, with warm overnight lows in the upper
60s to around 70. Another round of hot temperatures is possible
Wednesday, mainly focused from the interior to the coast.

2. An approaching cold front will bring chances for
thunderstorms today and chances for showers and storms Wednesday
when the front crosses. Any thunderstorm that develops this
afternoon will have the potential to become severe.

3. The second-half of the week will feature cooler temperatures
and drier conditions. Unsettled weather is possible this
weekend.
&&

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

Not much has changed regarding the hot temperatures expected
today and tomorrow. Any lingering fog over the coastal areas or
interior should dissipate early this morning, giving way to a
clear sky and plenty of sunshine. Rapid heating will lead to
well above normal highs in the upper 80s and lower 90s across
southern New Hampshire and portions of interior Maine. The Heat
Advisory for Hillsborough and interior Rockingham counties
looks to be in good shape with no changes anticipated. With
limited moisture, heat indices will be a bit on the marginal
side (approaching 95) but quite a change from what we have seen
thus far in the Spring.

Temperatures should remain quite warm overnight tonight as a
southwest breeze continues ahead of an approaching cold front.
Lows may only dip into the upper 60s and lower 70s across the
south. Wednesday will be quite warm again but not as hot as
today. Southern New Hampshire and interior/coastal Maine should
still see highs in the mid 80s to around 90, but locations
around and north of the mountains will be a bit cooler behind
the front, mainly in the lower 70s to lower 80s.

KEY MESSAGE 2 DESCRIPTION...

The severe weather setup for today has become a little bit more
interesting, especially over southern New Hampshire. A
mid/upper level ridge will break down slightly through the day
and most of the region will see some modest height falls. A weak
surface low will move across Maine, dragging a surface trough
with it. This boundary may be a focus for some isolated
shower/storm development in the afternoon. These storms will be
very hit or miss, and most locations will remain dry with
limited synoptic forcing in the area. The one exception may be
southern New Hampshire where a compact shortwave will move in
from Vermont and provide some better lift. A few CAMs are now
suggesting that a cluster of storms may develop in the early
afternoon over the higher terrain in southern Vermont before
moving into southern New Hampshire mid/late afternoon. NAM Nest
soundings ahead of this modeled cluster suggest an environment
characterized by 1500 to 2000 J/kg MLCAPE and 30 to 35+ knots of
0-6 km bulk shear. This environment will be favorable for a few
organized multicell clusters or even a transient supercell
structure/bowing segment. Thus, any storms that move across
southern New Hampshire could become severe capable of damaging
winds up to 60 mph and some large hail. Forecast Significant
Hail Parameter (SHIP) values are generally just less then 1 so
the threat of very large hail seems low, but hail up to the size
of ping pong balls seems plausible if we do see any transient
supercell structures or sustained updrafts. The tornado threat
appears to be fairly low given weak low-level shear.

For the rest of the forecast area, some strong to marginally
severe storms will be possible but instability will be
decreasing moving north/northeast and forcing becomes more
nebulous. The shear profile will be fairly similar. Showers and
storms will move out and/or diminish with the loss of heating
but we could see a few showers linger across the mountains
overnight. A cold front then moves across most of the forecast
area early in the day on Wednesday. Thunderstorms on Wednesday
will generally be limited to areas along and ahead of the front,
which will likely be south of the mountains. We could see
enough heating to see a stronger storm or two around the
interior or extreme southeast New Hampshire before the front
pushes out over the waters, but the probability for severe
weather appears low at the moment. A few showers may linger
behind the front.

KEY MESSAGE 3 DESCRIPTION...

High pressure moves in from the west, bringing cooler and drier
conditions. This high pressure will keep more active weather to the
south of the region. Over the weekend, a low may move into the area
and bring meaningful rain to the area. However, there is still some
uncertainty in timing as some guidance brings in the unsettled
weather on Sunday while others don`t have precipitation moving in
until Monday. High temperatures will generally be in the 60s with
lows in the lower 40s.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
Through 06z Wednesday...Onshore flow along the ME coast could
develop low stratus and/or fog to RKD this morning. Fog should
then lift later this morning after sunrise and a offshore wind
shift for PWM south. 35kt LLWS possible through most of the
morning with a steep surface inversion in place.

SW winds increase after sunrise, with gusts 15 to 25 kt.
Isolated to scattered showers develop into early afternoon, with
TS possible through to the evening. TS may be focused along a
line, passing west to east with MVFR to IFR vis possible in
SHRA/TSRA. SHRA chances exit the coast this evening with VFR
prevailing overnight.

Outlook:

Wednesday: Scattered showers and TS may bring localized restrictions
late morning early afternoon. Otherwise mainly VFR.

Wednesday night: VFR with NW winds gusting up to 20 kts.

Thursday through Friday: Mainly VFR.

Friday night through Saturday: Clouds may increase and lower across
southern NH and Coastal Maine. Low confidence in height and extent,
but could see periods of MVFR south of the mountains.

&&

.MARINE...
Onshore winds advect moisture over the coastal waters this
morning which may lead to some areas of fog. Showers and storms
develop inland this afternoon and may track towards the NH/ME
coast by evening. SW winds continue overnight, nearing 25 kt but
confidence isn`t high enough to issue a SCA at this time.

Southwest winds turn westerly Wednesday as a cold front approaches
and crosses the waters during the afternoon. Winds may gust up to 25
kts with seas approaching 5 feet. Winds and seas are forecast to
remain below SCA thresholds Thursday into Saturday as high pressure
builds over the Northeast.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Air Quality Alert from 10 AM this morning to 10 PM EDT this
     evening for MEZ023>028.
NH...Air Quality Alert from 10 AM this morning to 10 PM EDT this
     evening for NHZ013-014.
     Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for NHZ012>015.
MARINE...Small Craft Advisory from 5 PM this afternoon to 8 PM EDT
     Wednesday for ANZ150-152.

&&

$$

DISCUSSION...Hargrove/Palmer
AVIATION...Combs/Dumont/Hargrove