-- Discussion containing changed information from previous version are highlighted. --
618
FXUS61 KGYX 141510
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1110 AM EDT Tue May 14 2024

.SYNOPSIS...
-- Changed Discussion --
Warmer air spreads across southern NH and far southwestern ME
for the day today. A cold front will then drop towards the
region bring the chance for showers and thunderstorms this
afternoon and evening. A stalled frontal boundary will result in
unsettled weather for the middle and latter portions of the
week with temperatures remaining seasonable for mid May.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...

-- Changed Discussion --
11:10am Update... Mostly only minor adjustments to temps and
POPs for today based on trends so far this morning. Skies are
clearing out and temps are quickly rising through most of New
Hampshire, with this trend expected to begin over the next
couple hours through western Maine. Still expected some gusty
thunderstorms and possibly some small hail across northwestern
areas later this afternoon. Overall, no notable changes at this
time.

620 AM Update...Minor tweaks to PoP/Wx to better capture the showers
crossing into western ME.

Previous...

An area of showers currently across New Hampshire will steadily
push east through this morning, bringing some measurable rain
for portions the area but nothing significant. Amounts across
central and northern areas may amount to a tenth to a quarter of
an inch with up to a few hundredths for areas to the south.

Once this batch of showers moves out of the area, mostly dry
conditions will prevail into this afternoon with partly sunny
skies and warm temperatures before an approaching cold front
brings increasing chances for showers and storms into this
evening.

CAMs are in pretty good agreement focusing initiation across
northern areas sometime mid-late afternoon with activity
spreading southward into this evening. The warm temperatures and
cooler temps aloft will provide enough instability to support
thunderstorms, especially across northern and central NH over
into the western Maine mountains and foothills, and a few of
these could be strong with gusty winds and small hail. In
addition to this threat, the mean flow is roughly parallel to
the orientation of the convection in what some of the CAMs are
depicting, particularly the HRRR and NAMnest. Although the
location is uncertain, there is a signal that this could result
in heavy rainfall persisting over some areas which may cause
some hydro issues.

Farther south, CAMs are not showing much in the way of
development, but with these very warm temps, development of
isolated-scattered showers along with a couple of storms doesn`t
seem out of the question.

Central NH and southwest ME are expected to get well into the
70s for highs with southern NH closer to 80 degrees as a warm
front slowly advances eastward. Farther east it will be cooler
where winds will also be onshore, keeping temperatures in the
60s.

Convection is expected to linger into this evening, especially for
central and northern areas, but potential for thunderstorms will
steadily wane as instability is lost. Short-range guidance indicates
most showers will then dissipate by midnight to 2am, but with the
frontal boundary lingering nearby, can`t rule out a few additional
showers overnight. The main concern then becomes the potential for
fog to develop, especially over areas that receive rain, and I
wouldn`t be surprised for some of it to be locally dense with light
winds and dewpoints in the 50s.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Mostly cloudy skies are expected Wednesday with the frontal
boundary stalling across the area. More than sufficient
moisture will still be present, and another wave of low pressure
riding along the frontal boundary will bring more showers to
the area with perhaps a storm or two. Precipitable water is
progged to be around 1.25", which is quite high for this time of
year, so will have to watch for heavy rainfall potential once
again. CAMs and global models are focusing in on
central/northern NH along with areas from the foothills
northward in western ME, which could be some of the same areas
that receive heavy rainfall this afternoon. Have taken more of a
consensus approach to high temperatures with clouds expected to
limit temps to the 60s, but southern NH may still reach the
lower 70s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
A slow moving cut off low pressure system tracks through the
Mid Atlantic and offshore from Wednesday through Saturday before
dissipating. Another slow moving low pressure system will take
a similar track south of New England this weekend.

Details...

Overall the forecast over the last couple of days has trended
toward warmer and a longer duration of unsettled conditions. So
Thursday doesn`t look quite as wet as they had, but Friday and
Saturday now look to continue the chances for showers.

Cut off low pressure systems are notoriously tricky for both
the models and forecasters to discern. With these being the
main drivers of our forecast this week, it`s worth noting that
further changes are likely as well in the coming days. The cold
front approaching from the north looks to be trending a little
slower, and not making as much southward progress. This allows
warmer temperatures into Thursday as the marine air is delayed
by at least a couple of days. At the same time, the cut off low
looks to be tracking more slowly. This causes the forecast to
be quite similar for Thursday through at least Saturday with
times of showers.

At least scattered showers are expected Thursday through
Saturday. POPs on these days are likely to increase in some
spots as we get closer in time and certain areas become more
highlighted as seeing a better chance for rain. Overall, the
best chance for seeing the most frequent showers looks to be
across interior areas and the higher terrain. As for
temperatures, highs looks to generally warm into the 60s and 70s
each day, with the warmest readings found across western
locations, and generally cooler toward the coastline.

As we get into next weekend, the next system will be following
closely behind the first one. This likely increases chances for
showers further during the day on Saturday and Sunday. It also
looks to bring cooler temperatures, as easterly flow brings in
cooler and damp maritime air. As mentioned, this forecast has
been volatile over the last couple of days as the cut off low
regime continues. This weekend`s forecast is subject to change,
but that`s the way it looks to be trending at this point. Over
the last week or so, the trend has generally been toward warmer
and less wet conditions as we get closer in time, but it`s too
early to know at this point if that trend will continue this
weekend.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
Short Term...Lingering restrictions give way to mostly VFR by
this afternoon. A slow- moving cold front will then provide
focus for showers later this afternoon and evening, and
thunderstorms may occur as well. IFR restrictions and gusty wind
could accompany showers and storms with the higher potential
for these impacts toward HIE, LEB, and CON. There is lesser
confidence elsewhere. Showers and storms will diminish in
coverage through this evening with a low chance of additional
precip overnight tonight. However, low ceilings and fog are
expected, especially in areas that receive rain. Additional
showers are possible on Wednesday as the cold front will be
stalled across the region with highest shower coverage generally
north of a LEB- LEW-AUG line.

Long Term...Generally VFR conditions are expected more often
than not from Thursday through Saturday, but periods of MVFR
conditions with showers are likely during this time period. By
next weekend, longer periods of MVFR to possibly IFR look likely
with more showers and some marine fog possible.
-- End Changed Discussion --

&&

.MARINE...
Short Term...Southerly winds continue to increase today as a cold
front slowly approaches. Gusts are expected to remain shy of SCA
criteria, although a brief period of 20-25 kt is possible over the
outer waters late this afternoon or early evening.  The front then
stalls to the northwest of the water through Wednesday with a south
to southwest flow continuing but still remaining below SCA
levels.

Long Term...A slow moving low pressure system tracks south of
the waters from Wednesday night through Saturday. Seas begin to
build by Friday, with SCA conditions possible by late in the
week and this weekend.

&&

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

&&

$$


NEAR TERM...Clair
SHORT TERM...Combs
LONG TERM...Clair