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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KGYX 131409
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1009 AM EDT Thu May 13 2021

.SYNOPSIS...
Much of today will feature mostly sunny skies and warmer
temperatures. Late in the day, a weak cold front will drop in
from the north and deliver a band of showers and perhaps an
isolated thunderstorm to the mountains and foothills.
Thereafter, warming weather will continue but we`ll likely have
to dodge a few afternoon and evening showers and isolated
thunderstorms over the weekend as the morning sunshine provides
some instability. A cold front looks to approach from the north
around Tuesday of next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Update...
Have updated the forecast for the rest of today. Have added more
cloud cover as latest satellite imagery continues to show the
growth of Cu over the region. Have upped the forecast highs for
this afternoon as well. Winds have already begun to gust in the
10 to 20 mph range and that will continue for the rest of the
day. Tweaked wind forecast upwards.

Prev Disc...
625 AM Update...Have adjusted temperatures and sky cover a
little bit for the next few hours based on observational data
but otherwise the going forecast remains largely untouched.

Previously...

Mid level clouds have been been a bit stubborn early this
morning across southern zones but are gradually doing so.
However, as a result of the cloud cover lasting well into the
night, will cancel the frost advisory in one or two zones early
this morning.

Today should be quite a nice day with partly to mostly sunny
skies and temperatures warming well into the 60s to around 70
degrees at many locations which is right around average for this
time of year.

Later on in the afternoon, a short wave trough and
attendant weak SFC cold front will approach from the north. They
will aid in the development of scattered showers and isolated
thunder in the mountains, which will then move into the
foothills by early evening before weakening. A few of these may
contain brief wind gusts from the north of up to 35 MPH due to
inverted-V low level thermodynamic profiles. The HRRR has been
pretty consistent with this scenario over the last 24 to 30
hours and it`s not out of the question that a special weather
statement or two may be required after about 4 pm. A few of
these may make it as far south as central NH and southern ME
early in the evening, but would likely be more isolated in
coverage and exhibit a weakening trend due to loss of daytime
heating.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
Any showers will dissipate during the early evening hours with
the loss of daytime heating. At this time, overnight lows do not
look to be as low tonight due to lingering clouds and
occasional boundary layer mixing. Have therefore not planned any
sort frost/freeze products at this time.

A good amount of sunshine on Friday with continue to lead to
warming temperatures. Highs are expected to get to a few degrees
above normal, with readings 70 or higher at many locales. Again,
an isolated shower or thunderstorm will be possible during the
afternoon hours, especially across southwestern NH.

Marginal red flag conditions may be met Friday afternoon across
portions of central ME as well as the western ME mountains as RH
values dip to the 20 to 30 percent range with winds gusting
between 18 and 25 MPH.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
A series of upper level disturbances will promote the development of
afternoon showers and thunderstorms this weekend. Temperatures
will be near to just above normal with 70s across the interior,
60s to the north and low to mid 60s near the coast where
afternoon sea breezes will develop. Going into the next work
week there are not many signals for a persistent dry pattern nor
any signs of a widespread precipitation event. There will
continued chances for afternoon showers Monday with similar
temperatures experienced over the weekend. A northern stream
wave will cross southeastern Canada towards the middle of the
week that has the potential to push a cold front through the
area sometime between Tuesday and Wednesday.

The current thinking with regards to the shower and thunderstorm
potential this weekend has not changed much since previous forecast
packages. A short wave at H5 will approach Saturday afternoon with
morning sunshine leading to few hundred J/kg of CAPE developing
by afternoon. This will lead to scattered showers and a slight
chance for thunderstorms Saturday afternoon and evening with
activity diminishing towards sunset.

Another shortwave will cross the area Sunday closer to peak
heating leading to greater chances for showers and
thunderstorms. There will again be a few hundred J/kg of CAPE to
work with, but effective shear will be weak both days this
weekend minimizing the potential for organized cells with
sustained updrafts. However, low level lapse rates will be steep
with inverted-V soundings that will enhance gusty outflow winds
with stronger cells. PWATs will generally be around 0.5 to 0.75
inches, which is slightly below normal for this time of year
minimizing the potential for torrential rain and hydrologic
concerns.

Chances for afternoon showers will continue Monday as another
weak upper level wave crosses southern New England. Temperatures
will generally be in the 70s with cooler conditions near the
coast. Global models continue to vary on the timing and
placement of a northern stream wave crossing southern Canada
Tuesday leading to low confidence towards the end of the
forecast period. At this time this wave looks to push a cold
front through the region Tuesday into Wednesday have have keep
chance PoPs in the forecast through the middle of the week.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Short Term...Mainly VFR expected through Friday. The exception
may be later this afternoon and early evening in the mountains
and foothills as well as portions of central ME. A band of
showers and isolated thunderstorms may move from north to south
with brief lower conditions and SFC wind gusts to 30 kt. This
would mainly be from 20z through 01z today. At this time the
seabreeze looks to remain offshore today and Friday but it`s
possible it could sneak in for an hour or two late this
afternoon.

Long Term...There will chances for afternoon showers and
thunderstorms each day Saturday through Monday that have the
potential to bring brief periods of MVFR/IFR with VFR
prevailing during the mornings.

&&

.MARINE...
Short Term...Winds/seas stay below SCA criteria through Friday.
A gusty shower not out of the question late this afternoon and
early evening with a brief 25 kt gust from the north possible.

Long Term...Winds and seas will remain below SCA thresholds into
early next week. There will be chances for afternoon showers and
an isolated thunderstorm during the afternoons Saturday and
Sunday that may bring some gusty winds.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
ME...None.
NH...None.
MARINE...None.
-- End Changed Discussion --

&&

$$
NEAR/SHORT TERM...Cannon
LONG TERM...Schroeter