950 
FXUS61 KGYX 210318
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1118 PM EDT Fri Aug 20 2021

.SYNOPSIS...
An onshore easterly flow develops this weekend keeping humid 
conditions in place. Tropical Storm Henri may affect our region
Sunday into Monday with rain, a period of gusty winds, and some
minor coastal flooding. Thereafter, summery weather continues
through the week with mainly dry weather, although a few
rounds of scattered showers and thunderstorms cannot be ruled
out.

&&

.NEAR TERM /TONIGHT/...
1115 PM Update... A quiet evening in progress at the moment with
another round of minor tweaks to overnight T/Td trends.

715 PM Update... Refreshed T/Td/sky/fog through the overnight 
according to observations and model trends. Looking like a soupy
atmosphere yet again producing patchy fog for most places, 
though clouds hanging around won't allow for a clean decoupling 
for most places besides perhaps the north. 

Previously...
A weak cold front that is associated with an area of high 
pressure near the Canadian Maritimes is currently located across
northern Maine with slightly lower dewpoints behind it. This 
front will largely dissipate tonight while attempting to sink 
south bringing little to no relief from the ongoing warm and 
humid conditions. Other than an isolated sprinkle across 
southern NH it will be a quiet and dry night as large scale 
subsidence settles in. Expecting fairly widespread fog overnight
with some areas of localized dense fog possible, especially in 
valley locations. Skies will be partly cloudy with the most 
cloud cover across southern NH. Low temperatures will be into 
the lower to middle 60s from north to south.

&&

.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
715 PM Update... Boosted clouds tomorrow evening and overnight 
with hires models favoring stratus filling in, in increasing 
onshore flow.

Previously...
Fog will lift by early to mid morning on Saturday with partly 
sunny skies expected in the afternoon with high temperatures 
into the lower to middle 80s. Scattered showers and isolated 
thunderstorms are possible as daytime heating and high surface 
dewpoints provide weak instability over the region under broad 
shortwave troughing. Showers will continue to be a possibility 
through Saturday night as Tropical Storm Henri begins to 
approach southern New England or Long Island towards Sunday 
morning. Low temperatures will be into the lower to middle 60s 
with once again the possibility of fog development.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
12z deterministic and ensemble guidance has once again shifted a
bit west with Henri. In general this means lesser affects to 
our region if this trend continues to hold, with negative 
impacts from winds not looking a big issue here at this time. 
Heavy rainfall may be an issue for southwestern NH and the 
eastern slopes of the whites and will continue to monitor that.
However, the sensible weather for most folks on Sunday and
Monday will be cloudy and muggy conditions with occasional 
bouts of heavy showers moving in from off the ocean and a few 
wind gusts possibly up to 30 MPH. Minor coastal flooding will 
be possible, especially Sunday night.

This is conditional on the latest continued westward shift in 
track. If an eastward shift commences, then the area may see 
greater impacts. 

Thereafter, a summery pattern continues with highs well into the
80s for most throughout the rest of the week with a few bouts of
scattered showers and thunderstorms possible.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR conditions expected through early this evening
before patchy fog and low ceilings result in IFR/LIFR conditions
overnight through early Saturday morning, especially across
valley terminals. VFR conditions return tomorrow, although a 
few scattered showers and isolated thunderstorms may result in 
brief MVFR conditions. 

Long Term...MVFR with occasional IFR conditions expected to
prevail Sunday and Monday in moist east flow with occasional
showers. Improving conditions foreseen Tuesday and Wednesday.

&&

.MARINE...
Short Term...Winds and seas to remain below SCA criteria through
Saturday night under weak high pressure. 

Long Term...Winds will begin to increase on Sunday out of the
northeast. Seas will build as well to possibly near or over 10
feet across the outer waters Sunday into Monday. Continue to 
monitor latest NHC forecast for details about Henri. It's 
possible that tropical storm conditions will impact the region
late this weekend or on Monday. However, latest trends in track
are westward and this may keep the tropical storm winds out of
our region.

&&

.HYDROLOGY...
The track of Henri remains a bit uncertain, but a westward trend
continues. This could keep most of our region out of the very
heavy rain. The exception may be southwestern NH where the main
batch of tropical rainfall could move across that region late
Sunday and Sunday night with flooding issues.

&&

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

&&

$$

UPDATE...Casey
NEAR/SHORT TERM...Tubbs
LONG TERM...Ekster