Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 231839
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
239 PM EDT Sun Jul 23 2017

.SYNOPSIS...
A ridge of high pressure will gradually shift offshore into the
maritimes tonight into Monday. Low pressure will approach from
the southwest later tonight and Monday and will deliver cooler
temperatures and the likelihood of rain in an onshore flow. Conditions
will gradually improve by Tuesday night and Wednesday as high pressure
moves in. A cold front approaches late in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
At 18z a 1019 millibar high was centered near the southern tip
of Hudson Bay...while yesterday`s cold front remains stalled
from Lake Erie southeastward through the Mid Atlantic region.
We enjoyed a brief break today as the Canadian surface high
briefly nosed into the forecast area. The surface ridge will
gradually retreat offshore tonight with onshore flow and an
approaching shortwave impulse spreading increasing and lower
cloud into the area overnight. Any precipitation should be
confined largely to southern and western New Hampshire tonight.
Lows tonight will range from near 50 along the international
border with readings in the 50s to around 60 elsewhere.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
A cool damp day in expected Monday as a series of weak lows
traverse the surface boundary situated to our south and west.
Rain should be lightest and of shortest duration over our far
northern and eastern Maine zones as the precipitation has a
hard time overcoming the dry air with the surface ridge over the
maritimes. Highs will be well below normal for the date and
confined to the 60s. Rain tapers to scattered showers Monday
night as the first shortwave exits offshore along with an
associated surface low. We`re then left with cloudy skies and
areas of drizzle and fog for the balance of the overnight
period. Lows will be in the 50s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Low pressure will exit into the Canadian Maritimes on Tuesday as
winds switch to the west aloft. However, an upper level trough
will remain overhead. Steep lapse rates and low level moisture
will allow for mainly diurnally driven scattered showers to pop
up across the region during the day. This precipitation will
diminish around sunset. There will only be a slow improvement
in maximum temperatures, with readings limited to the 60s in
most areas.

Patchy fog will dominate the region Tuesday night as high
pressure parks itself over the region.

As the surface ridge exits the region Wednesday, a cold front
will approach northern sections, bringing scattered showers and
storms to that region by Thursday. On Friday, it appears a
surface low will cross Southern New England. This will bring a
period of rain to southern areas, with some of it being heavy.
The Canadian, and to some extent the Euro model are most
agressive with the cyclogenesis with this system.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Short Term /through Monday Night/...VFR. MVFR conditions are
expected to arrive Monday morning as rain moves into the
region...areas of IFR developing Monday night in areas of
drizzle and fog.

Long Term...
Conditions will begin to improve on Tuesday and return to VFR
with just some valley fog possible on Tuesday night as high
pressure crests over the region. Wednesday will return to VFR.
A front will cross the region on Thursday with scattered showers
and thunderstorms possible at all locations into Friday.

&&

.MARINE...
Short Term /through Monday Night/...the onshore flow will
strengthen as we head into Monday afternoon and evening and we
may need a small craft for our southern most offshore waters
late Monday into Monday night.

Long Term...
Winds and seas will subside by Tuesday with high pressure
building in for Wednesday. Low pressure approaches the waters
Thursday and Friday.

&&

.TIDES/COASTAL FLOODING...
High astronomical tides tonight and Monday night may contribute
to some localized minor coastal flooding right around the times
of high tide during the late evening hours.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Coastal Flood Advisory from 11 PM this evening to 1 AM EDT
     Monday for MEZ023-024.
NH...Coastal Flood Advisory from 11 PM this evening to 1 AM EDT
     Monday for NHZ014.
MARINE...None.

&&

$$
SYNOPSIS...Schwibs
NEAR TERM...Schwibs
SHORT TERM...Schwibs
LONG TERM...Cannon
AVIATION...Schwibs
MARINE...Cannon/Schwibs
TIDES/COASTAL FLOODING...Cannon


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