Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 211009

Area Forecast Discussion
National Weather Service Gray ME
609 AM EDT Mon Oct 21 2019

High pressure builds today with clearing skies. Onshore winds
pick up Tuesday with rain returning Tuesday night through
Wednesday as a cold front and low pressure cross the area. High
pressure builds into the area again for the end of the work
week, then a fast moving front crosses late Friday with light
showers possible.


615 AM Update...
Forecast on track with only minor sky tweaks at this time.
Clouds associated with the weak disturbance have all but shoved
offshore and river valley fog has formed over NH.

This morning, a weak disturbance continues to
track eastward into the Gulf of Maine with clouds scouring out
in its wake. Fog has developed over the Connecticut River Valley
and other interior valleys this morning as a result. Surface
high pressure centered over Quebec builds by Monday afternoon
and gradually clears skies out locally. High temperatures in the
mid-60s are expected across the coastal plain and interior NH,
about 5 degrees above normal, with a couple more degrees of
warmth possible if mixing conditions improve this afternoon.


Strengthening high pressure over the Canadian maritimes and an
eastward-drifting Mid Atlantic low increases the pressure
gradient over Gulf of Maine, which gradually builds easterly
onshore flow through the short term. Ridging overhead and high
pressure to the east may allow some fog to develop over portions
of interior Maine, although increasing cloud cover could instead
mitigate this. On the flip side increasing low level moisture
from the SW could lead to patchy fog over portions of interior
NH. Otherwise hires models point to onshore flow leading to a
period of low clouds along the coast especially during Tuesday

Further West, a well-developed closed low aloft and accompanying
occluded surface low crosses into the Great Lakes. High and
mid- level clouds gradually increase from the south and west
Tuesday as the associated cold front crosses into the northeast.
Warm frontal rain approaches from the south by the end of
Tuesday, but significant moistening will need to be accomplished
for anything to reach the ground, and models are thus far
inconsistent handling this. Went on the dry side of a model
consensus, although PoPs may ultimately hold off until Tuesday
night, when what moisture and energy remains of Nestor is
ingested in deep southwest flow.


* Precipitation Tuesday night - Wednesday.

Overall, the models have come better in line for the frontal system
that will move through our area Tuesday night and Wednesday. Storm
total rainfall amounts are forecast to be around 1 to 2 inches.
Highest amounts are expect in the White Mountains, capital area of
Maine and along Mid Coast. There may be locally higher amounts
in upslope areas of White and Western Maine Mountains. Minor
nuisance flooding because of heavy rainfall and clogged
culverts from leaves and debris cannot be ruled out at this
point. The heaviest rainfall is expected to occur around
midnight to mid morning on Wednesday. Area wide breezy winds
(10-20 MPH) with higher gusts to 45 MPH cannot be ruled out.

Once the front exits the area, high pressure will build in for
Thursday. After this, the models start to diverge again on timing
and location of the next system, which may affect the weekend
weather. Friday night into early Saturday has the potential to
see a fast moving front to produce rain and/or snow showers.
This will all depend on the time and location. This could be
amplified by a low pressure system in the Mid Atlantic.


Short Term...
Tonight, low moisture will lead to patchy fog development,
mostly likely further west (LEB/CON) where rain had fallen
earlier today, and in sheltered valleys (HIE). Otherwise, broken
VFR decks tonight should stave off fog restrictions elsewhere,
though could briefly build into IFR/MVFR ceilings. Brief
periods of LIFR fog cannot be ruled out in spots further east should
cloud breaks allow for radiational cooling overnight.

Skies clear out for the most part Monday with light
northeasterly flow. Winds turn more easterly Monday night,
which may allow for low stratus and fog along the coast. Patchy
fog elsewhere leaves restrictions on the table at most sites
Tuesday morning. VFR conditions are expected Tuesday accept for
in possible rain across the south.

Long Term...IFR in RA and fog on Tue Night and Wed. Winds
gusting 25 to 40 kts near the coast. Possible MVFR on Friday
night in areas of -SHRA/-SHSN.


Short Term...
Light northeasterly flow Monday increases out of the east by
Tuesday with increasing likelihood of SCA seas developing
through the day.

Long Term...SCA likely on Tuesday night through Thursday AM.
Gales possible outside the bays...especially closer to Downeast




LONG TERM...Becker
MARINE...Becker/Casey is the U.S. government's official web portal to all federal, state and local government web resources and services.