Area Forecast Discussion
Issued by NWS Portland, ME

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229
FXUS61 KGYX 260731
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
331 AM EDT Tue Sep 26 2017

.SYNOPSIS...
Warm, humid weather continues today and Wednesday, though it
will be cooler for areas closer to the coast. A cold front will
move into the area Wednesday night, bringing an end to this warm
and humid air mass, replacing it with a cooler and drier one.
This cooler, drier weather will last through the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Plenty of fog will remain early this morning and dense fog
advisories have been expanded in areal coverage. Visibilities
are down to a quarter mile in many areas.

If LEB or CON were to reach 90 degrees today, they would have an
official heat wave with three consecutive days in a row with
readings at or above 90. With fog this morning and high clouds
crossing the region today, have forecasted slightly cooler
readings than yesterday. Nevertheless, most areas will top out
between 80 and 90 degrees today with the warmest readings once
again in southwest New Hampshire. Coolest readings will be along
the coast, particularly the Midcoast region where ocean
temperatures are the coolest with the onshore breeze.

Otherwise, a large ridge of high pressure will continue to
dominate the region today.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Plenty of fog redevelops tonight through early Wednesday
morning. By Wednesday afternoon, the long awaited cold front
will be approaching the region. There will be a chance of a late
day shower over northern areas. CAPE values increase and there
may be sufficient instability for a thunderstorm or two as well.

There may be a shower along the Midcoast as well as moisture
converges along a prefrontal trough. Readings will continue to
be above normal with temperatures still between 75 and 85
degrees for afternoon highs. This will be due to an increased
southerly flow off the Gulf of Maine, so the warmest readings
once again will be over southern and western New Hampshire away
from the marine layer.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Cold front crosses the area Wednesday night with a chance of
showers or a thunderstorm as it does so. The best forcing for
precipitation will be sliding to the northeast, so precipitation
in our area will not be very widespread, with the northwest
portion of the area most likely to see any rainfall. This front
will be an air mass changer, with a cool, dry air mass moving in
behind it and lasting through the weekend. An upper trough
slides by on Saturday, possibly triggering a few showers, but
mainly just serving to reinforce the cooler air. High pressure
builds out of the Great Lakes and into the Northeast Sunday and
Monday, bringing light winds and good nighttime cooling
conditions.

&&

.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Short Term...Areas of LIFR conditions early this morning in fog,
improving today. Areas if IFR and LIFR conditions redeveloping
tonight with this very humid airmass.

Long Term...There could be areas of IFR especially along the
coast Wednesday night ahead of the cold front. The front should
clear this out, though, with VFR conditions expected through the
weekend outside of valley fog at night.

&&

.MARINE...
Short Term...Have placed areas of dense fog in the marine layer
for much of the day. Visibilities will frequently be near a
quarter mile in fog.

Long period swells have arrived along the Midcoast region from
Maria. Periods on 4 to 6 foot swells are up to as long as 6
seconds. Have issued SCAs for seas for the eastern outer waters
based on this trend.

Long Term...Long period swell may reach 5 to 6 FT through
Thursday. A cold front Thursday morning will shift winds to the
north, though wind speeds are expected to remain just below 25
KT.

&&

.TIDES/COASTAL FLOODING...
Borderline situation for High Surf Advisories for the eastern
counties. Expect long period four foot waves to reach the
shoreline today, which will allow for a moderate rip risk but is just
below the high surf advisory criteria.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 9 AM EDT this morning for MEZ007-008-
     018>028.
NH...Dense Fog Advisory until 9 AM EDT this morning for NHZ001>003-
     005-007-008-010>015.
MARINE...Small Craft Advisory for hazardous seas until 6 PM EDT
     Wednesday for ANZ150-152.

&&

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



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