Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 241939
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
339 PM EDT Wed May 24 2017

.SYNOPSIS...
Low pressure over the Ohio Valley will slowly drift east and
redevelop along the Mid Atlantic coast Thursday. The system will
then move northeast into the Gulf of Maine Friday and into the
Canadian Maritimes Saturday. Weak high pressure will build over
the region on Saturday. Low pressure will approach from the
west on Sunday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Temperatures have peaked in the 60s and 70s with coastal
locations already cooling under the influence of a weak sea
breeze.

An extensive cirrus shield associated with low pressure passing
offshore will gradually shift east with time along with a
baroclinic zone. Over the Ohio Valley a deepening low pressure
system is being fed by tropical moisture and lofting additional
cloud cover towards New England. A warm front extending from
this system snaked into NY State and was lifting north. Models
are still showing some light showers over the mountains along
the warm front...but currently we seem to be too dry for
anything to reach the ground. There is still a possibility of a
light shower late this afternoon and evening over the higher
terrain.

Expecting a quiet and dry night for most locations with mostly
cloudy skies. Overnight lows drop into the 40s and 50s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
Clouds and precipitation chances increase Thursday as the Ohio
Valley stacked low nears from the SW. Showers arrive in southern
NH late morning and move east during the day. The surface low
will rotate offshore near Cape Cod and generally stay well south
of the Gulf of Maine as it moves east. This will keep more
precipitation on the coast and less inland. Easterly winds will
be gusty and keep conditions raw and cool in a marine layer
which will extend well inland. This will prevent any chance for
thunderstorms. Highs will be capped in the upper 50s and 60s.

Thursday night into Friday morning will have widespread rain
with some heavy downpours. The majority of the heaviest rains
will fall during this time. Once again more precipitation will
fall along the coast and just inland than falls towards the
north. Expect some fog and drizzle during this time as well.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
An overall very active, cool, and wet pattern for the outlook
period.

Low pressure will continue to redevelop along the mid atlantic
coast and move into the Gulf of Maine Friday. A broad damp
onshore flow with cool temps expected. Widespread rains are
expected across the region with total QPF amounts from the storm
ranging from around a 1/2 inch in the mountains to 1.25 along
the coast. Astronomical high tides will continue to be a problem
due to the onshore flow (see Tides/Coastal Flooding section).

The system exits the region northeast into the maritimes on
Saturday with weak high pressure following allowing for some
clearing.

By late Sunday another approaching upper s/wv rotating
northeast toward New England will spread another period of cool
damp onshore flow as it allows another weak secondary low
to redevelop off the southern New England coast and moves it into
the Gulf of Maine Monday. This system quickly exits into the
maritimes Monday night followed by another weak area of high
pressure for Tuesday.

Another upper trof with more wet unsettled weather should arrive
for Wednesday.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Short Term...VFR today through tonight. IFR/LIFR ceilings and
visibilities will develop on Thursday in showers for southern
terminals before spreading north. RA which will become heavy
between 00Z-12Z Friday for coastal/southern terminals. Fog and
drizzle will be prevalent- especially along the coast further
decreasing flight conditions. Areas of MVFR ceilings/
visibilities are more likely for the north.

Long Term...IFR conditions Friday. Significant improvement
likely will not occur until Sat...when low pressure begins to
pull away. Weak ridging Sat into Sun will allow a return to VFR
conditions.

&&

.MARINE...
Short Term...SCAs have been issued beginning early Tuesday
afternoon through Friday afternoon for building seas and gusty
winds.

Long Term...SCA conditions will continue into Fri night as a
coastal storm strengthens in the Gulf of ME. Low pressure will
not pull away until Sat...so winds and seas will only gradually
diminish into the weekend.

&&

.TIDES/COASTAL FLOODING...
Astronomically high tides begin tonight with an 11.5 ft peak
forecast overnight. With increasing onshore flow, we may see
some minor splash-over tonight for the 10:39 PM high tide at
Portland...however this appears to be a marginal concern at this
time. Coastal flooding is still more likely with higher tides
Friday night.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory from 2 PM Thursday to 2 PM EDT Friday for
     ANZ151-153.
     Small Craft Advisory from 11 AM Thursday to 2 PM EDT Friday
     for ANZ150-152-154.

&&

$$

NEAR TERM...Hanes
SHORT TERM...Hanes
LONG TERM...Marine


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