Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 221839

Area Forecast Discussion
National Weather Service Gray ME
239 PM EDT Tue May 22 2018

Showers will end tonight as weak low pressure and an associated
frontal system slide offshore. A cold front will drop south
across the area on Wednesday producing scattered showers and a
few thunderstorms across northern and mountain sections. High
pressure will build into the region Thursday. The next weather
maker nears the northeast for the weekend.


At 18z a 1013 millibar low was over Lake Ontario with a warm
front extending eastward through central New England and a
trailing cold front through the upper midwest. NWS Doppler
Radar mosaic showed a large area of showers in advance of this
disturbance overspreading the remainder of the forecast area at
moment. For tonight...showers will end from west to east as the
system exits the coast with patchy fog developing in the predawn


On Wednesday...a cold front over Quebec will drop south and
cross the area during the afternoon and early evening hours.
The best moisture and instability will be confined to our northern
and eastern Maine zones where a few showers and thunderstorms
will develop by afternoon. Elsewhere...a mostly sunny day with
westerly downslope flow will boost temperatures into the 70s and
lower 80s. Convection ends quickly tomorrow evening with loss of
heating and upper support. Should be mainly clear tomorrow night
with some patchy late night fog developing.


A warm front is expected to approach northern New England on
Thursday from the west. There is relatively good model consensus
within the 12Z run in the timing of the front which appears to
be late Thursday night. Ahead of this boundary, temperatures
will be relatively seasonable for this time of the year with the
coolest readings and onshore winds along and near the coastline.

This front will be relatively moisture starved as it crosses
the region. It will introduce much warmer and more humid air. H8
temperatures will run close to +14C and with ample sun,
temperatures should easily climb into the 80s in all areas
except the Midcoast region.

There will be a greater chance for showers on Saturday as the
front begins to slip back southward as a cold front. Additional
moisture and instability may yield a thunderstorm or two, mainly
over southern New Hampshire during the afternoon and early
evening hours.

By Sunday, this front will be in full retreat, slipping to the
southern New England coastline. A northeast flow will develop
over the region, keeping temperatures mainly in the 60s which is
significantly cooler from Saturday`s highs. Showers and perhaps
patchy drizzle and fog may form over the region with similar
conditions lasting into Monday.


Short Term /through Wednesday Night/...Areas of MVFR through
tonight in -shra with lcl IFR psb in fog. Becoming VFR
throughout aft 13z Wed. Sct MVFR developing btw 16z and 22z Wed in
shra and isold -tsra from Northern third of New Hampshire
through central Maine with a cold front. Aft 22z becoming VFR
throughout with lcl mvfr psb aft 08z Thu in fog.

Long Term...VFR with high pressure dominating through Friday. A
frontal system will bring lowered ceilings on Saturday in
scattered showers and possibly a thunderstorm. Low ceiling and
areas of MVFR conditions will continue into Sunday as the
frontal system slips south of our region.


Short Term /through Wednesday Night/...Winds and seas expected
to remain below SCA level throughout the period.

Long Term...Winds and seas will be increasing to SCA thresholds
along and behind a frontal system Thursday night into Friday.




NEAR TERM...Schwibs
SHORT TERM...Schwibs
LONG TERM...Cannon is the U.S. government's official web portal to all federal, state and local government web resources and services.