Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 220430 AAC

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
1230 AM EDT Tue May 22 2018

High pressure will slide offshore to the south of New England
this evening. A moisture starved cold front will drop south
from Quebec and stall nearby tonight. This front will return
north as a warm front on Tuesday, spreading showers into the
area. Another cold front drops south through the region
Wednesday. Weak low pressure tracks along the international
border late Thursday into Friday. A frontal system tracks into
the area for the holiday weekend bringing widespread showers.


1230 AM Update: Minor changes to the forecast database for
current observational trends. Cloud deck will be moving into
the region from the south and west eventually.,,which has
reached Boston and Albany so far. Latest KGYX 00Z sounding
shows a dry adiabatic layer from the surface to 10k ft, with a
moist layer at 10k ft, followed by another extremely dry layer

915 pm Update: Quiet evening with no issues. No ESTF changes
needed at this time.

605 pm Update: Skies generally clear across most of the region
with only some high clouds noted over northern areas. Minor adj
to temps based on latest obs otherwise no changes to forecast.

Previous Discussion:
At 18z a 1025 millibar high was draped across the lower Great
Lakes. A weak cold front extended from the rooftop of Maine
through the Saint Lawrence Valley. GOES visible imagery showed a
band of broken mid cloud with the cold front otherwise skies
were clear across the forecast area. The weak boundary will drop
south across the area tonight and stall. GOES water vapor shows
an impulse over the northern plains. This impulse and an
associated surface low will race eastward with clouds arriving
from west to east across the area during the morning hours.


On Tuesday...the impulse and surface low will cross the region
and push the boundary northward as a warm front into southern
sections of the forecast area. A mostly cloudy day with showers
developing from west to east by afternoon. It`ll be cooler than
today with highs in the 60s to around 70. Showers taper from
west to east Tuesday night as the impulse and surface low slide
offshore with patchy fog developing. QPF from this system will
average from 0.10 to 0.20 inches.


There will be a gradual clearing on Wednesday. However an upper
level trough will linger to the west which may allow for some
destabilization and the threat of an afternoon or evening shower
or possibly a thunderstorm.

A ridge of high pressure over the region early Thursday will
give way to the approach of a warm front. H8 temperatures in the
+10C to +12C in southern Canada will advect eastward. This will
allow for much milder conditions by Friday as Maine and New
Hampshire will be in the warm sector along with scattered
showers in the northern mountains. This front will become
relatively stationary over the region Saturday. Temperatures
will lower from the 80s to the 70s in most sections except for
southwest New Hampshire. Expect more shower activity by Sunday
as the front settle south to the southern New England coastline.
12Z model suite in relatively good agreement with the front
slipping south of our region.


Short Term /through Tuesday Night/...Gusty westerly winds will
diminish by early evening. VFR through tonight. Areas of MVFR
developing aft 16z tomorrow in shra. LCL IFR aft 03z Wed in fog.

Long Term... Generally VFR conditions with a few scattered
showers and possibly a thunderstorm Wednesday afternoon and
evening. More showers with lowering ceilings Friday night into


Short Term /through Tuesday Night/...
Westerly flow could briefly approach small craft in gusts
through early evening as a weak boundary drops south across the

Long Term...Seas will gradually build to near SCA thresholds in
the proximity of a warm front Friday into Saturday.


Good relative humidity recovery expected tonight with moderate
to high relative humidity tomorrow and tomorrow night in





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