Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 242109 AAA

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
509 PM EDT TUE MAY 24 2016

Low pressure surface and aloft will drift northward across the
region through early tonight. This system will bring unsettled
weather with clouds and scattered showers and thunderstorms. This
weakening system will exit into the Canadian Maritimes tonight.
Warmer weather will return on Wednesday ahead of a cold front. The
cold front will bring clouds and a few showers and thunderstorms
to the area Wednesday afternoon and evening. A ridge of high
pressure will build over the area Wednesday night and will hold
over the region on Thursday as a warm front approaches from the
west. The warm front will stall over the region Thursday night and
Friday and will finally push east of the region on Saturday. A
cold front will cross the region Saturday night followed by high
pressure and dry air to round out the holiday weekend.


507pm update: Have updated this hour to clear out PoPs to the
east of exiting band of showers, with anything to the east of this
taking the form of drizzle. Have seen some improvement in sky
cover from recent visible satellite imagery and have also tried to
capture this trend heading through the evening hours. Temperatures
are generally on track.

Previous Discussion Below...
Upper level trough over Cape Cod continues to slowly migrate off
to the north and east. Band of precipitation extends from northern
Coos county in New Hampshire south and west across southern
Vermont. Instability under the trough will be just enough to keep
a mention of showers in the forecast overnight.

Onshore flow along the coast has been producing a very low cloud
deck along with fog and drizzle. Those conditions should persist
until the winds turn around to the west later tonight. Once the
winds switch then the drizzle should come to an end.
will likely take sunshine tomorrow morning before the fog


Upper level trough will finally pull away from the area tomorrow
and tomorrow night... leaving a more progressive and zonal upper
air pattern in place. A weak frontal boundary tries to nudge south
out of Canada and into the mountains of New Hampshire and western
Maine tomorrow afternoon. This feature may generate enough
instability to get some scattered thunderstorms going...but they
should be relatively weak and unorganized.


Warm weather continues Thursday as high pressure builds in
further at the surface and aloft. Temperatures should warm
quickly in a relatively dry airmass with some clouds remaining
over the higher terrain and mostly sunny skies across the coastal
plain. A warm front approaches from the SW during the late
evening hours...but it will take a while for the atmospheric
column to saturate so not expecting anything but sprinkles and
scattered showers over NH early on.

By the early morning hours Friday we should see more coverage over
NH and western Maine. The warm front will lift across
northern sections providing a focus for showers and thunderstorms
along the boundary with decent instability for areas far enough
away from the onshore flow.

PW values during the Friday to Saturday time frame jump from 1.4
inches areawide Friday to around 1.7 inches along the coast
Saturday as a cold front crosses the region. The cold front will
trigger more widespread convection with another chance at
thunderstorms Saturday.

The cool air regime continues with more air moving in from
the Canadian maritimes through early next week. In the upper
levels of the atmosphere we will shift to NW flow keeping skies
cloudy and a few showers around as weak impulses move SE. High
pressure builds in from eastern Canada Sunday with slightly
cooler temperatures as cool, dry air filters in. Likewise Monday
morning will be a little cool with temperatures primarily in the
40s. Preliminary guidance indicates ridging building in again by
midweek with increasing temperatures.


Short Term...IFR/LIFR conditions tonight in fog...drizzle and low
ceilings. Expect conditions to improve tomorrow once the sun has a
little bit of time to burn away the fog. Expect VFR conditions
tomorrow and tomorrow night.

Long Term...VFR conditions Thursday with rain showers developing
across NH and northwestern Maine Friday. MVFR or IFR conditions
are most likely across KHIE and KLEB. TSRA is possible. On
Saturday more widespread showers and thunderstorms are possible
with MVFR or IFR conditions possible at all terminals through the


Short Term...No flags expected.

Long Term...Winds and seas will remain on the calm end of the
spectrum Thursday through next Tuesday. The pressure gradient will
increase Friday afternoon causing a few gusts to 20 kts.


Thursday will be one of the only dry days of the week. RH values
may hover near 30% but winds will be light. We are forecasting all
areas to receive rainfall this week albeit light.





NEAR TERM...Arnott
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