Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 241347

Area Forecast Discussion
National Weather Service Gray ME
947 AM EDT Sun Jun 24 2018

An upper level disturbance will approach the New England today
and tonight, before crossing the region Monday. High pressure
builds east out of the Great Lakes on Tuesday and Wednesday. A
broad trough swings across the Northeast on Thursday with
showers possible. Then much warmer air builds in for the rest of
the week and into next weekend.


10am update...Very variable cloudiness this morning with patches
of sun as well as low clouds. Resulting temperatures are varying
a lot too although as a whole the area is running a bit cooler
than forecast. Updated temperatures and cloud cover. Not
expecting shower development until early afternoon.

Have update the grids based on current observations and latest
set of mesoscale models this morning. A few patches of patchy
fog remain in portions of the forecast area, however this should
be diminishing early this morning. Significant breaks in the
clouds over southern interior New Hampshire and southwest
interior Maine per latest satellite imagery. Expect partly sunny
conditions in these areas for a good portion of this morning
before the clouds fill back in.

Made minor adjustments to near term temperature, dew point and
wind forecast for this morning as well.

Prev Disc...
Not much in the way of dynamic forcing this morning
for any widespread precipitation. One weak short wave will exit
into the Canadian Maritimes as a second more significant piece
of energy embedded in the cyclonic flow aloft approaches the
region from the Eastern Great Lakes today.

This second short wave will trigger the development of more
widespread showers later this afternoon and evening. Mesoscale
models suggest the atmosphere will destabilize during the
afternoon and evening over southern Maine and southern New
Hampshire with CAPE values at or above 500 J/KG, mainly away
from the coast. Therefore, we can expect a thunderstorm in some
sections. Increasing precipitable water values may allow for a
brief period of heavy rain in some areas.

All in all, the cloud cover will keep temperatures at or below
normal for this time of the year in many areas, especially along
the shoreline.


A weak area of low pressure will develop in the Gulf of Maine
tonight, briefly enhancing some of the precipitation in our
forecast area. Widespread heavy rains will be needed to provide
a reprieve of our dry conditions, however most areas will be
capped off at around a half inch through Monday morning.

During the day Monday, a drier northwesterly flow will develop.
However, there will still be plenty of instability in the
atmosphere as the core of the upper level low crosses the
region. A slight chance for a thunderstorm will continue,
however temperatures will still remain below normal for this
time of the year.


High pressure will continue building in from the west Monday night
and will clear lingering clouds by Tuesday morning. Lows overnight
will generally range through the 40s.

Tuesday looking mostly sunny as high pressure crests over the
region before shifting offshore southeast of New England. Expect
seasonable temperatures with highs ranging through the 70s to near
80. High pressure will continue to drift off to the southeast
Tuesday night. Lows will range from the upper 40s to upper 50s.

Low pressure approaching from the west will lift a warm front
toward the region on Wednesday bringing increasing high clouds
during the day and a chance of showers in western zones by late in
the day. Highs will range from the mid 70s to lower 80s.

Low pressure will turn northeast and track into the St Lawrence
Valley Wednesday night. Looking for showers and some thunderstorms
overnight and this activity will extend into much of Thursday as a
trailing cold front pushes in from the west. Lows Wednesday night
will range from the upper 50s to mid 60s. Highs on Thursday will
range from the mid 70s north to the mid 80s across southern New

Showers and thunderstorms will come to an end Thursday evening as
the front pushes east of the area. A shallow ridge of high pressure
will build in from the west Thursday night. Very little in the way
of cold air behind this departing boundary and expect temperatures
to soar on Friday as massive ridge builds over the eastern half of
the country. Looking for highs ranging through the 80s to near 90
in what will be the beginning of an extended period of heat and
humidity which will last through the weekend and into early next


Short Term...Low cloud ceilings and patchy fog will allow for
areas of MVFR conditions with localized IFR conditions this
morning and again later this afternoon and tonight as showers
become more widespread. There is the possibility of a
thunderstorm over southern Maine and southern New Hampshire
during this period. Ceilings gradually will be lifting on
Monday, however there will still be a threat for a passing
shower or two.

Long Term...
VFR Monday through Wednesday. Areas of MVFR/IFR ceilings
developing Wednesday night and persisting into Thursday.


Short Term...Winds and seas will continue to remain below SCA
thresholds through tonight with patchy fog, mainly at night.
Winds to top out near 20 kt by Monday for much of the outer
waters by Monday.

Long Term...
SCA`s likely Wednesday night and Thursday.




NEAR TERM...Curtis
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