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nh discuss

Office: GYX

FXUS61 KGYX 251103

Area Forecast Discussion
National Weather Service Gray ME
703 AM EDT Fri May 25 2018

High pressure moves offshore today and increasing SW flow west
of this system will produce breezy and very warm conditions
today into tonight. A cold front pushes in from the northeast
on Saturday, providing a chance of showers or thunderstorms and
making Sunday much cooler. Cool and cloudy conditions linger
into Monday, before we start to see it warm up during next week.
Canadian high pressure to bring dry conditions back to the
region Tuesday through Thursday.


7 AM...Other than some cirrus work across the SW zones, forecast
looks good. Still in store for a very warm and windy day.

Previously...High pressure building to our south and weak low
passing to our north will provide a warm westerly flow today ,
with +15C 850 temps advecting in and mixing down. Sfc winds look
generally westerly, which should warm up most places in our CWA
into the 80s, with 90 F possible in some of the warmer spots.
The west winds will gust to 25-30 mph at times as well, but
skies remain mainly sunny with some cirrus moving in late. This
will create favorable meteorological conds for fire growth, and
this is discussed further in the fire weather section.


That weak will pass to our N this evening, and good produce a
few showers or thunderstorms along the intl border, as cold
front approaches from the N. The better ch for showers will
come after midnight, as another wave move Se into the St.
Lawrence valley and could bring some showers into NH and
interior west/central ME. It will be warm and muggy night as dew
points rise and persistent west flow keeps temps in the 60s
across most of the CWA.

On Saturday, that second wave will pass across the nrn part of
the CWA and push the cold front SSW across the area. Some
showers are possible in the morning in all but the srn part of
NH and far SW ME, but the front will not really progress SW
until the afternoon. So highs in srn NH will be in the mid to
upper 80s, while they will only be 70-75 along the ME coast and
the ME coastal plain, and only in the upper the 60s in the ME
mtns. Some t-storms will possible in the srn half of NH and
parts of wrn ME outside the mtns as the front pushes thru. That
front will be quite noticeable as it pushes SW along the coast
Saturday after noon, when temps drop from the mid to upper 70s
to the low to mid 60s in a short period as the flow quickly
shifts onshore, and could become briefly gusty. Srn NH looks
like it should hold onto to the warmer thru much of the
afternoon, but could see that front push thru late in the day or
early evening.


High pres over the maritimes will continue to push south
driving the cold front south of the southern New England coast
Sat night. As the large ridge of high pres becomes better
established over the maritimes it will allow a deeper moist east
flow to develop with the nosing of the high across the region,
which is well advertised on the models. This ridge of high pres
will remain anchored over the maritimes through the rest of the
holiday weekend as a weak wave of low pres moves east along the
stalled frontal system located south of New England. This
combination will produce a cool, damp, moist east flow with sct
light showers at times through Mon. By Sun afternoon areas of
fog and patchy drizzle will also develop over southern areas
and then move north Sun night and Mon.

QPF amounts from this system will be very minimal.

An upper short wave will move through the area Mon night with a
drier northwest flow at the sfc/aloft to develop in its wake.
This will allow clearing later Mon night with a very dry air
mass and warmer temps to return midweek.


Short Term...LLWS should end after sunrise as we start mixing
the strong W flow down to the sfc, and W winds gust to around 25
kts today.

Mainly VFR at the terminals thru tonight. Will start to see
flight restrictions develop in low cigs as a cold fronts moves
across the area from NE-SW on Saturday.

Long Term...IFR/lifr ceilings in developing stratus/patchy fog Saturday
night in southern New Hampshire and southwest Maine. Areas of
MVFR/IFR ceilings in southern zones Sunday. Widespread IFR/LIFR
ceilings/vsby Sunday night and continuing through Monday, then
becoming VFR Monday night. VFR Tuesday.


Short Term...SCAs remain in effect today for all but Casco Bay
as west wins gust to 25 kts or so. These will diminish tonight.
A cold front cross the waters Sat afternoon from the NE, and
could see a brief burst of SCA gusts Saturday afternoon behind
the front.

Long Term...East winds will remain below SCA conditions but
with a long and persistent easterly fetch, the seas are
expected to build to 4-7 ft over the outer waters Sun and
continue through Mon so an SCA will be likely needed for that
time period.


A strong westerly gradient will develop today, preventing a sea
breeze from forming and allowing the RH to fall to below 30%
across portions of the area. Through collaboration on the fuel
and green up conditions with Maine and New Hampshire, have opted
to issue an SPS for both states for the elevated fire weather
conditions.  Winds diminish with good recovery tonight.


MARINE...Small Craft Advisory until 8 PM EDT this evening for