FXUS61 KGYX 210410

Area Forecast Discussion
National Weather Service Gray ME
1210 AM EDT Tue May 21 2019

A cold front crosses the region this evening, bringing cooler
and drier air to New Hampshire and western Maine for midweek.
Another area of low pressure crosses the region Thursday night
into early Friday. It will be seasonably mild, but unsettled
through the weekend.


Minor edits for temperatures, dew points and wind values across
the region with this latest update.

10 PM Update...
We have a few hours between the rain and the gusty winds which
will set in towards daybreak. In between we are seeing fog
develop, especially in areas where it has rained. Have kept
patchy fog for the forecast area with areas of fog expected over
the waters, at least until NW kick in which again will be
several hours even in the western zones. We may see some spots
of dense fog. Skies are gradually clearing out as well but will
keep clouds and showers over the mountains as per previous
discussion at 645 PM. Made minor changes to the forecast to
further trim back PoPs and adjust temperatures and dew points.

645 PM Update...
Have gone ahead and cancelled the Severe Thunderstorm Watch as
storms move out of the area and we continue to lose diurnal
heating. Any thunder will be confined to eastern Maine and along
or off the coast for the next couple of hours. A warm front
has pushed into northeastern Maine with a pre-frontal
trough/cold front already moving into southern NH and coastal
Maine. The warm sector will gradually push offshore this evening
allowing gusty NW winds and drier air to work their way in.

Adjusted PoPs to drop them quite a bit where there is no forcing
for ascent. Expect some showers in the mountains however,
especially overnight as Froude numbers and pattern recognition
support this.

Previous discussion...
Low pressure moving tracking near the Saint Lawrence Valley is
sending a cold front eastward across New England. Ahead of it, a
warm and humid air mass is in place. This has led to some
moderate instability and a few isolated to scattered showers and
a few thunderstorms. Overall wind flow environment still favors
storm organization, although the limiting factor is
instability. It remains possible for storms to strengthen and
produce damaging winds and small hail through this evening along
and ahead of the front. Will continue to monitor the severe
weather threat through the evening and update Watch 198 as

Expect the cold front to shut activity off as it moves through
and reaches the coast by early evening. Winds shift to the west
with drier air moving in behind it. Lows tonight should reach
the 40s to upper 50s.


West northwest winds become strong and gusty on Tuesday as cold
advection combines with a strong pressure gradient. The
combination of strong winds aloft, good mixing in cold
advection, and downsloping conditions on the coastal plain will
allow the stronger winds to reach the ground level. Currently
expect gusts to be just below advisory levels... topping off in
the 30 to 40 MPH range with a few gusts to 45 MPH possible.
Temperatures on Tuesday will reflect the northwest flow pattern
with cooler conditions up north and the warmest conditions in
the south and coast. Winds die down a bit Tuesday night as high
pressure builds in from the west. Most of the area falls into
the 40s. Temperatures in northern valleys may approach the mid
30s, but expect winds will remain strong enough to prevent
dropping to freezing or for frost to form. However, this will
need to be monitored.


500 MB continues to show blocking pattern over ern Canada and N
Atlantic thru the long range, but ridge development over srn
CONUS will push the coldest air poleward, and this should help
moderate temps closer to normal in the extended, despite
continued unsettled conditions, as troughs continue to affect
nrn New England.

Sfc high pressure squeezes in from the south for Wed into thu,
and for the most part those days look dry. Warm air starts to
move back in by Wed and highs will mostly be in the 60s, with
partly to mostly sunny skies. Wed night will be calm and nearly
clear so lows will drop off to around 40 in the north to the
mid to upper 40s in the south. Thu will feature increasing
clouds as the next system approaches, and highs in the mid 60s
to low 70s.

Fast moving 500 MB wave moves across the CWA Thu night, and
resembles a ridge rider type MCS, although expect CWA to be on
the cools side and end up with just some rain which will mainly
be confined to the overnight. A more significant trough passes
to our N around Saturday and will drag a cold front across the
region Saturday , which provides an other chance of showers.
Another wave follows quickly for Sunday or Monday. Temps thru
the period will run close to normal.


Short Term...A cold front moves through today with a few showers
and strong storms possible ahead of the front. However, coverage
is too low to keep mention of thunder in any TAF at the moment.
Should see winds shifting to the west and clearing conditions
through the night. Winds on Tuesday will gust to 30 to 35 KT out
of the northwest before diminishing a bit Tuesday night.

Long Term...MVFR-IFR possible in SHRA Thu night, with some
showers briefly producing flight restrictions on Sat.


Short Term...Southwest winds shift to west this evening behind a
cold front. Expect stronger northwest winds beginning on Tuesday
and gradually diminishing Tuesday night. Small Craft Advisory
has been issued for Tuesday. It's possible a few gusts to 35KT
could occur near the immediate coastline.

Long Term...Generally quiet on the waters with sub-SCA
conditions through Friday.


MARINE...Small Craft Advisory from 7 AM this morning to midnight EDT
tonight for ANZ151-153.
Small Craft Advisory from 7 AM this morning to noon EDT
Wednesday for ANZ150-152-154.


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