Area Forecast Discussion
Issued by NWS Portland, ME

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557
FXUS61 KGYX 282330
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
730 PM EDT SAT MAY 28 2016

.SYNOPSIS...
A cold front will push westward across Maine and New Hampshire
tonight as high pressure builds into New Brunswick and Nova
Scotia. An easterly onshore wind will bring much cooler
temperatures on Sunday, although to the west of the mountains it
will be hot and humid again. Warm, moist air moves into the area
again on Monday with showers and thunderstorms expected. A cold
front moves through from the northwest late Tuesday with high
pressure building behind it through late week.

&&

23z update...
Quick update to adjust temps/tds/sky grids based on current
observations. With the loss of heating will also be removing
mention of thunderstorms in the forecast. Have only seen some
widely scattered shower activity across mainly southern areas and
expect this to die out over the next few hours. Still looking for
ocean stratus and areas of fog to develop across the region after
midnight. No other changes planned attm.


Previous discussion...
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Any afternoon showers and thunderstorms that develop will diminish
this evening. Winds will shift to the east northeast as high
pressure moves into New Brunswick and Nova Scotia and a back door
cold front moves westward across the region. This will bring a
cool, maritime air mass into the low levels this evening. Water
temperatures are in the low to mid 50s and air temperatures within
this air mass will not be much warmer than that. Should see some
low level cloudiness develop as that cold air wedges itself in
below the warm/moist air above it. By morning there could be some
fog and drizzle as well, especially over southwest Maine and
eastern New Hampshire.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Onshore easterly flow will keep cool air wedged in at the surface
across Maine and eastern New Hampshire on Sunday. Near the coast
temperatures may not get out of the upper 50s to low 60s, while
inland areas could rise a little warmer. This cold air will not
make it all the way across the mountains, though, so western New
Hampshire will see another hot and humid day with temperatures in
the 80s. Afternoon showers and storms are more likely to pop up
across New York, Vermont, and western Massachusetts but there
could be a stay shower or storm move through western New
Hampshire.

Remnant showers and thunderstorms associated with a shortwave
trough moving through the eastern Great Lakes will eventually
make their way into New Hampshire and western Maine Sunday night.
This activity should be diminishing as it moves through.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
High impact wx: there is a small chance that heavy downpourslate
Sunday night into Monday morning could produce localized flooding.

The hemispheric 500 mb pattern will continue to feature a western
Atlantic ridge, although it will not reach as far poleward as it
is this weekend. After one short wave moves through Monday, will
see a few more during the course of the week, but none of them
are strong enough to break down the ridging, but just temporarily
dampen it. Overall, 850 mb temps through the period will be above
normal, but bouts of onshore flow will help keep sfc temps in the
normal to above range, and not expecting anything quite as warm
as this weekend.

Monday starts off fairly murky and rainy, with fog and shra like
in the morning, as marine layer undercuts the warm air loft. Also
as weak 500 mb trough approaches from the west will see showers
out ahead of the front, with some tropical moisture from TD 2
being drawn northward. Could see a few heavier showers and some
thunderstorms, especially Monday morning. Also RH will be on the
rise during the day as well. May see some brief clearing late in
the warm sector, but a frontal boundary will approach from the
west and could spark off a few sct thunderstorms...especially in
the mountains late. Despite a fair amount of clouds highs Monday
will manage to get into the mid to upper 70s in inland areas, and
to around 70 on the coast. The front moves thru Mon night and
skies will clear but air mass not much different behind it and
will have to wait for second 500mb wave to pull another cold front
thru late Tuesday, but without much in the way of showers, which
would be limited to the mountains. Highs Tuesday will generally be
in the low to mid 80s inland, and mid-upper 70s on the coast.

Sfc high then builds in from north Wed beneath decent ridging
aloft on Wed, and then shifts off to the northeast on Thu. Both
days look fair although Wed will be warmer as flow will be from
the west with highs in the mid 70s to low 80s. The onshore flow
will keep the coast close to 70 on Thu, but will warm into the
mid 70s inland. Next chc of rain will be Fri or Saturday as cold
front approaches from the west. GFS/Euro seem to be struggling
with TD 2 during the mid-late week as they keep it lingering near
the Carolinas until late week, and then start to move it E-NE.
This could affect the timing of our rain chances late in the week
into next weekend.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Short Term...VFR conditions to start off the night, but an onshore
flow should lead to low clouds developing again tonight along the
coast. Expect IFR conditions from Portsmouth to Rockland, but VFR
should continue for western New Hampshire except for a brief
period of possible valley fog at Lebanon. Low clouds will likely
linger through much of the day Sunday along the coast while
western New Hampshire will be VFR with an outside chance of a
shower or thunderstorm in the evening.

Long Term...IFR or lower Monday morning will improve to VFR from
SW to NE Monday afternoon. After which, VFR is expected through
Thursday.

&&

.MARINE...
Short Term...Easterly flow develops over the waters tonight
behind a back door front. Winds should remain below advisory
levels. Wave heights will be building in the western Gulf of Maine
on that easterly fetch, but at this time are forecast to stay
below 5 feet.

Long Term...Monday will see a surge in SW flow ahead of a cold
front, and may need SCA Monday afternoon into Monday night.
Otherwise, the rest of the week should remain blow SCA levels.

&&

.FIRE WEATHER...
Expect cool and moist onshore flow Sunday. It will warm up Monday
and Tuesday but will still be fairly moist. Although showers and
thunderstorms are possible several days during the coming week,
widespread significant rainfall is not expected.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...Cempa
AVIATION...
MARINE...
FIRE WEATHER...



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