Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 281309
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
909 AM EDT Fri Apr 28 2017

.SYNOPSIS...
A warm front will work northward across the region today
followed by a trailing cold front this afternoon. Another cold
front will push across New England on Saturday. High pressure
will build in from the northwest Saturday night and will shift
offshore on Sunday as the stalled frontal boundary lifts north
as a warm front. The warm front will stall over the region
Sunday night and Monday. Low pressure lifting northeast out of
the Great Lakes will drive an occluded front toward the region
Monday night and will across the region on Tuesday. Low pressure
will slowly move east through southern Canada Tuesday night
through Wednesday.

&&

.NEAR TERM /UNTIL 7 PM THIS EVENING/...

905 AM...At 13z a warm front extended through eastern New
England with a trailing cold front through eastern New York
State. NWS Doppler Radar mosaic showed a band of convection from
the Penobscot Valley southward through coastal New England. For
today...low clouds and fog will gradually lift ahead of the
surface cold front with additional scattered convection
developing by afternoon with daytime heating and passage of weak
impulse. For this ESTF update...I made adjustments to near term
grids to reflect current satellite and radar trends as well as
the mesonet.

Prev Disc...
6 AM Update...Not much change to the previous forecast. Locally
dense fog across mainly ME should gradually improve as the
morning progresses. Otherwise, a short wave trough moving
through the region this morning may bring a few showers and
possibly a rumble of thunder before quickly moving out.

Previously...

A warm front situated over southern NH at 3 AM early this Friday
morning will gradually work northward this morning and finally
reach eastern zones this afternoon. Showers and isolated
thunderstorms over Upstate NY in association with a short wave
trough will continue to work northeastward early this morning,
with the bulk of that activity missing our CWA to the northwest.
However, we cannot rule out a shower or two this morning across
the region as that weak forcing for ascent moves through.

Locally dense fog and patchy drizzle will be around this
morning as well, especially on the coast. It`s possible that a
relatively small dense fog advisory may be needed for a few
hours early this morning, but at this time visibilities are
generally a half mile or more.

Otherwise, a much warmer air mass moves in from sw to ne today
in the wake of the warm front. Highs should reach 80 across
southern NH with 70s in many other areas. The exception will be
the immediate coast as well as the mid coast zones where fog may
persist much of the day.

Another short wave trough approaches from the west early this
afternoon. This short wave will be accompanied by a SFC trough
as well. This may be enough to spark a few convective showers
this afternoon - perhaps even a thunderstorm or two as weak
SFC-based instability develops. In fact, the HRRR and a few
other convection allowing models do develop a storm or two
today, particularly affecting central Maine. Have therefore
inserted low PoPs this afternoon - mainly north of Cumberland
County.

&&

.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/...
Quiet and dry weather is expected tonight, with perhaps some
patchy fog. A short wave trough and associated cold front
quickly approaches from the west late tonight and crosses the
region Saturday. This will come through will little fanfare -
just an increase in clouds and a couple of showers. Temperatures
will once again be warm Saturday, with highs mainly in the 70s.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
High pressure will build in from the northwest Saturday night
bringing clearing skies and diminishing winds. Lows overnight
will range from the mid 30s north to the mid to upper 40s
south.

Stalled frontal boundary south of New England will begin to
lift north to the west of the region on Sunday as high
pressure shifts offshore. Looking for variable cloudiness
during the day with a chance of showers....mainly in
northwest zones. Highs will range from the mid 50s north to
the mid 60s south.

Warm frontal boundary will continue to lift into the region
Sunday night with shower activity focused mainly across
northern zones overnight. Increasing onshore flow will bring
ocean stratus and patchy fog into the region overnight. Lows
will range from the upper 30s north to the mid 40s south.

Warm front will remain draped across the region on Monday as a
moist onshore flow continues ahead of of a slow moving area of
low pressure over the western Great lakes. Looking for
occasional drizzle or scattered showers under cloudy skies.

Surface low trapped under a broad upper low over the great
lakes will drive an occlusion toward the area Monday night.
Looking for showers and possibly a few thunderstorms as this
boundary pushes into the region from the west by Tuesday
morning. Expect this boundary to push east of the region on
Tuesday with an increasing southwesterly flow behind the front
clearing low level moisture. Highs on Tuesday will generally
range through the 60s to near 70.

Slow moving closed upper low will shift into the northeast
Tuesday night and Wednesday. Will see increasing clouds
Tuesday night with scattered showers shifting into the region
from the west. Wednesday will remain cloudy...cool and unsettled
as upper low remains in place over the region. Highs will range
through the 50s to near 60.

Another deep shortwave digging into the Ohio Valley will bring
more wet weather for the end of the week after a brief respite
on Thursday. Low pressure is forecast to spin up along the east
coast and will bring another round of rain to the area Thurday
night and Friday. System will likely slow as the upper low
closes off over the northeast producing a prolonged rainfall
across the area with several inches possible.

&&

.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
Short Term...Low conditions early this morning will give way to
VFR conditions by late morning, except the mid coast of Maine
where fog may linger even into this evening. Otherwise, mainly
VFR tonight and Saturday.

Long Term...VFR Saturday night and Sunday. MVFR/IFR ceilings
developing Sunday night with IFR/LIFR ceilings Monday through
Monday night. Areas of MVFR ceilings on Tuesday.

&&

.MARINE...
Short Term...SCA for seas remains in effect for today on the
ocean waters as swells of 4-6 ft continue to affect the waters.
These will diminish tonight. Gusty winds will be possible
Saturday in association with a cold front.

Long Term...SCA`s likely Monday night and Tuesday.

&&

.FIRE WEATHER...
Warmer and drier conditions are expected today as a warm front
moves to the north. A cold front will move across the region
Saturday allowing for continued dry weather into Sunday.

&&

.TIDES/COASTAL FLOODING...
11.7 ft tide at Portland once again tonight (1:32 AM Saturday).
However, swells are expected to be lower tonight and winds
offshore. Therefore we are not expecting any flooding at this
time and will forgo any sort of coastal flood advisory at this
this time.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory for hazardous seas until 8 PM EDT this
     evening for ANZ150-152-154.

&&

$$

ES



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