Area Forecast Discussion
Issued by NWS Portland, ME

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FXUS61 KGYX 282258 AAA
AFDGYX

Area Forecast Discussion...UPDATED
National Weather Service Gray ME
658 PM EDT Wed Sep 28 2016

.SYNOPSIS...
Canadian high pressure will continue to build into the region
from the north through Thursday. The high will remain parked to
our north while low pressure over the midwest drifts slowly north
and east. Moisture from this system may spread into southern areas
Friday. The best chance of rain will be this weekend when a large
upper level low pressure system over the Great Lakes lifts to the
north, and may spread rain into New England.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Update...Drier NE flow continues...but will take some time to
scatter out the stratus deck...especially as nocturnal cooling
lowers dewpoint depressions a bit. Forecast soundings show
continued drying in the lower levels however...with clouds
forecast to scatter out after midnight for most locations. This
should allow for some cool pockets and patchy valley fog.

Previous discussion...A strong ridge of high pressure to the
north and east of Maine in the Canadian Maritimes will continue to
funnel down dry air in the lower levels of the atmosphere tonight.
Meanwhile, low pressure over the Ohio River Valley will remain
relatively stationary through the night. This will allow for
varying amounts of cloudiness with the driest air over eastern
sections and the deepest moisture over far southern portions of
the forecast area.

Areas that do remain mainly clear overnight, mainly over northern
and eastern locations may have the potential for some patchy fog
under light winds.

With some cold air advection from the northeast, as well as
differentiating cloud cover, expect a wide range in overnight lows
tonight. 30s will be the rule in the mountains with 40s elsewhere.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
The surface low pressure system associated with a large upper
level low will gradually shift east, with a coastal low along the
Carolinas by late Thursday night. Mesoscale models suggest dry
conditions Thursday along with sunshine for the northern 2/3 of
the forecast area. Thereafter, clouds begin to re-advance
northward as a northeasterly flow gradually veers to the east with
time.

Mesoscale models suggest some moisture beginning to reach coastal
locations by late Thursday night. Will introduce low chance pops
for late in the period.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
High impact weather: None

Overview: The forecast period begins with a cut off low over the
south eastern United States which lingers through early next week
before being reabsorbed into the main flow. As is often the case
with cutoffs, confidence is generally low as to when the low will
dissolve as a number of high amplitude ridges remain in place
across the northern hemisphere preventing forward progression in
the pattern. The good news is that despite the variability in the
low center through the weekend, northern new england will remain
on the periphery of the system allowing for just a chance for
showers and storms.


Friday:The cut off low to our south will keep clouds and a chance
of showers across southern New England and as far north as the
southern portion of New Hampshire.

Saturday: Clouds and showers will creep northward through the day
on Saturday as the upper level low cuts off. Along the coast,
onshore flow may result is some fog/drizzle/low stratus.

Sunday: Inland locations will see an improvement in conditions on
Sunday as high pressure nudging in from New Brunswick keeps the
showers at bay everywhere except the4 immediate coastline where
onshore flow continues.


Monday - Tuesday: By the start of next week the cut off low tries
to get absorbed back into the hemispheric flow. Here the
uncertainty increases with deterministic and ensemble members
showing a wide split in the timing and strength. With low
confidence have opted to go with a blend for the extended... with
a chance of showers through out the time period. Expect we will
see a period of precipitation as the disturbance moves over us and
off to the east but timing is hard to pin down at this point.


Wednesday and beyond: Tropical season is still in full swing so a
sideways glace at the tropics is always appropriate however the
high amplitude flow, large ensemble spreads, and low
predictability of the atmosphere in general means that any of the
potential tropical systems depicted in deterministic guidance for
late next week should be taken with a healthy dose of skepticism.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Short Term...Variable conditions through Thursday with VFR
conditions over central and mountain areas with mainly MVFR
conditions over southernmost areas. Some overnight and early
morning valley fog til 13z will allow for lcl IFR conditions.

Long Term...
Conditions will being with VFR on Friday. Coastal sites
PWM/RKD/PSM will see ceilings return to IFR by early morning
Saturday and stay below 1000ft through the day with periods of
drizzle in onshore flow. intermittent IFR will continue along
the4 coast through Sunday. Sunday afternoon showers will move
inland and north bringing MVFR to LEB and HIE.

&&

.MARINE...
Short Term...Strengthening Northeast flow will bring SCA
conditions outside the bays through Thursday.

Long Term...
Generally light flow with weak high pressure over the region
through the weekend will keep winds and seas below SCA.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 9 PM EDT Thursday for ANZ150-152-
     154.

&&

$$

NEAR TERM...Legro



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