Area Forecast Discussion
Issued by NWS Caribou, ME
FXUS61 KCAR 271330
Area Forecast Discussion
National Weather Service Caribou ME
930 AM EDT Tue Sep 27 2016
An occluded front will cross the region today. An area of low
pressure will develop in the Gulf of Maine today and will move
east of Nova Scotia tonight. Low pressure will pass south of the
region Wednesday. High pressure will build into the region
Wednesday through Friday from the north.
.NEAR TERM /THROUGH TONIGHT/...
920 AM Update...Most of the rain with the occlusion will be out of
the forecast area by noon...except towards Aroostook County where
the front stalls in the col and the resultant convergence will
continue to spark showers into the evening. For tonight and
tomorrow, the Labrador high builds and leaves persistent low
clouds in a moist east flow. Have reduced pops tonight and
tomorrow and took out mention of drizzle and fog for most areas.
The exception is the western mountains where upslope will be a
The day begins with upper lows across the northern Great Lakes and
northern Gulf of Saint Lawrence with weak mid level ridging across
maine. The pattern breaks down as the Canadian low pulls east and
the Great Lakes low drops down to the vicinity of Chicago by 12Z
Wednesday. There will remain a weakness aloft to the north of the
area. At the surface, high pressure over northern Quebec settles
down into western labrador tonight. A 994mb low over lake Superior
this morning drops south and weakens to 1008mb across southern
Lake Michigan tonight. An occluded front will weaken as it moves
into Maine today. A weak secondary low is expected to form in the
Gulf of Maine today and scoots east of Nova Scotia tonight.
Ridging and a cold air damming pattern sets up across Maine
tonight. A very weak wind regime this morning will give way to
increasing northeast low level flow this afternoon into tonight.
Expect that light rain moves across the area this morning, likely
continuing along coastal areas, especially washington County into
the afternoon. QPF is expected to be quite light, and on the
order of several hundredths of an inch to a couple tenths of an
inch for most areas. A bit more is possible along the immediate
coast where 2 to 4 tenths of an inch are possible along coastal
Washington County. Temperatures this afternoon will be on the cool
side with highs 50 to 55 degrees across the Crown of Maine with
55 to 60 degrees common across the Down East Region. Tonight will
feature lots of clouds along with patchy fog and drizzle. The
extensive cloud cover and northeast flow will keep lows mostly in
the 40s region wide.
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
Large upper low pressure will continue to spin across the Great
Lakes and Ohio River Valley through mid week, while an upper ridge
of high pressure noses into New England. A shortwave will attempt
to sink south out of Canada, but the aforementioned upper ridge
will cause it to be shunted to the east. Meanwhile, high pressure
dominate at the surface. Expect Wednesday will be a gloomy day as
moisture streams into the region on easterly flow and becomes
trapped under subsidence aloft. While a shower or two can`t be
ruled out, expect the main weather element to be patchy drizzle
due to plentiful low-level moisture. Otherwise, mostly cloudy
skies and highs in the 50s to around 60 can be expected. Low
pressure will move by well to our south Wednesday night and may
result in scattered showers over far Downeast areas, but the main
effect will be increasing winds as the pressure gradient tightens,
particularly along the coast. Lows will range from around 40 in
the north to around 50 south and along the coast. Thursday should
see some improvement as winds become more northerly behind the
low, though skies will be only partly sunny at best. A few showers
will still be possible, mainly in the Central Highlands down to
the coast. Highs will be similar to Wednesday, perhaps a couple of
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Although the GFS and ECMWF seem to have come into better
agreement early in the period, the discrepancies grow over time.
The main difference is the handling of an upper low, especially
heading into early next week. This feature is shown by both
operational models to be positioned over the Ohio River Valley
Thursday night, and both lift it back northward toward the Great
Lakes heading into the weekend. Heading into next week, the low
looks to slide eastward with the GFS the faster and weaker of the
models. Regardless, moisture will gradually lift northward ahead
of the low, especially toward the weekend as the low drifts
further east. Upper ridging should keep the worst of any rain away
through Friday though a few showers can`t be ruled out along the
coast. The best chances for rain really don`t arrive until Sunday
or Monday, depending on which solution you prefer. Have kept pops
at low chance at most due to the uncertainty. Temperatures will be
seasonable through the period, with highs in the low to mid 60s
and lows ranging from around 40 north to the mid and upper 40s
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: Ceilings will lower this morning to MVFR at the
northern terminals and to IFR at the Down East terminals. Little
change likely tonight with predominately IFR ceilings Down East,
and low MVFR to at times IFR at the northern terminals.
SHORT TERM: Lots of low clouds will keep conditions MVFR across
the region Wednesday and Wednesday night, with local IFR possible
in patchy drizzle. Ceilings will slowly rise Thursday, perhaps
rising to above 3000 ft by 18z or so. VFR will likely prevail
heading into Friday, but more ceilings in the MVFR are expected
for the weekend, especially along the coast where showers will
also be possible.
NEAR TERM: The wind and seas will remain below small craft advisory
levels through tonight. The wind will begin to freshen up out of
the northeast later tonight, and seas will begin to slowly build
as high pressure builds to the north of the waters and low
pressure passes off the mid Atlantic coast.
SHORT TERM: Winds and waves will increase through the day
Wednesday into Wednesday night as low pressure moves south of the
waters. Gusts to around 30 kt and waves of 5-7 ft are expected, so
a Small Craft Advisory will likely be needed. Conditions will
gradually improve on Thursday with winds dropping below 25 kt in
the afternoon. Seas are expected to remain at or above 5 ft
through Thursday night, however.