Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 260120

Area Forecast Discussion
National Weather Service Caribou ME
920 PM EDT WED MAY 25 2016

A cold front will cross the region this evening. High pressure
builds tonight into Thursday. A warm front will lift north across
the area Friday and a cold front moves through Saturday morning.


920 pm update...the last of the thunderstorm activity has pushed
off into New Brunswick. Just a few isolated showers remain that
will die off by around midnight. drier and cooler air will filter
into northern Maine in the wake of a cold front overnight. some
low clouds are expected along parts of the coast until the cold
front pushes offshore overnight. only minor tweaks to the ongoing
forecast based on the latest radar and near term model trends, and
the 9 pm observations.

Previous discussion...
A shortwave upper trough and associated cold front will cross the
area late this afternoon into the early evening. The timing of
the frontal passage coincides well with max daytime heating and
destabilization. Surface-based CAPE will reach values of 1000 to
2000 J/kg ahead of the front with decent low level lapse rates and
diffluence aloft.. The LFQ of an upper jet entering Maine at this
time is also enhancing activity. All of this will support max CB
tops to 35k ft and the potential for some heavy downpours with
PWATs up to 1.5 inches and back building cells ahead of the front.
Still expect a narrow sliver of dew points nearing 60F just ahead
of the front. The low freezing levels...but relatively skinny CAPE
could generate up to quarter-sized hail. Shear is unimpressive. An
inverted V and decent lapse rates could produce locally strong
wind gusts with the strongest cells as they collapse. The primary
threat will be in the northern half of the forecast area. Much of
Washington and Hancock counties will be affected by the
stabilizing onshore flow and northward spread of fog and stratus
this evening until the front passes. Precipitation will end later
this evening with total QPF ranging from a half inch in northeast
Aroostook County to less than a tenth of an inch for Bangor and
Down East.

After frontal passage, clearing will move into the western
portions of the forecast area with weak cold air advection. Lows
tonight will drop into the mid to upper 40s north and low to mid
50s for Bangor and interior Down East. The onshore flow near the
coast will lower temperatures to the upper 40s. Clouds will tend
to linger along the eastern border of the state tonight into
Thursday with a moist H925-H850 layer. The combination of the
offshore flow...weak cold air advection and increased sunshine
will lift Thursday`s highs to the upper 70s to near 80F for Bangor
and the Down East region. It will be significantly warmer along
the coast with the offshore flow.


1025MB sfc high will be making a last ditch effort to hold on acrs
ern Maine at the start of the short term.  Sfc winds veer around to
the southeast arnd midnight. Wk s/wv traversing nrn periphery of upr
lvl ridge wl lkly result in sfc low south of James Bay by 06z Fri.
Overrunning expected late Thur night ahd of approaching wmfnt
leading to showers working in fm the west aft 06z.

Wmfnt wl mv thru on Fri leading to sctd showers mainly acrs nrn
zones in area of maximum convergence. Skies wl lkly be mocldy which
wl lead to temps near normal ovr the area in the 60s. Isold thunder
possible Fri aftn/evng in area of elevated instability.

Cdfnt wl lkly go thru sometime Sat mrng per GFS, EC and CMC with
Nam being about 6 hrs too fast. Depending on timing of fropa may
need to add in thunder for srn zones Sat aftn but models diverge
by this point. Timing of cdfnt wl also play big role in max temps
for Sat.


Expect mainly unsettled weather through next week. High pressure
will bring a brief period of dry weather on Sunday, but there will
be waves of showers and possible thunderstorms each day thereafter
as shortwaves trek through the zonal flow aloft. The long range
guidance differs on the handling of these waves and their
associated precipitation especially timing and placement. The
result is at least a slight chance of showers every day through
the extended after Sunday. There may be a cold-frontal passage on
Wednesday, leading to cooler temperatures, but overall the period
looks to be mild with near to warmer-than-normal conditions.


NEAR TERM: the thunderstorm threat has ended for the night. low
ifr ceilings are expected at times along and near the coast until
around 06z. mvfr ceilings are expected at times tonight at the
northern maine terminals, with conditions to improve to vfr by
thursday afternoon.

SHORT TERM: VFR expected Thur afternoon and evening before
lowering to MVFR in -shra. Expect occasional MVFR conditions at
terminals in warm sector Fri into Sat. VFR Sat afternoon following
fropa into Sunday. Restrictions expected again Mon in -shra.


NEAR TERM: Fog is the primary concern until later tonight when a
cold front will pass the waters.

SHORT TERM: Seas and winds will remain below SCA criteria through
the period.


.CLIMATE...The high of 82F at caribou this afternoon was the
warmest temperature observed so far this year. there have been a
total of 3 days with high > 80 degrees at caribou so far this May.
On average, there are 2 days during the month of May at Caribou with
a high of 80 degrees of warmer.





Near Term...CB/MCW
Short Term...Farrar
Long Term...Hastings
Climate...CB is the U.S. government's official web portal to all federal, state and local government web resources and services.