Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 260506
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1206 AM EST Sun Feb 26 2017

.SYNOPSIS...
A warm front will finish lifting north of the region tonight. A
cold front will cross the region after midnight. High pressure
will build across the region later Sunday. A second cold front
will cross the region Monday afternoon.
&&

.NEAR TERM /THROUGH TODAY/...
Update... As of 02z cdfnt has made it to the NH/VT border and
steadily mvg east. Widespread showers hv just entered into the
state and current mvmnt has them mvg into wrn sections of FA
around 0430z. Warm advection showers dvlpng ahd of the line wl
be increasing in cvrg bfr then. Widespread dense fog has
overspread entire CWA and hv covered with Dense Fog Advisory
tonight. Received a call from employee of zero visibility btwn
PQI and CAR and expect this is likely the case in most areas
until line of showers mvs in.

Wl lkly hv to cancel advisory in sxns ovrngt as vsbys improve
with showers mvg fm west to east. Hv made just minor adjustments
to temps and dwpts with values holding fairly steady, but ever
so slightly beginning to rise ovr the past 30 min. Wl hv to keep
an eye on temps for the next couple of hrs immediately ahd of
bndry but once fropa occurs expect temps to fall fairly steady
drg the day Sun.

Prev discussion blo...
The first concern may be the return of dense fog...potentially
requiring an adv...across the N this eve where warm air just alf
has not quite made it to the sfc. Fog may return to Downeast
areas this eve as the sfc cools a few deg aft sunset.

Otherwise...the other main concern will be the arrival of the
cold frontal shwr band later ovrngt. With the potential of
elevated CAPE, we kept the mention of isold tstms just ahead of
thew cold front as it crosses W to E ovr the region. Temps
should cont to rise ovr Cntrl and Nrn ptns of the region ahead
of the front this eve...but exactly how much is uncertain. We
blended 12z dtmnstc GFS and CANGem model temps thru 1 am, then
blend to fcst low temps at 7am Sun.

Lastly, most model guidance indicates that shwrs will end as
brief pd of sn shwrs immediately behind he cold front across the
N and spcly the NW where upwards to an inch or two may fall ovr
the higher trrn before sn shwrs diminish later Sun morn.
Elsewhere across the N any sn accumulation will be msly less
than an inch. Cntrl and Downeast areas will see increasing
sunshine as the day progresses Sun. Hi temps Sun will only make
about a 5 deg rise from fcst lows due to mdtly strong llvl cold
advcn which will be accompanied by wrly wind gusts up to 30 to
35 mph during the late morn and erly aftn.
&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...
Next concern is a weak system/cold front for Monday. Limited
moisture with this system and strongest dynamics are over the
north, where we could see some snow squalls, possibly mixed with
rain. Best shot looks to be around midday. Any snow
accumulations should be less than an inch, and limited to the
north. Steep low-level lapse rates will bring some gusty winds
to the surface areawide, with gusts to around 30 mph most areas
and locally stronger.

Behind the Monday system, look for a seasonably cold night Monday
night with lows in the single digits to teens north and low to
mid 20s toward the coast.

A bit warmer for Tuesday with a chance of mixed precipitation
late in the day Downeast on the leading edge of the next system.
&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Active weather Wednesday and Thursday with one or potentially
two systems in quick succession. Models are having a lot of
issues though. Operational Canadian model is south and gives
most areas snow, operational GFS is further north with mostly
rain, and operational ECMWF is between the two. ECMWF, GFS, and
Canadian ensembles show high uncertainty, but their ensemble
mean is right in the middle, and went close to this in the
forecast. This ensemble mean solution would mean multiple
precipitation types Wednesday/Thursday, generally favoring snow
or rain/snow over the extreme north and favoring rain Downeast.
Will have to keep a close eye on this system/series of systems
as it does have the potential to be a high impact event. Will
probably take some time, though, for the models to come into
better agreement on it.

High confidence in colder air behind this system, moving in
Thursday night into the weekend. Good shot at below average
temperatures and probably no significant systems Thursday night
through Sunday.
&&

.AVIATION /05Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: LIFR for northern terminals ahead of front and then
rising as -shras move in between 06z-07z. -SN may mix in toward
daybreak acrs the north. Expect cigs to rise to MVFR after 12z
and eventually low VFR by afternoon.

BGR and BHB will be IFR tonight as fog and -DZ returns ahead of
the front. Cold front will bring -SHRA around 07z tonight then
quickly improve to VFR after 13z Sun.

SHORT TERM: Generally VFR Sunday night through early Tuesday.
Exception is localized MVFR in showers over the north on Monday.
Gusty winds Monday also. Lower ceilings and visibilities Tuesday
night and especially Wednesday/Thursday with the next likely
weather system.
&&

.MARINE...
NEAR TERM: We converted the gale watch to an SCA for our waters
for late tngt thru late Sun ngt with fcst max gusts of 30+ kt
not quite strong enough for a gale wrng. Otherwise, areas of
fog tngt will end with the passage of the cold front by early
Sun morn. We kept close to WW3 wv guidance for fcst wv hts.

SHORT TERM: Likelihood of gale conditions Monday with
west/southwest winds. Think that steep lapse rates/unstable
atmosphere will help mix some of the stronger gusts down to the
ocean surface. Calming down quite a bit for Tuesday. Increasing
winds and seas midweek with the next system.
&&

.HYDROLOGY...
No changes to the Flood Watch were made with this forecast cycle.
Snow melt from the deep snowpack continues through tonight with
rainfall amounts of just over a half inch by Sunday morning.
Water levels are starting to rise modestly on the river gauges
on the Piscataquis and its branches, but the best response
should be later Saturday night into Sunday. NERFC and ensemble
river forecasts continue rises into Sunday morning, but nothing
close to flood stages. The subtlety in the forecast is that the
Piscataquis River is expected to rise some 4 feet at Dover-
Foxcroft. The last estimate of ice thickness is just over a
foot. This rise would likely sufficient to break the ice and
cause some movement. Any movement means ice jams are a threat.
While the rises are nearly three feet at Grindstone, ice
thickness is greater and the odds of breaking up the ice are
less. Thus the focus is now sharpened towards southern
Piscataquis County.
&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 4 AM EST early this morning for
     MEZ001>006-010-011-015>017-029>032.
     Flood Watch through this evening for MEZ010-011-015>017-031-
     032.
MARINE...Small Craft Advisory from 4 AM early this morning to 4 AM EST
     Monday for ANZ050>052.
&&
$$

Near Term...Farrar/VJN
Short Term...Foisy
Long Term...Foisy
Aviation...Farrar/VJN/Foisy
Marine...Farrar/VJN/Foisy
Hydrology...



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