Area Forecast Discussion
Issued by NWS Caribou, ME-- Highlight Changed Discussion --
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FXUS61 KCAR 241820
Area Forecast Discussion
National Weather Service Caribou ME
120 PM EST Fri Feb 24 2017
High pressure will briefly ridge across the region today. A
warm front will lift northward across the region tonight. The
warm front will lift north of the area on Saturday as low
pressure moves into Ontario, Canada.
.NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --100 PM Update: We are really struggling to keep up with temps
thru midday, with obsvd temps as of 1pm in some cases as much as
10 deg F warmer than the fcst we had from erly this morn. Latest
sfc obs indicates that the cold front is likely just E of a
Frenchville Clayton Lake line and slowly moving Ewrd.
Also, based on latest Sat imagery and radar ref trends, we also
pushed back the arrival of thicker cld cvr and rn arrival 2 to 3
hrs later this aftn. With sfc temps having warmed so much, we
may also delay the onset of fzra adv an hr or two tngt. Will
watch the trend of temps across the N ovr the next couple of hrs
before deciding, though.
Orgnl Disc: A bit cooler today with rain and mixed precip later
today into tonight.
08Z sfc analysis showed the cold front sliding across the CWA
early this morning w/cooler air in its wake. Temps are forecast
to cool down further this morning. Areas of fog have developed
across downeast areas this morning as skies had cleared. Further
n, clouds have held on longer keeping the fog at bay. Weak high
pressure will move across the region early today bringing
cooler and drier air into the region. The NAM and RAP show this
setup well and are supported by the 00z GFS. Temps are expected
to rebound some w/the help of the sun and a west wind. We are
talking upper 30s to lower 40s n and w while central and
downeast will see mid 40s. Clouds will return by early afternoon
as a warm front lifts n into the region. Some precip in the
form of rain can be expected to break out across portions of the
central and downeast areas. The NAM shows decent llvl
convergence in this area. Further n, the drier air looks like
it will keep the precip shield at bay until late afternoon or
The NAM and GFS support this w/evaporative cooling allowing
temps to fall back w/the column moistening. The precip across
the northern areas will start out intially as some snow/sleet
but will quickly transition to freezing rain overnight into
Saturday morning. Based on ice will be the main impact for this
event, decided to issue a Freezing Rain Advisory for Northern
Maine and portions of the Central Highlands including
Millinocket and Greenville from late this evening into Saturday
morning. Total ice accumulation of around a tenth of an inch is
expected. Confidence attm is low for the central areas
including Dover-Foxcroft and Lincoln as temps will be
marginal(32-33F). This will need to be monitored today and if
that cooler air seeps further s, then some light icing could
occur. Across the downeast and coast, temps will be well above
freezing w/low clouds and light rain or drizzle as the warm
front lifts into Northern Maine.
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.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
For Saturday morning, will lean towards the NAM with a very
gradual warming due to cold air damming under a persistent
frontal inversion. Maintained freezing rain in the forecast in
northern Aroostook until late morning. The moist southeast flow
and warm air advection will likely cause a lot of very low
clouds, fog and drizzle...especially in the upslope terrain of
Piscataquis and northern Penobscot counties. The warming will
arrive earlier for Bangor and most of the Down East region with
highs reaching near 50F by late afternoon. These temperatures
and dew points in the mid to upper 40s will accelerate snow melt
in the Flood Watch area. The cold front will work its way into
the forecast area Saturday night with temperatures and dew
points still rising before midnight. In general, most areas are
expected to receive a quarter to a half inch of rain. The front
will move quickly across the area and that`s good news. On the
other hand, with a sharp, negatively-tilted upper trough and the
entrance region to a strong upper jet, the potential for
locally heavy showers or even a thunderstorm will have to be
monitored. Forecast soundings are showing instability aloft on
Saturday night with up to 400 J/kg along the front. Did add
mention of heavy rain in the forecast. The frontal precipitation
will end as snow early Sunday morning with potential for a
quick coating of a half-inch or less. This much colder air
aloft...and comparatively less cold air advection at the surface
will mean steep low level lapse rates and a lot of wind on
Sunday. West winds with gusts to 40 mph will be the primary
story on Sunday...besides watching the rivers. Temperatures will
tend to drop during the afternoon with all areas below freezing
by later in the afternoon. The winds will likely continue well
into the evening. All areas will fall well into the 20s and
reduce ice movement concerns. Due to the winds and increasing
clouds later in the night, did go well above MOS lows.
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
For Monday, most guidance is indicating a fast-moving shortwave
crossing in the morning with most precipitation falling in
northern zones as snow. Less than an inch of snow is forecast.
Winds will continue to be strong with gusts up to 35 mph. The
winds will finally decrease Monday night with high pressure
building and an opportunity for radiational cooling. As a
result, will go below consensus guidance. The picture becomes
more confused Tuesday afternoon into Thursday. Guidance is
starting to lean towards a two separate events. The first
arrives later Tuesday into Tuesday night with a fast-moving
shortwave causing a mix of rain and snow. This is mostly an
overrunning situation ahead of the primary system that will
arrive for Wednesday into Thursday. For the first system, a
couple inches of snow are possible...mostly in the southern
portions of the CWA. For the second system, the rain/snow line
will move much further north as the parent low is expected to
move through Quebec. The warm advection may be blunted by the
development of a secondary low moving across the Down East
region and have maintained all snow for northern Aroostook
County. Steered away from MOS highs on Wednesday between the
threat of precip and the probability of another frontal
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: MVFR for the northern terminals this morning
w/conditions holding much of the day w/a tempo period of VFR by
the afternoon. KBGR was VFR this morning while KBHB was IFR
w/low vsbys. BHB will see improving conditions after 12Z to VFR.
Conditions are expected to drop back to MVFR by later afternoon
and then to IFR w/rain and fog. Across the northern terminals,
conditions will deteriorate to MVFR by evening and then IFR
overnight w/sleet and freezing rain. Icing potential is there
for up to 0.10 inches.
SHORT TERM: IFR cigs are forecast Saturday and Saturday night
with thicker fog by later in the afternoon and evening.
Freezing drizzle will be an issue on Saturday morning for CAR
and FVE. An embedded thunderstorm is possible Saturday night
with a cold front. The cold front will bring mostly VFR
conditions for Sunday, but strong west winds with gusts to 40
mph. The predominant VFR conditions continue into Tuesday with
the exception of snow showers north of HUL on Monday. These
could bring temporary IFR vis.
NEAR TERM: No headlines this term as high pres ridges across
the region. Light winds becoming sse this evening and increasing
to 10-15 kts as a warm front lifts n. Seas will drop off today
back to 2-4 ft, but are expected to gradually build later
tonight to 5 ft.
SHORT TERM: Fog is expected Saturday into Saturday night. A
long duration SCA will likely develop Saturday night and
continue through Monday. Another SCA...with some risk of gale
conditions...will arrive Wednesday into Thursday.
No changes to the Flood Watch were made with this forecast
cycle. Snow melt from the deep snowpack continues today through
Saturday night 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 to rises into Sunday
morning, but nothing that generates strong concerns at this
point. The focus will remain on the southern half of the
forecast area where temperatures will stay above freezing into
Sunday and where more melting has already occurred with this
thaw. Localized ice movement followed by jams is the scenario to
watch...mostly for southern Piscataquis and Penobscot basins.
ME...Freezing Rain Advisory from 11 PM this evening to 10 AM EST
Saturday for MEZ001>006-010.
Flood Watch from Saturday morning through Sunday evening for