Area Forecast Discussion
Issued by NWS Caribou, ME-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
FXUS61 KCAR 281257
Area Forecast Discussion
National Weather Service Caribou ME
857 AM EDT Fri Apr 28 2017
-- Changed Discussion --A cold front will cross the region this afternoon. High
pressure will briefly build into the area, followed by a
stronger cold front on Saturday afternoon. High pressure will
build for Saturday night and Sunday.
-- End Changed Discussion --
.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --850 am Update...
Light rain, drizzle and fog will continue under the subsidence
inversion this morning. The weakening cold front will cross this
afternoon and gradually push out the low level moisture later
this afternoon into the evening. The exception will be towards
the coast and Down East region where fog will linger through the
evening. Winds will be the big concern for Saturday with deep
mixing and gusts over 30 mph...a big change from recent days.
Widespread low clouds with areas of fog and drizzle was once
again occurring across all of northern and down east Maine this
morning. This is in association with light southerly flow and
low level moisture trapped beneath an inversion. The inversion
begins to break by late this afternoon with the passage of a
weak cold front from the west. Until then, expect plenty of low
clouds to linger into the afternoon. Latest MRMS reflectivity
data was showing a weakening band of showers extending from
Ontario through New York State. Latest HRRR shows the band
weakening as it moves east into northwest Maine later this
morning. Some weak surface based cape will be present this
afternoon toward Piscataquis county and the central highlands.
There is an outside chance of an isolated thunderstorm toward
this area late this afternoon but feel that the chance is too
minimal to mention attm. Highs today will range from the low to
mid 60s north and central areas, but it will be much cooler
along the downeast coast, where low clouds and areas of fog
will hold temperatures in the 50s.
Tonight should see partial clearing with the passage of the
front, but low level moisture will keep low clouds and areas of
fog along the coastal plain until the front crosses later this
evening. It will be cooler tonight with lows falling into the
40s across much of the area by morning.
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.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Models agree that fast movg s/wv from the Great Lks associated
with an upper lvl jet streak will rapidly cross the region durg
the day Sat. What models do not agree is how wide spread rn
shwrs will be with this system or how much QPF will occur.
In producing PoPs for this system, we first blended fcst QPF,
which resulted in less QPF than the most aggressive model, the
opnl 00z GFS, but a little more than the 00z ECMWF and sig more
than the 00Z CanGem with the max QPF axis across Cntrl ptns of
the FA, where max PoPs reach categorical lvls. This fast movg
system will then rapidly move E of our Rgn by late Sat aftn,
resulting in clrg by eve. Subsequently, hi temps will be tricky,
with hrly temps rising quickly in the morn before shwrs, then
again aft shwrs end, before a mdtly strong secondary cold front
sweeps the Rgn by Sat eve. In addition, stronger winds alf will
be allowed to mix to the sfc with steeper low to mid lvl lapse
rates Say aftn into Sat eve.
Ovrngt lows will be cooler with much drier conditions following
the secondary cold front later Sat ngt as breezy NW winds cont.
Followed by msly sunny, somewhat breezy and cooler Sun. Aft the
sfc ridge axis crosses the region erly Sun eve, winds will
become calm as hi/mid cldnss advc into the Rgn from the W ovrngt
Sun. The leading edge of rnfl from low pres advcg from the Great
Lks will reach far Wrn ptns of our Rgn by erly Mon morn.
.LONG TERM /MONDAY THROUGH THURSDAY/...
Unsettled and cooler conditions will prevail thru the long term.
Rnfl will spread across the rest of the Rgn Mon and then cont
Mn ngt into Tues as the main Great Lks sfc low tracks into Cntrl
QB and a secondary low forms alg the occlusion point ovr
Downeast ME. This set-up will allow llvl cold air damming to
msly hold across th region Mon into Tue with hi temps in the 40s
across the Rgn on Sun and 40s N to lower 50s Downeast on Tue.
Total event rnfl amts thru Tue vary greatly across the models,
with the 00z GFS indicating as much as 1.5+ inches to as little
as a half inch from the 00Z CanGem...so even if we assume total
rnfl somewhere between these two scenarios, there will lkly be
some rvr rises following the event.
Rn will taper to sct shwrs Tue ngt, with unsettled cool shwry
conditions contg Wed into at least Thu morn spcly across then N
hlf of the FA as whats left of an upper trof crosses the region.
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: Widespread LIFR conditions will continue this morning
in low ceilings and fog. IFR ceilings will persist through early
this afternoon before gradually improving to MVFR by late
afternoon and then to VFR. The exception will be Bar Harbor
KBHB where IFR conditions will persist into this evening in low
clouds and areas of fog. Conditions will improve to VFR tonight
across the northern terminals, but patchy fog could still
result in IFR conditions toward KBGR/KBHB through early tonight.
SHORT TO LONG TERM: VFR conditions will prevail across our TAF
sites Sat thru Sun ngt, xcpt briefly MVFR clgs/vsbys with rn
shwrs late Sat morn into erly aftn. Aftwrds, clgs/vsbys will
lower to MVFR in steady rn on Mon then IFR in rn Mon ngt and
NEAR TERM: Long period swell around 11 seconds continues with
seas running between 5 and 7 feet across the outer waters.
Expect long period swell to continue into this afternoon before
diminishing by early this evening. Have extended the small craft
advisory for seas through this afternoon. Visibility will be
reduced to 1 nm or less in areas of fog into this evening before
improving tonight with the passage of a weak cold front.
SHORT TO LONG TERM: Near SCA wind/sea conditions are xpctd late
Sat into Sat ngt, then no hdlns xpctd Sun thru Mon midday. SCA
conditions are again possible late Mon aftn thru Tue ngt. We
went with about 85 to 90 percent of WW3 wv guidance for fcst wv
hts thru these ptns of the fcst.
MARINE...Small Craft Advisory for hazardous seas until 4 PM EDT this
afternoon for ANZ050-051.