Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 140821

Area Forecast Discussion
National Weather Service Caribou ME
321 AM EST Wed Feb 14 2018

High pressure will move off to our east today. Low pressure will
track to our north on Thursday. A cold front will approach
Thursday night into Friday and cross the area Friday evening.


Low pressure will pass well to the north of the State today. At
the same time high pressure over the Atlantic will continue to
move away from the region. A cold front will approach from the
north tonight an cause clouds to increase in the north late


Region wl be in fairly zonal flow aloft on Thur with perhaps subtle
s/wvs rippling by at times. Sfc low currently in the Prairie
Provinces wl head east acrs Canada and wl lkly be just northwest of
CWA Thu aftn. This wl draw in warm air aloft leading to low-lvl
inversion effectively trapping moisture acrs the area drg the day.
Warm advection at the sfc wl compete with mocldy skies but feel that
most of the area wl rise abv frzg in the aftn. With saturated low-
lvls in the mrng and deep layer moisture holding off until the aftn
hrs may need to add in patchy frzg drizzle/drizzle in the mrng hrs
but wl evaluate likelihood with later model runs.

Warm advection wl continue Thu night with fog lkly to dvlp acrs srn
half of area by midnight as wmfnt rmns to the north in the St.
Lawrence Vly. Med range guidance displaying a fair amnt of
uncertainty with low mvg out of the Ms Rvr Vly late Thur aftn and
where it heads Thu night. Models run the gamut fm srn Maine to
Nantucket. Given amnt of uncertainty still present wl cap at high
chc to low lkly for Fri mrng as extensive moisture present in btwn
bndrys drg the ovrngt wl lkly be sufficient enuf to generate some
lift to result in convective showers and dz/fzdz at times. Hv also
include mention of patchy fog ovr Downeast zones Thur night.

Frontal bndry expected to cross area Fri aftn with latest guidance
indicating snow squall activity with fropa acrs the north. BTV snow
squall parameter > 1 in the aftn with low-lvl CAPES arnd 50 J and
low-lvl lapse rates > 8 C/km around 18z-21z per NAM and GFS. Temps
wl fall rapidly in wake of fropa.


1030mb sfc high wl be building in following cdfnt passage Fri with
dry wx expected thru the day Sat. By 00z Sun high shifts into New
Brunswick with return flow kicking in acrs the area Sat evng.

Models continue to struggle with system heading out of the Srn
Plains on Saturday. All guidance is now indicating sfc low somewhere
in the wrn Atlantic by 12z Sun in the vicinity of Cape Cod but still
struggling on where low wl be located by this time. Latest GFS is
closest to Cape Cod with CMC approx 100 miles to the southeast and
EC ~400 miles southeast. Wl keep pops at lochc for Sat night and Sun
as ensemble members hv quite a spread btwn sfc low position Sun
morning. Temps wl be just slightly abv seasonal norms but still
expecting light snow acrs the area except possibly along the
immediate coast Sun aftn depending on ultimate track of low.

Considerable discrepancies in model guidance in wake of sfc low on
Sunday with either hipres for Mon or stationary bndry draped acrs
srn Canada leading to isold sn/ra showers. Potential exists for a
wet pd into the middle part of the week as an upr lvl trof digs acrs
the intermountain west with abv normal temps expected.


NEAR TERM: Expect VFR conditions today and tonight.

SHORT TERM: Conditions lower Thu morning mainly across the north
in low stratus ahead of surface front. Moisture gets trapped
under inversion leading to MVFR cigs across the north Thur night
and MVFR/IFR vsbys and cigs over southern terminals. May see
brief improvement over southern terminals Fri morning with
restrictions still possible across the north. Front moves
through in the afternoon with brief IFR vsbys in -shsn across
the north. Northwest winds will gust during the afternoon at all
sites as fropa occurs. VFR returns Fri night.


NEAR TERM: Have used the NAM for sustained wind speed today and
tonight . For Waves: A southerly fetch will develop across the
Gulf of Maine this morning and persist into the afternoon. Wind
speed across the fetch will diminish late in the afternoon.
Expect waves to build to 7 feet/6 seconds by late this afternoon
then begin to subside as winds diminish. Waves will subside
quickly tonight as both fetch length and duration are limited.
Timing on the SCA still looks good at this time, so will not
make any changes to marine headlines. Will use NWPS to
initialize the wave grids.

SHORT TERM: SCA conditions will return Friday evening in wake of
cold front. May see winds approaching gale force Fri night.
Winds and seas drop below SCA levels by Sat afternoon with high
pressure building over the waters.


MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ052.
     Small Craft Advisory until 1 AM EST Thursday for ANZ050-051.



Near Term...Mignone
Short Term...Farrar
Long Term...Farrar
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