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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

                            
000
FXUS61 KCAR 161705
AFDCAR

Area Forecast Discussion
National Weather Service Caribou ME
1205 PM EST Sat Feb 16 2019

.SYNOPSIS...
High pressure will build across the region Tonight through 
Wednesday night. Low pressure will approach the region on Thursday.

&&

.NEAR TERM /THROUGH TONIGHT/...
Update 12:00 PM: Have updated grids based on latest 
observations. No other changes.

Previous Discussion...
The first cold front is passing off to the east as of the 06z 
sfc analysis. Precip has pushed off to the east as well with 
some partial clearing. The Winter Weather Advisory was allowed 
to expire. Temps have dropped off into the 20s and 30s. The 
temps will rebound some today w/sw winds ahead of the 2nd cold 
front. Regional radar showed snow showers back across Quebec 
associated w/that 2nd front. The 00z NAM and GEM have matched up
well w/the latest conditions, and show an area of snow showers 
breaking out across northern and western areas later this 
morning through the afternoon. The 00z UA showed upper trof 
associated w/the sfc front back across Ottawa and Ontario. There
is a 50 kt jetlet that is connected w/the trof to provide the 
necessary forcing. Decided to increase the pops to 30% across 
the north and west using a blend of the NAM and GEM guidance. 
Winds will turn to the WNW w/the passage of the front. Snow 
squall dynamics do not look impressive, and therefore, not 
expected and snow squall activity w/the front. Winds will gust 
to 20+ mph w/the fropa. 

Clearing tonight w/temps falling back into the single numbers
across the northern 1/2 of the CWA while lower teens are
expected further south. There is a good chance a few sites 
across the nw could see temps by daybreak Sunday morning dipping
below 0F.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
A massive area of high pressure in northwestern Canada will
dominate area weather during this period. This high covers much
of Canada and a large portion of CONUS early next week.  Skies 
will generally be clear to partly cloudy. A wave of low pressure
will pass well to the south of New England on Monday. The
biggest challenge will be temperatures. With increasing sun
strength, highs may be a bit above guidance. On the other hand,
radiational cooling on Sunday night may produce lows below any
guidance. For now, have leaned towards bias-corrected numbers
and subzero readings across northern zones. Colder spots may
drop towards minus 15F to minus 20F. High clouds may mitigate
the radiational cooling further south on Sunday night. Winds
will increase Monday night as the low exits into the open
Atlantic and focus will shift from radiational cooling to wind
chills. An advisory may be necessary by late Monday night for
northwestern Aroostook County.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
The big high dominates through Wednesday night as it oozes south
out of Canada into the Great Lakes region by Tuesday. There will
still be gusty northwest winds on Tuesday into early Wednesday,
but the high will crest over the area on Wednesday night and
radiational cooling will be the forecast challenge again for
that night. The only action in the forecast period arrives for
Thursday. As with the system on Monday, most of the moisture and
the primary surface low will pass well to the south of the 
forecast area. However, this system will overrun the big high 
with some southern stream moisture...and following ECMWF and
GEMS...will phase with a northern stream shortwave. While the
primary low will be hundred of miles south of the coast, an
inverted trough extending into Maine towards a decaying low with
the northern stream trough may provide just enough moisture for
some advisories. High snow ratios may be in play here. A warming
trend appears to the in the offing for the end of the week as
the upper flow goes zonal.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
NEAR TERM: MVFR cigs from time to time across the northern
terminals today, especially n of KHUL. Otherwise expecting VFR
later this afternoon into tonight for all TAF sites.

SHORT TERM: Expect VFR conditions Sunday into Wednesday with 
the possible exception of MVFR cigs north of HUL on Monday 
afternoon.

&&

.MARINE...
NEAR TERM: Winds have dropped below 20 kts but seas stayed up
around 12 ft. Winds are expected to increase later today into
tonight the cold front. Decided to go w/a SCA for winds of 20-25
kts. Leaned w/a blend of the NAM12 and GFS for winds. Stayed
close to the daycrew's assessment on the seas. Seas will 
gradually subside as the swell abates.

SHORT TERM: A Small Craft Advisory may be required Monday night
and again Tuesday night.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 4 AM EST Sunday for ANZ050>052.

&&

$$

Near Term...Mignone