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Area Forecast Discussion (AFD)

Issued by Caribou, ME (CAR)

FXUS61 KCAR 172000

Area Forecast Discussion
National Weather Service Caribou ME
300 PM EST Sun Feb 17 2019

High pressure will build across the region early this week and 
remain in control through Wednesday then move east Wednesday
night. Low pressure from the the southeast states will pass 
well south of the state on Monday. Another low from the great 
lakes will approach the region on Thursday.


Strong high pressure will build in from the northwest tonight
bringing mostly clear skies into the early evening. At the same
time low pressure is expected to develop south of New England.
This system will spread clouds into the region from the
southwest later this evening. Clouds are expected to thicken
Monday as the low moves east northeastward into the Atlantic.
Snow is expected to spread into the southwestern portion of the
region by late in the day.


Most if not all of the lgt snfl affecting Srn ptns of the our
Rgn should have exited by the beginning of Mon eve, with remnant
cld cvr giving way to at least partial clrg across the area by
late Mon ngt. Arctic air of mdt residence will cont to hold ovr
the FA thru Wed with msly fair skies, with Tue looking to be 
the most brisk day and Tue ngt where there could be some
radiational cooling late as winds diminish, the coldest ngt.

Clds will then begin to increase from the W Wed ngt as a s/wv 
and associated sfc low from the great lakes begins to apch with
ovrngt lows likely occurring prior to mdngt. Snow from this low
will begin to move from the WSW to ENE across our Rgn late Wed


Longer range synoptic scale models are in reasonable agreement 
with the idea of sn contg across our FA thru Thu, with the 
greatest QPF fcst ovr Cntrl and Downeast areas of the Rgn.
Models differ somewhat in onset/exit tmg and the magnitude of
event QPF bullseye. Of the models, the 00z dtmnstc GFS (ECMWF)
runs is fastest (slowest) with onset/exit of snfl, while the 
00z ECMWF (CanGem) is lightest (heaviest) with fcst QPF
affecting our FA. For this fcst update, a compromise was taken
between the GFS/ECMWF model onset/exit snfl tmg with the middle
GFS used to weight PoP distribution across the FA with max PoPs
in the high likely to nearly categorical range. Wntr wx hdlns 
are possible, spcly ovr Cntrl/Downeast areas, but with the bulk 
of this event still past 72 hrs out in tm where we still do not 
depict 6 hrly QPF/snfl, it is still to erly to commit to any 
specific snfl amts with this event.

Snfl will taper to sct sn shwrs by Thu ngt across our FA,
followed by fair and not as cold (closer to seasonal norms)
temps for Fri thru Sat. The next potential event will be mainly
Sun thru Sun ngt with the 00z dtmnstc ECMWF and CanGem more 
intense with this system than the 00z GFS (and its ensm) with sn
looking to be the predominate precip type for the Rgn. For now,
we weighted max PoPs in the high chc category given that not all
of the models are in agreement for an event at the far edge of
our long range.


NEAR TERM: Expect VFR conditions tonight into Monday Morning
then expect MVFR/IFR conditions by late in the day Monday KBGR
and KBHB while the north stays VFR.

SHORT TO LONG TERM: VFR conditions anticipated across our TAF
sites Mon ngt til Wed eve, then clgs/vsbys lowering to IFR from
W to E acoss the Rgn in sn late Wed ngt and erly Thu morn, 
contg into the aftn, then improving to MVFR Thu ngt in exiting 
sn shwrs and then back to VFR again on Fri. 


NEAR TERM: Will use the Nam to initialize winds. For Waves: The
primary wave system is currently long period southeasterly swell
(currently around 2 feet/8-9 seconds). This wave system is
expected to remain the primary wave system tonight and into Mid
Day Monday. A new northeasterly wind wave is expected to develop
across the Gulf of Maine on Monday as low pressure passes to the
south of the waters. This system could become the primary wave
group by late in the day with combined seas remaining around 3
feet. Total Water Level: ESTOFS surge guidance continues to
perform well so will keep the Base Tide Anomaly along the coast
near +0.10 for the next several days. Spring tide produces
highest levels of the month Tuesday through Thursday so will
monitor coastal event on 21st closely. In Bangor large anomaly
due to ice persists so will continue to initialized the Base
Tide Anomaly based on RFC guidance then will adjust for
surge/reverse surge.

SHORT TO LONG TERM: A SCA will likely be required Monday night 
into Wednesday morning due to NW wind gust potential upwards to
30 kt. Lgt to mdt frzg spray is likely spcly late Mon ngt and
Tue morn and again late Tue ngt into Wed morn. After a break
with no marine hdlns Wed aftn and Wed ngt, another pd of
marginal SCA conditions is possible Thu with SE winds ahead of
weak sfc low pres from the great lakes. Kept close to WW3/NWPS
wv guidance blend for fcst wv hts thru this ptn of the fcst.





Near Term...Mignone
Short Term...VJN
Long Term...VJN