NWS Caribou, Maine Area Forecast Discussion

FXUS61 KCAR 180246

Area Forecast Discussion
National Weather Service Caribou ME
946 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.


945 pm update...
Updated to lower mins tonight acrs the north as temps have
nose-dived acrs the vly areas of nrn Aroostook tonight as vry
shallow inversion sets up. Hv delayed onset of snow until closer
to daybreak acrs coastal zones as dry air rmns acrs the state
per latest 00z raobs. Not other chgs needed with this update.

Prev discussion blo...
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 late Thu aftn and erly Thu
eve across our FA then end by late Thu ngt, 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: VFR conditions next 24 hours across northern
terminals as ovc mid-clouds move in by mid-late morning. At BGR
and BHB VFR mid-clouds give way to MVFR restrictions after 15z
in the morning in low clouds and possible light snow, especially
at BHB.

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...Farrar/Mignone
Short Term...VJN
Long Term...VJN

NWS CAR Office Area Forecast Discussion