FXUS61 KGYX 162232
Area Forecast Discussion
National Weather Service Gray ME
632 PM EDT Tue Oct 16 2018
After a brief break tonight...the second in a series of strong
cold fronts will arrive on Wednesday with another round of
showers and gusty winds with the coldest air of the fall season
arriving Wednesday night and Thursday with mountain snow showers
continuing. High pressure arrives late Thursday and Thursday
night with slackening winds and moderating temperatures through
the end of the week. The next chance for rain showers will come
Saturday ahead of another frontal system.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Have updated the forecast based on current conditions. Chilly
conditions will continue this evening with a brief period of
radiation cooling possible this evening with clear skies and
diminishing winds. Temperatures already down into the 30s across
portios of the mountains.
Minor modifications made to temperature, dew point and cloud
forecast. Mid level cloudiness to our north and west will lower
and cross the region later tonight.
High Impact Weather Potential: Minimal.
Pattern: Active pattern across the eastern United States early this
afternoon with a sprawling longwave trough taking up residence over
the eastern two thirds of NOAM with a longwave ridge centered along
the west coast. For the time being...the NAO remains positive...so
despite the depth of this trough...it will pull east through the
near and short term forecast period. Within this trough are two
significant shortwaves. The first is now departing the region to
the east while the second will arrive on Wednesday. Thus...
through the near term forecast period we find ourselves between
these two features with a weak surface ridge axis building in
from the west with a generally quiet night expected.
Through this evening: Winds will continue to diminish to less than
10 mph this evening with temperatures falling fairly rapidly in the
dry airmass under mostly clear skies...with most spots in the
upper 30s/lower 40s by 8pm.
Tonight: Ridge axis overhead this evening quickly moves east with
flow beginning to back ahead of upstream shortwave that will dive
into the Great Lakes through daybreak. Top down saturation will
commence during the overnight hours with cloudiness gradually
thickening and lowering. At the leading edge of a modest H8
Theta-E surge...recent high resolution HRRR runs have suggested
a blossoming area of very light precipitation in the 9-12Z
timeframe...with some support from the NAM nest and High res ARW
window run. While it would be light...could see some snow in
the mountains...with any precipitation to the south likely
falling as light rain. Temperatures will fall quickly this
evening...then level off and likely begin rising a bit overnight
with lows in the 30s in all areas except southeastern NH and
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
High Impact Weather Potential: Strengthening westerly winds
Wednesday followed by accumulating snow in the mountains and
favored upslope regions to the north Wednesday night.
Pattern: Secondary shortwave arrives during the short term period
with another northern stream...relatively moisture-starved cold
front arriving during the day Wednesday followed by strong cold
advection which will usher in the coldest air of the fall
season thus far. Forecast concerns center largely on winds given
the strength of this system...with attention paid to
precipitation chances as well...particularly in the mountains
where the pattern looks favorable for upslope snow showers.
Wednesday: PWATs ahead of arriving secondary front are fairly
meager /0.5-0.6 inch/...but more impressive will be
along/immediately behind the front as 1000-700 mb lapse rates
steepen with 50-100 J/kg of CAPE...cyclonic flow and support at
the jet level likely supporting a convective line of showers
that decays as it moves off the mountains and towards the
coastal plain. In these situations...you can occasionally bring
graupel to the surface given the cool airmass...however...wet
bulb zero heights are still 3-5kft so this looks like it will be
more of an exception than the rule. It will be a different
story in the mountains where precipitation will increasingly
become frozen towards evening with some light accumulations at
elevation. Highs will reach the 50s along the coast and
foothills...with 40s in the mountains. Temps in all areas will
fall in the afternoon.
Wind: Westerly winds strengthen ahead of the approaching front
with a surge of cold advection immediately behind the front
/combined with good mixing from lapse rates mentioned above/
potentially conspiring to bring 30-35 mph winds to the surface
for a short time /~2 hr/ immediately after frontal passage.
Wednesday Night: Robust cold advection continues through the
night with strong cyclonic flow and residual low level moisture
allowing upslope snow showers to continue in the mountains.
Lift/moisture actually reach into the DGZ as temps fall
overnight...so expect snow showers to increasingly be able to
accumulate overnight /as mentioned by previous forecaster/. Have
painted 1-2 inches over the terrain and in northern Coos and
far northern Oxford and Franklin counties. Further south...
expect a few sprinkles/flurries in the evening...but overnight
activity will increasingly be confined to the mountains /in line
with froude number diagnostics/ as moisture thins and flow
loses it/s cyclonic nature.
Winds: Stronger winds will hold off until daytime mixing
resumes on Thursday but 10-15 mph winds with gusts to around 25
mph will continue through the overnight.
Temps: T8s fall below -10C /-3 sigma/ under strong cold
advection...and despite mixing will push all areas into the 20s
and 30s. Still have a few active zones from a frost/freeze
perspective and while a frost is not likely given the winds...a
hard freeze is not out of the question for these remaining
.LONG TERM /THURSDAY THROUGH TUESDAY/...
A big push of cold air moves into the region on Thursday.
Temperatures aloft drop to well below normal with 700mb temps of
-20C near record cold for this time of year. Accompanying the
cold air will be a strong pressure gradient driving gusty
Winds will begin to increase in the early morning hours of Thursday
and continue through Thursday afternoon; a wind advisory will likely
be needed with more scattered power outages possible. Strongest
winds will be through the morning hours on Thursday when the
mixing begins to allow the higher wind speeds to reach the
surface and the strongest pressure gradient occurs. Have
increased gusts a bit through this narrow time window with a
few gusts to 40kts possible and widespread 25-5kt gusts across
the lower elevations and the summits correspondingly higher.
As the colder air moves into the region high temperatures on
Thursday will hold in the 40s to upper 30s, nearly 15 degrees below
normal. While the core of the cold air aloft will begin to shift
northeastwards on Thursday night the decreasing pressure gradient
will allow the winds to decouple by daybreak opening us up for good
radiational cooling in the mountain valleys. While it may take
until well after midnight to loose the winds, when we do
temperatures will drop rapidly and thus have pushed lows a bit
colder than much of the guidance. Even with a slight breeze this
airmass will be enough to end the growing season for the
remaining portion of the area and a Freeze warning will likely
be needed for the coast.
Friday temperature will moderate slightly as the cold air moves out
of the region, with good agreement amongst various guidance stuck
close to the consensus.
For the weekend the next chance of precipitation moves into the
area. It's increasingly looking like the northern and southern
stream will not phase allowing a weak disturbance to pass south of
us early in the day on Saturday with a northern stream shortwave
impacting the mountains through the weekend. Will see scattered
showers across the entire region with highest PoP in the mountains.
With temperatures marginal for snow, expect mainly rain for all but
the highest elevations during the day with a transition to some
light snow above 2000ft overnight Saturday into Sunday.
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
Summary: High pressure builds into the region tonight with a
fast moving cold front arriving Wednesday afternoon...and moving
south of the region Wednesday night.
Restrictions: Expect VFR conditions to continue through Wednesday
night. Could see some isolated restrictions in SHRA late Wednesday
at HIE/LEB...and possibly AUG...but not likely south and east of
Winds: Northwesterly winds will continue to gradually weaken through
this evening and tonight as high pressure arrives from the west. On
Wednesday...westerly winds strengthen to 15G25kts ahead of the cold
front before shifting northwesterly Wednesday night and continuing
15G25kts through the night.
LLWS: No LLWS expected through the period as the low levels remain
well-mixed given the strong wind field.
Lightning: No lightning expected through Wednesday night.
Long Term...VFR conditions will continue through most of the
extended. Strong cold advection will bring gusty northwesterly
winds for Wednesday night into Thursday morning. Another system
will bring a chance for showers to the entire area on Saturday
with highest Pop in the mountains where MVFR and overnight snow
showers are likely on Saturday night.
Short Term...Winds/waves have subsided a bit from this
morning...but SCA conditions will continue outside the bays
through tonight before waves strengthen ahead of our next system
late Wednesday with a Gale watch issued beginning late Wednesday
and continuing into the long term forecast period below.
Long Term...Cold air will move into the region overnight Wednesday into
Thursday. The cold air and tight pressure gradient will result in
strong northwesterly winds with gusts to Gale and a Gale Watch has
been issued. Winds will decrease as high pressure builds in on
Friday before again increasing to gusting 25-30kts will SCA likely
KGYX radar outage with parts on order this afternoon. Expect to
be back up around midday Thursday.
MARINE...Gale Watch from Wednesday evening through Thursday afternoon
FXUS61 KCAR 161942
Area Forecast Discussion
National Weather Service Caribou ME
342 PM EDT Tue Oct 16 2018
High pressure will build across the area later tonight and will
be followed by a cold front Wednesday afternoon. The coldest air
of the season arrives Wednesday night and Thursday with another
round of strong winds.
.NEAR TERM /THROUGH WEDNESDAY/...
Winds will continue to decrease through the evening, but not
enough to allow any radiation inversions to form overnight. A
transient flat surface ridge builds overnight. The strong upper
flow will bring mid level clouds into the area after midnight.
Between the winds and clouds, lows will only drop to the lower
30s north and mid to upper 30s for Bangor and the coast. For
Wednesday, there may be a few sunny breaks in the morning in the
southern half of the forecast area, but thicker cloud cover
arrives in the afternoon with the cold front. The cold front
will sweep across the area in the afternoon to early evening.
Anomalously cold air aloft is arriving with the front. Combined
with relatively steep low level lapse rates, there's actually
up to 200 J/kg of SBCAPE with the front. Can't rule out an
isolated thunderstorm with the low -20C threshold, but will not
include in the forecast yet. The low freezing levels make
graupel a potential threat too. Overall QPF with the front looks
modest with less than a tenth of an inch forecast, but do
expect showers for the entire forecast area with the front. The
cold air advection behind the front is so strong, that rain
showers may already change over to snow showers in the Allagash
by Wednesday evening. &&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Intense low pressure over the Maritimes will produce a strong
pressure gradient across New England Wednesday Night into
Thursday. This will result in strong gusty winds through the day
Thursday. This strong flow will also import a seasonably cold
air mass into the region with high temperatures Thursday only
in the 30s and 40s. Snow showers are also possible across
western and northern areas along with higher terrain Wednesday
Night into Thursday. A warm front will approach the region from
the southwest Thursday Night into Friday resulting in an
increase in clouds on Friday.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Another strong cold front is expected to approach the region
from the west on Saturday. This front will move across the State
later in the Day Saturday. Another cold airmass will move in
behind the cold front. Intense low pressure to the north of New
England will also produce strong gusty winds Saturday Night into
Sunday. Showers are also expected with he front Saturday into
Saturday Night. High pressure is then expected to crest over the
region late Sunday into Monday.
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: Winds will die off and VFR conditions are expected.
Showers are possible across the area on Wednesday afternoon, but
VFR conditions are expected. Graupel and a very slight risk of
thunderstorms will occur along the front.
SHORT TERM: VFR conditions are expected Thursday and Friday.
MVFR conditions are expected Saturday. VFR conditions are
NEAR TERM: Small Craft Advisory conditions will continue tonight
into Wednesday, but have opted to advertise the more significant
Gale Watch that will begin Wednesday night and continue
SHORT TERM: Have used a blend of the Gfs and Nam for surface
winds through Friday then transition to the Super blend. Gales
are possible on Thursday as low pressure intensifies over the
Maritimes. For Waves: Expect off-shore wind wave Thursday and
Friday. Waves expected to around 7 feet off-shore Thursday
subsiding to 3 feet Friday then building back to 6-7 feet again
Saturday and Sunday as off-shore winds increase. Total Water
Level: ESTOFS storm surge guidance is handling the reverse
surge the best and will continue to incorporate in the water
level forecast. Will keep the Base tide anomaly at +0.30 along
the coast. Will also continue to adjust low tide anomaly in
Bangor to +0.10.
MARINE...Gale Watch from late Wednesday night through Thursday evening