Storm Warning 1, NWS Caribou, ME

Area Forecast Discussion
National Weather Service Caribou ME
1212 AM EST Wed Jan 25 2023

.SYNOPSIS...
A cold front will exit across the Gulf of Maine overnight,
with high pressure then building across the region late tonight
into Wednesday. Strong low pressure will approach from the
southwest Wednesday night, cross the region Thursday, then exit
through the Maritimes Friday. A cold front will cross the region
Saturday. Low pressure will approach Sunday.

&&

.NEAR TERM /THROUGH TODAY/...
Midnight update...The sky has become mostly clear across the
area so decreased clouds. Temperatures look good. Adjusted temps
in some western areas up just a degree or two early in the
overnight period with a breeze still keeping the atmoshere
mixed. Otherwise, no major changes this hour.

Previous Discussion...
Winds will tend to die off later tonight as a 1030mb surface
high descends towards the area from Quebec. The high will ensure
clear skies. By dawn, a shallow radiation inversion is expected
for most of the area. H925 temps will be approaching minus 20C
in the Saint John Valley by that time. As a result, lows could
dip below minus 20F in the North Woods with subzero readings
across Aroostook County. The North Woods is most likely to have
calm winds earlier in the night and decoupling of the boundary
layer. Single digit lows can be anticipated further south. While
Wednesday will feature high pressure and sunshine, it will
feature the coldest highs of the winter so far for much of the
area. Given the very warm winter to date, it is not a very high
bar. High clouds thicken from the southwest later in the
afternoon, but precip will hold off until the evening.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...
A Major Winter Storm to Impact Wed Night-Thu Night...

Overview...A developing powerful storm system that is producing
Severe Weather in Texas today including Tornadoes is on tap to
be our next Winter Storm. The parent low pressure system will
track northeast into the Ohio River valley on Wednesday. Sharp
500mb trough will tilt negatively and support strong upper level
divergence over the NYC area to generate new surface
cyclogenesis and quickly this becomes the new low. This low
will track northeast over the area Thursday and exit into the
Canadian Maritimes Thursday Night with upper level energy
leftover head into the early morning hours of Friday.

Storm Details...Wednesday night expect the parent low over the
State of Ohio as surface cyclogenesis develops along the Mid-
Atlantic coast in response to 500mb trough tilting negatively
with the Jet Stream increasing and becoming significantly
divergent aloft. This will favor rapid surface cyclogenesis and
the energy transfer from the parent low to the new low. At the
same time across the area strong warm air advection aloft will
be transporting significant moisture from the Gulf of Mexico and
Atlantic similar to a "Miller A" type storm although this is
slightly modified. At the surface strong cold air damming is in
place with the significant overrunning taking place. Expect snow
to develop from southwest to northeast through the evening. Snow
gets underway even along the Downeast coast between 8-10pm and
may be moderate to heavy with significant strong warm air
overunning. Snow gets underway across Eastern and Northern areas
by 10pm-12am and rapidly becoming moderate to heavy at times.

After midnight expect snow to be Heavy at Times across much of
the Bangor area points northward. Warm air will begin working
into the Downeast coast so expecting a mix to sleet, freezing
rain then eventually rain by 2-4am. Sleet, Freezing Rain and/or
Rain may be heavy at times. Across the northern areas with
temperatures in the single digits and teens expecting really
good snowfall with very efficient DGZ temps & deep moisture.
Warm air through the early morning continues to work inland as
low pressure tracks into the Midcoast of Maine and tracks
towards Bangor and interior Downeast by afternoon. Expect a
tight thermal gradient to develop which will support strong FGEN
forcing and likely see a band of Heavy Snow from the Moosehead
Region into Northeast Aroostook county. As 925-850mb temps
increase above freezing expect rain to be across the Bangor area
to the Downeast coast but after all the snow expect slippery
travel. Inland expect a mix of snow, sleet and freezing rain.
The mixing area is a challenge and may stretch as far north as
Caribou, Presque Isle and Greenville but this will be after the
majority of the snow has fallen.

As the low pressure tracks into interior Downeast Maine during
the afternoon expect a dryslot to bring an end to precipitation
from southwest to northeast. It is possible across the north it
ends as freezing rain, freezing drizzle or some snizzle while
the North Woods remains snow. Elsewhere in southern areas expect
rain to taper to drizzle or just simply ends. Highs across the
north expect mid to upper 20s across the north, low to mid 30s
in Central Highlands with low to mid 40s from Bangor to the
coast. Cold air will crash southward and expecting all the melt
and rainwater south to freeze up during Thursday evening.

Snowfall Details...Intially as precipitation starts Wed Eve
expecting ratios to be 18:1 in the north, 15:1 in central areas
and 12:1 across the coast. By morning expecting ratios to fall
to 12:1 across the north, 7:1 in Central areas while the coast
becomes rain. Ratios fall to around 10-12:1 across the north as
the warm air works in aloft. Totals...Expecting a widespread 9
to 14 inches across the northern areas into the Moosehead and
Baxter region. Since confidence is high and with perhaps some
mixed precip in SE areas opted to upgrade the watch to a Winter
Storm Warning. Across the Central Highlands and interior
Downeast the warm air thump of precip before mixing will produce
heavy totals. Expect widespread 6-11 inches and given the
confidence in heavy snow + mixed precip opted to upgrade these
areas to Winter Storm Warning. Along the Downeast coast
expecting generally 3-7 inches but confidence isn't as high on
totals and perhaps 6" warning criteria is made...for now this
combined with timing opted to keep the Winter Storm Watch.

Wind Details...A strong LLJ will develop with modeled soundings
showing winds increasing 50-65kts across the area with much of
this able to mix down especially in Downeast areas. The
strongest winds will likely mix down after precipitation becomes
rain. Given the potential of gusts to 60mph opted to issue a
High Wind Watch for the Downeast coast. This will be a E-SE wind
across the area given the storm track. Inland with wind gusts
30-45mph there is the potential of whiteout conditions with very
heavy snow falling. I will be honest...contemplated the
Blizzard criteria but unsure if there will be frequent gusts of
35mph or greater. At this point expect significant blowing and
drifting of snow with heavy snow falling but unsure if wind
gusts are that frequent. For now, opted to enhance the Winter
Storm Warning wording for whiteout conditions. After the low
pressure passes Thu night blowing snow may become a problem once
again across the agricultural areas of Northern Maine with
westerly wind gusts 20-35mph.

Sleet & Freezing Rain Totals...Although there is uncertainty on
how much occurs, expect 0.1 to 0.3 inches across the Bangor
area north into the Highlands perhaps as far north as Presque
Isle. North of there expect mainly snowfall with perhaps some
freezing rain towards the end of the event. Speaking of freezing
rain cannot rule out a light glaze up to perhaps one tenth of an
inch especially across the Central Highlands.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Beyond the storm expect a much colder pattern to set up with
temperatures seasonably cooler than average. Daytime highs will
be in the teens to 20s with morning lows below zero north and
around 10-15F south. There will be periods of partly to mostly
sunny skies across the area with snow showers on Saturday. Next
potential system comes Monday with another weaker system cutting
across the area. Light snow will be possible with this system
but significant uncertainty in timing with operational runs
today will be a factor of need more retuning. Temps stay
slightly below normal into early week.

&&

.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
NEAR TERM: Variable conditions with any snow showers
through early morning. Otherwise, VFR/MVFR across the region
through early morning with VFR conditions then overnight
through Wednesday. Northwest winds 10 to 15 knots with gusts up
to 20 knots, becoming variable 5 to 10 knots overnight.
Variable winds 5 to 10 knots, becoming east Wednesday.

SHORT TERM: Wed night...IFR/LIFR south. MVFR/IFR north becoming
all IFR/LIFR. Snow, Heavy at Times. Snow mixing with Rain at BGR
& BHB. E-SE winds 15-25kts w/ gusts 30-40kts. LLWS likely.

Thu...IFR/LIFR. Snow, heavy at times north. Rain, heavy at times
south. E-SE winds 15-25kts w/ gusts 30-45kts shifting W 10-25kts
by late day. Precip tapers slowly from SW to NE by late day.
LLWS likely.

Fri...VFR. W-NW winds 10-20kts.

Sat...MVFR cigs. Snow showers. S winds 10-20kts w/ gusts to
30kts possible.

Sun...VFR/MVFR cigs. Snow showers. S-SW 5-15kts winds.

&&

.MARINE...
NEAR TERM: Small craft advisory conditions are expected overnight,
with conditions below small craft advisory levels Wednesday.
Although SCA conditions will exist tonight, will cancel the
ongoing advisory in favor of the Storm Watch. Northwest winds
will gradually shift to northerly, and then light northeast
winds for Wednesday.

SHORT TERM: Wed nights SE winds rapidly increase SCA into Gale
Force conditions. Gale force conditions become Storm conditions
across the outer waters by Thu AM. SE winds shift SW by Thu PM
behind the low pres and fall back to SCA & Gale conditions.
Gales or high end SCA winds last into Fri. Winds fall below SCA
from Fri PM through early Sat AM before SW SCA wind gusts become
possible again on Sat into Sun AM. Waves...Increase 4-7ft Wed
Eve becoming SE swells 8-14ft every 7-9sec by Thu AM. Waves
subside slowly into Friday and then back to 3-5ft by Saturday.

&&

.TIDES/COASTAL FLOODING...
For the Thursday afternoon high tide near 2PM, a storm surge
up to 2 feet and long period seas up to 14 feet could produce
wave runup issues for locations such as Seawall Rd on MDI and
along the southern edge of the Schoodic Peninsula. Beach erosion
at locations such as Rogue Bluffs will also be a threat. The
biggest surge will be between high tides and it is not a
particularly high astronomical tide.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning from 7 PM this evening to 1 AM EST Friday
     for MEZ001>006-010.
     Winter Storm Warning from 7 PM this evening to 1 PM EST
     Thursday for MEZ011-015>017-031-032.
     Winter Storm Watch from this evening through Thursday
     afternoon for MEZ029-030.
     High Wind Watch from late tonight through Thursday afternoon
     for MEZ029-030.
MARINE...Storm Watch from late tonight through Thursday afternoon for
     ANZ050-051.
     Gale Watch from late tonight through Thursday evening for
     ANZ052.

&&

Near Term...MCW
Short Term...Sinko
Long Term...Sinko
Aviation...MCW/Sinko
Marine...MCW/Sinko
Tides/Coastal Flooding...