Oakville, Connecticut 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

686
FXUS61 KALY 221201
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
634 AM EST Sun Dec 22 2024

.SYNOPSIS...
Unusually cold temperatures and wind chills continue through today
into tomorrow, but the weather should remain dry through this time
period. A clipper system will bring light snow to the region,
especially north of I-90, Monday night into Tuesday. Most of the
rest of the week looks relatively dry with temperatures moderating
to near or even slightly above normal levels by the end of the
week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Key Message:

- Very cold temperatures and wind chills continue today with
  Cold Weather Advisories in effect for portions eastern New
  York and western New England.

Discussion:
.Update...As of 6:35 AM EST...Bitterly cold start to the day
this morning, with temperatures in many areas below 0,
especially in the high terrain. Current GOES 16 Nighttime
Microphysics RGB satellite imagery shows some additional clouds
over and upwind of the high terrain areas, as well as some lake
effect clouds in the Mohawk Valley. Clouds in these areas are
keeping temperatures a couple degrees above the previous
forecast, while previous temperature forecast remains on track
elsewhere. NYS Mesonet obs show wind chills below -20 across
portions of the Adirondacks, with the coldest being Piseco at 24
below. Cold weather advisories will continue through 9 am this
morning, as temperatures should rise enough by that point for
wind chills to no longer be below criteria. Overall, previous
forecast remains in good shape with more details in the previous
discussion below...

.Previous...Our area remains under the core of a cold pool
aloft associated with upper troughing early this morning. Per
latest SPC mesoanalysis, 850 mb temps are currently below -20C
in the Adirondacks, which has translated to sfc temps
approaching 10 below zero here. The rest of the region is seeing
temperatures in the single digits to 5 below 0. Winds remain
breezy with a tight pressure gradient across our area, which has
led to wind chills several degrees colder than the actual
temperature. Based on latest temperature/wind obs from the NYS
mesonet, we have expanded the Cold Weather Advisory to include
souther Fulton and Montgomery Counties as apparent temperatures
here are already approaching -15F. Most areas are cloud-free
right now, although with blocked flow we are seeing some clouds
over and upwind of the terrain in northern Herkimer and Hamilton
Counties, as well as in the southern Greens.

Today will be quite cold, with temperatures only warming into the
single digits (terrain) to 10s (valleys) for highs today.
With strong large-scale subsidence, we should see dry weather and
mainly clear skies today. Winds remain breezy this morning but
should diminish through the day as a 1036+ mb surface high builds
eastwards from the Great Lakes region allowing the pressure gradient
to weaken.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Key Message:

- Continued very cold temperatures tonight. Due to calm winds,
  wind chills are not expected to reach cold weather advisory
  criteria.

- An Alberta Clipper will imact the region with light snow
  Monday night into Tuesday. Most areas will see a general 1 to
  3 inches of snow, with the lower amounts south of I-90 and the
  higher amounts to the north.

Discussion:

Tonight, the 1036+ mb sfc high builds directly overhead. With
continued subsidence, skies will be mainly clear. With winds
becoming calm under the high and a fresh snowfall, this will provide
ideal radiational cooling conditions. Confidence is high for
another night of very cold temperatures, and we undercut NBM
forecast lows by a few to several degrees. The largest departure
from the NBM was across the ADKs where lows will likely drop to
10F below zero or colder tonight. For the rest of the region,
lows will generally range from the low single digits near the
I-84 corridor to the negative single digits in the Catskills and
southern Greens. Apparent temperatures will be nearly identical
to the actual air temperature due to the lack of wind, so we
therefore are not expecting additional cold weather advisories
to be needed. Monday starts off very cold and dry, but as the
day progresses the surface high slides off to the east. With an
upper shortwave and associated surface low tracking into the
Great Lakes region, winds turn to the southwest, resulting in
warm advection. Daytime highs will still be well below normal,
but should be about 5 to 10 degrees warmer than on Sunday.
Clouds increase through the afternoon ahead of the
aforementioned clipper system, but most of the region (except
the far western ADKs) should remain dry through sunset Monday,

Monday night and Tuesday...The positively tilted upper shortwave and
associated weakening sfc low track from the Great Lakes through
upstate NY and into New England Monday night and Tuesday, bringing
widespread light snow to the region. Northern areas may see an
initial round of snow with the warm advection/isentropic lift Monday
evening and early Monday night, but the best chance for snow for
most areas looks to be ahead of the system`s cold front the second
half of Monday night and Tuesday morning. This system looks fairly
progressive and moisture is not overly impressive, so snowfall
amounts will likely be on eh lighter side. Valley areas south of I-
90 may only see up to around an inch, with a general 1 to 3 inches
north of I-90. The highest amounts will be in the southwestern ADKs
where a general 2-4 inches in expected. Probabilities for advisory
level snowfall amounts are quite low, especially outside of the
Adirondacks. Nevertheless, slippery travel conditions are possible
Tuesday morning, especially on untreated surfaces. Thermal profiles
favor all snow, and the snow should be on the fluffier side. Highs
Tuesday afternoon climb into the 20s(terrain) to 30s (valleys).

Christmas Event through Christmas night...Snow showers taper off by
Tuesday evening, resulting in dry conditions overnight as heights
rise aloft. A 1034+ mb sfc high will be located to our north beneath
confluent upper flow, and should ridge southwards into our area
Tuesday night. This will set the stage for another chilly
night, as conditions will be favorable once again for radiational
cooling especially where additional snow falls Tuesday. We
remain under the ridge of high pressure at the surface for
Christmas Day, resulting in dry weather and highs in the 20s
(terrain) to 30s (valleys) once again. For Wednesday night, the
most likely scenario is for continued dry conditions beneath the
surface high, although some deterministic and ensemble guidance
brings another weak shortwave overhead. There have been large
run-to-run jumps in the position of this feature over the past
several model runs, and due to the small- scale nature of the
shortwave in question it will not be well- resolved by coarser
numerical models. Therefore, confidence for Wednesday night is
low, but even if the shortwave does move overhead any
precipitation would likely be quite light due to a lack of
moisture. If this feature remains north of our area and skies
remain clear, then temperatures could be several degrees below
the currently forecasted lows in the 10s.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
Generally dry conditions are anticipated through the long term
forecast period with high pressure dominating the surface and
ridging the mid- and upper-levels through at least Saturday morning.
Some long-range guidance indicates a weak shortwave disturbance
traversing the eastern Great Lakes Thursday morning, generating
light, scattered snow showers for portions of the Southwest
Adirondacks, Mohawk, and possibly the Upper-Hudson Valleys. However,
the latest NBM ensemble has very low probabilities (10 to 20%) in
greater than 0.1" in these areas indicating the low likelihood in
accumulating precipitation likely due to counteracting sinking air
as the wave enters the region of high pressure engulfing much of the
Northeast. The only other chance for precipitation, though also
looking unlikely to fall within the temporal extent of this period,
comes Saturday night when the aforementioned high and associated mid-
 to upper-level ridge begin to shift east and exit the region. In
its wake, a once southern-stream cutoff low looks to broaden into an
open wave and adjoin a deepening, northern-stream trough associated
with a closed upper-low in south-central Canada. Taking on a
negative tilt as it tracks north and east, this now large-scale
trough will increase precipitation chances across the region from
west to east beginning Saturday night. However, due to significant
timing and evolution differences, have capped PoPs at chance to
slight chance.

Temperatures throughout the extended forecast period will follow a
gradual moderation from near/slightly below normal to slightly
above. Highs Thursday will therefore be the coolest of the period
with widespread 30s and pockets of upper 20s across higher terrain.
Friday will see highs similar to, though a few degrees warmer than,
Thursday before we rise to the mid/upper 30s to low 40s Saturday.
Low temperatures will begin in the upper 10s to low 20s Thursday
night before being widely in the low 20s Friday night and the upper
20s Saturday night.

&&

.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
Through 12z Monday...VFR conditions prevail across all terminals
this morning with the expectation of such continuing through the 12z
TAF cycle. Mainly clear skies are in place across the region this
morning with high pressure in place, and though some low FEW/SCT
clouds are possible later this morning/afternoon at many sites, no
ceilings are anticipated to form. Winds will likely pick up a bit
after sunrise this morning, but will then gradually decrease
throughout the day, remaining primarily out of the northwest.
Sustained speeds will be between 8-12 kt with gusts up to 14-18 kt.
By late this afternoon, gusts will cease and sustained speeds will
fall below 5 kt for the overnight period.

Outlook...

Monday Night: High Operational Impact. Definite SHSN.
Tuesday: Moderate Operational Impact. Chance of SHSN.
Tuesday Night: No Operational Impact. NO SIG WX.
Christmas Day: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
Cold Weather Advisory for much of the Adirondacks, Mohawk Valley,
eastern Catskills, Berkshires, and portions of the northern Taconics.

&&

$$

SYNOPSIS...Main
NEAR TERM...Main
SHORT TERM...Main
LONG TERM...Gant
AVIATION...Gant