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fxus61 kaly 120820 
afdaly

Area forecast discussion
National Weather Service Albany New York
320 am EST Tue Nov 12 2019

Synopsis...
a strong cold front will cross the region today taking the
wintry mixture and snow out of the area. Record setting cold
temperatures are expected tonight into Wednesday in the wake of
the frontal passage. A slow rebound in temperatures is forecast
for later in the week before another strong cold front
approaches to start the weekend.

&&

Near term /through today/...
..Winter Storm Warning and winter weather advisories remain in
effect this Tuesday morning for portions of the region...

As of 330 am EST, dual-pol Doppler radar reveals the leading
edge of the precipitation was mixed hydrometeors per the 0.5
degree cirrocumulus. As upstream support increases and the 925-850 f-gen
increases, we should see this band(s) of precipitation increase
with intensity as it moves across the region this morning. Per
New York mesonet and metar observations, valley locations are below
freezing with some of the higher terrain into the Catskills,
Berks and most of Litchfield County CT were above freezing. As
the combination of wet bulb processes and cold advection, the
upstream wintry mixture will spread east and within an hour of
fropa, a quick transition to snow is expected. The dacks will
likely remain the beneficiary of accumulation snowfall with the
rest of the region quite a bit less, but nevertheless, impactful
with the morning commute. Per 00z and hourly updated rap/hrrr,
this band of precipitation should quickly exit to the east by
18z today as brisk cold advection increases. High temperatures
will likely be obtained this morning with falling temperatures
the remainder of the day. H850 temperatures plunge at or below
-15c by days end. Mixing layer heights per BUFKIT profiles
suggest wind gusts close to 30kts are possible, combining that
with falling temperatures will result in wind chills falling
below zero across the higher terrain with 10-15 degrees for
valley locations.

Lake effect activity off Lake Ontario will also increase as
upper trough remains overhead and inversion heights near 5k
feet. While not the best inversion heights, rather steep low
level lapse rates due to average lake temperatures near 8c per
glerl analysis and extreme instability parameters per Delta T/S
should suffice the lower inversion heights. Wind trajectories
will initially be northwest then forecast to back a bit later
today to a west-northwest trajectory for the snow showers to
impact portions of the dacks initially, then into the Mohawk and
Schoharie valleys toward sunset.

&&

Short term /tonight through Thursday/...
tonight, multi-band of lake effect snow will likely remain
ongoing for a period of time where some of the bands may make it
into the capital region briefly before the inversion layer
heights drop even further to less than 4k feet per 3km-NAM
BUFKIT profiles. Portions of the Schoharie valley and western
Catskills within the County Warning Area may see some additional light snow
showers with up to an additional inch of fluffy accumulation.
Elsewhere, clouds will slowly dissipate along with those gusty
winds to result in what will likely be a recording setting cold
for many locations. As h850 temperatures settle back to just shy
of -20c, overnight lows will likely dip back to near or just
below 0 for the dacks (especially with a fresh snowpack) with
single digits to lower teens elsewhere. Wind chills will be
close to advisory levels for the dacks with current forecast of
-15f and the remainder of the region near 0.

Wednesday, high pressure will crest and transverse the region
during the daylight hours with tranquil but cold conditions for
the middle of November. Temperatures likely not reaching
freezing for most of the area under plenty of sunshine.

Wednesday night, weak warm advection and pseudo-warm front are
progged to move through the region in advance of our next short
wave. Mean relative humidity fields suggest mainly clouds will increase with
mostly cloudy conditions along and north of i90 per the best
isentropic lift and lowering cpd's. However, low level relative humidity fields
remain dry as we will keep the region dry with this forecast
update. Due to clouds, we will keep temperatures a bit milder
than the previous nights with overnight lows mainly into the
teens with single digits for portions of the dacks and southern
greens.

Thursday, upstream short wave dampens out a bit with best
vorticity advection tracking well to the north of i90. Here is
where we will place slight chance pops for light snow under
amplecloud coverage for the rest of the region. As thermal
profile continues to modify a couple more degrees, this too
should have a positive impact to our surface temperature with
most areas climbing above freezing.

&&

Long term /Thursday night through Monday/...
a strong northern stream upper level shortwave and associated
frontal boundary will be heading toward the area for Thursday
night into Friday. However, little moisture will be associated
with this feature. While a few light snow showers may accompany
the system for areas north/west of the capital region (mainly
during the day on friday), most areas won't see much more than
just some passing clouds with this system. While temperatures
should reach the upper 30s to mid 40s for most spots ahead of
the front, colder air will move back in behind the front for the
weekend. In addition, winds will be gusty for Friday into Friday
evening, with northwest winds over 25 mph at times.

Dry weather is expected over the weekend with high pressure in
control. It will be very cold, though, with daytime temperatures
below freezing for Saturday across nearly the entire area. After
overnight lows on Sat night in the teens and 20s, daytime temps
on Sunday will mainly be in the 30s.

There could be some precipitation for early next week as a
series of southern stream systems move up the eastern seabaord,
although model guidance is still unclear on the track and timing
of these features. Latest 00z European model (ecmwf)/GFS both keep it dry for
early in the week, but will continue to go with slight chc to
chc pops for Monday in case things trend back westward. With
temps both at the surface and aloft just warm enough, most of
the precip will be rain, but will still allow for some mixing
with snow across the higher terrain for the overnight periods in
case things trend colder. Max temps on Monday look to range from
the upper 30s over the mountains to the upper 40s in valley
areas.

&&

Aviation /08z Tuesday through Saturday/...
frontal boundary is heading towards the area. Steady area of
precip over central New York will spread across the taf sites for late
in the overnight and continue into the first part of the
morning on Tuesday. Precip looks to spread towards kgfl/kalb by
07z-08z. With a warm nose aloft, precip will likely begin as
-fzra as surface temps are already below freezing. It may start
to mix and changeover to pl due to a deep sub-freezing cold
layer near the surface shortly after starting and should
eventually transition over to just snow by 11z-12z as colder air
moves in aloft with the passage of the front. Precip looks to
then end by 14z-15z as the precip shield heads eastward. As
precip begins, flying conditions look to be MVFR but a period of
IFR looks to occur once the changeover to snow takes place
(mainly for visibility). At kpsf/kpou, the boundary layer is
warmer, so precip will begin as rain by 10z-11z. However, colder
air arriving both at the surface and aloft should allow for a
changeover to mixed precip and eventually snow before ending by
mid-morning. Snow may linger at kpsf due to upslope, so will
keep -sn there until 16z. As the other sites, flying conditions
will be MVFR and then IFR as snow begins, with visibility being
the best chance for reaching IFR thresholds.

Behind the snow, flying conditions should be VFR for most sites
(some MVFR cigs may linger at kpsf through the day). Clouds
will clear out by evening, with mainly clear skies for Tuesday
night.

North to northeast winds will increase through the rest of the
night. Winds will be west to northwest by daybreak Tuesday at 10
to 15 kts with some higher gusts (especially at kalb/kpsf).
These gusty winds will occur through the entire day. Winds will
diminish somewhat for Tuesday evening, but still be around 5 to
10 kts out of the west to northwest for Tuesday night.

Outlook...

Wednesday to saturday: no operational impact. No sig weather.

&&

Fire weather...
a strong cold front will cross the region today taking the
wintry mixture and snow out of the area. Record setting cold
temperatures are expected tonight into Wednesday in the wake of
the frontal passage. A slow rebound in temperatures is forecast
for later in the week before another strong cold front
approaches to start the weekend.

&&

Hydrology...
no widespread problems are expected on the main Stem rivers the
next several days.

No widespread problems are expected on the main Stem rivers the next
several days. Wintry mixture to snow will end from west to east
this morning. An unseasonably cold airmass will arrive in the
wake of this system, with temperatures remaining below freezing
throughout the region Tuesday into Thursday morning. No
hydrologically significant precipitation is expected through the
remainder of the week. This will allow some ice to form on area
waterways.

For details on specific area rivers and lakes, including latest
observed and forecast river stages and lake elevations, please
visit the advanced hydrologic prediction service /ahps/ graphs
on our website.

&&

Climate...
forecast temperatures may approach records on November 13 and
14. Here are the record low temperatures at eastern New York
climate sites...

Min 11/13 Max 11/13 min 11/14

Albany, New York 13 (1981) 31 (1911) 12 (1996)

Glens Falls, New York 13 (2001) 32 (1916) 5 (1905)

Poughkeepsie, New York 16 (2013) 35 (1986) 13 (1986)

&&

Aly watches/warnings/advisories...
CT...none.
New York...Winter Weather Advisory until 10 am EST this morning for
nyz058>061-063>065.
Winter Weather Advisory until 10 am EST this morning for
nyz048>054.
Winter Weather Advisory until noon EST today for nyz038>041-
043-047-082>084.
Winter Storm Warning until noon EST today for nyz032-033-042.
Massachusetts...none.
Vermont...Winter Weather Advisory until noon EST today for vtz013-014.

&&

$$
Synopsis...bgm
near term...bgm
short term...bgm
long term...frugis
aviation...frugis
fire weather...bgm

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