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fxus61 kaly 232131 
afdaly

Area forecast discussion
National Weather Service Albany New York
431 PM EST Tue Jan 23 2018

Synopsis...
a cold front will sweep across the region this evening, accompanied
by increasing wind and some rain and snow showers. In the wake
of the cold front, colder air will return with brisk conditions
through Thursday. Some snow showers may bring light snow
accumulations for areas mainly north and west of the capital
region tonight into Wednesday morning.

&&

Near term /through Wednesday/...
Flood Watch remains in effect into Wednesday morning for the
local area as rainfall along with some snowmelt may be enough to
dislodge river ice which would then move downstream and
potentially jam at preferred locations, or may allow water to
pool behind existing ice jams which currently remain in place.

A dense fog advisory has been issued until 7 PM this evening
for the Mohawk Valley, greater capital region, Lake George
Saratoga region, Schoharie valley, and helderbergs of eastern
New York, as well as eastern Windham County of southern Vermont.

Mid level dry slot moving east across the region. However,
strong upper level shortwave and cold pool is approaching from
the eastern Great Lakes. Strengthening forcing and shallow
surface based instability has allowed a line of showers and
embedded thunderstorms to develop across central nys, especially
close to the Tug Hill region. Strong wind gusts of 40-50+ mph
have been accompanying this line.

Will have to watch trends over the next 1-3 hours, as this line
should move across the southern Adirondacks, and possibly into the
Saratoga/southern Vermont region. At the very least, have added mention
of isolated thunder in these areas through early this evening, and
can not rule out strong wind gusts and perhaps some small hail
within any taller convective elements within this line. Showers and
gusty winds will be possible even for areas south of the Mohawk
River, although with decreasing chances farther south where overall
dynamics will be more limited.

Behind the line, expect increasing winds along with some spotty rain
and snow showers later this evening, changing to snow showers later
tonight. Some lake enhancement is expected across northern and
central Herkimer County, where 2-4 inches of snow accumulation is
expected through daybreak. Elsewhere, snow showers are expected to
extend into valley areas at times, especially toward daybreak. Some
scattered coatings to areas of less than one inch could occur,
greatest across higher terrain.

Winds will increase toward and especially after midnight, with some
gusts up to 45 mph possible. Strongest winds are expected to be
within the Mohawk River valley, capital region and Berkshires.

Overnight lows toward or shortly after daybreak are expected to
range from the mid 20s to around 30 in lower elevations, with upper
teens to mid 20s across higher terrain.

For Wednesday, a secondary cold front will be passing through the
region in the morning. Additional snow showers will be possible as
this front passes. Snow showers/flurries should then shift south and
west later in the morning through the afternoon, as low level winds
veer more into the northwest. It will continue quite windy in the
morning, with a slight diminishing of the winds later in the
afternoon. Still could see gusts up to 45 mph through midday. As for
temperatures, a slight recovery could occur later in the morning to
the upper 20s/lower 30s in valleys, and mid 20s across higher
terrain, before gradually falling off in the afternoon.

&&

Short term /Wednesday night through Friday night/...
Arctic high pressure will settle into the region bringing below
normal temperatures back and period of fair weather. Aloft, an
upper level trough will swing through Wednesday night into
Thursday with heights beginning to rise during the afternoon and
evening. The upper ridge axis is expected to crest over the
region Friday night while the surface high shifts directly over
the region Friday and with the center of the high shifting off
shore Friday night.



Temperatures Wednesday night will range from around zero degrees to
lower to mid teens. Despite some sunshine Thursday, temperatures
will be below normal with highs mainly in the teens and 20s with
brisk and gusty winds making it feel colder.

With ridging at the surface and aloft along with light to calm
winds and mostly clear skies temperatures will tumble bottoming
out mainly in the single digits Thursday night. With the surface
high shifting off to our east a southerly flow will develop
preventing temperatures falling tumbling Friday night; looking
at lows in the teens to lower 20s.

&&

Long term /Saturday through Tuesday/...
another warm up and round of rainfall expected this weekend ahead
slow moving cold front. Overall guidance is in agreement with the
longwave pattern with the ridge over the eastern United States
being replaced by a deepening trough as we head through the
weekend into early next week. However there are differences with
the amplitude and timing. The weather prediction center indicated
a blended model approach favoring the slower European model (ecmwf)/Canadian/UKMET
over the quicker GFS and we have favored this to maintain forecast
consistency and timing of features. Guidance indicates this system
taps into Gulf moisture and has the potential to transport it
northward into our region. The milder temperatures and another
round of rainfall could be renewed concerns for flooding especially
in the vicinity of ice jams.

&&

Aviation /21z Tuesday through Sunday/...
frontal system continues to impact the region, although the
steadiest rainfall is starting to move off to the northeast. Through
the remainder of the afternoon hours, there will continue to be some
lingering showers as the low pressure area crosses the region. With
our area still on the cool side of the storm system, plenty of
lingering low level moisture and light surface winds will keep lots
of low clouds and areas of fog around, with IFR/LIFR conditions in
place. Visibility will be as low as 1/2sm (mainly for kgfl) with
cigs less than 1000 feet for much of the area. Kpou may be the first
site to see some improvement by late this afternoon.

By this evening, the cold/occluded front will be moving
through the area, and westerly winds will allow for some mixing.
This should start to allow for flying conditions to improve for all
sites , initially to MVFR and gradually back to VFR during the
overnight hours tonight, as some drier air starts to work in from
the west. Any showers should be ending with the passage of the
front.

Although winds will be light this afternoon, they will increase from
the SW around 5 kts this evening and eventually become westerly
around 10 kts by overnight. Some higher gusts are possible later
tonight, especially at kalb/kpsf, with some gusts up to 25 kts
possible.

During the day Wednesday, mainly VFR conditions are expected with
bkn cigs around 3500 feet. West-northwest winds will be 10-15 kts with some
higher gusts from time to time.

Outlook...

Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
Thursday night: no operational impact. No sig weather.
Friday: no operational impact. No sig weather.
Friday night: no operational impact. No sig weather.
Saturday: no operational impact. No sig weather.
Saturday night: moderate operational impact. Chance of rain.
Sunday: high operational impact. Likely rain.

&&

Hydrology...
Flood Watch remains in effect as runoff from the rain and snow melt
will cause rises on rivers and streams and may move and dislodge
ice and/or cause flooding near existing ice jams including watering
to pool behind existing ice jams. Areas in the river channels
which are most prone to ice jam flooding include obstructions in
The Channel such as islands, locks, bridge piers and docks;
changes in The Channel such as narrowing of The Channel, bends,
gorges and intact ice cover; change in channel depth from deep
water to shallow water; and merger of river channels.

Within bank rises are forecast with some rivers coming close to
or reaching action stage with rivers/streams cresting tonight
and Tuesday. An areal Flood Warning remains in effect for
ongoing flooding due to an ice jam in Warren County. Otherwise,
there are ice jams are in place across the area that are being
monitored for potential flooding.

The mild temperatures across the area will be replaced with a
much colder and more seasonable airmass tonight which will slow
and eventually stop the runoff. It remains cold through the
remainder off the work week. Milder air and another round of
rainfall are expected over the weekend which could be lead to
renewed concerns for flooding especially in the vicinity of ice
jams.

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

&&

Aly watches/warnings/advisories...
CT...Flood Watch through Wednesday morning for ctz001-013.
New York...Flood Watch through Wednesday morning for nyz038>043-047>054-
058>061-063>066-082>084.
Dense fog advisory until 7 PM EST this evening for nyz039>043-
047>053-059-060-082>084.
Massachusetts...Flood Watch through Wednesday morning for maz001-025.
Vermont...Flood Watch through Wednesday morning for vtz013>015.
Dense fog advisory until 7 PM EST this evening for vtz015.

&&

$$
Synopsis...kl

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