Area Forecast Discussion
Issued by NWS Albany, NY

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000
FXUS61 KALY 240107
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
807 PM EST Wed Jan 23 2019

.SYNOPSIS...
A storm system approaching from the west will bring milder
weather to the area with periods of rain. Some of the rain will
freeze late this afternoon into this evening, especially north
of Albany. The rain could be heavy at times especially Thursday
morning. The combination of heavy rain, warmer temperatures and
melting snow could cause some flooding south and east of Albany
Thursday morning. The rain could end as some snow Thursday
afternoon, especially west of the Hudson Valley. Colder weather
will return for Friday into the weekend, with some lake effect
snow showers possible.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 800 PM EST...Numerous reports of ice on surfaces across
the region as per coordination we will extend both winter
weather advisory areas til 11 pm and 1 am respectfully.
Mesoscale observations show the terrain moderating on the
increasing low level jet which is also observed on our VWP but
valley locations are having a difficult time moderating. Given
our diverse terrain, and the fact temperatures and wet bulb
processes are around freezing, we will continue with these
headlines. That low level jet will eventually assist with
transporting those warmer temperatures northward as per the
HRRR/NAM3km and LAV/LAMP guidance.

Prev Disc...
Temperatures continue to rise slowly as slightly heavier and
more widespread precipitation is overspreading the area from the
west. Temperatures are near to just above freezing in most
areas from Albany southward, although with dew points mainly in
the 20s some wet bulb cooling could still result in some spotty
icing in those areas. Some of the warmest temperatures can be
found on the west slopes of the Berkshires, Taconics and Green
Mountains with locations as far north as Bennington Vt up into
the mid 30s. North and northwest of Albany, the cold air is
holding on more persistently with mid 20s to lower 30s in the
Mohawk Valley, southern Adirondacks, upper Hudson Valley. Many
places within this area will see another tenth or two tenths of
an inch of ice into this evening.

Overnight temperatures will continue to rise slowly with just
about all locations above freezing by midnight. Increasing
southerly winds will become very strong above the boundary layer
with speeds as high as 80-100 kts from 925 to 850 mb. These
winds will remain above the boundary layer but gusts up to 30 to
40 mph can still be expected over higher terrain in the
Catskills and Berkshires. Downsloping south-southeast winds will
lift temperatures well into the 40s along the west slopes of
the Berkshires and Taconics as far north as Bennington Vermont
overnight. Meanwhile, temperatures will hold on the cold side
west of the Hudson Valley and north of Albany with 30s from
Saratoga county northward. Rainfall will be maximized over the
slopes of the southern Adirondacks where some 1 to 2 inch
amounts. Showers elsewhere will result in precipitation amounts
ranging from 0.25 to 0.75 inches.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
An elongated area of low-level low pressure and frontogenesis
will translate slowly from west to east across our area on
Thursday. A dominant wave of surface low pressure will organize
near New Jersey and track northeast to western New England
Thursday morning and afternoon. Moderate to heavy rain will fall
along and just east of the track of this wave, with the CAMs
all indicating a narrow cold frontal rain band developing near
the Hudson Valley around or just after 12z, then progressing
east across Massachusetts and Connecticut during the late
morning through early afternoon. Temperatures will be highly
variable during this period with readings reaching the 50s in
Connecticut and the lower-to-mid Hudson Valley, with mid 30s to
lower 40s north of Albany where the cold air will never get
completely scoured out. Areas south and east of Albany that will
be relatively warm with gusty winds and snow melt could see
flooding as detailed in the hydrology section.

Rain will change to a period of light snow on the western edge
of the precipitation west of the Hudson Valley Thursday
afternoon with up to a couple of inches of accumulation. A brief
period of snow could reach the Hudson Valley by late afternoon
with very minor accumulations, then the snow could enhance a
bit as it goes into Vermont and Massachusetts with an inch or so
possible. Colder weather will overspread the entire area
Thursday night with some flurries re-developing west of the
Hudson Valley overnight.

Friday will be colder with scattered snow showers west of the
Hudson Valley during the morning. A re-enforcing shot of colder
air will approach from the west Friday afternoon possibly
associated with some snow showers that could reach the Hudson
Valley east to the Greens and Berkshires later in the day. Some
lake effect snow could develop Friday night east of Lake
Ontario extending toward the western Adirondacks. Saturday will
be cold with mainly dry weather for most of our area, except for
possibly some lingering snow showers east of Lake Ontario.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Broad upper troughing will be in place throughout the extended
period as an anomalous strong 500mb trough over the Great Lakes
region brings chances for snow and below normal temperatures.

To start, an upper impulse will round the base of the trough and
lift northeastward across our area Sunday into Monday. Ahead of this
impulse, a cold front will pass through the region Sunday night,
resulting in snow showers and potentially snow squalls. Temperatures
on Sunday are expected to warm into the mid 20s to mid 30s before
sharply dropping off behind the front, with overnight lows near zero
in the Dacks to the mid and upper teens elsewhere.

High pressure briefly builds into the region for the day Monday
before a strong upper impulse digs into the trough and helps deepen
the larger scale trough. There is still uncertainty in model
guidance but it looks like this system will bring snow chances to
the region Monday night through Wednesday. Temperatures on Tuesday
will be near normal before gradually cooling down through the end of
the work week as the broad trough moves overhead.

&&

.AVIATION /01Z THURSDAY THROUGH MONDAY/...
Freezing rain is forecast this afternoon at KALB and KPSF, and
this afternoon into this evening at KGFL as surfaces temps are
below freezing given the recent cold snap. Any freezing rain
should be fairly light, but could result in a glaze of ice on
surfaces.

Any freezing rain will gradually transition to plain rain during the
late afternoon into the evening hours, with KGFL likely holding onto
frozen precipitation longest. Rain will eventually become steadier
after 00Z, with flight category falling to lower MVFR to possibly
IFR levels. IFR cigs and vsby will become more common after 06Z as
dewpoints rise above 40F over the frozen/snow covered ground. Some
LIFR conditions cannot be ruled out.

Winds will gradually increase into this morning out of the south at
7 to 15 kt with some gusts to around 20 kt possible at KALB/KPSF.
Low-level wind shear conditions can be expected at KPOU and KPSF through
tonight as a strong low-level jet moves into the area.

Outlook...

Thursday Night: Low Operational Impact. Slight Chance of SHSN.
Friday: Low Operational Impact. Slight Chance of SHSN.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: Moderate Operational Impact. Chance of SHSN.
Sunday: Moderate Operational Impact. Chance of SHSN.
Sunday Night: Moderate Operational Impact. Chance of SHSN.
Monday: Low Operational Impact. Slight Chance of SHSN.

&&

.HYDROLOGY...
Flash Flood Watch has been expanded to include Berkshire,
Columbia, Dutchess and eastern Ulster counties, as well as
remaining in effect for Litchfield county Thursday.

A storm system will bring rain and freezing rain changing to
all rain across the area tonight and continuing into Thursday.
About one to two inches of liquid equivalent is expected with
heaviest amounts over the southern Adirondacks tonight and over
western Massachusetts and Connecticut Thursday. This rainfall,
along with the melting snow, will allow for some rises on rivers
and streams. Across the northern half of the area temperatures
will only rise to about 40 degrees and the rainfall will mostly be
absorbed by the snowpack. However, south and east of Albany
(where snow pack is more limited) more of the precipitation will
be converted to runoff. With a frozen ground in place, some
minor flooding is possible, including along the Housatonic and
Hoosic Rivers.

With river rises and ice movement on some rivers, ice jams can
not be ruled out. However the limited amounts of total runoff
should prevent this from being a major concern and this will be
more of an isolated issue.

Behind this storm system, colder weather will return to the
region for Thursday night into the weekend. Any additional
precip will be in the form of snow and fairly light.

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...Flash Flood Watch from 6 AM EST Thursday through Thursday
     afternoon for CTZ001-013.
NY...Winter Weather Advisory until 11 PM EST this evening for
     NYZ032-038>040-047>054-058>061-063-084.
     Flash Flood Watch from 6 AM EST Thursday through Thursday
     afternoon for NYZ060-061-064>066.
     Winter Weather Advisory until 1 AM EST Thursday for NYZ033-
     041>043-082-083.
MA...Winter Weather Advisory until 11 PM EST this evening for
     MAZ001-025.
     Flash Flood Watch from 6 AM EST Thursday through Thursday
     afternoon for MAZ001-025.
VT...Winter Weather Advisory until 11 PM EST this evening for
     VTZ013>015.

&&

$$
SYNOPSIS...SND/Frugis
NEAR TERM...SND/Frugis/BGM
SHORT TERM...MSE/Frugis
LONG TERM...JLV
AVIATION...BGM
HYDROLOGY...SND/MSE/Frugis


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