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Area Forecast Discussion (AFD)

Issued by Albany, NY (ALY)

                            
000
FXUS61 KALY 191440
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
940 AM EST Tue Feb 19 2019

.SYNOPSIS...
For today and tonight it will be mainly clear and cold. Low 
pressure, moving from the Ohio Valley to the mid Atlantic Coast,
will bring snow becoming a wintry mix later Wednesday into 
Thursday morning. Partial clearing and breezy conditions are 
forecast by later Thursday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 9:40 AM EST, skies remain mostly sunny with some thin 
cirrus streaking across the sky on the jet stream. 12Z Albany 
balloon sound showed a 199kt west to east jet across the area. 
Latest update mainly to refresh temperatures which have warmed a
little quicker than previously forecast. 

Previous...
After the cold start, expect mostly sunny skies through today 
which should allow temps to reach the lower/mid 20s for lower 
elevations, and teens across higher elevations. Temps may reach 
the lower 30s across portions of the mid Hudson Valley. Brisk 
west/northwest winds will later this morning, with some gusts up
to 20-25 mph possible.

Later this afternoon, as low level winds back into a more
westerly direction, some low level moisture from the Great Lakes
may extend into portions of the westernmost Mohawk Valley and
southwest Adirondacks with some clouds and flurries possible 
toward sunset.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
Tonight will be mainly clear with nearly calm winds, so expect
temps to drop off once again to between 5 below and 15 above
for many areas, with some sheltered areas of the southern
Adirondacks possibly dropping back to around 15 below. Some high
clouds will increase from southwest to northeast toward
daybreak. Also, some Lake Effect clouds and light snow
showers/flurries could extend into portions of central and
northern Herkimer County at times.

Wednesday-Wednesday night, the next storm system tracks into the
Great Lakes region during this time period, with a warm front
extending from the low into the mid Atlantic region. As the warm
front tracks northeast, strengthening isentropic lift along the
290-295 K surfaces should allow clouds to rapidly increase
Wednesday afternoon, with snow developing from southwest to
northeast late in the afternoon. It appears that the snow should
reach the I-90/I-88 corridors and points south/west by sunset,
and a few hours thereafter across the southern Adirondacks
extending into southern VT. This could lead to a slippery
evening commute, with snowfall accumulations up to an inch for
these aforementioned areas. The snow, light to moderate in
intensity, may become somewhat patchy as it tracks northeast, as
the deepest moisture begins to shunt eastward across the
northern mid Atlantic states and off the NJ coast Wednesday
evening, where a weak secondary surface wave may develop along 
the impinging low level warm front. In fact, models also suggest
a fairly deep wedge of dry air within the H700-500 layer 
translates northeast into the region by late Wednesday evening. 
Eventually, a warm nose aloft will track northward Wednesday 
evening, changing snow to a sleet/freezing rain mix, with mainly
freezing rain/freezing drizzle in many areas after midnight as 
the elevated warm nose coincides with the lack of ice nuclei 
within the impinging mid level dry layer. So, after a period of 
snow with generally 1-2 inches of accumulation (perhaps locally 
higher across higher terrain of the southern Greens, northern 
Berkshires, and SW Adirondacks), expect mainly light sleet and 
freezing rain to occur, with ice accretion of a light glaze to 
up to one tenth of an inch to occur. Given prospects for some 
freezing rain, it is likely that Winter Weather Advisories will 
be issued for at least portions of the region for Wednesday 
night.

Thursday, lingering freezing rain/freezing drizzle may persist
Thursday morning, especially for areas near and north of I-90.
As the weakening system's occluded front tracks east across the
region later Thursday morning, increased mixing should allow
temps to spike into the 40s for many areas, with even some 50s
possible across lower elevations within the mid Hudson Valley
and NW CT. Temps across higher terrain areas may then start to
fall later in the day back into the 30s. It will become windy by
afternoon, with west/northwest winds potentially gusting to
25-35+ mph.

Thursday night, increasing cold air advection and a
west/northwest cyclonic flow should allow for mostly cloudy
skies with spotty snow showers/flurries possible across the
Mohawk Valley and southwest Adirondacks. Otherwise, temps will
slowly fall back through the 30s with some 20s possible by
daybreak Friday.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Flat upper ridging in eastern North America will keep temperatures 
at or a little above normal through the period. Strong upper energy 
in the western and central U.S. will continue to weaken as it tracks 
within the northern periphery of the upper ridging and broadly 
confluent upper flow.

Dry weather is expected Friday and Saturday, although, Saturday 
there will be increasing clouds with the leading edge of some patchy 
light precipitation possibly approaching southern areas.  Highs 
Friday in the upper 30s to lower 40s but lower 30s northern areas. 
Highs Saturday in the lower 40s with mid 30s northern areas.

Upper energy and increasing low level moisture and forcing track 
toward our region Saturday night and through our region Sunday. 
Mixed precipitation Saturday night will become rain Sunday. There 
are questions as to the timing of the onset and exit of 
precipitation in the fast west southwest upper flow and adjustments 
will be made as we get closer to next weekend. Showers could linger 
into Sunday night. Highs Sunday in the lower to mid 40s but a few 
upper 40s southern areas and around 40 northern areas.

Any precipitation ends Sunday night, except for some possible lake 
effect snow shower activity that could extend into the southern 
Adirondacks and western Mohawk Valley. Highs Monday in the upper 30s 
to lower 40s but lower 30s southern Adirondacks.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
Mostly clear sky through tonight with high pressure in control of 
the weather. VFR ceilings and visibilities expected through tonight.

Variable winds at 6 Kt or less through mid morning will increase to 
10 to 15 Kt with gusts to near 20 Kt late this morning and 
afternoon. Northwest winds diminish to 6 Kt or less this evening and 
continue through the night.

Outlook...

Wednesday Night: High Operational Impact. Definite SN...FZRA...SLEET.
Thursday: Moderate Operational Impact. Windy With Gusts To 30.0 Chance of SHRA...RA.
Thursday Night: Low Operational Impact. Breezy NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.

&&

.HYDROLOGY...
Hydrological impacts are not expected through at least this
week.

Seasonably cold weather is expected through Wednesday, promoting
ice expansion on area waterways.

The next system arrives late Wednesday into Thursday morning
with snow transitioning to a wintry mix. Precipitation amounts
of generally a quarter to a half an inch are expected.
Temperatures are expected to run a bit above normal Thursday
into the weekend.

Another period of rain or mixed precipitation is possible
Sunday.

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...None.
NY...None.
MA...None.
VT...None.

&&

$$
SYNOPSIS...SND
NEAR TERM...SND/KL
SHORT TERM...KL
LONG TERM...NAS
AVIATION...NAS
HYDROLOGY...KL/Thompson