Albany, NY WFO Forecast Discussion

Forecast Discussion for ALY NWS Office
000
FXUS61 KALY 210553
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
153 AM EDT Thu Mar 21 2019

.SYNOPSIS...
The start of Spring will be unsettled with widespread rain and
snow Thursday through Friday night. A moderate to heavy snowfall
expected for areas mainly above 1000 feet. It will turn cold and
blustery for Friday night and Saturday.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 1248 AM EDT...Made some changes for the rest of the night
into this morning, mainly to delay onset of precipitation based
on latest HRRR and NAMNest. Will mention dry conditions through
5 AM, with slight to low chance pops developing across areas
south of Albany from 5-7 AM for spotty light rain and mountain
snow. Steadier precip not moving in until later.

High and mid level clouds continue to gradually thickening from
the south/west. Southerly flow keeping temperatures mild in the
Hudson Valley and other places where decoupling hasn`t
occurred, while sheltered spots have plummeted. Have attempted
to account for the temperature variation by raising overnight
lows in the Hudson Valley and lowering them in the north
country. It will be relatively mild with lows only expected to
drop into the mid 20s to mid 30s with a continuing southerly
flow occurring about the departing ridge.

Southern and northern stream energy are expected to phase
overnight with the development of secondary coastal low
beginning along the southeast coast.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
Winter Storm Watch has been issued for Friday and Friday night
for the western Adirondacks, western Mohawk Valley and higher
terrain of southern Vermont. A heavy, wet snowfall of 7+ inches
is possible.

The coastal low will continue to develop moving gradually up
the coast to the mid Atlantic region during the day Thursday.
Light precipitation is expected to develop/move into the local
area during the day becoming more widespread as the day
progresses. There are chances for some snow above 1500 feet in
the morning then the boundary layer warm up enough for rain by
the afternoon.

Additional northern stream energy will dive out of central
Canada Thursday resulting in the development of an upper level
low over the region by Friday morning. The mid-level trough
begins to take on a negative tilt and the coastal low deepens as
it continues its track northeastward along the coastline
reaching the Canadian Maritimes Friday night.

The precipitation will become heavier Thursday night as the
associated low level jet moves and through the area. The rain is
expected to mix with snow and maybe sleet Thursday night as the
boundary layer cools. However as the coastal low moves to up
the New England coast colder air will be drawn into the region
and change over to snow is expected late Thursday/early Friday
morning across mainly the higher terrain. Gets complicated
during the day Friday as the dry slot moves through with wrap
around and upslope precipitation expected to begin by late in
the day. Some rain is expected to mix in with the snow across
the higher elevations while below 1500 feet the precipitation
should remain all rain. We will be on the back side of the
system Friday night with cyclonic flow; a changeover to all
snow is expected during the evening hours.

Across the watch area, the western Adirondacks, western Mohawk
Valley and higher terrain of southern Vermont, 7+ inches are
possible. A moderate snowfall is possible across Fulton,
Montgomery, Schoharie, northern Warren and northern Berkshire
counties which have highlighted in our hazardous weather
outlook. Across the rest of the area, the Capital District including
the Saratoga and Glens Falls area, Washington County, Taconics, mid
Hudson Valley, central and southeastern Catskills, southern
Berkshires and northwestern Connecticut, a light accumulation
of snow is possible Friday night.

Westerly winds will become strong and gusty on the backside of
this deep coastal low. Gusts of 30 to 40 mph are expected
Friday night. A wind advisory will be needed if confidence
increase for gusts above 45 mph. Continued to have highlighted
in our hazardous weather outlook.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The large storm system is expected to close off and push east of the
region on Saturday. Upslope snow showers will continue through at
least Saturday morning across the favored areas of the Dacks, Mohawk
Valley and southern Vermont. Outside of the snow showers, gusty NW
winds will be an issue on Saturday as the upper trough/low lifts
into the Gulf of Maine. Wind gusts in the 30 to 40 mph range will be
possible, especially the first half of the day. Below normal temps
are anticipated with highs only reaching the upper 20s to lower 40s.

Dry and more seasonable weather will return Saturday night into
Sunday as upper level heights increase and a broad ridge builds into
the mid-Atlantic region. While temps Saturday night will still be on
the cool side, afternoon highs on Sunday are expected to reach the
40s to upper 50s with plentiful sunshine. Winds will also be much
calmer due to the ridging in place.

Model differences then arise for late Monday into Monday night, as a
strong cold front and associated upper level trough drop southward
from Canada. Guidance in relatively good agreement regarding the
synoptic features, although the discrepancy is the potential for
precipitation along and just behind the front. The GFS continues to
indicate rain showers changing to snow showers during this time,
while the ECMWF is showing a dry frontal passage. Will continue to
monitor trends and mention slight chance to chance pops for now.
Either way, it will turn colder again for Monday night and Tuesday
with below normal temperatures. Dry conditions look to return on
Tuesday.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
High pressure continues to move east of Nova Scotia this
morning, as mid and high clouds are increasing ahead of low
pressure approaching from the Great Lakes Region. Another low
pressure system will form over the Mid Atlantic States this
morning with the clouds further thickening and lowering with
moisture streaming northward into the TAF sites in the late
morning and into the afternoon with mainly light rain. The
precipitation will increase in coverage and intensity tonight,
as the coastal wave get closer.

VFR conditions are expected with the clouds gradually
thickening and lowering with the best chance of MVFR cigs/vsbys
by 15Z/THU at KPOU with light rain moving in. The trend
continues for the -RA to move north/northwest between 17Z-
21Z/THU with the potential of MVFR cigs/vsbys in the -RA at
KALB/KGFL. We were less certain at KPSF and used a PROB30 group
between 22Z/THU and 02Z/FRI due to the east/southeast
downsloping winds which may hold conditions at VFR there. The
rain will expand in coverage between 00Z-05Z with widespread
MVFR conditions impacting the eastern NY and western New
England terminals. Some IFR conditions may be possible first at
KPOU, but we kept at low MVFR in terms of vsbys/cigs after
01Z/FRI. Later issuances can address possible IFR conditions
further.

The winds will be from the south at around 10 kts at
KALB/KPSF early this morning with some gusts around 15-18 kts at
KALB. Expect the sfc winds to be 5 kts or less at KPOU/KGFL. The
winds will generally be south to southeast at 5-10 kts during
the late morning into the afternoon with some gusts in the 15-20
kt range at KALB. The winds will begin to back to the east to
northeast at less than 10 knots tonight, as the wave approaches
from the south.

Outlook...

Thursday Night: High Operational Impact. Definite RA.
Friday: High Operational Impact. Breezy. Chance of SHRA...RA.
Friday Night: Moderate Operational Impact. Windy. Chance of SHRA...SHSN.
Saturday: Moderate Operational Impact. Windy. Slight Chance of RA...SN.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: Moderate Operational Impact. Chance of RA.

&&

.FIRE WEATHER...
The start of Spring will be unsettled with widespread rain and
snow Thursday through Friday night. A moderate to heavy snowfall
expected for areas mainly above 1000 feet. It will turn cold and
blustery for Friday night and Saturday.

&&

.HYDROLOGY...
No widespread hydrology problems are anticipated into this through
the weekend.

Widespread precipitation will occur across the area Thursday
through Friday night. QPF amounts 1 to 1 1/3 inches are
expected. Mainly rain in the valleys with some light snow, while
across the higher terrain above 1000 feet a moderate to heavy
wet snow is expected. Where we have snowpack temperatures are not
expected to get warm enough to produce much snowmelt. Some
within bank rises on rivers are expected. The latest MMEFS
guidance does not have any points reaching flood stage. Any
runoff which does occur will slow and/or end at night with
temperatures dropping below freezing through the weekend.

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...Winter Storm Watch from Friday morning through late Friday
     night for NYZ032-033-038.
MA...None.
VT...Winter Storm Watch from Friday morning through late Friday
     night for VTZ013-014.

&&

$$
SYNOPSIS...IAA
NEAR TERM...IAA/Thompson/JPV
SHORT TERM...IAA
LONG TERM...JPV/JLV
AVIATION...Wasula
FIRE WEATHER...IAA
HYDROLOGY...IAA

NWS ALY Office Area Forecast Discussion