Albany, NY WFO Forecast Discussion

Forecast Discussion for ALY NWS Office
000
FXUS61 KALY 222034
AFDALY

AREA FORECAST DISCUSSION
National Weather Service Albany NY
434 PM EDT Fri Mar 22 2019

.SYNOPSIS...
Cold, cyclonic flow around low pressure in the Gulf of Maine,
will bring rain, snow and gusty winds into Saturday morning. It
will remain cold and blustery for Saturday afternoon, before
fair weather and milder temperatures return for Sunday.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Winter Storm Warning remains in effect for the western/southern
Adirondacks, western Mohawk Valley, eastern Catskills,
Helderbergs, northern Taconics, northern Berkshires and southern
Greens through Saturday morning...

Winter Weather Advisory remains in effect for the
central/eastern Mohawk Valley, Capital District, Lake George
Saratoga Region, central Taconics, southern Berkshires and
northern Litchfield Hills through Saturday morning...

As of 434 PM EDT...Radar shows precipitation falling over most
of the forecast area. Latest RAP analysis shows upper level low
along the NY/PA border near the southern tier of NY. This upper
low is forecast to move east southeast tonight and pass across
the far southern part of our forecast area before merging with
another upper level low now over the Gulf of Maine. As it passes
by, the Albany Forecast Area will be in a favored area for
precipitation, sort of a comma head. As temperatures fall
overnight, any rain will change to snow and all areas should see
at least a coating of snow overnight.

Current temperatures range from freezing or below at 2000` and
above, to the low to mid 30s in the hill towns to the low 40s
in the mid Hudson Valley. Web cams and METARS show that snow is
falling at elevations above 1000` and a mix of rain and snow
below that. We`ve seen a few wet snowflakes at times mixed in
with the rain here at the office.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/...
As the second upper level disturbance moves in from the west
and merges with the low over the Gulf of Maine, colder air
aloft will advect in. We are expecting a complete change to
snow to occur during the evening hours, with change from rain to
snow occurring more gradually and later for elevations below
500 ft. Snow-liquid ratios will start to increase as the entire
column cools. Last places to change will be right along Hudson
River which are near sea level and may not change over until
around midnight.

Widespread snow will then occur due to deformation/wrap-around
moisture from the large gyre centered over eastern New England.
With NW flow strengthening, upslope enhancement with occasional
moderate snow intensity will occur across the NW Adirondacks,
northern Catskills, and N-S spine of the Taconics and western
New England hills/mountains. Forecast Froude numbers from the
NAM tonight into early Saturday morning are between 0.3 to 0.7,
which implies slightly blocked to blocked flow. So we expected
the most accumulating snowfall along and just west of the
southern Greens, Berkshires, Litchfield Hills and Taconics. The
snow will gradually taper off to scattered snow showers Saturday
morning, as the strong low pressure system moves into the
Canadian Maritimes and the best moisture fluxes shift east of
the region. Additional snowfall expected to be highly elevation
dependent, with 6-12+ inches above 1500 ft, 3-6 inches below
500-1500 ft, and a coating to 3 inches below 500 ft.

After the snow ends, it will be blustery and cold through the
rest of the day Saturday. Wind gusts of 30-40 mph will be
common across the region, but we are expecting gusts to be just
below Advisory criteria due to relatively shallow mixing heights
around 900mb based on forecast soundings. We will continue to
monitor trends and mention threat in the HWO. Highs on Saturday
from around freezing in the hill towns to the mid 40s in the mid
Hudson Valley, and the windy conditions will make it feel
colder.

Cold and breezy, but dry conditions expected on Saturday night.
NW Winds will not be as strong, but a breeze will persist due
to high pressure moving eastward across the Carolinas. Lows
Saturday night in the teens and 20s. A warming trend is expected
for Sunday with continued dry conditions. highs on Sunday from
the 40s in the hill towns to the 50s in the Mid Hudson Valley.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Expect below normal temperatures for the first half of the final
week of March as an arctic cold front on Monday ushers in
temperatures 10-15 degrees normal through Wednesday. Temperatures
should rebound back near to and even a bit milder than normal
heading towards the weekend. Read on for details.

The aforementioned arctic cold front will be pushing southeastward
from the St. Lawrence River Valley into eastern NY and western New
England during the morning hours on Monday. Surface winds look to
shift to the northwest early in the day denoting the surface frontal
boundary with the associated surface low still far to our west in
the Ohio Valley. Moisture along the actual surface frontal boundary
looks fairly limited so we only expect linger rain (valley) and snow
(elevation) showers from the overnight to continue progressing south
and east from the Capital District into the mid-Hudson Valley Monday
morning. As the surface low travels eastward from the Ohio Valley
into the mid-Atlantic on Monday, an enhanced period of precipitation
looks possible but all of the global guidance members keep that wave
well to our south in the mid-Atlantic. In fact, there is good model
consensus showing an abundance of dry air at 700mb arriving in the
wake of the frontal passage which should lead to clearing skies and
deepening mixing heights through the day Monday. BUKFIT profiles
support this with breezy conditions developing within the deep layer
northwest flow resulting in continued cold air advection. Such a set-
up likely will keep high temperatures below normal, only reaching
into the 30s to low 40s.

Winds shift northerly Monday night denoting the arrival of the true
Canadian air mass into the Northeast. 850mb isotherms fall to
-10C to -18C by 12z Tuesday (2-3 standard deviations below normal
per the GEFS) and with breezy winds continuing overnight, expect a
chilly night with lows falling into the teens and 20s (single digits
for the Adirondacks and Greens). Tuesday will remain chilly as the
Northeast remains on the west side of the large scale ~1035mb high
pressure responsible for this air mass change which will keep
northerly flow in play. Tuesday should be the coolest day of the
week with high temperatures 10-15 degrees below normal, only
climbing into the 30s for most areas. Luckily, skies should be
mostly sunny so the strengthening March sun angle should make it
feel a bit warmer.

Our large scale high pressure should move overhead Tuesday night
into Wednesday. Increasing subsidence and dew points very low in the
single digits should lead to calm winds and clear skies resulting in
nearly ideal radiational cooling conditions Tuesday night. Low
temperatures should once again fall much below normal, even cooler
than Monday night with calm winds, reaching the low - mid teens
(single digits again Adirondacks/Greens) by Wednesday morning.

Another sunny day expected Wednesday as high pressure is positioned
over the Northeast. As it heads eastward during the day, we should
see return southwesterly flow develop allowing high temperatures to
turn a bit milder reaching into the 30s and 40s. However, this is
still 5-10 degrees below normal but again the March sun should help
make it feel warmer.

Thursday - Friday turns warmer into the 50s to potentially near 60
as high pressure moves into eastern New England and southwesterly
flow remains in place over eastern NY and western New England. We`ll
have to monitor a few systems from the Midwest that looks to travel
northeastward but high pressure firmly in place off the New England
coast could steer them to our north and west until possibly the
weekend. Keep tuned to future updates for details.

&&

.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
Challenging forecast as coastal low continues to intensify in the
vicinity of the Gulf of Maine.  Increasing pressure gradient across
the region will result with a magnitude increase in wind speeds from
the northwest direction.  As for precipitation, boundary layer
temperatures remain in the vicinity above freezing for Hudson Valley
locations where rain and some snow mixing in from time to time.  For
KPSF, upslope conditions and cooler temperatures will result in
mostly snow that is expected to continue into the overnight period.
So IFR conditions are expected to linger for KPSF, with MVFR/VFR
conditions at KGFL-KALB with mostly VFR conditions at KPOU.

Precipitation is expected to end across the entire region Saturday
morning within a couple hours of sunrise.  Otherwise, brisk
northwest winds will continue with VFR conditions for Hudson Valley
TAF locations and improving to MVFR at KPSF.

Outlook...
Saturday Night: Low Operational Impact. Breezy NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: Low Operational Impact. Slight Chance of RA...SN.
Monday: Moderate Operational Impact. Chance of SHRA...SHSN.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.


&&

.FIRE WEATHER...
A coastal storm will bring rain and snow to the region tonight
through early Saturday. High terrain areas will see a moderate
to heavy snow accumulation, which will add to the snowpack
already in place. This will help limit fire weather concerns for
the time being across the region. Gusty northwest winds of
25-35 MPH are forecast tonight and Saturday.

&&

.HYDROLOGY...
No hydrologic issues are anticipated for the next week.

After rain and snow today into Saturday morning, high pressure
is expected to bring mainly dry conditions for the upcoming
week. Forecast Precipitation for the next week after Saturday is
less than a tenth of an inch. Minor rises are forecast from
today`s rain and snow. Diurnal snow melt will lead to minor
changes in river stages during the upcoming week.

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...Winter Weather Advisory until noon EDT Saturday for CTZ001.
NY...Winter Weather Advisory until noon EDT Saturday for NYZ039>041-
     043-048>050-052-053-061-083-084.
     Winter Storm Warning until noon EDT Saturday for NYZ032-033-
     038-042-047-051-054-058-063-082.
MA...Winter Weather Advisory until noon EDT Saturday for MAZ025.
     Winter Storm Warning until noon EDT Saturday for MAZ001.
VT...Winter Storm Warning until noon EDT Saturday for VTZ013-014.

&&

$$
SYNOPSIS...SND
NEAR TERM...SND
SHORT TERM...SND
LONG TERM...Speciale
AVIATION...BGM
FIRE WEATHER...SND
HYDROLOGY...SND

NWS ALY Office Area Forecast Discussion