Area Forecast Discussion Issued by NWS Albany, NY
000
FXUS61 KALY 191045
AFDALY
AREA FORECAST DISCUSSION
National Weather Service Albany NY
645 AM EDT Tue Mar 19 2024
.SYNOPSIS...
Cool and brisk conditions will continue today, with lake effect
snow showers in favored areas again. It will become cold and
windy Wednesday afternoon into Thursday, as a strong cold front
moves across the region bringing additional accumulating snow
mainly to higher terrain areas north and west of the Capital
Region.
&&
.NEAR TERM /THROUGH TONIGHT/...
.UPDATE...Main change with this update was to increase PoPs to
mention scattered snow showers moving across northern/eastern
parts of the Capital District early this morning based on
current radar imagery. Also increased wind gusts this morning
based on current obs. Otherwise no significant changes.
.PREV DISCUSSION[0359]...Upslope snow showers oriented N-S
along and just west of the spine of the southern Greens,
Taconics, and Berkshires as the flow remains slightly blocked
(Froude # < 1.0). The upslope snow east of the Hudson Valley
should dissipate quickly after sunrise as the flow becomes
unblocked (Froude # > 2.0). Also a broader area of upslope and
lake effect snow showers should diminish early this morning
across the W. Adirondacks and Mohawk Valley, as a small area of
low level ridging develops. Otherwise, mainly dry conditions in
place early this morning with just isolated to scattered light
snow showers or flurries in the W-NW flow regime.
Later this morning into the afternoon, some lake effect snow
bands are expected to develop over the W. Adirondacks again as
the flow backs to a more westerly trajectory ahead of the next
disturbance approaching from the Great Lakes. The lake effect
should be relatively weak within the low level ridging though.
So any additional accumulations will be minor (Trace-1").
Outside of the lake effect it will be dry. Winds will remain
breezy, shifting to a more westerly direction by this afternoon.
Peak gusts will be around 20-30 mph. Highs look to be slightly
below normal with upper 20s/lower 30s in the mountains and
40-45F in the valleys.
Snow showers will increase in coverage this evening mainly for
areas north/west of the Capital District as forcing increases
with the short wave approaching. Scattered to numerous snow
showers will then spread eastward across most of the the higher
terrain areas through the rest of the night as the disturbance
moves through. Westerly downslope flow will reduce snow showers
in the Hudson Valley. Mainly light accumulations of 1-3" are
expected in parts of the W. Adirondacks and S. Greens with
Trace-1" elsewhere. Snow-liquid ratios are still expected to be
above climo, around 13:1 to 16:1 so snow showers should be of
dry consistency. Lows should be mainly in the 20s to lower 30s.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
Snow showers should be ongoing across higher terrain areas
north of Albany Wed into morning before decreasing in coverage
by late morning. However, a potent upper level short wave and
associated surface cold front approaching from the Great Lakes
are expected to move across the region Wed afternoon and
evening. With fairly strong forcing expected, will continue to
mention likely PoPs west of the Hudson Valley and high chance
east. Precip type should be mainly snow above 1500 ft, rain/snow
mix 500-100 ft, and mainly rain with some graupel due to steep
low level lapse rates. It will become windy with gusts of 30-45
mph possible by late Wed as mixing heights increase to ~650-600
mb. Highs should reach the well into the 40s across lower
elevations with 30s in the mountains prior to the cold front
passage Wed afternoon. Main complicating factor with regards to
snowfall will be low confidence in the ability to accumulate
during daylight hours with late March sun angle and marginal
temperatures.
Temperatures aloft will become quite cold Wed night, with 850
mb temperatures anomalies of -1 to -2 STDEV developing and 500
mb height anomalies of -1 to -3 STDEV. This colder air along
with strengthening W-NW flow will result in reinvigorating lake
effect and upslope snow showers. Additional light to moderate
accumulations may occur in the W. Adirondacks and S. Greens. A
Winter Weather Advisory may eventually be needed for these areas
if confidence increases. It will continue to be windy as the
pressure gradient strengthens through the night. Max wind gusts
of 30-45 mph look to be common. Temperatures will steadily fall
in the cold advection regime, with lows ranging from the mid 10s
in the Adirondacks to upper 20s in the mid Hudson Valley by
late Wed night.
The main core of the upper level trough will shift east into
northern New England Thu morning, so snow showers should
diminish. It will be dry, cold and brisk on Thu, with highs
around 10 degrees below normal. This will be the first day of
significantly below normal temperatures the entire month of
March. Highs only expected to be in the lower/mid 30s for most
valley areas and 20s in the higher terrain. NW winds will
continue to be quite gusty, with 30-45 mph gusts through the
day.
Thu night will start out breezy, with wind speeds gradually
decreasing through the night as high pressure builds east across
NY state. It will remain dry and cold, with lows expected to
range from the single digits in the W. Adirondacks to around 20F
in the mid Hudson Valley.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
The long term period opens with brief shortwave upper ridging
overhead, with cold high pressure centered to the north and
northwesterly flow through much of the column allowing for
continued below normal temperatures. Highs Friday afternoon look
to only reach the mid 20s to low 30s in high terrain and mid
30s to mid 40s at lower elevations beneath increasingly cloudy
skies thanks to the cold advective pattern.
The forecast rapidly becomes a low confidence affair for Friday
night and beyond. Numerical guidance remains in good agreement
about the large-scale features which will determine the weather
through the weekend, however there remains much disagreement in
the details of how the flow evolves over the Northeast. An upper
trough, reinforced by a relatively vigorous northern stream
shortwave, will dig southeastward across the Great Lakes and
Northeast Friday night through Sunday, while at the same time, a
former cutoff upper low over the Southwest weakens into an open
southern stream wave sliding toward the Southeast coast. This
southern disturbance looks to support the development of a
moisture-rich coastal low while its northern counterpart
supports a incipient frontal system over the Great Lakes and
Ohio Valley. With these ingredients in place, the primary
forecast question remains the degree to which these features
phase in a way that transports subtropical moisture northward
into the Northeast, which would result in more significant
impacts for the local area. The GFS remains the outlier among
numerical guidance suggesting significant phasing and robust
northward transport of moisture, while other global
deterministic guidance maintains a lesser degree of phasing and
limiting the northward extent of moisture transport. Ensemble
guidance lends further support to the tendency for more robust
phasing to result in the potential for heavier precipitation
across the region.
At this lead time, there will likely be precipitation spreading
across the region from west to east Friday night into Saturday,
with the cool antecedent airmass and cold overnight
temperatures in the upper 10s to low 30s supporting
precipitation initially falling as snow. The amount of liquid
equivalent precipitation will go a long way toward determining
the impact of this system, with plowable snowfall possible,
particularly across the southern Adirondacks and southern
Greens. Precipitation lingering into Saturday will transition to
rain at lower elevations as temperatures warm to afternoon
highs in the upper 30s to upper 40s, with low to mid 30s in
higher terrain.
Precipitation looks to end late Saturday as the upper trough
exits to the east, bringing a return to dry but cool weather
across the region. Temperatures dip to lows in the 10s to mid
20s Saturday and Sunday nights, recovering to only the mid 20s
to low 30s in high terrain and mid 30s to low 40s at lower
elevations on Sunday. Temperatures may rebound toward seasonal
norms for the beginning of next week.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Through 12Z Wednesday...VFR conditions largely expected to
prevail at all terminals through the TAF period, however snow
showers may briefly reduce vsbys this morning and late in the
period.
Isolated snow bands continue to reach across portions of the
region, with recent observations at ALB/PSF of light snow and
IFR/MVFR vsbys. Showers are continuing to dissipate this
morning, and have not mentioned showers beyond 12Z Tue, however
amendments will be issued if any coherent bands approach either
terminal. Otherwise, sct-bkn fair wx cu/strato-cu at 3-6 kft
will persist across the region, with coverage trending upward
after 18Z Tue as the next clipper system approaches from the
west. Another round of snow showers may reach northern
terminals, namely ALB/GFL/PSF, after 00- 06Z Wed.
West winds of 10-15 kt gusting 15-25 kt, with the strongest
gusts expected at ALB/PSF, will continue at all terminals
through this afternoon. Speeds diminish to 10 kt or less after
21Z Tue-00Z Wed, turning initially out of the southwest trending
toward southerly flow late in the period, after 03-06Z Wed.
Outlook...
Wednesday Night: Moderate Operational Impact. Windy. Chance of SHSN.
Thursday: Moderate Operational Impact. Windy. NO SIG WX.
Thursday Night: Low Operational Impact. Breezy. NO SIG WX.
Friday: No Operational Impact. NO SIG WX.
Friday Night: High Operational Impact. Likely SN.
Saturday: High Operational Impact. Likely RA...SN.
Saturday Night: Low Operational Impact. Slight Chance of RA...SN.
Sunday: Low Operational Impact. Breezy. NO SIG WX.
&&
.FIRE WEATHER...
Relative humidity expected to drop to minimum values around 35 to
40 percent this afternoon with wind gusts of 20 to 30 mph across
portions of the Hudson Valley and northwestern Connecticut. Most
areas are expected to see some light precipitation on Wednesday,
but Thursday afternoon may also feature low RH values and
breezy/gusty conditions in the afternoon, but also colder
temperatures.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...JPV
NEAR TERM...JPV
SHORT TERM...JPV
LONG TERM...Picard
AVIATION...Picard
FIRE WEATHER...JPV