National Weather Service Text Product Display

Area Forecast Discussion
Issued by NWS Albany, NY
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FXUS61 KALY 010525
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
1225 AM EST Wed Feb 1 2017

.SYNOPSIS...
A fast moving low pressure system will bring a widespread light
snowfall to the region into this morning. The snowfall will
taper off to scattered snow showers and flurries this afternoon
except across the western Adirondacks and the southern Green
Mountains where light snow will continue. Brisk and cold
conditions will persist Wednesday night into Friday with
intermittent lake effect snowfall for the southern Adirondacks
and western Mohawk Valley.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
As of 1225 AM EST...Winter Winter Advisory continues until
midnight tonight for the western Adirondacks of northern
Herkimer and Hamilton Counties.

Minor changes were made to the forecast grids with this update.
Mainly freshened up the hourly temps and pops to reflect recent
obs and trends. Please see our latest Public Information
Statement with snow amounts from the light snowfall event.

Another disturbance in the channeled vorticity associated with
mid and upper level trough move across the region overnight into
early this morning. Strong differential vorticity advection
with the secondary sfc trough/clipper will cause the snowfall to
increase again especially from the northern Catskills...Capital
Region...northern Berkshires northward. Total snowfall amounts
across the region will range from 1 to 3 inches. Our forecast
favors the NAM12/GFS20 which both show the synoptic lift
increasing along the western spine of the Adirondacks and the
southern Greens. We were not as confident for advisory level
snowfall for the southern Greens with the collab with the
neighboring offices /BGM and BUF/ we posted the advisory for the
western Adirondacks where our confidence was greatest.

Lows tonight will range from the mid and upper teens across the
mountains to 20-25F in the valley areas.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
Tomorrow...The secondary trough/clipper low moves east of the
region with the light snow tapering to scattered snow showers
and flurries, except in the favored westerly upslope regions of
the southern Greens and Adirondacks. The H500 flow becomes
flatter and more zonal in the wake of the disturbance. An
additional 1 to 3 inches of snowfall is possible in the advisory
area with totals approaching 3 to 5 inches. Scattered snow
showers and persist north of the mid-Hudson Valley and NW CT.
Any accumulations will be light as the boundary layer warms
some, Highs will be in the mid and upper 30s in the valley
locations...and a few 40F readings are possible in the mid-
Hudson Valley. Expect mid 20s to lower 30s across the mountains.
We will continue to monitor if an advisory is needed for the
southern Greens but for now we have 2 to 4 inches total with a
few higher amounts of around 5" over the higher peaks.

Wed night...We kept the advisory running until midnight for the
westerly upslope snowfall. It appears a transition to pure lake
effect snowfall will occur in the wake of a cold frontal
passage during the nighttime period. It was unclear on the set-
up of a Lake Ontario band so we did not issue a watch, but will
mention lake effect snowfall in the HWO. Temps will be falling
into the -12C to -15C range north and west of the Capital Region
by daybreak with the best chance of snow showers north and west
of the Capital Region. Total snowfall amounts in the advisory
area will range from 3 to 6 inches. Lows will be in the mid
teens to mid 20s across the forecast area.

Thursday into Friday...The cold front moves across the entire
forecast area early in the morning. Another quick shot of
upslope and lake effect snow showers initiates in the wake of
the front. The initial lake effect band may be south the Mohawk
Valley into the northern Catskills....but then the flow will
likely back from the west/northwest to the west THU-THU night.
Transitory lake effect snow bands impacting the western Mohawk
Valley into the western Adirondacks are possible with multiple
disturbances in the flow. We tried to trend northward with a
better defined single band THU night into FRI...but it is still
a bit unclear on the timing...and downstream extension. We will
continue to mention in the HWO, and in time we will be able to
refine the appropriate winter headline if necessary. For now,
have light snow accums of a few inches Thu night into FRI for
totals of 2 to 4 inches or so near Old Forge and the northern
Herkimer/northwest Hamilton corridor.

Brisk and cold conditions will ensue THU and continue into Fri.
Temps will be near normal to slightly below normal with highs in
the teens to lower 20s over the southern Adirondacks...and
southern Greens with mid 20s to lower 30s from the Mohawk Valley
south and east...and single digits to teens THU night with wind
chills near zero to below zero. Highs on FRI will be in the
teens and 20s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Broad upper level trough over the northeastern U.S. will finally
shift east as the pattern transitions to a more zonal flow and weak
ridging by Saturday afternoon. A weak trough and southern stream
impulse passes through the region Sunday but the zonal flow is
maintained through the end of the extended period.

At the surface, westerly flow and lake effect snows will be
persistent across the Adirondacks through the first half of the
weekend. Lake effect snows should gradually break apart as a large
surface ridge builds over the region Saturday evening/overnight.
However, the next low pressure system passes by to our north (with
the southern stream energy passes by to our south) on Sunday,
allowing for a slight chance of snow showers area-wide. Ridging
builds back into the southeast CONUS Sunday night into Monday before
another quick-hitting low pressure system clips us on Tuesday. All
in all, it doesn`t look like any major winter storms are on the
horizon during the extended period, just nuisance clippers and
chances for snow showers at times.

Temperatures will moderate through the extended period from
seasonably cool (in the low 20s to low 30s) to above average by mid-
week. In fact, we may see some 50 degree high temperatures by
Wednesday. Overnight lows will also moderate with readings starting
in the single digits to upper teens over the weekend then warming
into the upper teens to upper 20s next week.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Light snow across most of the area this evening but is beginning
to trend down in intensity/coverage, especially at POU/GFL.
This trend should continue through the remainder of the
evening and first part of the overnight. Snow may re-enhance
after 06z as upper level energy lifts back through the area.
Most sites should still see IFR through most of the night, but
POU/GFL may see some improvement back to at least MVFR.

Tomorrow morning, snowfall will be ending as some scattered
snow showers/flurries and all sites will go MVFR eventually VFR.
MVFR conditions may hang on the longest at PSF. Clouds will
begin breaking up during the afternoon as drier air works into
the area. Winds will become west and increase to 10-15 kts with
some higher gusts, especially at ALB and PSF.

Outlook...

Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Low Operational Impact. Breezy Slight Chance of SHSN.
Thursday Night: Low Operational Impact. Slight Chance of SHSN.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SN.

&&

.HYDROLOGY...
Little change in river levels or flow is expected into the
weekend.

A gradual cooling trend with seasonable temperatures is forecast
from the mid week into the weekend. Precipitation will be in
the form of snow. River ice will form and thicken this week due
to cold temperatures especially across the northern basins in
the Hydro Service Area.

Lake Effect snow will persist across the western Adirondacks
and the western Mohawk Valley. Accumulating snowfall is possible
from tonight until the end of the 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...None.
NY...Winter Weather Advisory until midnight EST tonight for NYZ032-
     033.
MA...None.
VT...None.

&&

$$
SYNOPSIS...Wasula
NEAR TERM...JPV/JVM/Wasula
SHORT TERM...Wasula
LONG TERM...JVM
AVIATION...Frugis/JVM
HYDROLOGY...JPV/Wasula
National Weather Service Regional Headquarters
