FXUS61 KALY 161817
AREA FORECAST DISCUSSION
National Weather Service Albany NY
117 PM EST Sun Dec 16 2018
A complex storm system near the Mid Atlantic Region
approaches this afternoon will continue to bring a wintry mixture
of precipitation to eastern New York and western New England. The
storm system will move northeast toward Cape Cod tonight that
will transition all the mixed precipitation to snow. Then a strong
cold front will move through on Monday with isolated to scattered
snow showers and possibly a few snow squalls to be followed by
blustery conditions into Tuesday.
.NEAR TERM /THROUGH TONIGHT/...
Winter Weather Advisory been canceled across eastern Ulster,
Dutchess, and southern Litchfield Counties.
Winter Weather Advisory continues for the eastern Catskills,
Schoharie Valley, Mohawk Valley, Greater Capital Region,
northern and central Taconics, and the northern Litchfield
Hills until 4 am.
Winter Weather Advisory continues for southern VT, northern
Saratoga, southern Washington, and southeast Warren Counties
As of 115 PM EST...Wintry mix of sleet, light freezing rain,
snow and some rain continues north and west the mid Hudson
River Valley and NW CT with mainly plain rain in the mid Hudson
River Valley and most of Litchfield County CT. Numerous sleet
reports have come in late this morning into this afternoon, and
a bright band of mixed pcpn continues to lift north of the
Capital Region. Believe the dynamical cooling will allow the
precipitation to moderate to heavy snow briefly over the
northern reaches of the Capital Region, Saratoga Region toward
KGFL this hour. Many of these locations saw little pcpn this
morning due to down sloping off the southern Greens/Berkshires.
We are maintaining the advisories in all other locations, and we
should continue to see a transition to snow by the late pm into
the early evening, as the storm continues to organize and move
northeast of the Delmarva Region. We may have to increase the
snow totals some across portions of the region, as we started an
upward trend of 2-4" over the eastern Catskills, southern
Greens, and northern Taconics with this update. We could see
1-2" or 1-3" in the valley areas too. Again, we will further
address with the next update.
A wintry mix of precip continues to gradually
progress northward across the forecast area with several reports
of mainly sleet or rain/sleet mix. An observer in Kingston
reported almost a tenth of an inch of sleet earlier this
There is downsloping evident in the valleys with mainly
easterly winds so it may some extra time for the column to
saturate in these areas. The 12Z Albany upper air sounding
showed substantial mid- level dry air between 2-12 KFt. That
being said, no major changes were made to the forecast as we
still expect a wintry mix to continue for much of the day with
temperatures hovering within a couple degrees of freezing.
Tonight, coastal low deepens just outside of the benchmark as
this system approaches eastern Cape Cod. Deformation zone moves
across the region through the evening hours as thermal column
cools further for wintry mixture becoming more snow. This is
where the potential for some accumulating snow occurs with the
higher terrain the better potential with orographic lifting.
.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
Monday-Monday night...A strong northern stream short-wave
trough accompanied by impressive height falls approaches and
follows in the heels of the southern stream complex low pressure
system. Some scattered rain/snow showers are possible with the
short-wave trough and associated cold front. The better chance
for a few snow squalls will be northwest of the Capital Region
where steeper lapse rates, colder temps, and moisture profiles
line up which is also support by the experiential snow squall
parameter. The greatest threat would be in the afternoon. Highs
get into the upper 30s to lower 40s in the Hudson River Valley
and NW CT. Temps will be in the upper 20s to mid 30s in most
other locations. The winds will increase from the west to
northwest at 10-20 mph late in the day with gusts 30-40 mph.
Snow amounts will vary from a coating to an inch in the heavier
snow showers/squalls, mainly across the higher terrain.
A brief lake connection occurs Monday night in the strong cold
advection as the flow veers to the northwest which would impact
portions of the western Mohawk Valley, eastern Catskills and
Schoharie Valley. Some upslope snow showers are possible for
the north-central Taconics and southern Greens too as the Froude
values are less than 0.5 . Snow amounts could range from a half
an inch to a few inches. Blustery and cold conditions as
forecast mixing layer heights and momentum transfer suggest we
tap into the high 20 to high 30 kts of winds. Wind chills in
the 10 below to teens across the region with actual air temps in
the teens and lower 20s with a few single numbers of the
.LONG TERM /TUESDAY THROUGH SATURDAY/...
Sharp upper level shortwave trough will be departing off New England
on Tuesday, with surface high pressure building into the region from
the Great Lakes and Midwest. Enough of a pressure gradient will be
in place to continue to allow for breezy conditions on Tuesday
morning, although winds should be diminishing by afternoon and
evening as the high pressure approaches from the west.
Aside from some patchy morning clouds, skies will be clearing out on
Tuesday and any lingering upslope snow showers should be over,
allowing for dry conditions through the day. With continued chilly
temps aloft in place, temps will range from the upper teens over the
Adirondacks to the low 30s over the mid-Hudson Valley.
Surface high pressure will be passing over the area for Tuesday
night, which will allow for good radiational cooling, thanks to
clear skies and light winds. Lows will be in the teens, with some
single digits over the Adirondacks.
High pressure will continue to allow for dry weather on Wednesday
into Wednesday night with a partly to mostly clear sky. Although
temps will be a little milder than Tuesday, they still will be below
normal, with highs in the 30s and lows in the 20s.
The next storm system will be arriving for late in the week as a
digging trough over the Mississippi Valley closes off over the Deep
South and allows surface low pressure to track northward across the
Appalachians. Although most of Thursday should be dry with
increasing clouds, precip will be arriving for Thursday evening
through Thursday night and continuing into the day on Friday. Strong
warm advection will allow for steady precip, and with a strong
southerly flow in place, plenty of moisture will arrive out of the
Gulf of Mexico and western Atlantic. Along with the plenty of
moisture will be much warmer temps, both at the surface and aloft,
with temps in a warm nose exceeding +5 C. Although a few sheltered
spots may briefly begin as some freezing rain across the
Adirondacks, most of the region will only be seeing rainfall. Any
ice will be limited and fairly isolated in coverage. Temps will
start out in the 30s for Thursday into Thursday evening and will be
rising on Thursday night, with highs reaching into the 40s for most
spots on Friday. In addition, the strong E-SE winds within the low-
level jet may allow for some strong wind gusts across the typical
channeled flow areas within the Taconics, southern Greens and
Berkshires on Thursday night into early Friday.
The steadiest rainfall will be tapering off by late Friday, although
some showers will continue for Friday night into Saturday, as low
pressure tracks across the eastern Great Lakes. Eventually, the
storm's cold front will pass through the region, allowing for some
colder air aloft to move into the region, as the upper level low
tracks across the eastern Great Lakes and into Ontario and Quebec
and our region is dominated by moist cyclonic flow. Some western and
high terrain areas may see rain showers change over to snow showers
before ending late on Saturday, although most valley areas will only
see rain showers. Temps on Saturday with range from the mid 30s over
the high terrain to the mid 40s in valley areas.
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Light to moderate intensity, mixed wintry precipitation has
enveloped most of the region. This has resulted in MVFR to IFR
flying conditions based on VISBYs and lowering CIGS. Expect these
types of conditions throughout the remainder of the day with a mix
of rain, freezing rain and sleet before transitioning over to a snow-
sleet mix this evening into the overnight period. Precipitation
should end as all snow showers late tonight from west to east as
the storm systems starts to move away from the area.
Tomorrow, additional snow showers will be possible as an arctic
front passes through the region.
North to northwest winds will be around 5 to 10 kts through the TAF
Monday Night: Low Operational Impact. Breezy Slight Chance of SHSN.
Tuesday: Low Operational Impact. Breezy NO SIG WX.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Low Operational Impact. Slight Chance of RA.
Thursday Night: High Operational Impact. Likely RA.
Friday: High Operational Impact. Likely RA.
No major hydro problems are expected into the mid week.
Dry weather is expected into early this morning before some
light mixed pcpn moves into the southern extreme of the Hydro
Service Area by mid-morning. The mixed pcpn will expand across
the region before transitioning back to snow tonight with light
accumulations of ice and snow expected. Total QPF for this
event will range from a tenth of an inch of less over the
northern portion of the HSA with a half to three quarters of an
inch over the Mid Hudson Valley, southeast Catskills and
Litchfield Hills. Some localized one inch amounts are possible
in the Housatonic Basin. Some within bank rises are possible on
the main stem rivers due to some rain, mixed pcpn and snow melt,
but flooding is not expected at this time (caution stage for
Poughkeepsie due to the east/southeast flow and the tidal impact
and for Stevenson Dam which is regulated).
A strong cold front moves through on Monday with much colder
air moving into the region for Tuesday, as flows will continue
to lower during the early to middle portion of next week with
some ice formation and build up possible on the waterways.
The next chance for a widespread precipitation event arrives
toward the end of this 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.
CT...Winter Weather Advisory until 4 AM EST Monday for CTZ001.
NY...Winter Weather Advisory until 4 AM EST Monday for NYZ038>040-
Winter Weather Advisory until midnight EST tonight for NYZ041-
MA...Winter Weather Advisory until 4 AM EST Monday for MAZ001-025.
VT...Winter Weather Advisory until midnight EST tonight for
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