Area Forecast Discussion
Issued by NWS Albany, NY

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319
FXUS61 KALY 170912
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
412 AM EST Tue Jan 17 2017

.SYNOPSIS...
A storm system moving towards the region from the Great
Lakes will bring a wintry mix today into tonight, with the largest
impact across the higher elevations.  As the storm moves away from
the area, there may be a few lingering rain or snow showers on
Wednesday, especially in the morning hours.  Behind this system,
above normal temperatures will be in place for the remainder of the
week, with mainly dry conditions.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
As of 412 AM EST...Low pressure is currently situated near
Chicago and will be moving across the southern Great Lakes today.
A warm front extending eastward out of this low pressure area will
be headed northeastward towards upstate New York and western New
England. Mid and high level clouds have already been increasing
across the region, with the thickest clouds across southern parts
of the area. This cloud cover has already allowed for a large
difference in temperatures across the region, as the thinner
clouds further north have allowed temps to fall into the teens to
lower 20s, while far southern parts of the area remain in the
lower to middle 30s.

As seen in the 00Z KALY sounding, plenty of dry air is in place at
the lowest levels of the atmosphere. Although regional mosaic
radar shows some returns for western/central NY, the dry air is
preventing this from reaching the surface, and the nearest sfc obs
showing precip are way back in the Buffalo area, as well as
northeastern Ohio, and southern Ontario.

With a S-SE flow in place at low to mid levels, warm air
advection/isentropic lift will be ongoing this morning.
Eventually, once the column saturates, some spotty light
precipitation will spread across the region from southwest to
northeast. Based off the latest 3km HRRR and 00Z NCAR WRF
ensemble, this looks to occur by the mid to late morning hours.
P-type will be variable across the region and will likely vary due
to the exact boundary layer temps, elevation, and precip
intensity. Overall, it looks like some very light snow or rain
will move across the region this morning. In a few spots, this
could occur as freezing rain if sfc temps remain at or below
freezing. This precip looks very light and fairly spotty, with any
accumulation for this morning very light (if any at all).

Precipitation will become steadier and more widespread during the afternoon
hours, and most of the area will be seeing some type of
precipitation by the mid afternoon or so. P-type will continue to
be variable, although areas north of the Mohawk Valley and
Interstate 90 will have the better chance of seeing snow or sleet,
with rain or rain mixed with sleet further south (perhaps
freezing rain in higher elevations areas that are still below
freezing).

Temps look to warm up into the 30s today, although will likely
rise or fall at times depending on precip intensity. Best chance
of staying closer to freezing will be across higher elevations and
northern/northeastern parts of the region.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
Low pressure will continue to lift towards western New York this
evening. At the same time, another area of low pressure be forming
along the storm`s triple point over New Jersey and will be
strengthening as it heads east to northeast along the eastern
seaboard.

Precipitation will continue for this evening into tonight. The
combination of a light northerly flow and some cooling aloft
thanks to the approaching upper level trough will continue to
allow for plenty of snow and sleet across northern areas
overnight. Further south (basically I-90 on southward), valley
areas will see a mix of rain and sleet, with freezing rain across
the higher elevations. Some snow may even occasionally mix in at
times for the Capital Region into the Berkshires depending on
precip intensity, but primarily looks like messy mix of
rain/sleet. Best chance for seeing snowfall will be across
Southern Vermont and far northern Berkshires, where the cold air
looks to be the deepest.

Steady precip will be tapering off towards daybreak Wednesday. By
this time, several inches of snowfall looks to occur across
northern areas (Adirondacks, Southern Greens), with perhaps as
much as 6 inches across southern VT. Elsewhere, a light coating of
snow/sleet and ice looks to occur, although high terrain areas
(such as the Helderbergs, Taconics, Berkshires, Litchfield Hills)
may see up to a quarter of an inch of ice. There will likely be
large differences in snow/ice accumulation over short distances
due to elevation and precip coverage.  Overnight temps look to
remain fairly steady in the lower to middle 30s across the area.

Although the storm`s occluded front will pass early in the day, with
the upper trough moving across the area, cyclonic flow will allow
for some lingering rain or snow showers into the day Wednesday.
Best chance of seeing snow will be across the higher elevations.
Outside of this precip, still could be some pockets of drizzle at
times. Any additional snow accumulation on Wednesday looks
minimal. Temps will mainly be in the 30s, with temps rising above
freezing over the majority of the region.

With the shortwave moving away, precip should be ending for most
locations on Wednesday night, but it will continue to remain
fairly cloudy. Overnight temps will only fall a few degrees, with
lows in the upper 20s to mid 30s. However, with temps falling
below freezing, any wet surfaces may freeze over, so some black
ice will be possible for any untreated surfaces.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
As mentioned in the previous AFD, complex pattern remains in place
per the 00Z global model consensus.  The idea favors an increasing
ridge over the eastern CONUS with trough over the center of the
nation.  Eventually, this aforementioned trough amplifies enough
with a strengthening storm that may impact our region toward the end
of the long term forecast period.

We begin this long term with the approach and passage of a weakening
frontal boundary.  Now, each model differs with timing and placement
of this front but they all agree moisture profiles will be lacking.
So we will leave in a slight chance PoPs for the northern half of
the CWA.  Otherwise mainly dry with mainly 30s and lower half of the
40s for valley locations.

Friday and into the weekend, seems the ridge may evolve and hold off
the approach of the upper low currently situated over the four-
corners region. The ECMWF has come more in line with the global
model consensus with a weakening trend of the approach of this wave
as ridge builds.  So slight chance mainly southern areas Friday into
Friday evening.

Then the ridge becomes increasingly dominant heading into the
weekend as thermal column moderates further with above 0C H850
temperatures.  While there could be lots of clouds around, breaks of
sunshine should allow for highs well into the 30s and low-mid 40s
with lows generally between 25-35F.

Potent wave and strong Pacific jet comes ashore and develops a
deepening trough and surface cyclone over the center of the nation
later Sunday.  This storm is progged by both the ECMWF/GFS/GGEM to
tap into deep moisture from both the Gulf of Mexico and Atlantic
heading into Monday as this storm lifts ENE.  As this system becomes
negatively tilted, that moisture will assist with a prolonged mainly
rain event for next Monday per latest thermal profiles.

Temperatures through the period should average above normal with
below normal precipitation until Monday.

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
VFR conditions will likely continue the remainder of the nighttime
period then begin to deteriorate from south to north during the
morning daylight hours.  Precipitation start time appears to occur
late this morning for KPOU then spread toward KALB-KPSF by Noon then
onto KGFL by early-mid afternoon hours.  Precipitation types will vary
as wet bulb process will likely start as a wintry mix at all TAF
locations.  Warmer air should allow for mainly rain at KPOU with
northern locations likely sticking with a mix for the balance of the
afternoon hours.  This is when the high potential for IFR conditions
will occur.

As sun sets, those wintry conditions are expected to linger north of
KPOU with perhaps KALB warming just enough to reduce FZRA potential
with periods of rain and sleet.

Wind will be light and variable overnight with a trend toward the
northeast during the daylight hours at speeds less than 10kts.

Outlook...

Wednesday Night: Low Operational Impact. Slight Chance of SHRA...SHSN.
Thursday: Low Operational Impact. Slight Chance of SHRA...SHSN.
Thursday Night: No Operational Impact. NO SIG WX.
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: No Operational Impact. NO SIG WX.

&&

.HYDROLOGY...
A storm system will bring a wintry mix to the region today into
tomorrow. Total liquid equivalent amounts will be one half inch
to one inch. Although some of this precipitation will be frozen,
some minor rises on rivers and streams can be expected, especially
from the Mohawk River on southward. However, no flooding is
expected.

Behind this storm system, temperatures will average above normal
for the remainder of the week. Some snow melt over the Adirondacks
and southern Vermont may contribute to some additional runoff,
but any rises on rivers and streams will only be very minor and
overnight lows should fall below freezing most of the time.
Little, if any, precipitation is expected for Thursday into 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...Winter Weather Advisory from 10 AM this morning to 7 AM EST
     Wednesday for CTZ001-013.
NY...Freezing Rain Advisory from 7 AM this morning to 7 AM EST
     Wednesday for NYZ038-040-047>054-058>061-063>066.
     Winter Weather Advisory from 10 AM this morning to 7 AM EST
     Wednesday for NYZ032-033-039-041>043-082>084.
MA...Winter Weather Advisory from 10 AM this morning to 7 AM EST
     Wednesday for MAZ001-025.
VT...Winter Weather Advisory from 10 AM this morning to 7 AM EST
     Wednesday for VTZ013>015.

&&

$$
SYNOPSIS...Frugis
NEAR TERM...Frugis
SHORT TERM...Frugis
LONG TERM...BGM/IAA/NAS
AVIATION...BGM
HYDROLOGY...Frugis



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