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fxus61 kaly 260242 
afdaly

Area forecast discussion
National Weather Service Albany New York
1042 PM EDT Sat Mar 25 2017

Synopsis...
high pressure will briefly build in tonight as the cold
front settles well south of the region. However, the front will
slowly lift back north tomorrow with light wintry mixed
precipitation returning to the region. The best chance of light ice
accumulations through Sunday night will be north and west of the
capital region. A wave of low pressure and its warm front will
bring periods of rain to eastern New York and western New England
Monday into Monday night.

&&

Near term /until 6 am Sunday morning/...
as of 1042 PM EDT...00z alb sounding shows significant dry
layer above 850 mb. However, moisture trapped beneath a strong
inversion keeping plenty of low clouds in place. Skies have
cleared north and east of Albany, but it will be a slow clearing
trend overnight. Updated sky grids to account for the slower
erosion of lower clouds. Will continue to mention dry conditions
through 6 am Sunday. Dry layer is impressive and model trends
continue to show precip-free conditions through tonight.

Latest GOES water vapor imagery shows an area of drying quickly
pushing southward from northern New York. A frontal boundary
will settle well south of the region tonight. However, a mid-
level front (around 850 mb) will be located right on the
southwest periphery of the forecast area. Temperatures should
cool off quite a bit with low level clouds gradually dissipating
overnight. Temperatures are expected to drop into the upper
teens and 20s north of the greater capital district and into the
upper 20s/lower 30s south.

Towards dawn, the surface frontal boundary will begin to lift north
as a warm front. This will bring chances for freezing rain
shortly after daybreak to areas south and west of the greater
capital district.

&&

Short term /6 am Sunday morning through Tuesday night/...
Winter Weather Advisory issued for the eastern Catskills,
helderbergs, and western and central Mohawk Valley from 6 am to
1 PM EDT...

Winter Weather Advisory issued for the eastern and southern
Adirondacks of northern Fulton, northern Warren, and Hamilton
counties from 2 PM Sunday to 9 am EDT Monday...

Winter Weather Advisory issued for southern Vermont from 6 PM
Sunday to 9 am EDT Monday...

A challenging and complex forecast continues for the second half
of the weekend into Monday morning. A strong Canadian
anticyclone with anomalously cold air for late March moves
southeast across southern Quebec to near eastern Maine, and New
Brunswick during the day. A old cold front tries to lift
northward from the mid-Atlantic region, but plenty of shallow
cold air is dammed into place across the region. Weak isentropic
lift with an impulse rotating around the low and mid level ridge
may kick off some light sleet and freezing rain south and west
of the capital region shortly after sunrise. We felt confident
to place high chc and likely pops in for a short time frame in
the late morning and collaborated with weather forecast office bgm for a Winter
Weather Advisory. The main threat should be freezing rain, but
there is a chance of sleet. The model soundings do show quite a
bit of dry air in place before the clouds rethicken and lower
further north and east. Any ice accretions look light on
untreated surfaces west of the capital region. There is a chance
of freezing rain from the capital region south and east during
the late morning into the early afternoon based on the critical
partial thicknesses and the BUFKIT model soundings from the
NAM/GFS. The question will be how quick the sfc temps warm
despite low level east to northeast winds due to the sfc high
downstream. We favored a blend of the GFS/NAM thermal profiles.
It should be stressed that if the mixed pcpn threat increases,
then the advisories may need to be expanded.

The southern Adirondacks are tricky tomorrow as temps may
struggle to get above freezing. It is possible a brief period of
freezing rain occurs in the early PM, and temps rise slightly
above freezing, then fall below prior to nightfall. With the
east northeast winds in the boundary layer shifting to east to
southeast, some upglide or upslope is possible for freezing rain
there. In collaboration with weather forecast office we started one in the afternoon
when our pops increased to likely values. It may take the
better part of the day before the pcpn reaches southern Vermont with
the warm advection well ahead of the warm front and the wave
approaching from the lower Great Lakes region. Again, special
weather statements may need to be used for light spotty -fzra
too. Highs will generally be in the lower to mid 30s over the
mountains, and mid 30s to lower 40s in the valleys. Any ice
should melt quickly due to warming temps above freezing and the
March sun angle.

Sunday night...some of the guidance continues to show the
potential for elevated locations like the southern
Adirondacks/southern greens and perhaps the Berkshires and
Litchfield Hills having some elevated freezing rain before
warmer air breaks through Monday morning. A brief lull in the
pcpn is possible between 00z-06z with the mid-level ridge axis
sliding downstream. However, low pressure will be churning
eastward from the eastern Great Lakes region, and the qg lift
will start to increase for periods of rain and freezing rain
especially along the eastern slopes of the Adirondacks, and
southern greens. The low-level ageostrophic winds from the
northeast to east in the boundary layer /925 hpa/ are hinting at
cold air being dammed into place early on again, especially for
the eastern Adirondacks, portions of the Lake George and
northern Saratoga region and southern VT, as well as the
northern Berkshires. Some freezing rain is possible again Sunday
night into Monday morning. Ice accretions may range from a few
hundredths to a quarter of an inch /though a lot could change
with these amounts depending on temperatures/.The advisories run
overnight for around a tenth of an inch of ice (maybe two
tenths in a few spots). Pops were increased to categorical with
the increasing isentropic lift and moisture advection into
Monday morning. Temps will be rising into the lower to upper 30s
across the region.

Monday-Monday night...all the mixed pcpn /freezing rain or
spotty sleet/ should transition to periods of plain rain. The
latest GFS/NAM/ECMWF/can ggem have a stripe of moderate rain
ahead of the sfc wave and warm/occluding front moving across the
region in the late morning and early afternoon. The cyclonic
vorticity advection with the upper level low will keep the rain
going into the early PM before diminishing to scattered showers
early at night. Temps rebound into the 40s across the region
with mid 40s to close to 50f in the valley areas, and lows will
be above normal in the mid 30s to around 40f.

Tue-Tue night...the latest ec and can ggem both build a weak
ridge in early Tuesday with a drier forecast, as a wave passes well to
our south. The GFS/NAM continue to have a short-wave pass just
to the south of the region with an inverted trough or weak wave
bringing some scattered showers or a period of rain back into
the region during the afternoon and evening. With all the
uncertainty we keep a chance of showers in the forecast with
temps actually getting into the upper 40s to mid 50s across the
region. Lows in the 30s with a few upper 20s over the southern
dacks. Some snow showers could produce few light accums over the
western dacks at night as cold advection kicks in the wake of
the disturbance.

&&

Long term /Wednesday through Saturday/...
the period starts out on Wednesday with an upper level low moving
eastward across southern Quebec and northern New England. Our region
will be under a neutral northwest flow aloft resulting in mainly dry
but breezy conditions. There might be a few rain/snow showers over
the higher terrain well north of Albany, which will be under a
slightly more cyclonic flow. Despite cold advection, the environment
should be well mixed, so Max temperatures will be close to normal.

Dry conditions will prevail Wednesday night, but it will still be
breezy as the upper low moves east of New England and into the
Canadian Maritimes. Thursday looks to be a pleasant early Spring day
across the area with high pressure building in with increasing
sunshine and lighter winds. Dry and seasonable conditions should
persist through Thursday night with high pressure in control.

Friday may end up being dry as well, with models trending slower
with a potential upper low approaching from the south-central U.S.
Large model spread for the Friday night to Saturday time frame, as
guidance having a difficult time resolving what will happen with
regards the the upper low. The GFS suppresses the system well to our
south, with a dry northern stream flow dominating. However, the
European model (ecmwf) continues to indicate the low opening into a progressive
trough and tracking across the region. For now will mention low
chance pops until models are able to better resolve the main
features.

&&

Aviation /03z Sunday through Thursday/...
varying conditions exist across the terminals early this
evening, as drying occurring from north to south. This has
resulted in a myriad of flying conditions, ranging from VFR at
kgfl/kalb, IFR at kpou and LIFR at kpsf. Initially the drying
is occurring above the inversion layer, so low clouds remain
trapped beneath the inversion. However, cigs have been rising
for the past few hour at kalb/kgfl, so this trend is expected to
occur at kpou then kpsf. Conditions should improve to VFR
generally by around 03z at kpou and 04z at kpsf.

VFR conditions will then persist at all terminals until late
morning or early Sunday afternoon, as light rain and/or some
frozen precip develops. Still much uncertainty exists with
regards to precip types initially, with sleet and/or freezing
rain possible, especially at kgfl/kpsf. All sites should change
to plain rain by mid afternoon Sunday.

Winds tonight will be northeast around 5 kt, becoming southeast
around 5-10 kt on Sunday.

Outlook...

Sunday night: high operational impact. Definite rain.
Monday: high operational impact. Definite rain.
Monday night: moderate operational impact. Chance of rain showers...ra.
Tuesday: moderate operational impact. Chance of rain.
Tuesday night: moderate operational impact. Chance of rain.
Wednesday: no operational impact. No sig weather.
Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.

&&

Fire weather...
the snow pack remains in place across much of eastern New York
and western New England. The weather pattern will remain
unsettled late this weekend into early next week with
occasional rain and wintry mixed precipitation. High pressure
will build in tonight, but the boundary and a wave of low
pressure brings additional rounds of precipitation tomorrow
into Monday.

&&

Hydrology...
an unsettled weather pattern will impact the Hydro service area
the next several days.

There is a potential for several rounds of precipitation into
early next week.

Tonight into Sunday, the front will slowly lift back northward
from PA and the mid Atlantic region bringing a mixture of mainly
sleet, freezing rain, and rain to the region. The front stalls
over central New York into eastern PA and Long Island for mix
precipitation to occur again Sunday night into early Monday
especially north and east of the capital region. A wave of low
pressure approaches from the eastern Great Lakes region with the
warm front moving through finally with periods of rainfall. The
rainfall looks the heaviest late Sunday night into Monday.

Temperatures look to be warm enough during the afternoon hours
each day that most of the precipitation should fall in the form
of rain before changing over to a wintry mix at night for some
locations. While there is still some uncertainty with
precipitation types and amounts, there is the potential for
between half an inch to an inch of rain through Monday.

The latest mmefs forecast indicates a few locations going into
action stage by early next week, but confidence is not high for
potential of any flooding at this time. Some snow melt is likely
the next few days.

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.
New York...Winter Weather Advisory from 6 am to 1 PM EDT Sunday for
nyz038>040-047-048-051-058-063.
Winter Weather Advisory from 2 PM Sunday to 9 am EDT Monday
for nyz033-042-082.
Massachusetts...none.
Vermont...Winter Weather Advisory from 6 PM Sunday to 9 am EDT Monday
for vtz013>015.

&&

$$
Synopsis...wasula
near term...jpv/jvm
short term...wasula

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