Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Albany New York
1050 PM EDT sun Mar 9 2014
a clipper low...and its associated warm front will
approach from the northern Great Lakes region overnight through
tomorrow morning with some light snow. Another quick moving low
pressure system moves across southern Quebec on Tuesday with a
cold frontal passage. This front stalls from the Tennessee Valley
to the Virginia coast Tuesday night...as middle week a storm will
organize along this front...and move up the East Coast with a
mixture of rain and snow for the forecast area.
Near term /until 6 am Monday morning/...
as of 1050 PM EDT...a clipper type system will be moving across the
upper Great Lakes and southern Ontario allowing a warm front to move
into northern New York this morning. This system has limited moisture to work
with so not expecting significant snowfall. The 00z kaly sounding
is still fairly dry below 750 hpa. The column should gradually
saturate between 06z-09z. A general 1 to 3 inches is expected across
the western Adirondacks and southern Green Mountains...and a
dusting to an inch elsewhere.
This update the probability of precipitation have been retrended based on the observations
upstream. The light snow looks to hold off due to the thermal
advection until close to midnight. Also...the probability of precipitation have been
increased to high likely and categorical values overnight based on
collaboration with btv...and the near term model trends across the
northern tier of the forecast area. Have phrased the wording as light snow
in the grids and products.
Lows were increased 3 to 5 degrees based on the cloud and temperature
trends...and mins will occur during the middle of the night /2-4
am/. Expect lows tonight to be in the middle teens to middle 20s.
Short term /6 am Monday morning through Tuesday night/...
Monday and Monday night look unsettled with mainly a precipitation event for
the higher terrain as clipper swings by just north of the Canadian
border. Once again a few inches of snow will be possible across the
higher terrain especially the western Adirondacks and southern
Green Mountains with some rain in the valleys. Expect highs on Monday to
be in the middle 30s to middle 40s with lows Monday night in the middle 20s
to around 30.
On Tuesday expect a cold front to be just east of the forecast area early
in the day with a much stronger cold front up across southern Canada. The
airmass behind the first front is fairly mild and as a result
expect highs to range from the upper 30s to upper 40s and perhaps
even above 50 at kpou.
Tuesday night expect clouds to be on the increase as a strong cold
front drops southeast from Canada as a complex series of low
pressure systems move along the stalled frontal boundary to the
south which will be across the middle Atlantic region late Tuesday night.
Lows are expected to be in the 20s.
Long term /Wednesday through Sunday/...
the medium range guidance continues to show a significant late
winter storm will impact the region Wednesday into Thursday with
exact ptype...and track of the system still uncertain.
However...most locations look to receive some snow with this system.
A cold front will be moving across the region Wednesday
morning...while low pressure will be approaching from the Ohio
Valley. The wpc/ECMWF/GFS and even the Canadian ggem are in pretty
good agreement with the initial set-up with the can ggem a little
faster and further east. The longwave trough is positively tilted
over the upper MS river River Valley...Midwest...and the Great Lakes
region. A middle and upper level confluent zone sets up over the
northeast with over running precipitation commencing in the late
morning...and early PM...as the surface wave moves toward the WV/PA/MD
corridor. An impressive baroclinic zone sets up over the region
with strong isentropic lift on the 285/290k sfcs. The GFS indicates
the 850-700 hpa 2d fgen enhancing over NE PA into southern...and eastern New York
for the potential of a MDT-heavy burst of rain or snow. The critical
thickness profiles indicate this event will be a rain/snow
ptype...as well as the BUFKIT and buffer soundings. Some rainfall
is possible based on the GFS track as far north as the capital
district Wednesday afternoon...before cold air is drawn into the
system into the late afternoon...and early evening. The rain could
cut down on the snow accums in the southern zones during the
day...before accumulating snowfall at night.
The big question is when another short-wave phases into the upper
trough for it to take on a neutral tilt...which will help in aiding
the cyclone to hug the southern New England coastline. This is where the
European model (ecmwf) is a little bit colder with the profiles...and a little bit
further south than the GFS with the cyclone near southern New Jersey at
00z/Thu...and the GFS is over eastern Long Island. There is a
consistent trend for the cyclone to deepen and intensify...and the
dynamics increasing for a transition to snowfall everywhere between
00z-06z/Thu. The latest GFS shows a second impressive h850-700 fgen
zone setting up over southern Vermont/western Massachusetts southwest through the capital
region...and into the Catskills. Periods of MDT-heavy wet snow look
possible with the column cooling down quickly. Overall...a moderate
to potentially heavy wet snowfall is shaping up for the capital
region...Berkshires...and Catskills north and west. A much higher
level uncertainty on the amount of rainfall south and east cutting
into accumulating snow. Confidence is not high enough for a watch
this far out...but a mention of a significant snowfall will continue
into the severe weather potential statement. Snow to liquid ratios could be low on this event
/8-10:1/. The quantitative precipitation forecast varies a bit with the guidance...but agree with
wpc a 1-1.25" swathe is possible Wednesday-Thursday morning through most of the
forecast area with slightly higher amounts in some locations. Precipitable waters on
the latest gefs get to 1 to 2 Standard deviations above normal south
of the capital region Wednesday afternoon. There is still quite a bit of
spread on the latest 12z/gefs aly plume diagram with the mean close
to an inch of quantitative precipitation forecast...and the range from 0.29" to 1... several
clusters between 0.80" to 1.2".
Daytime temperatures were used close to the wpc guidance with highs in the
u30s to l40s from the capital region south and east into the middle
Hudson Valley...southern Taconics..and Litchfield city CT. Lower to m30s
will be common further north and west...except u20s over the southern
dacks. Lows will be teens to lower 20s with some single digits over
the southern dacks.
Thursday-Thursday night...the GFS has the cyclone over Nova Scotia by the
morning...and the European model (ecmwf) has the storm in the Gulf of Maine. The
European model (ecmwf) would have deformation zone snow continuing in the morning and
likely probability of precipitation were kept in the forecast early on before transitioning to
chance values. The snow should taper to snow showers by the
afternoon with blustery and cold conditions. Additional light
accumulations of snow are expected. Maximum temperatures will generally be in
the teens to m20s. High pressure builds in from the south over the
East Coast with clearing skies...diminishing winds and very cold
conditions with lows in the single digits in most locations...except
zero to 5 below over the southern dacks region.
Friday-Friday night...fair conditions will give way to increasing clouds
late in the day...as a clipper low approaches. Warm advection ahead
of the clipper will allow temperatures to rise back into the middle and u30s
from the capital region south and east...and u20s to l30s to the
north and west. The clipper will bring a slight chance to chance of
snow showers Friday night to the region.
Saturday into Sunday...the cold front to the clipper will move
through on Saturday with some rain or snow showers. Saturday looks
like the mildest day in the long term with 40s from the Mohawk
Valley and capital region south and east...and middle and u30s to the
north and west. Strong cold advection in the wake of the front will
allow temperatures to fall back below normal to close the weekend.
Aviation /03z Monday through Friday/...
a warm front ahead of a clipper low moving towards the northern Great
Lakes region will bring some light snow to eastern New York and western New
England tonight through Monday morning.
VFR conditions will begin the taf cycle for kgfl/kalb/kpou/kpsf
prior to midnight...but the clouds will thicken and lower ahead of
the warm front. Some warm advection light snow will overspread the
taf sites from north to south from 06z-09z. The exception will be
kpou where a vcsh was maintained. MVFR ceilings and visibilities are expected
for kgfl/kalb/kpsf. There is a chance a brief period of IFR may
occur at kgfl...but it has not been included in the taf there yet.
The warm advection precipitation will taper between 13z-15z...but lingering
MVFR ceilings will continue at kgfl and kalb. The visibilities will likely
remain MVFR at kpsf with some light snow persisting until noontime.
Kpou will remain VFR with ceilings 4-5 kft above ground level. MVFR ceilings will
continue into the afternoon at kpsf and kgfl /2-3 kft agl/...with
kalb improving to VFR levels by the middle PM.
The winds will become light and variable early this evening. They
will slowly increase from the S to SW at 4-7 kts towards daybreak.
The winds will further increase from the S/SW at 5-10 kts during
the late morning into the afternoon.
Monday night: low operational impact. Slight chance of shsn.
Tuesday: no operational impact. No sig weather.
Tuesday night: low operational impact. Slight chance of shsn.
Wednesday: high operational impact. Likely rain...sn.
Wednesday night: high operational impact.Breezy likely snow.
Thursday: high operational impact.Breezy chance of shsn...sn.
Thursday night: no operational impact. No sig weather.
Friday: no operational impact. No sig weather.
no widespread Hydro problems are anticipated over the next week
Early in the week a clipper type system will bring some light snow
to the region while a significant storm will impact the region
Wednesday and Wednesday night. The precipitation is expected to be mainly
snow across the northern half of the forecast area with the precipitation starting as
rain in southern areas and change to snow Wednesday night. Little in
the way on runoff is expected with this system as temperatures will be
under 40 most of the time and the snowpack which is in place will
soak up much of the rain that falls.
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.