Scientific Forecaster Discussion
fxus61 kaly 132114
Area forecast discussion
National Weather Service Albany New York
414 PM EST Tue Nov 13 2018
colder and blustery conditions are expected tonight with
some lake effect snow showers, especially for western parts of the
area. It will be continued cold and breezy on Wednesday with some
additional lake effect snow showers and flurries. Temperatures will
be frigid Wednesday night into Thursday morning before another storm
system brings widespread snow, rain and sleet to the region for late
Thursday into Friday morning.
Near term /until 6 am Wednesday morning/...
as of 414 PM EST...departing coastal storm is located over
eastern New England, while a secondary cold front is just
crossing across the area this afternoon. Mrms imagery shows a
few lingering rain showers or sprinkles associated with this
frontal boundary, but best moisture has shifted east of the
Behind this front, strong cold air advection will be ongoing for
this evening into tonight. 850 hpa temps are expected to fall as
low as -11 to -17 degrees c across the region by daybreak
Wednesday. The combination of the good mixing thanks to colder
air aloft and decent pressure gradient in place will allow for
gusty northwest winds tonight. Some winds may exceed 30 mph
especially in areas of channeled flow and across the higher
Meanwhile, the cold air aloft passing over the warm water of
Lake Ontario (glerl lake surface temps are around 49 f) will
allow bands of lake-effect snow to develop. With a northwest
flow in place, the best accumulation with this setup is
generally across central New York. However, (as shown in cam
guidance), some pieces towards the end of the lake-bands look to
reach into the Mohawk and Schoharie valleys, helderbergs and
northeastern Catskills tonight, especially for after midnight.
Based on cstar inland extent research, this setup would be
favorable for pieces of the bands to reach as far as 170 miles
from the Lakeshore, so the capital region, Mid Hudson valley and
Taconics could all see a brief snow shower or two overnight.
Cams suggests to occur by late tonight, so will include at least
slight to chance pops across these areas, with a light dusting
possible. Areas further northwest across the western Mohawk
Valley could see a few inches of snow, depending on quickly the
Temps overnight look to fall into the 20s across the entire
region. With the gusty winds, it will feel even colder as well.
Short term /6 am Wednesday morning through Friday/...
some lake effect snow showers may still be ongoing across our
area for Wednesday morning, but by the activity, most of the
snow showers should be confined west of the region across cny.
Strong shortwave trough will be passing by to the north and
temps will continue to be very cold aloft for mid-November
(around 3 Standard below normal according to the naefs). The good
mixing will continue to allow for gusty winds during peak
heating/mixing, with some gusts over 30 miles per hour at times. Despite
some sun in place, temps will only reach the mid 20s to mid 30s
for most spots for highs.
Dry and frigid weather is expected for Wed night into Thursday
morning, with mainly clear skies and light to calm winds as high
pressure passes over the region. Good radiational cooling is
expected, especially in areas with snow cover. Lows look to fall
into the teens, and some single digits are possible across the
high terrain of the Adirondacks and southern greens.
After a cold and clear start, skies will gradually increase
during the day Thursday, as the next storm system approaches.
This will be a large cutoff low over the Mississippi Valley that
will be heading towards the Ohio Valley and mid-Atlantic states.
As this occurs, a rapidly developing surface storm will form
along the eastern Seaboard of the mid-Atlantic states and head
northeast for Thursday night into Friday morning.
Plenty of cold air will be in place at the start of this storm.
Despite fighting some dry air at low levels, isentropic lift
should allow for a period of snowfall to move from south to
north after sunset on Thursday and continue into Thursday night.
Depending on the exact track of the developing storm, some
warming temps around 800-850 hpa could allow for precip to
change over to sleet/freezing rain or plain rain by late
Thursday night into Friday morning, although the greatest threat
for this looks to be for areas south and east of the capital
region. Steady precip looks to continue into Friday morning
thanks to nearby coastal storm. Have included some mixed precip
or rain for southern/eastern areas, as well as valley areas
towards the end of the storm, as boundary layer temps warm
during the day on Friday.
Although the models show some variability of exact qpf, there is
some consistency amongst the 12z nam12/ECMWF/fv3-GFS, while the
GFS and some members of the sref are much lighter with precip
amounts (thanks to a farther east track of the surface storm).
For now, will favor heavier precip solutions. This would results
in a widespread 2 to 6 inches of snow across the area, with
some locally higher totals in the high terrain (especially
across southern vt). We will continue to mention this storm in
our severe weather potential statement. Precip should end by early afternoon Friday, with a
few lingering rain or snow showers (especially northern and high
terrain areas). Temps look to mainly be in the 20s to near 30 for
thurs night and rising into the 30s for Friday.
Long term /Friday night through Tuesday/...
Friday night and Saturday...cool and breezy conditions will build
into the region as the cyclone departs to the northeast with some
lake enhanced snow showers over the Adirondacks. West-northwest flow will favor
some upslope snow showers over the Adirondacks and southern Green
Mountains of Vermont resulting in light snow accumulations under an
inch. Lingering isolated snow showers will persist through Saturday
with moist cyclonic west-northwest flow overhead. Lows Friday night will be in
the mid 20s to mid 30s and highs on Saturday will be in the mid 30s
to mid 40s.
Sunday through Tuesday...deterministic guidance begins to deviate
greatly starting Sunday and continuing through the end of the long
term period. The past couple runs of the GFS and Canadian have been
hinting at a clipper-like low progressing through the region on
Sunday while the European model (ecmwf) has high pressure building overhead. Subtle
differences within the mean longwave trough seem to be resulting in
large differences in the surface pressure fields and tangible
weather. Regardless, multiple pieces of energy look to break off a
zonally oriented pv streamer, resulting in weak forcing for ascent
in regions of high pressure advection on the 1.5 pvu surface, and
multiple chances for widely scattered rain and snow showers over the
Some guidance suggests the potential for lake-effect snow over the
Adirondacks and western Mohawk Valley Monday into Tuesday as
westerly flow moves in and 850-hpa temps drop to -10 to -13 c. Heat
flux off the Great Lakes is evident in the boundary layer thermal
fields as an inverted thermal trough extending to the northwest over the
Great Lakes region. Confidence is very low on the potential for
early week lake effect snow though, given the large discrepancies in
the upper flow patterns between the deterministic models.
Temperatures throughout this period will continue below normal
thresholds with highs in the 20s and 30s and lows in the teens and
Aviation /21z Tuesday through Sunday/...
as of 17z a surface low centered over The Forks of Long Island
and Martha's Vineyard. This low will continue to strengthen as
moves off to the northeast this afternoon and evening. Higher
pressure will build in from the west late tonight and Wednesday.
Conditions are expected to improve to VFR by late in the day.
However at kpsf, MVFR conditions are expected to persist through
the overnight before improving. While at kalb, a period of MVFR
conditions are expected to return due to lake effect clouds and
possibly some snow showers late at night/early in the morning
with VFR returning by around sunrise. Have addressed threat of
snow showers at kalb with a vcsh.
As the low moves off to the east westerly flow will pick up across
the local area and will become gusty with gusts in the teens.
West-northwest flow will persist through the night and will
pick up early Wednesday morning. The pressure gradient between
the departing low and advancing high will tighten resulting in
brisk and gusty with gusts approaching 30 knots.
Wednesday night: no operational impact. No sig weather.
Thursday: no operational impact. No sig weather.
Thursday night: high operational impact. Definite snow.
Friday: high operational impact. Definite rain...sn.
Friday night: low operational impact. Slight chance of rain showers...shsn.
Saturday: no operational impact. No sig weather.
Saturday night: low operational impact. Slight chance of shsn.
Sunday: low operational impact. Slight chance of rain showers...shsn.
drier, colder and breezy conditions are expected tonight into
tomorrow. Some gusts may exceed 30 miles per hour at times. More widespread
precipitation (mainly in the form of snow) is expected late
Thursday into Friday.
no hydrologic issues are anticipated through the rest of the
Aside from some lake effect snow showers over the Mohawk and
Schoharie valleys, helderbergs and Catskills, mainly dry
weather is expected tonight into tomorrow. This will allow river
and streams levels to recede from the precipitation that fell
last night into this morning. Temperatures will be turning much
colder and it will rather frigid for Wed night into Thursday,
which could allow for some thin ice to begin to form on shallow
lakes and ponds.
A widespread precipitation event is expected late Thursday
through Friday morning. Precip will mostly be snow, but some
mixed precip or rain is possible for the second half of the
storm, especially for areas south and east of the capital
region. There probably won't be enough liquid precip to have an
immediate impact on rivers and streams. Drier and continued
chilly weather is expected behind this system for 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