Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Buffalo New York
450 PM EST Thu Nov 14 2019
a weak cold front will cross the lower Great Lakes tonight with snow
showers northeast of the lakes that may mix with rain at times.
Another cold front will move south across the area later Friday
afternoon with a few snow and rain showers. Another fresh batch of
cold air will arrive behind this cold front for Saturday. A warming
trend will then begin Sunday and last through early next week.
Near term /through Friday/...
a well defined...albeit it narrow...band of Wet Lake snow extends
from Lake Erie across the buf Metro area to Genesee and Orleans
counties at 2130z (430 pm) while a much less organized area of mixed
rain and snow is developing northeast of Lake Ontario. This lake
supported pcpn is blossoming ahead of a weakening cold front that is
in the process of Cross Lake Ontario. Given the wet nature and low
cap (roughly 8 kft) associated with both areas of lake effect...am
not expecting more than an inch or so of snow for sites like the buf
Metro and areas north of Watertown.
The activity will peak between 7 and 10 PM tonight, then slowly
taper off and end later tonight as inversion heights further lower.
Precipitation type should continue to be mainly snow, with some rain
possible near the lakeshores.
There is a chance that as inversion heights lower later tonight we
may loose ice nuclei in the cloud bearing layer as the boundary
layer warms. If this occurs, it would support some drizzle or
freezing drizzle depending on surface temperature. At this time
however, it appears precip will end by the time the column warms.
Outside of the lake enhanced areas, it will be partly cloudy
tonight. Lows will be in the lower 30s on the lake plains beneath
cloud cover, and mid to upper 20s farther inland where skies
Friday will likely start mainly dry in the morning with plumes of
lake effect clouds northeast of the lakes, and partly cloudy skies
farther inland. A cold front will cross the eastern Great Lakes
during the mid to late afternoon. This front will again be moisture
starved and largely orphaned from stronger large scale ascent across
Quebec. The low level convergence zone may support a few scattered
snow showers, and there may be some lake enhanced scattered snow
showers as well east and southeast of the lakes. All of this will be
light, with any accumulation less than an inch. It will be quite
breezy northeast of the lakes, with gusts up to 30-35 mph prior to
the arrival of the cold front. Highs will reach the mid 30s in most
locations by early afternoon, then begin to drop by late afternoon
following the frontal passage.
Short term /Friday night through Sunday night/...
following the passage of friday's cold front...one more shot of
much colder but also rather dry air will build across our region for
Friday night and Saturday. The very dry nature of the incoming
airmass and veering/short northwesterly to northeasterly fetch will
help to confine any lake response to some clouds and scattered snow
showers/flurries southeast and south of the lakes Friday night...
with these diminishing over time as the low levels dry out and the
capping inversion drops to a meager 2-3 kft. Outside of these dry
weather will prevail...along with a return to well below average
temperatures. Overnight lows will range from the teens south of
Lake Ontario to around zero across the north country...where light
winds and clearing skies will allow for excellent radiational
cooling...and where we have aimed significantly below forecast
guidance for temperatures.
The core of the ridge will pass by just to our north on Saturday...
then will make its way to the Canadian Maritimes on Sunday...with
remnant weaker ridging still extending back southwestward and across
our region through Sunday night. This will result in fair dry weather
prevailing across our region through the remainder of this period...
along with mainly clear/mostly sunny skies. Meanwhile the fresh cold
airmass will keep temperatures well below normal through Saturday
night...with highs only in the mid to upper 20s Saturday followed
by lows again ranging from near zero across the north country to
10 to 15 south of Lake Ontario Saturday night. Such readings will be
a solid 20 to 25 degrees below normal areawide...and could once
again threaten record low temperatures at points (particularly
at watertown). For more information on these...please refer to
the climate section below. After that...a developing warm air
advection pattern on the backside of the departing ridge will allow
readings to notably moderate on Sunday...when highs will recover
into the mid to upper 30s east of Lake Ontario and to the upper 30s
and lower 40s elsewhere.
Long term /Monday through Thursday/...
in the long term portion of the forecast...the guidance has trended
a bit faster and more aggressive at breaking down lingering ridging
across our region early in the week...with this feature giving way
to an initial coastal system making its way northeastward offshore
of the East Coast...and/or a broad mid-level trough and second
surface low/trough approaching from the upper Great Lakes. Regardless
of which of these scenarios you would believe...increasing lift and
moisture out ahead of these features should eventually provide the
impetus for some scattered rain and snow showers across our region...
though the exact timing and coverage of these remains in question
given continued notable differences between the various guidance
packages...as well as their recent history of favoring drier weather
persist longer into early next week. With the above in mind...for now
have only increased pops a little for the Monday through Wednesday
time frame...with broadbrush slight chance to lower-end chance pops
favored until the forecast picture can become less muddled. Following
the passage of these systems...general subsidence and dry/cold air
advection should bring about a return to relatively dry weather for
Wednesday night and Thursday...before the next system approaches
toward the end of the period.
As for temperatures...a modest low-level warm air advection pattern
early in the week should continue to result in a gradual warming
trend with daytime highs rising into the lower to mid 40s through
Tuesday...with readings then flatlining and/or falling back a little
Wednesday and Thursday as cold advection overspreads our region in
the wake of the departing system(s).
Aviation /22z Thursday through Tuesday/...
while VFR conditions will be found across the vast majority of
western New York tonight...a chilly southwest flow will support lake
snow for sites like kbuf and kart. These sites will experience MVFR
conditions at the very least...with IFR conditions through
at least 02z expected at kbuf.
The lake response will weaken during the course of the night...
although MVFR conditions are likely to persist at kbuf, kiag and
While most areas will pcpn free Friday morning...MVFR cigs will be
rather widespread. The exception to the pcpn free weather will be
east of Lake Ontario where some lake snow showers will still be in
place. As we work deeper into Friday afternoon...MVFR cigs are
forecast to lower to IFR levels across the southern tier and Finger
Lakes region. The lowering cigs ahead of a second cold front will be
accompanied by a new round of rain and wet snow showers.
Saturday and Sunday...mainly VFR.
Monday and Tuesday...mainly VFR with a chance of showers.
moderate southwesterlies will continue through tonight and Friday...
as a pair of cold fronts will cross the lower Great Lakes. The
strongest winds will occur late tonight through early Friday
afternoon...as the pressure gradient will tighten ahead of the
second cold front. This will continue to support solid Small Craft
Advisory conditions on both lakes. Winds will become north Friday
evening behind the cold front, with Small Craft Advisory conditions
continuing along the south shores of the lakes. Winds will then
diminish Saturday as high pressure builds into the eastern Great
another unseasonably cold airmass will settle across our region
Friday night through Saturday night. This will not only knock
temperatures back to 20 to 25 degrees below typical mid-November
averages...but could also lead to some additional new low
temperature records. This will especially be the case at Watertown...
where it appears that records for all three time periods listed
below will likely be broken. At Buffalo and Rochester...new record
low temperatures also appear to be a possibility on November 17th.
Record low minimums for Saturday November 16th...
Record low maximums for Saturday November 16th...
Record low minimums for Sunday November 17th...
Marine...Small Craft Advisory until 10 PM EST Friday for lez040-041.
Small Craft Advisory until 7 PM EST Friday for lez020.
Small Craft Advisory from 7 am Friday to 10 am EST
Saturday for loz043-044.
Small Craft Advisory from 3 am Friday to 10 am EST
Saturday for loz042.
Small Craft Advisory until 1 am EST Saturday for loz045.