Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Buffalo New York
639 am EST Thu Nov 14 2019
a weak cold front will cross the lower Great Lakes this afternoon
and evening, producing wet snow and rain showers northeast of the
lakes in the process. A second cold front will move south across the
area late Friday. This may produce a few light snow showers and will
bring one last push of very cold air to start the weekend. A warming
trend will then begin Sunday through the first half of next week.
Near term /through tonight/...
regional radar is showing light radar echos from Northern Ohio
and northwest Pennsylvania to the northern shore of Lake Ontario
this morning. Dry air below 10k feet and below will result in
mostly dry conditions through daybreak. Scattered flurries to a
brief snow showers are possible across western New York this morning
and into the north country through mid- morning.
A mid-level trough is located across the Great Lakes with a 850mb
trough axis located from Eastern Lake Superior to central Illinois
early this morning. A southwesterly 35 kt low level jet will persist
across the eastern Great Lakes through the morning hours. Forcing
along the leading edge of the low level jet may result in scattered
showers across the region this morning however most places will
remain dry due to low level dry air. A cold front will approach
from the central Great Lakes today. While we remain in a warm
air advection regime today, temperatures will remain cold enough
to generate lake induced instability. As the front nears,
southwest flow across Lake Erie, combined with moisture from the
frontal system will lead to lake enhanced rain and snow showers
northeast of Lake Erie by noontime. A similar case will occur
northeast of Lake Ontario but by mid-afternoon. Temperatures
will warm into the mid to upper 30s today so marginal
temperatures will limit any snow accumulation during the day.
The approaching cold front and mid-level trough axis both get
washed out into the evening hours. Southwest flow will slowly
become more westerly into the evening hours and lake enhanced
rain and snow showers will move south into the northtowns/Metro
Buffalo and northern Jefferson County. Temperatures will fall
into the evening hours resulting in colder boundary layer
conditions. Any rain showers will transition to snow showers as
the bands move south through the evening. Light accumulating
snow will likely start this evening across the northtowns and
northern Jefferson County. The window for accumulating snowfall
will be short as warm air advection aloft continues while
inversion heights fall into Friday morning. Marginal
temperatures will lead to little to no snow accumulation along
the adjacent lakeshores. A localized amount of 1-2 inches is
likely inland from the city of Buffalo into the northtowns and
northeast of Watertown into northern Jefferson County. While
this will be localized in the most persistent bands, places
nearby may pick up a dusting to an inch. Outside of lake bands,
mainly dry conditions with flurries are expected through
tonight. Low temperatures will fall into the mid to upper 20s to
the low 30s near the Lake Shores.
Short term /Friday through Saturday night/...
starting out on Friday morning upper level trough over Hudson Bay
will continue to dig toward southern Quebec allowing a resurgent
cold front to sweep across the eastern Great Lakes region.
Expect the lake response that weakens late Thursday night to
increase again to the northeast of both Lake Erie and Lake
Ontario, with better chances of more notable precipitation over
northern Jefferson County to the St. Lawrence River, closer to
upper level troughing and stronger forcing.
Even earlier in the day before coldest air arrives, 850 mb temps
around -7c and lake water temps around 49f/9c will result in
sufficient over water instability for some lake effect. If a
more dominant, focused band develops soundings point to more
favorable conditions for lake effect downstream of Lake Ontario
with longer over water fetch with west-southwest winds in the lake
convective layer leading to lake equilibrium levels to around
6kft while levels are mainly below 5kft off Lake Erie. Possible
that a couple inches of snow could occur in the highest terrain
east of Lake Ontario in the Tug Hill region, though less than
stellar snowfall rates and marginal temps in the mid 30s suggest
minimal impacts to travel. Elsewhere as winds shift to the west
and northwest as the front moves through, could see at least a
few rain/snow showers scattered about with the fropa. High
temperatures mostly will top out in the upper 30s.
Once the front moves through, soundings even where flow remains
onshore look awfully dry to support much in way of lake effect
beyond late Friday evening. Will keep small pops in mainly along
Lake Ontario, but overall skies Friday night should steadily clear
out by late night. A chilly night looks in store, with areas east of
Lake Ontario dropping back toward zero. Readings may fall as low as
the lower teens elsewhere. The cooler than average temperatures will
continue Saturday with most areas staying in the mid to upper 20s
for highs despite a fair amount of sunshine. With the center of high
pressure overhead on Saturday night, expect temperatures to fall a
couple degrees either side of 10f most areas, though again, temps
may drop toward zero east of Lake Ontario.
Long term /Sunday through Wednesday/...
overall theme of the long term will be moderation in temps, though
it still looks to be a struggle to reach levels normal for this part
of November. Normal highs by middle of next week are mainly in the
Upper trough over the region this weekend will be replaced by upper
level ridging on Sunday with high temps warming into the upper 30s,
near 40f. There will be some mid to high clouds but there will also
be decent amount of filtered sunshine. Steady warming trend will
continue into early next week with highs mainly reaching the low and
maybe mid 40s, though it will be cooler to east of Lake Ontario.
Small chances of mainly rain showers return by Monday, but medium
range models are not at all set on the pattern early to mid next
week due to what looks like split upper flow streaming in from the
nations mid section. Main issue for our region is extent of southern
stream energy that eventually lifts north-northeast along the
eastern Seaboard and how far any precipitation from these systems
would extend into western and north central New York. Could be cool enough
at times for at least a mix of rain and snow in parts of the area,
though at least right now, main emphasis from models is for majority
of precipitation from these systems to stay east of our area.
Canadian is more aggressive with qpf into western New York late Monday
into Tuesday though. Main Point for now though is forecast details
certainly may change over the coming days as consensus, model blend
used for this forecast may ultimately be too low for pops, at least
at times. Trouble is with all the model differences, cannot really
pin down for what time frame that would be.
Eventually it does look like our modest warming trend will slow down
by middle of next week as cooler air works in once larger scale
trough axis slides across eastern Great Lakes and New England. Just
how we get there is the main question.
Aviation /12z Thursday through Monday/...
snow showers are possible across western New York early this morning
and east of Lake Ontario through mid-morning. Brief periods of
IFR vsbys are expected from kjhw to kroc this morning.
Elsewhere, VFR conditions will continue this morning. A cold
front will approach the region today. Lake enhanced rain and
snow showers will form northeast of Lake Erie and Lake Ontario
and cigs will fall to MVFR at kiag, kbuf and kart late this
morning through the afternoon. Showers in lake bands will become
all snow this evening and persist northeast of the lakes. Lower
vsbys expected in the lake bands. Elsewhere, VFR conditions
Friday...a chance of lake effect snow showers east of the lakes with
local MVFR/IFR. Otherwise VFR.
Saturday through Monday...mainly VFR.
a cold front will approach the eastern Great Lakes today before
crossing the region tonight. Freshening southwest winds ahead of the
front will support another round of Small Craft Advisory conditions
from on Lake Erie and the northeast end of Lake Ontario. Small craft
conditions will continue at the east end of both lakes through
Marine...Small Craft Advisory until 4 PM EST Friday for lez040-041.
Small Craft Advisory until 7 PM EST this evening for
Small Craft Advisory until 10 PM EST Friday for