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fxus61 kbuf 150924 
afdbuf

Area forecast discussion
National Weather Service Buffalo New York
424 am EST Fri Nov 15 2019

Synopsis...
very light snow showers and patchy freezing drizzle will continue
northeast of the lakes this morning. Another cold front will move
south across the area later this 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 tonight/...
a west-southwest flow persists across the eastern Great Lakes region
this morning. Very light echos are present northeast of the lakes
per kbuf and ktyx due to lingering low-level moisture from a weak
cold front and moisture advection from the lakes. This moisture is
mainly below 5k feet and below the dentritic growth zone. A mix of
patchy drizzle and flurries have been observed northeast of the
lakes while outside of these "bands," a mix of clouds and clearing
with dry conditions will continue. Due to surface temperatures near
freezing east of Lake Erie, a Winter Weather Advisory continues for
Erie, Genesee and Wyoming counties for a trace of ice from freezing
drizzle through daybreak (9 am.) If ice forms it will be mainly on
elevated surfaces as pavement and soil temperatures average the mid
30s. Temperatures remain above freezing northeast of Lake Ontario
and drizzle or flurries are expected.

Another cold front will approach the region today and moisture will
begin to increase ahead of it through the morning hours. It won't be
a lot of moisture but mainly an increase in the 850-700mb layer
which will likely intensify any lake activity east of the lakes
through the afternoon. Due to the lack of ice in the dendritic growth
zone, drizzle may mix in with rain or snow showers through the
afternoon. Marginal temperatures expected today with temperatures
above freezing at lower elevations and staying near or just above
freezing on the higher terrain including the Tug Hill and western
southern tier. This will limit accumulation across the lake
plains/lower elevations while a dusting is possible at higher
elevations. As the front approaches the north country this
afternoon, lapse rates will steepen and the coverage of snow showers
will increase east of Lake Ontario. As the front enters the north
country late this afternoon/evening, snow squalls are possible along
the front which may reduce visibility with a quick burst of snow and
gusty winds. A north-northeast flow behind the front will also add
an upslope component to the northern Tug Hill region where a quick 1-
2 inches is possible through this evening. The front will move into
western New York by this evening. While there will be an uptick in
coverage of rain and snow showers, it won't be much. Some places may
even see close to nothing as the front comes through due to the lack
of moisture as it moves south. Winds will sharply change to the
north-northeast behind the front tonight as cold air advection
rushes into the region. Lake effect clouds and snow showers are
possible late tonight along the southern shore of Lake Ontario from
Wayne to Niagara counties. Due to the very dry air, little to no
accumulation is expected at this time. Temperatures will fall to the
single digits to zero east of Lake Ontario to the mid teens across
western New York.

&&

Short term /Saturday through Sunday night/...
in wake of the cold front that moves through this afternoon into
this evening, high pressure with mslp peaking near 1040mb builds
across the Ottawa Valley and northern New England through Saturday
afternoon. East to northeast flow out of the high will be quite dry
overall, but soundings indicate low-level lake enhanced moistening
aimed along shore of Lake Ontario, mainly from Rochester to the
west. NAM and Gem both show this moisture plume and show it cold
enough at top of 2-3kft inversion for a few flurries or light snow
showers mainly over Niagara and Orleans counties. Increased sky
cover through midday over our northwest forecast area and kept a
small mention for lake effect as well. Otherwise, will be a mostly
sunny and cold day with highs struggling into the upper 20s most
areas and even staying in the mid 20s in the north country east of
Lake Ontario.

Mostly clear skies on Saturday night with high pressure nearby will
allow for a very chilly night. Some concern that a steadier east
wind on southern edge of high may restrict cooling potential more
toward western New York. But still looking at min temps dropping to record
or near record values in the lower teens. Winds will be lighter over
the north country and see no reason temps there will not drop toward
zero, especially at typical cold spots over the higher terrain.

Return flow and more sunshine than clouds will allow temps to
rebound nicely on Sunday across the area. Expect highs to only crack
the mid 30s east of Lake Ontario and mainly reach the upper 30s
elsewhere though with the downslope se flow the Mercury should climb
at least into the lower 40s over far western New York. A bit more cloud
cover later Sunday night along with persistent se winds will keep
min temps on Sunday night much warmer than the previous two nights
with readings in the upper teens at the coolest (north country) to
near 30 at the warmest (lake Erie shoreline of western ny).

&&

Long term /Monday through Thursday/...
this forecast period starts out on Monday with a complicated split
flow upper level pattern from the mid Continental U.S. To the eastern Seaboard.
One southern stream wave will be supporting stronger low pressure
system riding northeast just off the East Coast while another
southern stream upper level trough dives across the southeast Continental U.S..
finally a northern stream trough will be sliding across the upper
Great Lakes. Though the initial system off the East Coast should
stay east of here into northeast New England through Monday night,
the European model (ecmwf) and Canadian indicate as other two systems slide toward
the lower Great Lakes and northeast Continental U.S. That precip in the form of
mixed precip may try to expand over at least our eastern areas from
Rochester and Wellsville on to the east and north into the north
country. Sfc temps look right on the edge for rain/snow and based on
warm nose with Max tw aloft staying above 0c, there may be some
sleet mix in as well east of Lake Ontario. All the while, latest GFS
keeps second southern stream too far east of here to produce much if
any precip late Monday into Monday night. Kept main mention of
precip on Monday night and mostly east of Rochester. Will need to
keep eye on this time though for possible mixed precip. Too much
uncertainty to mention in the severe weather potential statement though at this point.

On into Tuesday and Wednesday, axis of the northern stream upper
trough crosses the lower Great Lakes which brings slight increase to
pops. Deep moisture and strong forcing is lacking though so the pops
still don't look that very significant right now. Could be more
mixed precip though (with best chance of snow at night into early
morning) as temps during this period will be in the upper 30s to
lower 40s during the days and right around freezing at night.

Upper trough slides east of lower Great Lakes later Wednesday into
Thursday while another sharper trough takes shape over the northern
plains. Thursday now looks like a warmer day with SW flow ahead of
that trough. Increased temps a bit into the lower 40s most areas and
brought next chances of rain especially later Thursday as the strong
trough upstream and sfc low begin to cross the Great Lakes.

&&

Aviation /10z Friday through Tuesday/...
low-level moisture resides across western and north central New York this
morning. A west-southwest flow has resulted in MVFR cigs at kbuf,
kjhw and kart. VFR conditions will continue at kiag and kroc through
daybreak. Moisture will increase ahead of a cold front today and
cigs will become MVFR at times. While cigs fall to MVFR at kiag and
kroc late this morning, they should become VFR for the afternoon.
MVFR likely at kbuf and kart while IFR cigs expected at kjhw mid
morning through this evening. A mix of rain and snow showers with
patchy drizzle expected today. Lingering patchy freezing drizzle is
possible at kbuf through daybreak.

The cold front will cross kart around 00z and into western New York 00-
03z. Winds will sharply become north-northeast behind the front.

Outlook...

Saturday and Sunday...mainly VFR.
Monday and Tuesday...mainly VFR with a chance of showers.

&&

Marine...
moderate southwesterlies will continue today... as a cold front
approaches from the north. The strongest winds will occur through
early afternoon...as the pressure gradient tightens ahead of the
cold front. This will continue to support solid Small Craft Advisory
conditions on both lakes. Winds will become north this 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
Lakes.

&&

Climate...
another unseasonably cold airmass will settle across our region
tonight 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...

Buffalo..........9f (1967)
Rochester........8f (1933)
Watertown........5f (1972)

Record low maximums for Saturday November 16th...

Buffalo..........22f (1933)
Rochester........23f (1883)
Watertown........29f (1980)

Record low minimums for Sunday November 17th...

Buffalo..........13f (1959)
Rochester........15f (1959)
Watertown........13f (1995)

&&

Buf watches/warnings/advisories...
New York...Winter Weather Advisory until 9 am EST this morning for
nyz010>012-085.
Marine...Small Craft Advisory until 10 PM EST this evening for lez040-
041.
Small Craft Advisory until 7 PM EST this evening for
lez020.
Small Craft Advisory until 10 am EST Saturday for
loz043-044.
Small Craft Advisory until 10 am EST Saturday for loz042.
Small Craft Advisory until 1 am EST Saturday for loz045.

&&

$$

Synopsis...hsk/rsh
near term...hsk

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