Area Forecast Discussion
Issued by NWS Buffalo, NY

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBUF 241845
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
145 PM EST Fri Feb 24 2017

.SYNOPSIS...
A strong cold front will move through Western and Central New
York during Saturday, marking the end of a long stretch of
unseasonably warm weather. Showers and some potentially strong
thunderstorms will accompany the front, followed by gusty to
windy conditions behind the front later Saturday afternoon and
evening. A quick shot of colder air Sunday may bring some lake
effect snows east of the lakes.

&&

.NEAR TERM /THROUGH SATURDAY/...
Record, high temperatures are being experienced through parts of
WNY this afternoon, with some February all-time highs on the
verge of being toppled.

This is due to a surge of warm air aloft and downslope winds
behind a warm front that is now stalled just south of the
southern Lake Ontario shoreline. Temperatures on the immediate
edge of the lake are in the 40s with a NE flow, while 70s can
be found further inland. This battle between the unseasonable
warm airmass and the cold lakes will continue into the afternoon
hours.

This evening, expect areas away from the lakes to remain almost
summerlike, with temperatures in the lower 60s for much, if not
the entire night. There may be a stray shower late over far
WNY, but in general expect a dry night ahead of an approaching
cold front tied to the slowly deepening surface low that will
be crossing Lake Huron overnight.

Saturday...The main event will be early Saturday over far WNY,
midday for the Genesee Valley, and in the afternoon for points
east. Overall, expect a line of showers, along with some
potentially strong thunderstorms to move across the region, with
a continued marginal risked denoted by SPC. The strength will
be in part due to a low level 50kt wind that may be able to mix
down in the stronger storms. Many climatic signals are near the
extreme, including excessive warmth aloft and high moisture
content.

Winds Saturday...Once the line passes, cold air will rush in.
Some mixing will allow for windy conditions behind the front.
Although the surface low track is favorable for a wind event
together with a continued deepening center, the low center and
accompanying low level jet is not excessively strong, not
deepening rapidly and winds aloft (ex 850mb) generally remaining
in the 50kt range with slowly increasing wind speed with
height. A high wind signature typically features strong winds
aloft reaching closer to the surface with a rapidly deepening
low to the NE. Will expand the advisory a little to include
Monroe County due to the location of the low level jet, but
otherwise will keep the wind advisory as is. There still is a
chance for a high wind event along the Lake Erie shoreline, but
confidence remains too low for an issuance at this time.

There is also a flood threat east of Lake Ontario. Please see
the hydrology section at the bottom below for further
information.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
Saturday night  and Sunday the deep low will exit to the
northeast across Quebec. A period of wrap around moisture and
ascent with the passage of the mid level trough will produce a
few scattered snow showers Saturday night. The airmass will also
become cold enough to support a modest lake response east of
the lakes, with lake induced equilibrium levels rising to around
8K feet briefly. East of Lake Erie expect lake effect snow
showers to peak from late evening through the early overnight
Saturday night across the western Southern Tier and portions of
southern Erie and western Wyoming counties, with snow showers
then weakening by Sunday morning and ending by Sunday afternoon.
Expect total amounts of 2-3 inches across the higher terrain
east of Lake Erie. East of Lake Ontario, expect snow showers to
peak later Saturday night and Sunday morning across the Tug Hill
and portions of Oswego County, with lake effect then weakening
in the afternoon. Expect total accumulations of 2-5 inches east
of Lake Ontario, with the higher amounts restricted to the Tug
Hill Plateau.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
The main feature to contend during this period will be yet another
Colorado Low cutting across the Great Lakes around the middle of
next week.

The overall pattern during this time frame will be quite
transitory...as a broad low amplitude trough over the country will
give way to a progressive longwave trough that will start over the
western states. Significant cutter storms typically mark the change
in the overlying pattern...and this time period will feature such a
storm. The details...

Sunday night and Monday, a weak mid level trough and associated
surface low will track from the northern Great Lakes east across
Quebec, with a trailing weak trough brushing by the Lower Great
Lakes. The combination of weak synoptic scale forcing and very
limited lake enhancement may produce a few snow showers east and
northeast of the lakes Sunday night and Monday morning, with any
leftover precip changing mainly to a few rain showers by Monday
afternoon as the boundary layer warms.

Significant cyclogenesis will begin across the central High Plains
late Monday and Monday night. For what its worth...the operational
ECMWF again looks to be most realistic with this whole storm...so
have leaned more heavily with this guidance package.

The newly formed storm system will track across the Plains to near
Chicago on Tuesday...while its associated far reaching warm frontal
boundary will approach our region. This could lead to some light
rain or snow for our region...which will transition to all rain and
increase in coverage and intensity Tuesday night and Wednesday as
the parent low is forecast through the Lower Great Lakes.

In the wake of this system...there will be the risk for gusty winds
Wednesday night and Thursday...although guidance is not quite as
impressive looking with it than it was in earlier runs. There is
also markedly more spread in the various ensemble solutions.

Following this storm system, model guidance continues to support a
return to winter for Thursday through the following weekend with
temperatures returning to at or below normal, and a series of
clipper systems bringing several opportunities for snow and lake
effect snow.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR conditions should be expected for areas S of Lake Ontario
for the afternoon and evening hours. Some IFR conditions are
possible at times along a stalled warm frontal boundary along
the lakeshore, but this should remain N of KIAG-KROC. Watertown
was IFR at 18Z...but with some improvement expected during the
afternoon based on cloud trends.

Tonight conditions will lower to MVFR across the area with
increasing moisture ahead of an approaching strong cold front
boundary for Saturday morning. A stray shower may form as some
instability forms ahead of a cold front over far WNY, but most
areas should remain dry.

The cold front will plow across WNY during Saturday morning,
Genesee valley midday, and across eastern Lake Ontario later in
the afternoon. Expect MVFR and possible IFR with the frontal
passage, including the threat for convection with the front.
Breezy to windy SW winds will pick up behind the front for the
afternoon. Some limited lake effect rain/snow is possible east
of Lake Erie late in the day.

Outlook...

Saturday Night. Windy with some lake effect east of the lakes.
Sunday...VFR, but IFR to MVFR in lake effect snow SE of both lakes.
Monday...VFR, possible MVFR with chance of -SHRA/-SHSN.
Tuesday and Wednesday...Chance of rain with MVFR/IFR possible.

&&

.MARINE...
A stalled warm front will linger across Lake Ontario this
evening. A strong cold front will move across Lake Erie Saturday
morning and Lake Ontario later Saturday morning and afternoon.
Some convection is possible, along with strong winds with the
frontal passage. Small craft advisories with W winds to 30kts
will then last through the weekend.

&&

.HYDROLOGY...
There is a potential for flooding across the Eastern Lake
Ontario Region starting late Friday night and lasting into
early next week. Warnings have been issued for forecast points
along the Black River, while a general flood watch remains in
place for the remainder of the region.

While the snow pack has largely melted across Western New York,
a significant snow pack remains east of Lake Ontario, including
the Black River basin. Snow water equivalent values are about
130% of normal, with this snow pack expected to become
increasingly ripe through into the weekend due to the warm
weather.

On Saturday, a strong system will pass to our north with
a prolonged period of warm (50+ degree) temperatures expected
late Friday through Saturday until the passage of a cold front
drops temperatures below freezing Saturday night. This will be
combine with gusty winds and high dewpoints to rapidly melt a
significant portion of the snow pack in place. This system will
also bring a period of rain Saturday, with amounts expected to
average around an inch.

This may result in multiple issues east of Lake Ontario. First,
the combination of snowmelt and rain may cause areal flooding on
small, faster responding creeks and rivers starting late
Saturday. Some ice jams are also possible. After this, runoff
will cause the Black River and its tributaries that drain the
Tug Hill Plateau and the western Adirondacks to respond
Saturday night and Sunday and lasting into next week. Flooding
is also possible on the Salmon River and other rivers in
northern Oswego County that drain the western slopes of the Tug
Hill.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Flood Watch from 7 PM EST this evening through Sunday evening
     for NYZ006>008.
     Wind Advisory from 10 AM to 10 PM EST Saturday for NYZ001>003-
     010>012-019-085.
MARINE...Small Craft Advisory from 7 AM Saturday to 7 PM EST Sunday for
         LEZ020-040-041.
         Small Craft Advisory from 7 AM Saturday to 5 AM EST
         Monday for LOZ042-043.
         Small Craft Advisory from 10 AM Saturday to 5 AM EST
         Monday for LOZ044-045.

&&

$$

SYNOPSIS...ZAFF
NEAR TERM...ZAFF
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK/RSH
AVIATION...CHURCH/ZAFF
MARINE...ZAFF
HYDROLOGY...APFFEL/HITCHCOCK


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.