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
683
FXUS61 KBUF 250242
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
942 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/...
The frontal boundary remains draped across the CWA this late
evening, with locations to the north within the 40s and lower 50s,
while to the south of the front, mild air and temperatures within
the 60s are found. A cold front is working its way across the
midwest this evening, with the lead edge of convection now
reaching central lake Erie, and Ohio. This activity will slowly
push eastward, reaching our western boundary past midnight
tonight.

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 MONDAY NIGHT/...
Saturday night, the strong surface low will continue to deepen below
980mb while shifting north across Quebec. Strong cold air advection
and wrap-around moisture behind the cold front will continue a
chance of some scattered rain changing to snow showers across the
area along with development of some modest lake effect snows east of
Lakes Erie and Ontario. 850mb temps will drop to around -14C which
will support lake induced equilibrium heights rising to between 6k
and 8kft feet during the day Sunday. East of Lake Erie expect lake
effect snow showers to peak from late evening into Sunday morning
across the western Southern Tier and portions of southern Erie and
western Wyoming counties, with snow showers ending by Sunday
afternoon. Expect total amounts of 1-3 inches across the higher
terrain east of Lake Erie. East of Lake Ontario, expect snow showers
to peak towards midnight Saturday night into Sunday morning across
the Tug Hill and portions of Oswego County, with lake effect then
weakening in the afternoon but still weakly persisting possibly into
Sunday night perhaps as some light snow and cant completely rule
out a risk for freezing drizzle. Expect 24-36 hour total
accumulations of 2-5 inches east of Lake Ontario, with the higher
amounts restricted to the Tug Hill Plateau. In addition to any snow
chances, winds will rain quite gusty through Sunday as the tail end
of an 850mb jet lingers over the eastern Great Lakes. Gusts into the
30s will be common. Low temperatures will dip down into the 20s
Saturday night then rebound only into the 30s for Sunday.

Sunday night through Monday night, a general zonal mid level flow
with weak warm air advection and limited synoptic moisture will
support mainly cloudy skies with low to slight chances for some
isolated showers or sprinkles. Temps will dip down to around
freezing each night with temps rising into the 40s for most on
Monday.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Our next storm system will track across the Plains to near Chicago
on Tuesday with its associated far reaching warm front shifting
across our region bringing a chance for some showers. This will
transition to all rain and increase in coverage and intensity
Tuesday night and Wednesday as the parent low is forecast to move
through the Lower Great Lakes with its trailing cold front crossing
western and central NY. A 30-40kt low level jet will allow for gusty
winds in the wake of the front which may approach advisory levels
early Wednesday. Temps will run back above normal with highs into
the mid-upper 40s on Tuesday and low 50s on Wednesday just ahead of
the cold front.

Following this storm system, model guidance continues to support a
return to winter for Thursday and Friday into next weekend with
several surges of Arctic air and one or two clipper systems bringing
several chances for snow and lake effect snow.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
For the first 10-12 hours of the 00Z TAF cycle concern will mainly
be upon the surface front, with IFR and lower flight conditions off
Lake Ontario impacting the southern shoreline of Lake Ontario. There
may also be periods of MVFR flight conditions east of Lake Ontario
tonight, but as southerly winds increase we should see an
improvement over the TAF sites impacted by the low stratus clouds.

For now expect the low stratus around KROC to dissipate over the
next few hours, though it may linger longer if the northeast winds
hold on.

Early Saturday a line of convective showers and possible
thunderstorms will reach WNY. This eastward bound activity will
bring strong winds and a brief period of heavy rain with flight
conditions lowering to at least MVFR within the rain. Behind the
cold front there may be a brief period of IFR CIGS with gusty winds
lingering.

Precipitation will be as plain rain as the cold front crosses. Later
in the day as cold air deepens over the Eastern Great Lakes some
lake effect snow showers may fly east of Lake Erie, and also...with
potential greater lake band structure east of Lake Ontario, but just
south of the KART airfield.

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 localized areal and small stream
flooding across the entire Eastern Lake Ontario Region starting
overnight and lasting into early next week. River flood
warnings have been issued for forecast points along the Black
River and Moose River. A general flood watch remains in place
for the remainder of the region to highlight the potential risk
for areal and small stream flooding.

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 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...THOMAS/ZAFF
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...THOMAS
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.