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000
FXUS61 KBUF 171907
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
307 PM EDT Wed Apr 17 2024

.SYNOPSIS...
A warm front will move into the region this afternoon with showers
crossing the area. A cold front will track across the region tonight
with more showers and a few gusty thunderstorms, especially across
western New York this evening. High pressure will move into the
region Thursday and Thursday night. A secondary cold front will
bring scattered showers Friday.

&&

.NEAR TERM /THROUGH THURSDAY/...
Band of showers continuing to lift northeast into central New
York this afternoon with shower activity diminishing greatly
across western New York as modest dry slot works into the
region. Warm frontal boundary pushing into far southwest New
York at this writing with southern portions of Chautauqua county
into the mid 60s and southerly winds. Warm front will continue
to push northward through this evening. Surface based
instability will to grow within the warm sector this afternoon,
with the greatest instability across far southwest New York.
Will need to monitor ongoing upstream convection along the
surface cold front as it approaches far western New York early
this evening. There remains the potential for damaging wind
gusts, especially if the upstream convection can remain
organized and linear while moving eastward into the region.
There is a Marginal risk of Severe Weather across portions of
Chautauqua and Cattaraugus counties with the main concerns being
strong winds and large hail, mainly between 23z-02z.

Instability will be greatly lacking for areas farther to the east.
The expectation is that convection will weaken fairly quickly as it
pushes into a more stable air mass, as it moves eastward across the
rest of the region tonight.

Surface boundary will finish pushing through the eastern half of the
area Thursday. A few lingering showers may remain through late
morning, before ridging makes its way into western New York bringing
improving conditions for the afternoon. Deeper moisture ahead of the
boundary will keep steadier showers going east of Lake Ontario
through the morning hours, before tapering off to more in the way of
scattered activity behind the boundary. Temperatures will run mainly
in the mid 50s to lower 60s.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
A weakening mid-level ridge across the Eastern Seaboard Thursday
night will give way to broad troughing overhead of the Great Lakes
by Friday where it will remain overhead into the weekend. Within
this troughing pattern a few shortwave troughs will round its base
creating on and off active weather.

Thursday night, an occluded front sprawled across the eastern Lake
Ontario region will continue to exit east, supporting lingering
light rain showers. In the wake of the frontal passage, a transient
ridge will slide east across the region providing a short period of
dry weather.

A shortwave will begin to round the base of the trough Friday and
Friday night, supporting a the low pressure system over northern
Ontario to strengthen and gradually move into central Quebec by
Friday night. This will introduce an associated strong cold front to
sweep across the region from west to east, supporting steady rain to
fall. Rainfall amounts will average between a tenth to a quarter of
an inch. By Friday evening, rain showers will be exiting the North
Country, while a dry air mass fills with the approaching surface
ridge.

The aforementioned potent shortwave will then round the base of mid-
level trough and cross the area Saturday. This will support a
secondary cold front to pass across the region starting Saturday
morning with an uptick in rain shower activity Saturday afternoon.
Broad surface high pressure over the Central Plains will begin to
work its way east Saturday night.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
High pressure centered over the Plains States at the start of this
period will ridge eastward across our area through Monday...then
will drift east across New England Monday night. This will help to
keep any passing weak northern stream systems confined to Ontario
and Quebec...thereby resulting in fair dry weather for our region.
With broad/flat troughing aloft on Sunday giving way to more of a
zonal flow during Monday...initially below-normal highs in the mid
40s to lower 50s Sunday will be followed by a return to near-normal
readings in the mid 50s to lower 60s on Monday.

While the medium range guidance packages continue to differ in some
of the details...there remains general agreement that a low-
amplitude mid-level trough and its associated surface reflection
will push east and across our region between Tuesday and Wednesday.
This system will bring our next general chance of showers...with
slightly above normal temps (upper 50s-mid 60s) out ahead of it on
Tuesday giving way to slightly below normal readings (generally low-
mid 50s) following its passage on Wednesday.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Showers and lower ceilings will expand east resulting in low-
end VFR conditions across western New York this afternoon. VFR
conditions will persist east of Lake Ontario (KART). Unsettled
conditions with degraded flight conditions will continue into
this evening with showers in vicinity of Lake Ontario and the
eastern Lake Ontario region. Mainly MVFR conditions are expected
across the region but IFR conditions are possible across the
Finger Lakes region and into central NY (outside of TAF sites.)

Another round of showers with a chance of thunderstorms will enter
western NY this evening. Thunderstorms and heavy showers may result
in IFR or lower at KIAG, KBUF, and KJHW through this evening.
Confidence is low for coverage of convection, however best chance
will be between (22z-03z). Showers will move east overnight and
flight conditions will remain MVFR with a chance of IFR after 06z
across a majority of the forecast area.

Outlook...

Wednesday night and Thursday...MVFR/VFR with showers likely.
Friday and Saturday...MVFR/VFR with a chance of showers.
Sunday and Monday...Mainly VFR.

&&

.MARINE...
Small Craft conditions will remain through early tonight on the
western end of Lake Ontario of an approaching warm front. A
cold front will then cross the lakes tonight, with the
potential for strong thunderstorms and special marine warnings
on Lake Erie this evening. A southwest-west flow will develop
by Friday into Saturday and could approach 20 knots with a
period of small craft conditions possible on both lakes at some
period during this period. High pressure building into the lower
Great Lakes will bring weakening winds Sunday and Monday.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 2 AM EDT Thursday for LOZ042-043.

&&

$$

SYNOPSIS...HSK/TMA
NEAR TERM...TMA
SHORT TERM...EAJ
LONG TERM...JJR
AVIATION...HSK/TMA
MARINE...TMA