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671
FXUS61 KBUF 190530
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
130 AM EDT Wed Mar 19 2025

.SYNOPSIS...
Fair dry weather will be in place throughout the region through at
least Wednesday evening...as high pressure will remain in place
along the eastern seaboard. Meanwhile...a deepening southerly flow
will direct warmer air in our direction with the mercury reaching
well into the 70s for many of the western counties. The next deep
storm system will track by to our west on Thursday...and this will
push a series of cold fronts through our region which will support
some widespread rain.

&&

.NEAR TERM /THROUGH TODAY/...
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High pressure extending down the eastern seaboard will maintain fair
dry weather throughout our region overnight with just some
passing cirrus. It will be notably milder than recent nights
though...a precursor of what we can expect on Wednesday.
Temperatures tonight will only bottom out in the low to mid 40s
over the western counties...with the 30s to near 40 east of Lake
Ontario.

Wednesday will feature the warmest temperatures of the week...as a
thermal ridge will build across the lower Great Lakes. H85 temps
will soar to between +10C and +12C...which fully mixed would yield
max temps in the mid to upper 70s. Will thus continue to aim well
above most forecast packages...which will place our forecast area in
the upper quartile of the forecast envelope. Southerly downslope
flow will continue to increase...giving an added boost of
compressional warming to the lake plains. Expect highs in the low to
mid 70s in most areas, with mid to upper 60s limited to higher
terrain. The southerly wind will direct most of the cooling
influence from Lake Erie and Lake Ontario into Canada. Winds will
gust in the 25-35 mph range Wednesday afternoon and again overnight
Wednesday night, strongest in downslope areas.

A deep...mature storm system will then track by to our west during
the course of Wednesday night while slowly weakening. This will keep
a very mild southerly flow over our region which will hold overnight
temperatures near or above 50 in most areas. The first of two cold
fronts extending southward from the aforementioned surface low will
cross Lake Erie and southern Ontario during the wee hours of
Thursday. Showers will break out ahead of this boundary for sites
west of the Genesee valley.
-- End Changed Discussion --

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
Thursday and Thursday night upper level troughing will continue to
sharpen and take on more of a negative tilt as it pivots across our
area and eventually into eastern New York/western New England. As it
does so...the initial elongated surface low will gradually slide its
pair of cold trailing cold fronts across our region between Thursday
and Thursday evening...with secondary surface cyclogenesis taking
place along the mid-Atlantic and southern New England coastlines
Thursday night.

As these features translate eastward...they will help to lift an
antecedent swath of moisture of subtropical origins...thereby
leading to 6-8 hour period of fairly widespread light rain that will
cross our region from west to east. Based on the amount of available
moisture (PWATs of near 1 inch) and the quality of the forcing
provided by the surface and upper-level features...have pushed PoPs
further up into the categorical range areawide. The best rain
chances currently appear to come between Thursday morning and early
Thursday afternoon across far western New York...late morning and
mid-late afternoon across the Finger Lakes...and Thursday afternoon
and early Thursday evening east of Lake Ontario...with this timing
slowing a little further given the continued increasing negative
tilt and slightly slower overall eastward progression to this system
seen in the latest guidance.

Immediately in the wake of the main swath of rain...lingering
upsloping will keep some lighter precip going across the higher
terrain east of both lakes for a time (mainly Thursday afternoon
east of Lake Erie and Thursday evening east of Lake Ontario)...with
this then fading out from west to east Thursday night as surface-
based ridging and associated drier air/subsidence begins building in
behind the departing system. The incoming drier airmass and
subsidence will also help to greatly mute any possible lake response
later Thursday night...just as temps aloft get marginally cold
enough to support such.

As for temps Thursday and Thursday night...these will start out
rather mild out ahead of the initial cold front on Thursday...with
fairly widespread highs in the mid-upper 50s across the far west and
in the upper 50s-mid 60s across our central and eastern zones.
Following the passage of this first boundary...steady cold air
advection will send readings steadily downward through the balance
of Thursday and Thursday night...with readings eventually bottoming
out in the mid-upper 20s in most locations by Friday morning. This
should result in the rain mixing with and eventually changing to
snow as it winds down Thursday night...possibly resulting in up to
an inch of accumulation across the Tug Hill/western Adirondack
foothills east of Lake Ontario...and maybe a dusting to a few tenths
of an inch across the higher terrain east of Lake Erie. Elsewhere
expect little or no accumulation.

There may also be a short period of rather windy conditions across
far western New York Thursday afternoon as cold advection increases
and winds turn more southwesterly/the pressure gradient tightens
with the approach/passage of the secondary cold front...with more
efficient downward momentum transport and funnelling effects
possibly helping to briefly produce some 35-45 mph gusts from the
Lake Erie shoreline across portions of the Niagara Frontier. These
winds should then quickly diminish following the passage of the
secondary cold front late Thursday afternoon and early Thursday
evening.

On Friday the aforementioned surface ridge will build eastward
across our area...with attendant drying/warming/subsidence and
strong late March diurnal influences helping to quickly squelch
whatever meager lake response there is southeast of the lakes...
which at this point appears to be limited to just some lower cloud
cover. Otherwise we can expect a dry and cooler day with highs
ranging from the upper 30s across the higher terrain to the lower
and mid 40s across the lower elevations. Dry and quiet weather
should then follow for Friday night as the surface ridge slowly
drifts east to eastern New York...with lows expected to range from
around 30 east to the mid 30s along the Lake Erie shoreline as a
milder return flow begins to set up behind the departing ridge axis.
At this point still expect the next system to hold off until during
the day Saturday...more details on that follow below.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
A pair of troughs will rotate across the Great Lakes Region Saturday
through the start of early next week, with a brief period of ridging
in between each trough`s passage. Overall this will support periods
of cool and wet weather, with a potential for some winter weather.

Diving into the details, a fast moving trough and associated cold
front will slide across the region Saturday, supporting chances for
widespread rain/snow. After a brief lull in active weather Sunday,
due to mid-level ridging passing across the region, the next mid-
level trough as corresponding surface low will slide northeast out
of the Ohio Valley and just west of New York State. With this
system, expect chances for rain and snow to return to the region.

Temperatures throughout the weekend and into the start of next week
will average near to slightly below normal.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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Widespread VFR conditions will be in place through Wednesday evening.

A low level jet will continue move into the region through
Wednesday. Low level wind shear is possible into early Wednesday
morning as surface winds remain south-southeast and under
10kts. The greatest risk will be across the Niagara Frontier
(KBUF/KIAG/KJHW.) Good diurnal mixing will create breezy
conditions at the surface Wednesday. The strongest winds will be
across the higher terrain of western and north- central NY.
Surface winds will subside into Wednesday evening, with the
exception of downslope regions (KDKK/KART) where gusts may reach
+35 knots. Low level wind shear is possible at TAF sites
Wednesday night as winds aloft increase to 50kts between 1-2k
feet.

Outlook...

Late Wednesday night...VFR. Scattered showers over the far
western counties late. Thursday...VFR/MVFR. Rain. Windy.
Thursday night...MVFR/IFR with rain showers changing to snow
showers. Breezy. Friday...Mainly VFR but with MVFR cigs east of
the Genesee valley in the morning when there can be some snow
showers. Saturday...Mainly VFR with a chance of rain showers.
Sunday...VFR conditions.
-- End Changed Discussion --

&&

.MARINE...
High pressure will remain anchored along the eastern seaboard
through Wednesday with increasing southerly flow over the lower
Great Lakes. Winds will remain relatively light through tonight,
then increase Wednesday, approaching Small Craft Advisory criteria
toward the east end of Lake Ontario later Wednesday afternoon and
Wednesday night.

A strong cold front will sweep east across the lower Great Lakes
late Wednesday night and Thursday. Moderate southerlies ahead of the
front will become southwest and west behind the front and increase
Thursday, before veering northwesterly Thursday night into Friday.
This will bring a period of Small Craft Advisory conditions for both
lakes: For Lake Erie, this would be mainly later Wednesday night
through some or all of Thursday night. For Lake Ontario, this would
be Thursday through a portion of Friday, just depending on location.

&&

.HYDROLOGY...
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High flows will continue into Thursday along the middle and
lower reaches of the Black River in Lewis and Jefferson
counties. A River Flood Warning remains in effect. Flooding
will be minor, with the forecast point at Watertown expected to
crest in the lower end of minor flood stage. At these levels,
flooding is mainly limited to agricultural land along the river
and a few secondary and side roads. Water may approach a few
commercial properties in Dexter with levels just exceeding the
10 foot flood stage.
-- End Changed Discussion --

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...RSH
NEAR TERM...Hitchcock/HSK/JM/RSH
SHORT TERM...JJR
LONG TERM...EAJ
AVIATION...HSK
MARINE...Hitchcock/JM
HYDROLOGY...Hitchcock/JM