655
FXUS61 KBUF 241012
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
612 AM EDT Wed Apr 24 2024

.SYNOPSIS...
A cold front will push away to our southeast today...but for many
areas...leftover clouds and showers will linger into the early
afternoon. An expansive area of Canadian high pressure will then
assure us of fair dry weather Thursday and Friday. While some
showers will be likely this coming weekend...the majority of the
time will be rainfree. Looking further down the road...we can look
forward to a summer-like warm up Sunday and Monday with the mercury
surging well into the 70s and even a few spots into the 80s.

&&

.NEAR TERM /THROUGH THURSDAY/...
...Downright Cold Tonight...

A series of weak surface waves over the St Lawrence valley this
morning will drag a cold front southeast away from our region during
the course of the midday and afternoon. A wealth of relatively deep
moisture will linger in its wake though with a northerly upslope
flow and moderately strong frontogenetic forcing supportive of some
lingering showers through the midday hours. Some wet flakes may even
mix in across the higher terrain...mainly over the Tug Hill.

As we work through the afternoon...notably drier air will work
southwards from Ontario. This in combination with increased
subsidence will lead to slow but pronounced clearing from north to
south. Unfortunately...this could mean that areas closer to the
Pennsylvania border could be fairly cloudy right up to sunset.

In any case...it will be chilly for most areas today...as a gusty
northerly wind will accompany temperatures that will only be in the
mid and upper 40s.

A large Canadian sfc high over the Upper Great Lakes this evening
will then gradually expand across the whole Great Lakes region
overnight and Thursday. This will GUARANTEE fair dry weather
throughout the region...although temperatures will be solidly BELOW
normal. Mins tonight will be solidly in the 20s away from the
immediate lake shores with highs on Thursday only ranging from the
Upper 40s to lower 50s. These readings will average some 10 degrees
below typical late April levels.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Sprawling surface high pressure centered directly overhead at the
start of Thursday evening will slowly drift eastward to New England
by Friday morning...then off the New England coast by Friday
evening. This will keep fair...dry...and tranquil weather intact
across our region right through Friday...along with mainly
clear/mostly sunny skies. Favorable conditions for radiational
cooling (especially across eastern sections) will allow for one last
chilly night with lows ranging from the mid 20s east to the lower
30s west Thursday night...before a developing SSE return flow of
milder air and building ridging/subsidence aloft help temps to climb
back into the lower to mid 60s in most areas Friday. The warmest
readings on Friday will be found along the Lake Erie shoreline due
to an added boost from downsloping...while areas along the south
shore of Lake Ontario will be notably cooler (50s) due to an ENE
flow off that lake.

Friday night and Saturday an initial weakening cutter-type system
will lift northeastward across the northern Plains and Upper Great
Lakes. A warm frontal boundary snaking southeastward from this low
will approach our area from the west later Friday night before
partially crossing our region during Saturday...while also weakening
as it pushes further out ahead of its filling parent surface low and
runs smack dab into the sharp upper ridging that will still be in
place aloft. It still appears that enough isentropic ascent and
moisture will be in place to bring a decent likelihood of some
showers to far western New York late Friday night and Saturday
morning...with this activity then tending to weaken and diminish in
coverage as it pushes further east during the afternoon hours.
Meanwhile persistent warm air advection will result in a continued
upward arc in temperatures...with lows in the lower 40s east to
around 50 west Friday night followed by fairly widespread highs
ranging from the upper 50s/lower 60s east to the mid-upper 60s west
on Saturday. Should the showers break up quickly enough across far
western New York Saturday afternoon...the presence of a stiff
southerly downslope flow and 850 mb temps of around +10C may well
provide a sneaky potential for readings to surge into the lower 70s
along the Lake Erie shoreline and across portions of the Niagara
Frontier...even in spite of what should still be fairly cloudy
skies.

Saturday night the weakening initial surface low will lift further
northeast across central Ontario and into Quebec Province...while a
second and stronger cutter-type low takes shape across the central
Plains States. At the same time...upper level ridging will also
begin to rebuild northward across the Ohio Valley and New York
State. Additional scattered to numerous showers and perhaps an
isolated thunderstorm will remain possible attendant to the
weakening/departing warm frontal boundary (with chances for these
highest across north central New York)...with a few much more widely
scattered showers/storms remaining possible elsewhere due to
continued modest/ broad warm air advection aloft. Otherwise it will
be a mild night more typical of late May/June as the warm sector
establishes itself across our area...with overnight lows ranging
from the lower 50s east to around 60 across the lake plains of far
western New York.

&&

.LONG TERM /SUNDAY THROUGH TUESDAY/...
On Sunday the initial surface low will wash out across northern
Quebec...while the second cutter system develops into the northern
Plains States. These developments...coupled with continued building
upper level ridging aloft...will help to stall out the initial
system`s cold front to our north...leaving our area awash in warm
air typical of late spring/early summer with 850 mb temps reaching
the +11C to +13C range by afternoon. Such warmth will be supportive
of highs reaching well into the 70s south of Lake Ontario...and into
the lower 70s across the North Country. The warmest readings overall
will be found across the Genesee Valley and western Finger
Lakes...where it`s appearing increasingly likely that some locations
(for example, Dansville) could crack the 80 degree mark. With
synoptic-scale forcing notably weaker with our region lying within
the warm sector and under the building upper level ridge...any
convective potential will likely be more dependent upon diurnal
heating of our warm and borderline humid airmass...and with this in
mind have focused some chance PoPs across the typical areas inland
from the lakes during the heating of the day...though the day is
also likely to feature a considerable amount of dry time overall.
Any such activity should then tend to fade with the loss of heating
and continued building of the upper ridge Sunday night...leaving
behind mainly dry and unseasonably warm conditions for the bulk of
the night...with lows mostly ranging between 55 and 60.

Expect similar conditions to prevail on Monday as the second cutter
low makes its way northeastward and across Lake Superior...with
temps likely to reach even a few degrees higher than those of Sunday
as 850 mb T`s climb to between +12C and +15C. Better chances for
showers and thunderstorms may then arrive Monday night and Tuesday
as the surface low makes its way to Quebec and slides its trailing
cold front across our region...with somewhat cooler (but still well
above normal) temperatures expected on Tuesday owing to the frontal
passage.

&&

.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
Fairly widespread IFR cigs will be in place this morning along with
leftover rain or wet snow showers...as a slow moving cold front will
exit to our southeast. During the course of the afternoon...these
low cigs will thin and clear from north to south...leaving VFR
weather for the latter portion of the day. Along with the pronounced
clearing...a gusty north to northwest wind will occasionally gust to
30 knots at times.

High pressure centered over the Upper Great Lakes this evening will
then slowly settle over the region tonight and Thursday. This will
guarantee fair dry VFR weather.

Outlook...

Friday...VFR.
Saturday...VFR/MVFR. A chance of showers.
Sunday...Mainly VFR. A chance of showers.

&&

.MARINE...
In the wake of a passing cold front...winds will shift to the north
and freshen through the midday hours. While this will result in
small craft advisory conditions on Lake Ontario...the short fetch
and relative brief duration of the elevated winds will only produce
choppy to occasionally rough waters on Lake Erie.

Expansive high pressure centered over the Upper Great Lakes this
evening will then gradually build across the Lower Great Lakes
overnight and Thursday. This will significantly lower winds and
waves throughout the region tonight...with only gentle breezes and
negligible wave action expected for Thursday as the sfc high passes
overhead.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for LOZ042-
         045.
         Small Craft Advisory until 8 PM EDT this evening for
         LOZ043-044.

&&

$$

SYNOPSIS...RSH
NEAR TERM...RSH
SHORT TERM...JJR
LONG TERM...JJR
AVIATION...RSH
MARINE...RSH

NWS BUF Office Area Forecast Discussion