Forecast Discussion

371
FXUS61 KBUF 091829
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
229 PM EDT Wed Oct 9 2024

.SYNOPSIS...
One more passing shortwave trough combined with the cool
temperatures and increasing moisture will result in lake enhanced
showers south and southeast of the lakes into tonight. Expect
dry and cool weather Thursday before a brief warm up for the end
of the week and into the weekend.

&&

.NEAR TERM /THROUGH THURSDAY/...
Water Vapor imagery showing a potent shortwave trough pivoting
southeast toward the lower Great Lakes this afternoon. Showers
associated with the incoming shortwave and increasing synoptic
moisture helping to blossom showers across southern Ontario and
Lake Ontario. These showers will continue to develop southward
through the afternoon, becoming fairly widespread across the
area. This will especially be the case downwind of the lakes,
particularly Lake Ontario aided by lake enhancement with 850
mb temperatures dropping to near -2C by early this evening.
There will be the potential for some thunder and graupel or even
some small hail as this colder air aloft works into the area.

Once the short wave trough works through the area this evening,
the parent cold upper low will start to pivot away from the
area and mid-level ridging and associated surface high pressure
will begin to build into the region. This will bring a downward
trend to the shower activity as we work through the night with
nearly all the shower activity done by Thursday morning,
although there could still be some lingering lake induced showers
southeast of Lake Ontario Thursday morning. Latest HRRR/HREF
suggest a fairly amount of lake induced cloud cover remaining
across the area through tonight. Those areas which can clear
enough could certainly see some patchy frost with temperatures
potentially reaching the lower to mid 30s, although most areas
will remain with some degree of cloud cover and temperatures
holding in the upper 30s to lower 40s.

High pressure and associated dry air will continue to build into
the region Thursday completely ending any lingering shower
activity by midday. Cloud cover will take a bit to clear, but
expect by afternoon there will be increasing amounts of
sunshine. Temperatures will be quite cool within a still rather
chilly airmass with highs only in the 50s, with some upper 40s
holding in across the higher terrain.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
High pressure centering over the Ohio Valley on Thursday night will
result in fair dry weather through the night and through the day on
Friday. Lingering lake clouds southeast of Lake Ontario will clear
out during the evening. Clearing skies, lights winds and the region
under the influence of the high pressure will result in one of the
cooler nights in the season, with lows dropping down to the low and
mid 30s for the higher terrain and to the upper 30s to low 40s for
the lower elevations. Conditions continue to look favorable for at
least some frost, mainly across the higher terrain.

Friday, a tightening pressure gradient over the region will cause
winds to increase out of the southwest as the sfc high sinks south
some and an area of low pressure tracks across northern Ontario.
Clouds will slowly increase out of the north as the sfc low tracks
well north of the region, and as its cold front approaches from the
northwest. Temperatures will increase with the southwesterly flow
over the region. Temperatures will warm to around 5 to 10 degrees
above normal with highs reaching the upper 50s to near 70 from the
higher terrain to the lower elevations respectively.

Friday night, the sfc low well to the north of the region will
continue to track east across Eastern Canada, dragging its trailing
cold front across the entire area from northwest to southeast during
the middle of the night (around 6Z). The front will bring some
showers through the area while it tracks through, but with weak
forcing and minimal moisture, along with its quick passage, shower
coverage across much of the area should be minimal and with minimal
time. Shower potential will increase from southwest to northeast,
with better chance for showers will be found over the North Country,
where forcing is a little better with closer proximity to the sfc
low and the trough. Friday night lows will dip down to the low 40s
to mid 50s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Behind the earlier passing front, the weather is expected to remain
dry for most of Saturday. Cooler, but still above normal temperatures
are expected for the day.

From Saturday night through Sunday night, the weather becomes more
active again. A sfc low will track northeast across the Ohio Valley
and into the WNY area through the day Sunday, and then cross the
entire forecast area Sunday night. Out ahead of the approaching sfc
low, a warm front, what was left over from the Saturday morning cold
front, will push north into the area, causing showers to develop
ahead of the sfc low. Showers will expand in coverage as the sfc low
tracks toward and crosses the area later Sunday. There is still some
timing and placement differences among guidance packages for the low
track. There is the potential for some thunderstorms across the area
where the warm front passes north and the instability increases
south of the warm front, within the warm sector of the approaching
sfc low. Behind the passing sfc low on Sunday night/Monday morning,
a cold front will cross the area, with showers increasing ahead of
and along it.

Monday through Tuesday, the sfc low will continue to shift
northeast, but the mid-level trough and low will linger over the
Ohio Valley, Great Lakes and the Northeast through the remainder of
the period. This will result in showers to continue on and off both
synoptic and lake effect/enhanced through the period. Some of the
guidance is indicating an Omega Block will develop over the CONUS
through the middle of the week as the northern jet potentially
phases with the Pacific jet over the mid-Mississippi Valley, and the
western phase of the Pacific Jet builds into a strong ridge over the
western third of the CONUS.

Temperatures on Sunday will remain a few degrees above normal for
most areas. Behind the passing cold front Sunday night, cooler,
below normal temperatures for the start of the new work week can be
expected.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
A potent shortwave trough will work through the region into this
evening. Increasing moisture ahead of the trough will blossom
widespread showers, causing flight conditions to drop to MVFR at
times. Some of these showers may produce small hail and gusty
winds and a few rumbles of thunder.

High pressure will build into the region tonight, causing shower
activity to diminish. Ceilings will primarily be 3-4K feet, with
some isolated 2K foot ceilings possible, southeast of the lakes.

Flight conditions will return to VFR Thursday.

Outlook...

Thursday Night through Saturday...VFR, but a chance for showers
Friday night with MVFR flight conditions.

Sunday and Monday...Restriction possible with showers likely.

&&

.MARINE...
Moderate to fresh northwest winds through tonight will support
Small Craft Advisory conditions on both Lake Ontario and Lake
Erie.

A chilly airmass and relatively warm lakes will produce steep
enough lapse rates to support the development of waterspouts,
especially on Lake Ontario through this evening.

High pressure builds over the lower Great Lakes by Thursday with
conditions improving for the second half of the week.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...Small Craft Advisory until 5 AM EDT Thursday for LEZ040-041.
         Small Craft Advisory until 5 AM EDT Thursday for
         LOZ042-045.
         Small Craft Advisory until 8 AM EDT Thursday for LOZ043-
         044.

&&

$$

SYNOPSIS...EAJ/TMA
NEAR TERM...TMA
SHORT TERM...SW
LONG TERM...SW
AVIATION...TMA
MARINE...EAJ/TMA

NWS BUF Office Area Forecast Discussion