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257
FXUS61 KBUF 031612
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1212 PM EDT Fri May 3 2024

.SYNOPSIS...
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High pressure will continue to slide east into New England today
supporting mainly dry weather through much of the day. A warm front
will move northeast near the Saint Lawrence Valley this afternoon
supporting a surge in warm air, allowing temperatures to soar well
above average today. A pair of slow moving cold fronts will then
pass across the area tonight through Sunday supporting a couple of
rounds of showers and possible a few rumbles of thunder. High
pressure then returns Monday, allowing for a dry start to the new
work week.
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&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Surface high pressure will slide east toward the New England coast
today, all the while the upper level ridge axis passes across the
area. Additionally, a warm front will push northeast to near the
Saint Lawrence Valley this afternoon. Overall this will support warm
air advection today, causing temperatures to surge into the mid to
upper 70s across the vast majority of the region with a few low 80s
possible across far WNY and the traditional warmer spots of the
Genesee Valley. Local lake breeze circulations will develop this
afternoon making areas along and near the lakeshores cooler,
particularly the southcentral and southwestern Lake Ontario
shoreline and well along and just inland of Lake Erie.

With the high exiting the region through much of today, expect the
vast majority of the day to be on the dry side. However, as the
aforementioned upper level ridge axis drifts east across the eastern
half of the state, southwesterly flow will advect in deeper moisture
this afternoon through evening. Eventually by late Friday a cold
front will interact with the increasing moisture, and in combination
of diurnal heating a few scattered showers and thunderstorms may
result. The best focus will lie along the lake breeze boundary
inland from Lake Erie.

The cold front will then gradually pass across Lake Erie tonight
before stalling across Western New York by Saturday morning. This
will support showers and thunderstorms to continue to spread across
WNY throughout the night. Expect a mild night Friday with lows
ranging in the 50s, with the warmer readings occuring along the Lake
Erie shoreline.
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&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
A mid level ridge axis will move from NY/PA Saturday morning to off
the east coast by Sunday afternoon. A few weak mid level shortwaves
will move east into the ridge position and weaken with time. Despite
the presence of a ridge aloft, the weekend will be unsettled as a
slow moving low level trough and associated plume of deep moisture
drifts across the eastern US beneath the mid level ridge. Model
guidance has shown some run to run variability with respect to
timing of the most organized rain. The general trend since yesterday
has been to decrease rain potential on Saturday (especially in the
afternoon) while increasing rain chances Sunday.

Saturday, a mid level shortwave will move across the eastern Great
Lakes and weaken as it encounters the persistent ridge over NY/PA. A
weak surface trough and associated area of low level moisture
convergence will move across the area in the morning and provide
some focus for a few areas of showers and possibly an isolated
thunderstorm or two, with the best coverage likely found across
Western NY. This trough largely washes out by the afternoon, and
ascent and moisture temporarily fade across the eastern Great Lakes.
While there may still be a few spotty showers, Saturday afternoon
and evening should feature plenty of rain free time.

Saturday night will start with only spotty coverage of showers and
plenty of rain free areas during the evening. Another mid level
shortwave will then move from the Ohio Valley into NY/PA later
Saturday night through Sunday, bringing renewed ascent. A plume of
deeper moisture will be advected northward into the area as low/mid
level SSW flow increases in response to a digging trough over the
upper Great Lakes. The increase in forcing and moisture will allow
for a commensurate increase in rain coverage from southwest to
northeast late Saturday night through Sunday across the region.
There may be just enough instability to support some isolated weak
thunder.

The mid and low level trough axis will gradually move east into New
England later Sunday and Sunday night, with rain tapering off from
west to east.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Surface high pressure over northwest Ontario will ridge
southeastward into the Great Lakes Monday, with an associated bubble
of dry air bringing a return to dry weather. The dry weather will
last into at least Tuesday morning. Model guidance begins to show
some spread by Tuesday afternoon with the arrival of the next
system. The GFS and GEFS ensemble mean continues to be on the fast
side of the guidance envelope, while the ECMWF and GEM are slower.
For now kept some chance POPS for Tuesday afternoon, but if the
slower guidance verifies Tuesday will end up being dry.

Wednesday through Thursday an expansive mid level low will gradually
move east across the north central US. A series of mid level
shortwaves will eject out of this system and move east across the
Ohio Valley and eastern Great Lakes, with each feature bringing
ascent and deeper moisture to the region. This will produce
occasional rounds of showers and possibly a few thunderstorms for
mid to late week next week.

Temperatures will continue to run above average through all of next
week.

&&

.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
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A combination of exiting high pressure to the east into New England
today and a warm front pushing into the Saint Lawrence Valley this
afternoon will continue to support VFR flight conditions. Expect at
least some thickening mid and upper level cloud decks ahead a
weakening cold front slowly approaching from the west, especially
across western NY. Despite the increasing cloud cover, VFR
conditions will persist.

The weakening front will slowly move toward the area this afternoon,
with a low chance for a few showers and possibly a rumble of thunder
across far western NY late this afternoon into the evening with VFR
conditions remaining intact.

Showers become likely across western NY tonight, with just a chance
of showers from the Finger Lakes east. A few thunder storms will
also be possible, especially across western NY. Flight conditions
will slowly deteriorate through the overnight with MVFR/higher
terrain IFR CIGS possible by late in the TAF period for KBUF/KIAG
and KJHW respectively, mainly across western NY...with VFR/low VFR
from KROC to KART.

Outlook...

Saturday...MVFR to VFR with showers likely and possible
thunderstorms.

Sunday...Morning showers, then a chance of afternoon showers,
otherwise mainly VFR.

Monday...VFR.

Tuesday...Mainly VFR. Chance of showers and thunderstorms.
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&&

.MARINE...
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Mainly weak pressure gradients are expected to persist into this
weekend across the lower Great Lakes supporting winds to generally
remain below 15 knots. Expect this to bring some choppy waters at
times, however conditions will remain below headline criteria,
especially with an offshore flow developing tonight then persisting
through the weekend, keeping the highest waves over Canadian waters
for Saturday and Sunday. While quiet weather continues for the end
of the work week, a few showers and thunderstorms will be possible
tonight through Sunday. High pressure will build across the area for
the start of the new work week providing mainly gentle breezes with
no more than some light chop expected through Tuesday.
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&&

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

&&

$$

SYNOPSIS...JM
NEAR TERM...EAJ/JM
SHORT TERM...Hitchcock
LONG TERM...Hitchcock
AVIATION...JM
MARINE...JM