-- Discussion containing changed information from previous version are highlighted. --
700
FXUS61 KBUF 070751
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
351 AM EDT Fri Jun 7 2024

.SYNOPSIS...
-- Changed Discussion --
A cooler and less humid airmass will be in place through early next
week. Unfortunately, the cooler conditions will be accompanied by
unsettled conditions with fairly frequent showers. Warmer weather
will return later next week.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Water vapor imagery shows a well defined area of low pressure over
the Great Lakes region this morning. Regional radar shows little
weather across the forecast area as of 4 AM, however increasing
moisture from the west will bring a low chance of showers to the
region through daybreak.

An anomalously deep mid-level low will move from Georgian Bay to
southern Quebec today through tonight. Cool, moist air will filter
into the eastern Great Lakes region resulting in a unsettled and
cool period.

Daytime heating with cool air aloft will result in cumulus/strato
cumulus and eventually showers to develop by late morning across
much of the region. A southwest flow will create lake shadows
immediately downwind of the Lakes with drier conditions across the
Northtowns and northern Tug Hill region through the morning hours.
The flow will become westerly this afternoon and drier conditions
will move south into the Southtowns/Western Southern Tier and across
the Tug Hill through the afternoon. Scattered to numerous showers
will be ongoing outside of these areas. A few thunderstorms can`t be
ruled out with steepening lapse rates through the afternoon. Hi-res
guidance is keying in on steady showers along a convergence zone
from the Northtowns to Batavia through late afternoon. Rainfall
amounts will range severely across the region today. Higher amounts
of 0.25-0.5 inches are possible from the Niagara Frontier to
Rochester with less than 0.10 inches along the Lake Erie and Lake
Ontario shorelines. Breezy today with wind gusts up to 30 mph across
western NY and the northern Tug Hill region.

Showers and any thunderstorms will slowly lessen in coverage this
evening. Looking aloft, temperatures at 850mb will be around +5C
tonight and based on KBUF sounding climatology this is near the 10th
percentile for June 8. In other words, a pretty chilly airmass for
this time of year in western and north central NY. The loss of
daytime heating will suppress the coverage of showers, however lake
enhanced rain showers will keep showers east of the Lakes with an
uptick in showers east of Lake Ontario late tonight.
-- End Changed Discussion --

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
-- Changed Discussion --
The unsettled pattern will continue through the weekend as a
longwave trough remains established across eastern North America. A
multitude of shortwaves will move through the mean northwest flow
aloft, which each bringing a period of enhanced ascent and deeper
moisture. The timing of these features is starting to become more
clear in model guidance for the weekend.

Saturday, a mid level trough and closed low will move east across
New England and away from the area. Lingering forcing and deep
moisture will continue in the morning east of Lake Ontario, and
will combine with westerly upslope flow and even some lake generated
instability to support more showers. The showers east of Lake
Ontario will gradually taper off and end through the day. Meanwhile
across Western NY, a brief period of subsidence and drying behind
the departing trough will bring mainly dry weather and even some
sunshine. Highs will reach the lower 70s for the lower elevations of
Western NY, with 60s for higher terrain and east of Lake Ontario.

Saturday night, another seasonably strong mid level closed
circulation will move from northwest Ontario to southern Quebec,
with DPVA and height falls spreading into the eastern Great Lakes
overnight. The forcing from the approaching trough will combine with
a strengthening upper level jet streak rounding the base of the
trough to bring a period of deep layer ascent to the eastern Great
Lakes. Model guidance continues to suggest a baroclinic wave will
peel off of a system over the central High Plains and partially
phase with the incoming trough, producing a period of widespread
showers and a few scattered thunderstorms Saturday night across much
of the region as the baroclinic wave enhances frontogenesis and
deformation.

Sunday through Sunday night, the organized area of rain from
Saturday night will exit early Sunday. Several additional shortwaves
will move trough the mean trough across the Great Lakes and New
England, bringing a few more rounds of at least scattered showers
Sunday through Sunday night. Modest diurnal instability will
contribute to shower chances Sunday, and modest lake instability
and upslope flow will contribute Sunday night. Temperatures will be
on the cool side, with highs in the mid to upper 60s in most
locations.
-- End Changed Discussion --

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
-- Changed Discussion --
The same general longwave pattern will remain in place across North
America through early next week, with an expansive ridge in the west
and a trough in the east. In fact, the trough in the east will reach
its deepest extent on Monday when 850MB temps drop to around +4C
across the eastern Great Lakes. The trough and associated forcing,
deeper moisture, and cool air aloft will continue to support showers
and cool temperatures through Monday night. Weak diurnal instability
will continue to enhance showers by day, with lake instability
enhancing showers by night.

By Tuesday, the trough will begin to deamplify and drift to along or
just off the east coast. Temperatures aloft are still quite cool,
and this may still support a few spotty showers, but with less
coverage than Monday. Tuesday night height rises will spread across
the Ohio Valley and eastern Great Lakes ahead of another trough
digging into the upper Great Lakes. This will bring a brief
interlude of dry weather.

Model guidance begins to diverge by Wednesday and Thursday with the
handling of the next system. The 00Z GFS develops another closed low
over the Ohio Valley and eastern Great Lakes with increasing rain
chances. Meanwhile, the 00Z ECMWF/GEM are much weaker and farther
north with this shortwave energy, keeping a weak open wave moving
through southern Canada. Given the model spread and weak look of the
ECMWF/GEM solutions, kept POPS low for Wednesday, in the 20-30
percent range.

A warming trend will develop by the middle of next week after a few
cool days, with above average temperatures returning.
-- End Changed Discussion --

&&

.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
Mainly VFR flight conditions will continue across western and north
central NY this morning. Valley fog has developed across the western
Southern Tier but should stay out of the TAF sites. There is a low
chance that fog may develop at KART this morning. Right now, KART is
still carrying a 5kt wind and dewpoint depression of 3 degrees. TAF
will maintain VFR conditions however there is a chance of sudden
IFR/LIFR if winds go calm through daybreak.

Cool, moist air will rotate around a deep area of low pressure near
Georgian Bay into the weekend. A mix of MVFR/VFR conditions are
expected today as scattered to numerous showers and a few
thunderstorms develop through the afternoon. VFR conditions are
expected this evening.

Outlook...

Saturday through Monday...VFR/MVFR with mainly daytime showers
likely with possible thunderstorms.
Tuesday...VFR conditions.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
SW to WSW winds will freshen on both Lake Erie and Lake Ontario
today in the wake of the cold frontal passage with choppy waters
developing. Small Craft Advisory is in effect for Lake Erie today
through Saturday. Conditions may reach Small Craft Advisory criteria
for a couple of brief periods across Lake Ontario.

Winds relax Saturday night, before increasing again Sunday into
early next week. Small Craft Advisories may be needed during this
time.
-- End Changed Discussion --

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NY...Beach Hazards Statement from 11 AM EDT this morning through
     this evening for NYZ010-019-085.
MARINE...Small Craft Advisory from 9 AM this morning to 8 PM EDT this
         evening for LEZ020.
         Small Craft Advisory from 9 AM this morning to midnight
         EDT tonight for LEZ040-041.
         Small Craft Advisory from 5 PM this afternoon to 2 AM
         EDT Sunday for LOZ044-045.
-- End Changed Discussion --

&&

$$

SYNOPSIS...HSK/RSH/TMA
NEAR TERM...HSK
SHORT TERM...Hitchcock
LONG TERM...Hitchcock
AVIATION...HSK
MARINE...Apffel/HSK/JM/TMA