443
FXUS61 KBUF 111739
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
139 PM EDT Tue Jun 11 2024

.SYNOPSIS...
Extensive cloud cover across the region will gradually erode
through this evening. High pressure will build across the
region, bringing dry weather which will last tonight through
most of Thursday. A cold front will bring another round of
showers and scattered thunderstorms Thursday night through a
portion of Friday.

&&

.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
A deep mid level trough will continue to move slowly east
across New England tonight. A moist cyclonic flow on the
western flank of the trough will persist across the eastern
Great Lakes this afternoon. As this trough moves further away,
the cloud cover will gradually erode through this evening.
Mostly cloudy and cool weather early this afternoon, with some
warming where the sun breaks out late afternoon and evening.
Afternoon temperatures will be well below normal, only topping
out 60 to 65F.

High pressure will build over the eastern Great Lakes tonight.
This will clear out the low clouds, although some mid-level
clouds will enter Western NY late tonight. The clearing will
allow some patchy fog to develop in the Southern Tier river
valleys overnight. Light winds will also allow for good
radiational cooling when skies are clear, with lows ranging from
the mid 40s to lower 50s.

Surface high pressure will build across the region Wednesday and
Wednesday night, resulting in dry weather. A band of mid-level
clouds will move from west to east across the area Wednesday,
but outside of this skies will be mostly clear. It`ll also be
warmer during the day Wednesday, with highs in the lower to mid
70s. This is near normal for mid-June.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
Conditions will begin to deteriorate later Thursday afternoon
as the flow aloft becomes nearly zonal out ahead of the next low
pressure system. This will be forced by a mid-level trough
pivoting across the Great Lakes from southern MB/ON provinces.
Weak leading shortwave energy is expected to ripple through the
zonal flow over the Northeast, which combined with growing
diurnal instability will lead to additional clouds and possibly
a few showers or an isolated tstorm, mainly over and in the
vicinity of Lake Ontario where synoptic moisture will be
slightly deeper. Otherwise, a briefly tightening pressure
gradient over the region will lead to a breezier day
east/northeast of the lakes as afternoon temps across the area
top out in the low to mid 80s.

Broad surface low pressure ahead of the shortwave to the north will
lift northeast from eastern Ontario to central Quebec Thursday night
while deepening to near 990mb. The system`s trailing cold front will
sag southward through the eastern Great Lakes, leading to greater
chances for showers across the region overnight into Friday morning.
While the 00z suite of model guidance has come into better agreement
on a sharper parent shortwave and the arrival time of the initial
front, there remains greater forecast uncertainty in regards to
shower coverage and QPF overnight and on Friday as remnant moisture
from earlier convection moving east across the Ohio Valley
potentially interacts with the pre-frontal wave. At this juncture,
greatest chances for showers looks to be across the North Country
Thursday night in closer proximity to the surface low though
depending on how the aforementioned convection evolves, more
widespread showers could move through the Southern Tier overnight.
Outside of a spot shower or two, mainly dry weather should arrive
across the western zones by the afternoon. For temperatures, the
ushering in of the cooler overhead airmass should knock highs temps
back into the 70s Friday.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Any showers or thunderstorms associated with the earlier frontal
passage on Friday should be well south and east of the area by
Friday night as the axis of the parent upper-level trough will
quickly move east of the Great Lakes overnight. A large area of
surface high pressure and subsidence drying under a building ridge
aloft will expand east across the region through Saturday, then move
off to New England Sunday before settling off the coastline by
Monday. While there could be a few diurnal showers across the area
Monday afternoon, this pattern will otherwise support mainly dry
weather through the weekend.

While shower potential remains uncertain, confidence is much
higher in true summer`s heat building by early next week. Highs
on Saturday in the 70s will warm to the upper 80s and low 90s by
Monday as 850H temps are expected to reach or exceed +20C.
Though beyond the scope of the 7-day forecast...The strong
surface high is expected to remain off the coast through much of
the week which should continue to support warmer than normal
temperatures, as reflected well by CPC`s latest 6-10 and 8-14
temperature outlooks.

&&

.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
A mid level low across New England will maintain a cool and
cyclonic flow aloft here, resulting in some lingering MVFR
stratus. This cloud cover will continue to erode this afternoon
as the mid level low moves further away.

Mainly VFR flight conditions by this evening as surface high
pressure builds in. Some river valley fog may impact KJHW
tonight, depending on how long it clears. After the stratus
clear out, there will be a band of mid level clouds which moves
across the area from west to east late tonight into Wednesday.
VFR flight conditions on Wednesday.

Outlook...

Wednesday night and Thursday...VFR.

Thursday night and Friday...VFR/MVFR. Showers and thunderstorms
likely.

Friday night through Sunday...VFR.

&&

.MARINE...
High pressure will build across the Eastern Great Lakes,
resulting in light winds which will last through Wednesday
night.

A cold front will then move across the eastern Great Lakes late
Thursday night and early Friday. Southwest winds will increase ahead
of the front Thursday, with winds remaining elevated through Friday.
This will bring choppy conditions to both lakes. High pressure
will then build back across the waters with light winds and
generally favorable boating conditions during the weekend.

&&

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

&&

$$

SYNOPSIS...Apffel/Hitchcock
NEAR TERM...Apffel/Hitchcock
SHORT TERM...PP
LONG TERM...PP
AVIATION...Apffel
MARINE...Apffel