794 
FXUS61 KBUF 210238
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1038 PM EDT Fri Aug 20 2021

.SYNOPSIS...
A warm, humid airmass over the Northeast will provide for continued 
potential for some showers and thunderstorms through the weekend. 
This will especially be the case during the daytime hours, inland 
from the lakes.

&&

.NEAR TERM /THROUGH SATURDAY/...
Weak shortwave energy wraps back in across the area overnight 
from east to west, which could result in a some remnant showers 
wandering their way through the area during the usually more 
stable overnight hours. 

Saturday, a sprawling upper low will gradually shift its position 
over the region and subsequently interact with TS Henri over the 
next couple of days. This will bring progressively better moisture 
flow in from the east through the daytime hours. This should, as 
instability builds, result in a bit more shower and thunderstorm 
activity. 

Otherwise, with the aforementioned humid air mass in place, 
overnight inversions will again result in fog formation across 
portions of the area. This will likely be especially the case in the 
Southern Tier, where forcing for additional mid-level cloud cover 
will be reduced. However, some stratus and fog is possible across 
the board. This will mix out Saturday as mid-summer insolation does 
its work on the fog before diurnal instability results in shower and 
thunderstorm development away from the lakes.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
A closed upper level low across the mid-Atlantic states will 
interact with tropical system Henri during this period. While
there will be no direct impacts from Henri across our region with 
its center passing by well to our east...the weak mid-level flow 
will still slowly funnel some of its associated tropical moisture 
back across our region. This will result in continued sultry 
conditions along with the risk for some scattered showers and 
thunderstorms...with the greatest potential for these found during 
the afternoon and early evening hours of both Sunday and Monday... 
in tandem with peak diurnal heating and resultant instability. 
Overall coverage will be greatest across eastern portions of the 
Finger Lakes and North Country which will be closest to the moisture 
source...with both diminishing with increasing westward extent. 
While the convection will tend to be mainly scattered in nature...a 
few slow moving storms with locally heavy rainfall will be possible. 

With respect to temperatures...expect daytime highs to primarily 
range from the lower 80s across the higher terrain to the mid and 
possibly a few upper 80s across the lower elevations...while 
nighttime lows range from the low to mid 60s across the Southern 
Tier to right around 70 near the lakeshores. At the same time... 
humidity levels will remain uncomfortably high throughout.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
Generally quiet weather anticipated with muggy and very warm 
conditions through Wednesday as weak sfc ridge extends in over the 
region. Might see highs pushing into the upper 80s to near 90F as 
H850T climb to +20C. Any relief likely won't come until the latter 
half of the week. This is when a cold front nears the eastern Great 
lakes, but there still is a lot of uncertainty with the timing of 
the front. Have added chance POPs, no higher, for Wednesday night 
and Thursday time frame. After that, there isn't all that much 
agreement amongst the various guidance packages from sfc ridge 
build in and dry to a continuation of chance showers and storms.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Moisture and some light showers working west associated with 
shortwave energy wrapping back around the mid-level low. No issues 
as of yet expected with most terminals seeing VFR. 

Otherwise, later on some fog and stratus will likely form, 
especially around KJHW. Elsewhere, visibility restrictions seem 
likely across the board with MVFR likely at most sites for a time 
before sunup.

VFR conditions return to all sites Saturday afternoon and
showers and thunderstorms develop in a scattered fashion away
from the lakes.

Outlook...

Saturday through Monday...Mainly VFR with the chance of showers and 
thunderstorms.
Tuesday and Wednesday...Mainly VFR.

&&

.MARINE...
Winds will be weak with a light to gentle breeze through most of the 
weekend on both lakes. Some showers and thunderstorms will be 
possible through the weekend as well, as the active pattern 
continues.

&&

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

&&

$$

SYNOPSIS...SW
NEAR TERM...AR/Fries
SHORT TERM...Apffel/JJR
LONG TERM...AR
AVIATION...AR/Fries
MARINE...Fries