146
FXUS61 KBUF 181507
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1107 AM EDT Tue Jun 18 2024

.SYNOPSIS...
Hot and humid weather through at least Thursday with apparent
temperatures during this time likely to reach 100F at many locations
today and Wednesday. There will also be showers and
thunderstorms at times, especially during the afternoon and
early evening hours.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
The robust convective wave which developed early this morning
has weakened considerably by late this morning as it moves
slowly east across the lower Genesee Valley late this morning.
This wave was not captured well by previous model guidance, and
temperatures are cooler where it has moved through due to the
rain and cloud cover. It will still be very hot and humid today,
but for many areas this cluster of storms will result in
slightly lower heat index values today. Even so, high
temperatures will be in the upper 80s to lower 90s today, with
heat index values reaching the mid 90s to lower 100s. Heat
advisories remain in place for the entire forecast area.

This wave will also impact the potential for convection today,
likely resulting in reduced areal coverage in its wake. There
remains a risk of showers and thunderstorms as this wave moves
slowly eastward into the Western Finger Lakes region early this
afternoon. Also, instability will increase this afternoon,
especially across the Western Southern Tier where there is the
best chance for more showers and thunderstorms to develop.
Overall there is low forecast confidence in exact timing and
location of storm development.

The 12Z Buffalo sounding shows precipitable water values of 1.77
inches, and any storms that develop today will have the
potential to produce torrential downpours. Also, winds aloft
will be weak due to the ridging aloft, with storm motion
expected to continue to be only 10 to 15 mph. As a result there
is a marginal risk for flash flooding, mainly across the Western
Southern Tier and Upper Genesee Valley this afternoon although
it can`t be ruled out at other spots. The severe weather risk
appears limited due to the weak wind profiles and the departure
of the convective shortwave. However, the severe weather risk is
non-zero since disorganized pulse convection can still produce
damaging winds.

Any afternoon and evening convection will diminish overnight
tonight, other than perhaps a stray shower or storm. There will
be little reprieve from the muggy conditions with low
temperatures in the lower to mid 70s, with some upper 60s across
the Southern tier and North Country.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
...Heat Advisory in Effect for the Entire Area as Dangerous Heat
Builds Through Thursday...

Hot and humid daytime conditions and warm and muggy nights will
persist throughout the middle of the week as a result of surface
high pressure remaining anchored along the Eastern Seaboard in
conjunction with a slowly amplifying upper level ridge across the
eastern CONUS

Heading into Wednesday, the mid-level ridge will remain strongly in
place across the region, with some ensemble models depicting heights
closing in on 600 dm. This being said, temperatures at 850s mb will
remain around +20 Celsius and therefore support high temperatures in
the mid to low 90s. As mentioned previously, the humidity will
create sultry conditions with apparent temperatures ranging in the
90s during peak heading hours (mid-day through the afternoon).
Similarly, nighttime conditions will continue to feel muggy despite
a drop in the heat index values.

Thursday, the ridge will drop south and southeast. This slight jog
from it`s position Wednesday will allow for a slight drop in
temperatures and heat index values Thursday. Despite the slight drop
in conditions, Thursday will continue to be hot and humid, with heat
index values ranging in the mid 90s to low 100s for the bulk of
western and north central New York.

For both days, the positioning and proximity of the upper level
ridge will suppress most of the convection, however afternoon
heating and instability with some forcing along the lake breeze
boundaries may support some showers and thunderstorms. A better
chance for an isolated showers and/or thunderstorm will lie across
the North Country/Saint Lawrence Valley closer to the northern
periphery of the ridge.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Heading into the end of the week and into the start of the new work
week, expect a gradual day-to-day cooling trend due to multiple
successive shortwave troughs traverse eastward across central and
eastern Canada, acting to slowly suppress the ridge southward. As a
result this will create quasi-zonal flow across the CONUS by Monday.
Even with the "cooling" trend, conditions will continue to remain on
the warm and humid throughout the end of the week and into the
weekend. Temperatures Friday will feature upper 80s to low 90s
before cooling off to the mid to upper 80s by Sunday. As mentioned
previously with the humidity, heat index values will range between
the low to mid 90s Friday and then in the mid to near 90 by Sunday.

With regards to precipitation, there will be a slight increase in
the potential for convection Friday through Sunday due to upper
level disturbances riding the northern periphery of the upper level
ridge and a surface boundary sagging south into the region from
Canada. Areas that do receive storm activity will have a slight
reprieve from the warm muggy conditions, through it will be on the
shorter side.

Sunday night into Monday, a deep trough and associated surface low
and cold front will track east across the region, resulting in
widespread showers to pass across the region. With this system, air
conditions will be notably cooler in the wake of the front. Highs
Monday will return to near normal with highs in the upper 70s to mid
80s region wide.

&&

.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
Mainly VFR flight conditions through the day today, outside of
localized thunderstorms which will produce heavy rain and IFR
or lower at times. These will be very difficult to predict much
in advance since convection is being driven by very subtle
features. In general, expect coverage to increase this afternoon
and evening, then to diminish tonight.

Outlook...

Wednesday through Saturday...Mainly VFR, but a chance for afternoon
and evening thunderstorms inland from the lakes.

&&

.MARINE...
High pressure will be near the eastern Great Lakes through much of
this week, offering light winds, generally 15 knots or less on the
lakes.

&&

.CLIMATE...
A prolonged period of heat is expected for our region this week.
Below are record high temperatures for our three main climate
sites:

...Buffalo...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 18........95/1994............73/2006
...June 19........90/2001............73/1919
...June 20........92/1995............73/2012


...Rochester...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 18........97/1957............72/2018
...June 19........95/2001............72/1919
...June 20........95/1953............72/1923


...Watertown...

...Date.....Record Maximum (F)...Record warm Minimum (F)...

...June 18........91/1957............70/1992
...June 19........91/2007............70/1949
...June 20........90/1971............71/2012

Temperature records for Buffalo and Rochester date back to 1871.
Temperature records for Watertown date back to 1949.

&&

.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Heat Advisory until 8 PM EDT Thursday for NYZ001-002-006>008-
     010>012-019>021-085.
     Heat Advisory until 8 PM EDT Thursday for NYZ003>005-013-014.
MARINE...None.

&&

$$

SYNOPSIS...Apffel/Thomas/TMA
NEAR TERM...Apffel/TMA
SHORT TERM...EAJ
LONG TERM...EAJ
AVIATION...AR/Apffel/TMA
MARINE...Apffel/Thomas/TMA
CLIMATE...Thomas/TMA