-- Discussion containing changed information from previous version are highlighted. --
947
FXUS61 KBUF 170255
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
1055 PM EDT Sun Jun 16 2024

.SYNOPSIS...
Heat and humidity builds Monday and last through at least Thursday.
Apparent temperatures during this time will likely reach 100F at
some locations Tuesday and Wednesday. There will also be a chance of
a few isolated showers or a thunderstorm well inland from the lakes
each day. Some relief from the oppressive heat begins Friday into
the weekend.

&&

.NEAR TERM /UNTIL 6 PM MONDAY EVENING/...
-- Changed Discussion --
A warm frontal segment will pass by to our north, and this will
begin to bring in a more humid air mass. This frontal passage
will also bring a small chance of showers, mainly across the
Eastern Lake Ontario region very late tonight into early Monday
morning.

...Heat and humidity builds MONDAY and remains for much of the work
week...

Details...

In the wake of the warm frontal passage temperatures on Monday will
be notably warmer, and it will also be more humid. Apparent
temperatures will rise into the upper 90s in the lower Genesee
Valley and Western Finger lakes region, where a Heat Advisory was
issued starting Monday. Elsewhere, will be hot with high
temperatures in the upper 80s and apparent temperatures in the lower
90s.

For the most part, the day should be rain-free but some high res
models do develop some isolated thunderstorms in the afternoon.
Given forecast soundings, it appears this is likely overdone and
only supports a slight chance PoPs.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM MONDAY EVENING THROUGH WEDNESDAY NIGHT/...
...Dangerous Heat Wave Will Begin For The Region...

Surface high pressure will be anchored over the Atlantic and a deep
southerly flow will bring HOT and HUMID conditions during the day
and WARM and HUMID conditions during the night Monday night through
Wednesday night.

An anomalously strong upper level ridge will build across the
eastern Great Lakes region and Northeast through mid-week. Warm air
advection will take place Monday night through Tuesday with 850mb
temperatures climbing to +20C. Very warm Monday night with lows in
the upper 60s across the higher terrain and low 70s across the lake
plains. Temperatures will soar into the low 90s across the region
with valley locations reaching the mid to upper 90s Tuesday.
Dewpoints will climb into the upper 60s to low 70s with PWAT values
1.5 inches or greater. The combination of the heat and humidity will
drive heat index values into the upper 90s to low 100s Tuesday
afternoon. The forecast area will be on the northwest side of the
strong upper level ridge and should be enough in the ridge to keep
any upstream thunderstorm complexes outside the forecast area
Tuesday. There will be high surface based instability across the
region (sans the immediately shorelines.) Terrain circulations and
lake breeze boundaries will likely produce a cu field with isolated
to scattered showers and thunderstorms. Any convection will wane
into the evening hours. The very warm airmass will persist through
Tuesday night with overnight lows only reaching the low 70s.

There is little change in the sensible weather for Wednesday and
Wednesday night. Another HOT and HUMID day with highs in the low to
mid 90s, dewpoints in the upper 60s to low 70s, and heat index
values in the upper 90s to low 100s. There is some model guidance
that shows 850mb temperatures a few degrees higher (EC) which could
add a degree or two to high temps Wednesday. The forecast area will
remain on the northwest side of the upper level ridge Wednesday
through Wednesday night. The convective potential is similar to
Tuesday with low coverage of showers and thunderstorms. Another very
warm night with lows in the low to mid 70s.

A Heat Advisory is in effect for the entire forecast area
Tuesday through Thursday.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
...Dangerous Heat Wave Will Continue For The Region Through At
Least Thursday...

Model consensus shows the axis of the anomalously strong nearly 600
decameter ridge will be just to our south and southeast Thursday,
just a slight jog from its position on Wednesday. This may bring 500
mb heights down just a smidge, along with surface temperatures/dew
points possibly a couple of degrees cooler. All in all, very similar
to the hot and steamy conditions expected for Tuesday/Wednesday,
which will make Thursday the most oppressive day of the long term
period with heat index values again ranging from the mid 90s to very
low 100s for the bulk of western and northcentral NY.

Positioning/proximity of the upper level ridge will suppress most,
if not all convection, especially across western NY. Better chance
for an isolated shower/storm would be toward the North Country/Saint
Lawrence Valley closer to the northern periphery of the ridge.

A very gradual day-to-day `cooling` is then expected for the Fri-Sun
timeframe as successive shortwaves traversing eastward through
central and eastern Canada slowly suppress the ridge to the south,
leaving a quasi-zonal flow in place across the CONUS by the end of
the period. That said, still want to emphasize that conditions are
still going to remain very warm to hot with elevated humidity
levels. In terms of temperatures, upper 80s/low 90s Friday will
slowly trend downward to the mid and upper 80s by the end of the
weekend, with the highest elevations several degrees cooler
respectively on any given day. Heat index values will reach the low
to mid 90s for all of the lower terrain Friday afternoon, upper 80s
to low 90s Saturday afternoon, and mid 80s to near 90 by Sunday.

In terms of precipitation, there will be some increase in convection
potential as we close out the work week and head into next weekend.
This will be owed to mainly two things: Upper level
disturbances riding the northern periphery of the upper ridge
passing closer and closer to the area as the center of the ridge
slowly sags further south through the period, while a surface
boundary also sags south toward the region from Canada. Areas
that do receive some showers/storms, will enjoy some relief,
however any reprieve will only be temporary.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
VFR flight conditions expected through the end of the TAF cycle.

Outlook...

Monday night...VFR.
Tuesday through Friday...VFR, but a slight chance for afternoon
thunderstorms inland from the lakes.

&&

.MARINE...
-- Changed Discussion --
Winds will be light Monday through much of next week as high
pressure anchors over the Ohio Valley and New England.
-- End Changed Discussion --

&&

.CLIMATE...
A prolonged period of heat is expected for our region, starting
Monday June 17th. Below are record high temperatures for our three
main climate sites:

...Buffalo...

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

...June 17........94/1994............73/2006
...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 17........94/1994............70/1994
...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 17........89/1994............68/1949
...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 from noon Tuesday to 8 PM EDT Thursday for
     NYZ001-002-006>008-010>012-019>021-085.
     Heat Advisory from noon Monday to 8 PM EDT Thursday for
     NYZ003>005-013-014.
MARINE...None.

&&

$$

SYNOPSIS...AR/Apffel
NEAR TERM...AR/Apffel
SHORT TERM...HSK
LONG TERM...JM
AVIATION...AR
MARINE...AR/Apffel
CLIMATE...Thomas