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229
FXUS61 KBUF 171042
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
642 AM EDT Mon Jun 17 2024

.SYNOPSIS...
A warm front will pass across our region this morning, ushering in
summer`s heat and humidity. Hot and humid through at least Thursday
with apparent temperatures during this time likely to reach 100F at
several locations Tuesday and Wednesday. A few isolated showers and
thunderstorms during the afternoon each day, with more coverage area
to storms later in the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
This morning weakening convection from a convective shortwave
is along the northern waters of Lake Ontario to the Saint
Lawrence Valley. Warming cloud tops within this area of
convection will shrink the area of showers this morning, with
most shower activity ending by 11 am east of Lake Ontario.
Lightning, near the west and southwest side of this complex of
storms, and under the colder cloud tops will likely remain over
Canada this morning.

For today, a warm front will pass over our region, and this will
commence the period of heat and humidity for the work week.

Heat Details...

The surface pressure gradient will increase with the passing of the
shortwave aloft, with a bit of a southwesterly breeze in the 20 mph
range. While not a great magnitude, this southwesterly flow behind
the departed surface high will increase moisture advection through
the day, with humidity notably higher through the afternoon hours.

In the wake of the warm frontal passage temperatures today will also
be notably warmer as 850 hPa temperatures increase to the upper
teens to around 20C. Apparent temperatures will rise into the
upper 90s in the lower Genesee Valley and Western Finger lakes
region, where a Heat Advisory begins noontime. Elsewhere, will
be hot with high temperatures in the upper 80s and apparent
temperatures in the lower 90s.

This southwesterly flow off the eastern Great Lakes will also
develop a lake breeze circulation, stronger in the afternoon hours.
Deeper moisture across WNY behind the warm front may fuel a few
afternoon showers and thunderstorms. Instability will not be lacking
at all, with MUCAPE values of several thousand J/KG. Holding back
the convection will be a strengthening 500 hPa ridge, but a
convective shortwave over MI this morning that will near WNY this
afternoon and fading of a low level capping inversion should allow
for a few storms to blossom along the lake breeze boundary.

Northeast of the Lakes, skies will be mostly sunny this
afternoon.

Tonight will be warm and muggy. Lows only in the upper 60s to lower
70s. Mainly fair weather after evening convection wanes, but a stray
shower cannot be ruled out within this muggy and still unstable
atmosphere. Where it rains in the Southern Tier today and
within the valleys patches of fog are possible tonight.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
...Heat Advisory in effect for the entire area as dangerous heat
builds through mid week...

Surface high pressure will remained anchored along the eastern
seaboard as a slow amplification of the eastern CONUS ridge
takes place during the period. This will result in a deep southerly
flow which will bring HOT and HUMID conditions during the day and
WARM and MUGGY conditions at night.

Mid level ridge builds into the region Tuesday with 850 mb
temperatures climbing to +20C. This will allow surface temperatures
to soar into the lower 90s across the region with valley locations
reaching the mid to upper 90s. Surface dewpoints will climb into the
upper 60s to lower 70s with PWAT values 1.5 inches or greater. The
combination of the heat and humidity will send apparent temperatures
into the upper 90s to lower 100s from midday through the afternoon.
Some scattered afternoon convection could develop as diurnal
instability increases within the heat, with initiation along a lake
breeze boundary or across higher terrain. Any convection will wane
into the evening hours. The very warm airmass will persist through
Tuesday night with overnight lows only dropping into the lower to
mid 70s for most locations.

Mid level ridge will be firmly in place Wednesday with ensembles
showing heights around approaching 600 dm. 850 mb temperatures stay
around +20C. With the region underneath the ridge, chance of
convection should be less than Tuesday, potentially making Wednesday
a HOTTER day than Tuesday. Most high temperatures again in the lower
90s across the region with valley locations reaching the mid to
upper 90s, with apparent temperatures in the upper 90s to lower 100s
from midday through the afternoon.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
...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 /12Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
For the 12Z TAFS, VFR flight conditions are found and these
conditions are expected to remain through the end of the TAF
cycle with surface high pressure nearby. There will be a slight
southwest breeze this afternoon for KIAG and KBUF off Lake Erie,
and southwest breeze for KART off Lake Ontario. Gusts will end
in the 22-00Z timeframe.

Showers this morning will be near KART through the first few
hours of the TAF cycle.

There will be a low chance for afternoon convection on lake breeze
or terrain induced boundaries this afternoon...generally across the
inland Southern Tier and into the Finger Lakes region.

Outlook...

Tuesday through Friday...VFR, but a slight chance for afternoon
thunderstorms inland from the lakes.
-- End Changed Discussion --

&&

.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, 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 today to 8 PM EDT Thursday for
     NYZ003>005-013-014.
MARINE...None.

&&

$$

SYNOPSIS...Thomas
NEAR TERM...Thomas
SHORT TERM...TMA
LONG TERM...JM
AVIATION...Thomas
MARINE...Thomas
CLIMATE...Thomas