-- Discussion containing changed information from previous version are highlighted. --
314
FXUS61 KBUF 201831
AFDBUF

Area Forecast Discussion
National Weather Service Buffalo NY
231 PM EDT Mon May 20 2024

.SYNOPSIS...
Summer-like warmth today through mid-week with a chance of a shower
or isolated thunderstorm well inland form the lakes. Better chances
for showers and thunderstorms arrive Wednesday into Thursday with
the arrival of a cold front. Dry and cooler Thursday night through
Saturday.

&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
Cumulus field developing inland from the lakes this afternoon as
diurnal instability builds. Not much forcing for convection other
than lake breeze boundary. Latest HRRR and HREF suggesting the
potential for some convection later this afternoon from the interior
Southern Tier into the western Finger Lakes. With lack of forcing
think that any convection that does develop will be isolated and die
off very quickly this evening.

Dry weather expected for the duration of tonight. Looks like there
will be a bit more way of wind in the boundary layer, so less
efficient radiational cooling making it a bit harder for fog
formation overnight. Warm overnight lows in the mid 60s along
the lake plains with some upper 50s farther inland.

Summer-like warmth continues Tuesday. The mid-level ridge and
surface high will slide east to the coast through Tuesday
entrenching the area within the warm sector. Temperatures about
15 to 20 degrees above normal with most highs in the mid to
upper 80s, with perhaps a few 90 degree readings in the normal
warmer spots in the Genesee Valley. Warmest heat indices may get
into the lower 90s. Chances of afternoon convection look a bit
better with the approach of a weak shortwave trough. Though most
of this energy will focus north of the area, development along
a lake breeze boundary will be quite possible given the expected
higher instability.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
A broad based upper level trough spread across the western half of
the CONUS Tuesday night, will allow for a few shortwaves to ripple
through. Well to the north of New York, a remnant convective
shortwave trough will continue to pass east across northern Ontario
and Quebec. With its passage the lingering showers and
thunderstorms, now across the eastern portions of the North Country
will continue to diminish shortly after sunset due to the lack of
diurnal heating. Meanwhile to the west, the next potent convective
shortwave trough over Minnesota will continue to lift north, as a
result this will support surface low pressure over northern
Minnesota to continue to lift northeastward into southwestern
Ontario. Extending southward from this low is a cold front lying
across Lake Michigan towards the southern Mississippi Valley.
Provided this set up, warm moist air will continue to advect into
the area Tuesday night creating some muggy sleeping conditions with
lows ranging in the 60s.

Additionally, with the cold front to the west of the area Wednesday
morning, the day will start off dry ahead of its prefrontal trough.
As the front and prefrontal trough marches eastward Wednesday, there
is an increase in shower and thunderstorm activity by Wednesday
afternoon and evening. With the afternoon/evening arrival time, this
will support a few stronger storms as plenty of instability and
ample moisture. One of the saving graces and hindering the severity
of the storms is the later arrival of the stronger winds, thusly
limiting the shear. With all of this being said, a few gusty winds
are not out of question since there is bountiful instability and
moisture. In line with this thinking, the Storm Prediction Center
continues to support a Marginal Risk for severe thunderstorms on
Wednesday. Also, given the inch and a half PWAT values some heavy
downpours will also be possible, however ample storm motion should
keep the activity moving and limit flooding to a minimum. Similar to
Tuesday, southwest winds will transport warm moist air into the
region Wednesday and support another day of temperatures ranging in
the 80s, though Wednesday will be a few degrees warmer.

The cold front and the next round of showers will then cross the
area Wednesday night into the first half of Thursday. Due to the
timing of the frontal passage and the lack of diurnal heating,
severe chances are diminished. For the later half of Thursday, dry
air will begin to advect into the region drying out conditions from
west to east, where the area will be completely dry by Thursday
night. With the passage of the front Wednesday night into Thursday,
expect temperatures to cool in the wake of the front by nearly 10
degrees. Highs Thursday will rand in the 70s.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
-- Changed Discussion --
High pressure over our region will begin the period dry with fair
weather. Still some uncertainty when the next chance for showers
will arrive. A stationary boundary well to our south will lift
northward as a warm front through OH/PA...but moisture and showers
with this feature may just stay to our south Saturday - Saturday
night.

An area of deepening low pressure cutting through the western Great
Lakes Sunday will bring this warm front to our south up across our
region for Sunday with increasing chances for showers and
thunderstorms. Lingering boundaries and as the surface low draws
closer to our region Monday will continue chances for showers and
thunderstorms.

Comfortable dewpoints in the 40s to lower 50s Friday and Saturday
will become a bit higher with the warm front Sunday and Monday.
Dewpoints in the mid 50s to around 60F will give a touch of humidity
to the air for the end of the holiday weekend.
-- End Changed Discussion --

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
Widespread VFR conditions with light winds through this afternoon.
High based (above 5K feet), mostly scattered cu field developing
inland from the lakes this afternoon. Potential exists for some
widely scattered convection after 19z which is suggested by both the
HREF and HRRR from the interior Southern Tier into the Finger
Lakes. Confidence is low in exact coverage of any convection, with
any convection which does develop likely remaining south and east of
KROC and KJHW.

Tonight...VFR expected at all area terminals.

Outlook...

Tuesday...Mainly VFR. A chance of showers or a thunderstorm.
Wednesday...VFR/MVFR. Showers and thunderstorms likely.
Thursday...Mainly VFR. A chance of showers.
Friday and Saturday...Mainly VFR.

&&

.MARINE...
Light winds with minimal wave action expected on Lake Erie and Lake
Ontario through tonight.

South winds develop and begin to pick up by Tuesday as a cold front
near the eastern Great Lakes, but conditions will likely remain
below small craft levels. The next chance at small craft conditions
may materialize by midweek as low pressure sends a cold front into
the eastern Great Lakes.

&&

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

&&

$$

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