-- Discussion containing changed information from previous version are highlighted. --
503
FXUS61 KCLE 161735
AFDCLE

Area Forecast Discussion
National Weather Service Cleveland OH
135 PM EDT Sun Jun 16 2024

.SYNOPSIS...
A strong upper level ridge will remain in place through this week,
resulting in near-record heat across the region.

&&

.NEAR TERM /THROUGH MONDAY/...
-- Changed Discussion --
130 PM EDT Update...

The forecast remains on track through the next 12-15 hours.
However, late tonight into Monday morning, convection associated
with a shortwave/MCV will pivot across Michigan. Still some
uncertainty in the southward extent of the track of this
convection, but currently thinking it will largely remain to the
north of the CWA due to the building ridge. PoPs increase
slightly as the shortwave crests the ridge Monday morning and
afternoon, but still quite a bit of uncertainty in the placement
of any boundaries which will be the main source of
convergence for shower/thunderstorm development. Will need to
monitor CAMs over the next several updates, as any cloud
cover/precipitation could throw a wrench into the apparent
temperature forecast for Monday afternoon.

Previous Discussion...

A prolonged heat wave is expected to begin across the region on
Monday and persist through at least Friday. Daily maximum heat
indices of 100 to 105 degrees are possible with low temperatures
not expected to dip below 70 degrees. Although confidence is
low on heat indices reaching or exceeding traditional heat
warning criteria of 105 degrees, confidence is high in heat
indices exceeding 100 for an extended period of time. Therefore,
given the prolonged nature and rarity of the upcoming heat
wave, have gone ahead and issued an Excessive Heat Watch for the
entire area from Monday through Friday.

For today, the upper-level ridge will begin to establish itself
as surface high pressure exits east of the area into New
England. A dry air mass will remain in place through much of
today, so anticipate dew points to mix out quite a bit and
perhaps even lower than NBM guidance given high temperatures in
the upper 80s to lower 90s. This will feel more like a "dry"
heat, albeit still well above-normal temperature wise for this
time of the year.

The start of the heatwave will begin on Monday as a surface warm
front lifts northeast across the area, pumping in additional
low- level moisture which, combined with high temperatures in
the mid to upper 90s, will result in heat indices of 100 to 105
degrees. Given the anomalously-warm 850mb temperatures, not
anticipating much in the way of convection, although can`t rule
out a few isolated storms. The forcing mechanism for any
isolated storms would either be from a lake breeze or the
arrival of a weak surface trough from the south.
-- End Changed Discussion --

&&

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
Models now becoming a little more aggressive with an influx of
low/mid level moisture off the boundary layer which is going to
translate to some slightly higher POPs for the CWA come Tuesday.
Convection triggers will likely be a combination of strong heating
and weak waves in the flow aloft moving south to north into the
area. With some coverage of convection and added cloud cover
potential, this makes Tuesday a slightly cooler day than Monday,
although still hot and humid. A little less low/mid level moisture
once again for Wednesday as the upper level high retrogrades back
southward into the mid Atlantic and the POPs return to their now
weather status for the end of the short term.

&&

.LONG TERM /THURSDAY THROUGH SATURDAY/...
After Thursday, there will be a very gradual cooling trend heading
into next weekend, but the temperatures will still be well above
normal. Upper ridge will gradually drop southward into the SE CONUS
with 500mb heights slowly lowering for the CWA as distance from the
center of the upper high increases. The ridge itself will also
gradually degrade towards more seasonal type heights. As the flow
aloft attempts to go zonal towards the end of the long term, will
see a rain chance increase into the weekend.

&&

.AVIATION /18Z Sunday THROUGH Friday/...
-- Changed Discussion --
VFR will prevail through the TAF period, however
shower/thunderstorm chances may increase slightly as a shortwave
crosses the area late Monday morning/afternoon. With that being
said, precipitation will be somewhat disorganized and will rely
on any boundaries across the area which will be the main source
of convergence, so opted to omit any showers/storms from the
TAFs at this time.

Winds will generally be out of the south/southwest at 6 to 12
knots through the TAF period.

Outlook...Primarily VFR expected through Thursday. Isolated
thunderstorms are possible during the afternoon on Monday and
Tuesday, but confidence is low.
-- End Changed Discussion --

&&

.MARINE...
Northeast to east winds today around 10kts with wave heights 1-2ft
by this evening will become offshore through midweek less than
10kts, followed by light and variable Thursday and Friday. Wave
heights generally a foot or less through this period.

&&

.CLIMATE...
A prolonged stretch of hot weather is expected this week.
Temperatures are forecast to approach or exceed record highs on
several days. The records for Monday, June 17 to Friday, June
21 are listed below for our official climate sites.


Date   Toledo     Mansfield   Cleveland   Akron     Youngstown   Erie
06-17  97(1994)    94(1936)   94(2018)    94(2018)   95(1994)    90(2018)
06-18  98(1994)    93(1994)   96(1944)    96(1944)   95(1994)    92(2018)
06-19  98(1995)    94(1994)   92(1995)    94(1994)   94(1994)    92(1931)
06-20  98(1953)    94(1988)   96(1988)    95(1933)   95(1933)    92(2016)
06-21  100(2022)   96(1988)   95(2022)    97(1933)   98(1933)    95(1933)

&&

.CLE WATCHES/WARNINGS/ADVISORIES...
OH...Excessive Heat Watch from Monday morning through Friday
     evening for OHZ003-006>014-017>023-027>033-036>038-047-
     089.
     Air Quality Alert until midnight EDT tonight for OHZ010>014-
     020>022-089.
PA...Excessive Heat Watch from Monday morning through Friday
     evening for PAZ001>003.
NY...None.
MARINE...None.

&&

$$

SYNOPSIS...Kahn
NEAR TERM...Kahn/Maines
SHORT TERM...26
LONG TERM...26
AVIATION...Maines
MARINE...26
CLIMATE...