671
FXUS61 KILN 211808
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
208 PM EDT Fri Jun 21 2024

.SYNOPSIS...
A hot and humid airmass will be in place into the weekend. A
cold front will move through Sunday, bringing with it a more
pronounced chance for showers and storms. Following the frontal
passage, slightly cooler and drier air will filter in Monday
into early Tuesday before warmer and much more humid air quickly
returns by late Tuesday. More showers and storms will be
possible Tuesday night through Wednesday afternoon, with drier
and cooler conditions settling in by Thursday for the remainder
of the workweek.

&&

.NEAR TERM /THROUGH SATURDAY/...
Heat wave to continue today with mid and upper level ridge
centered over the Ohio Valley. An isolated stray thunderstorm
cannot be completely ruled out in central/south- central OH
during peak diurnal heating, but most locales remain dry today.
The better coverage of convection will remain around the
periphery of the high - north of ILN/s area.

The warmest stretch of this heat wave will be observed today and
Saturday. Slightly drier air may support surface dewpoints
about 2-3 degrees lower than yesterday. Net result in terms of
heat index and WBGT will be little change.

Highs will top out in the lower to mid 90s, with dewpoints in
the mid to upper 60s during peak heating, yielding heat index
values generally in the upper 90s to the lower 100s degrees.
Heat advisory continues through 8 PM Saturday for the entire
area.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH 6 PM SATURDAY/...
More of the same is on tap tonight as lows dip into the lower/mid
70s. Saturday may end up being the warmest day of the entire
week from strictly a temp standpoint as temps top out another
degree or two warmer than will be the case today. Highs in the
mid 90s are likely Saturday, with dewpoints generally in the
mid 60s during peak heating, yielding heat index values that are
within a degree or two of the actual air temp itself.

There are several items Saturday that will support it being the
warmest day of the week -- most notably the "driest" air that
we`ve experienced this week, meaning that clouds and storm
chances should be fairly limited. This, along with better flow
at the H8 level, should support deeper/more robust diurnal mixing
than has been the case thus far this week, further supporting
the potential for a few isolated upper 90s readings, especially
if dewpoints are able to mix out into the lower 60s. Now -- the
trend thus far within the past 5 days has been to not mix down
the dewpoints quite as much in reality as some guidance has been
showing, but even dewpoints in the mid 60s may allow for some
96-97 degree highs on Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/...
By the start of the extended period, the 700-500H ridge will have
retrograded back west and flattened out. To our north, a shortwave
will be moving into the Great Lakes, with its attendant surface low
dragging a cold front behind it.This places our CWA in the open warm
sector during the overnight hours and the WAA is strong.. overnight
lows will be some of the warmest of this heat wave with urban areas
only falling to the upper 70s.

Older guidance suggested that showers/storms forced out ahead of the
cold front wouldn`t arrive until Sunday afternoon, however, most
recent deterministic runs seem to be a bit faster with the onset of
precipitation... possibly arriving Sunday morning. Could throw a
confusing wrench in things should there still be a nocturnal
inversion in place during precip onset, which may limit severe
potential. However, if this happens, there`s quite a bit of
instability aloft and the front should provide enough forcing to get
storms off the ground... this combined with the 850 jet moving
through will likely allow for at least some organized storms with
strong to severe winds being the most likely threats. In terms of
hydro... the area was recently placed in the D0 Abnormally Dry
conditions category and, while our crops still seem to have enough
moisture to be getting along, the grass is starting to look pretty
dry. The system moving through Sunday will bring a surge of
moisture, with PWATS 2 sigmas above normal, however, given the
progressive nature of the system most areas will only receive a
quarter of an inch of rain or less (localized heavier downpours
possible).

In the relatively cooler post-frontal air, Monday will be a slight
respite from the heat, with highs in the upper 80s. While this
doesn`t sound like much, we might actually notice a difference,
given the surge of dry air that moves into the region behind the
front. In fact, dew points drop from the low 70s into the upper 50s.
Overnight low temperatures in the mid 60s.

This is all short lived, as we quickly rebound with return southerly
flow on Tuesday ahead of the next system poised to move into the
region and highs bounce back into the low 90s with Tds in the upper
60s/low 70s. Guidance has sped up the arrival of this next system
slightly, with the front now moving through sometime Tuesday
overnight into Wednesday next week.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
Ridge aloft and at the surface to continue to influence our
weather today and Saturday. Although an isold thunderstorm is
possible mainly across the central Ohio better coverage is
expected north of the TAF sites.

VFR CIGs are expected this afternoon into tonight with
SCT cumulus clouds dissipating this evening. Could again see
some MVFR or even brief IFR VSBYs overnight mainly at KLUK and
KILN.

Any fog will quickly improve Saturday morning with VFR cumulus
clouds again developing during late morning into the afternoon.

Winds will be westerly at 5-7kts this afternoon becoming light
and variable tonight. Southwest winds will increase to around 8
kts Saturday.


OUTLOOK...Thunderstorms possible on Sunday and late Tuesday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Heat Advisory until 8 PM EDT Saturday for OHZ026-034-035-
     042>046-051>056-060>065-070>074-077>082-088.
KY...Heat Advisory until 8 PM EDT Saturday for KYZ089>100.
IN...Heat Advisory until 8 PM EDT Saturday for INZ050-058-059-066-
     073>075-080.

&&

$$
SYNOPSIS...KC
NEAR TERM...AR
SHORT TERM...KC
LONG TERM...CA
AVIATION...AR