827
FXUS61 KILN 251919
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
319 PM EDT Wed Sep 25 2024

.SYNOPSIS...
Tropical remnants will bring rain and wind to close the work
week. Low pressure lingers around the Ohio Valley through the
weekend with continued rain chances.

&&

.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
The weak frontal boundary has stalled over the area, stretching
from the greater Columbus area down into southern Ohio and
northern Kentucky. Very weak convergence combined with upper
level diffluence aid the potential for light rain showers this
evening, but overall, coverage is expected to be scattered.

Overnight, the upper level low moving through the northern
Great Lakes will continue east, but the upper level low in the
lower Ohio Valley becomes cut off from the main jet stream flow.
The weak front is expected to meander, potentially shifting
northward back to Cincinnati and Wilmington, but remaining
stalled over Columbus. A continued fetch of moisture advection
focuses rainfall chances primarily along the front and south of
through the early morning hours.

&&

.SHORT TERM /7 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
The stalled front washes out during the day on Thursday as the
strengthening surface low pressure to the south deepens in
response to Hurricane Helene moving into the Gulf Coast. Not
much changes during the day with regards to the overall weather
because the rainfall chances are still focused to the south. The
only substantial change will be that the weak and variable
winds will become more northeasterly during the afternoon.

Low level southeasterly flow increases Thursday evening with
more significant tropical moisture advection moving north into
the Ohio Valley. This will be the first chance for periods of
light to moderate rain, primarily along the Ohio River and
south. Better chances for rain will be more plausible during the
long term period.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Friday is shaping up to be a wet and breezy/windy day as the
remnants of Helene move north then northwest across the
Tennessee Valley. The surface pressure gradient will increase as
the low moves northwest. This, along with strong winds aloft,
should bring wind gusts in the 25 to 35 mph range. There could
even be some isolated 40 mph gusts, especially along and south
of the Ohio River. Saturated low levels should prevent winds
from getting stronger (limited mixing). Widespread showers,
isolated thunderstorms, are expected south with decreasing
chances of pcpn as one heads north. Despite the tropical
moisture, the speed of the pcpn shield should limit rainfall
amounts which will actually be beneficial to our drought
stricken region. By Friday night, the mid level energy that once
was Helene will be merging into a synoptic mid level closed low
to our southwest. This process will result in a decrease in
pcpn chances overnight. Winds will also diminish as the surface
low undergoes frictional decay. Rainfall amounts will range from
0.25 to 0.50 inches north to 1.50-1.75 inches along and south
of the Ohio River.

For the upcoming weekend, more opportunities for rainfall will
be possible as the center of the mid level closed low slowly
rotates east/northeast across Kentucky and Tennessee, weakening
and shearing as it goes along. Will continue with clouds and
chances of showers, with some isolated thunder possible during
the peak diurnal cycle.

The mid level closed low is forecast to weaken, shear, and open
up as upstream energy digs east/southeast into the Great Lakes
Monday into Wednesday. This process will also be associated with
a cold front, expected to pass through during the
Tuesday/Wednesday time frame. Lingering pcpn chances should end
after frontal passage.

As for temperatures, they will be held down on Friday with
clouds, rain, and wind. The weekend will feature highs 75 to 80
and lows in the 60s. A cooling trend is then expected by
Wednesday behind the cold front, along with a much drier
airmass. &&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
CIGs have generally improved to VFR this afternoon, but can`t
rule out brief periods of MVFR depending on cloud coverage. A
weak front has stalled over CMH/LCK, but is now east of the rest
of the sites. Winds are generally light and variable due to the
stagnant pattern.

Main focus for this TAF period will be the onset of MVFR CIGs
tomorrow morning between 10-14Z. Confidence is lower for
widespread IFR CIGs, but was high enough to include mention for
MVFR.

Winds remain light and variable through much of the TAF,
becoming northeasterly after 12Z Thursday. By the end of the
TAF, winds will be around 10 knots.

OUTLOOK...Due to the remnants of Tropical Cyclone Helene, wind
gusts between 30 and 35 knots and LLWS are possible Friday.

&&

.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.

&&

$$
SYNOPSIS...McGinnis
NEAR TERM...McGinnis
SHORT TERM...McGinnis
LONG TERM...Hickman
AVIATION...McGinnis