854
FXUS61 KILN 020200
AFDILN

AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
1000 PM EDT Sat Jun 1 2024

.SYNOPSIS...
A weak front trailing low pressure tracking through the Great
Lakes will move into the area on Sunday. It will stall and
weaken further allowing high pressure to build in by Monday. An
unsettled pattern will then develop for mid week.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Evening update...
Periods of rain continue to move across the area this evening
with varying amounts of intensity. In the "heavier" corridors
across portions of eastern Indiana and west-central Ohio, up to
a half inch of rain has been observed. Elsewhere, around a tenth
of inch is being observed. With the rain, winds and wind gusts
did ramp up a little with some 25 mph winds observed. This
is likely due to rain induced boundary layer mixing stronger low
level flow to the surface. Outside the areas of rain, winds are
between 5-10 mph. The shortwave feature mentioned below remains
off to the southwest, so will continue higher PoPs for the next
few hours. Then, forcing becomes more limited and rain activity
becomes more showery in nature. Reduced thunderstorm mention to
the southwest late into the overnight as some elevated
instability builds during the early morning. Forcing remains
weak so thunderstorm coverage will still be quite limited.

Can`t rule out some patchy fog across portions of eastern
Indiana / southwestern Ohio / northern Kentucky, but this should
be limited due to widespread stratus.

Previous discussion... Short wave emerging out of the mid
Mississippi Valley will weaken and broaden as it heads east
overnight. Large area of showers extending from Michigan to
middle Tennessee will spread into the area late this afternoon
and this evening. But with time expect coverage to decrease as
forcing weakens. Some showers will continue into the late night.
Instability is pretty marginal and there has been very little
lightning upstream. Cannot rule out some embedded thunder, but
it seems like a fairly remote chance at this point. Lows will
generally be in the lower 60s.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM MONDAY/...
Lingering mid level troughing will be slow to exit, perhaps not
getting east of the area until Sunday evening. Meanwhile, an ill
defined front will push into western counties during the day.
This will stall and eventually wash out. Forcing overall will be
weak, but there will be plenty of low level moisture in place.
So there will continue to be some showers about the region
although they should be isolated to scattered.

There is some question about how quickly low clouds may decrease.
Consensus seems to be that there will be some improvement in
the afternoon although the possibility of it remaining mostly
cloudy cannot be ruled out. If there are sufficient breaks to
allow for some heating, then some instability may develop which
could allow for a few thunderstorms, if anything develops along
the diffuse boundary. Any remaining showers will diminish
Sunday evening.

Highs will be dependent on cloud cover with the current
forecast indicating mid 70s, a bit cooler in the east and a bit
warmer in the west. Lows will once again fall into the lower 60s
most areas.

&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
The Ohio Valley will be between weather systems to start the work
week on Monday. Upper level flow is modeled to be almost non-
existent and the surface pressure gradient is weak. Rain chances are
expected to be around 20% or less. Forecast highs are in the lower
80s with weak southerly flow in place. This stagnant setup continues
into Monday night although rain chances may increase toward late
evening with weak diurnal instability. Forecast lows fall into the
middle 60s.

The synoptic setup begins to become more dynamic Tuesday and
especially into Wednesday. By Wednesday, an upper level trough and
surface cold front are expected to be diving into the Ohio Valley
from the northwest. These approaching disturbances should initially
help to increase southerly flow ahead of them on Tuesday into
Tuesday night which corresponds with increasing PWATs. Chances for
rain do exist on during this Tuesday/Tuesday night timeframe
although instability and shear remains very weak. Better chances for
showers and storms will likely be on Wednesday ahead of the front
when better forcing overlaps with moisture, instability, and shear.

Temperatures and rain chances drop behind the cold front at some
point on Wednesday/Wednesday night when winds shift to the west and
broad upper level troughing develops over the Ohio Valley.
Temperatures are forecast to remain below average with anomalous
upper level troughing persisting through the end of the week. Rain
chances will increase again Thursday/Thursday night when a second
cold front moves through the area.

&&

.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Periods of light rain have occurred at several TAF sites with
rain light enough to prevent the onset of MVFR restrictions.
Can`t rule out pockets of locally heavy rainfall, leading to
brief periods of sub-VFR restrictions. However, pushed back
onset of MVFR in the predominant groups by a couple of hours
based on this trend and observations to the west. Still expect
lower levels will moisten resulting in ceilings falling into
MVFR/IFR restrictions along with some MVFR VIS.

After 12Z, can`t rule out some lingering showers, but the main
theme will be continued CIG restrictions into the early
afternoon (17-20Z). Expecting some gradual improvement through
the late afternoon, but confidence is low in how quickly
restrictions clear back to VFR.

Can`t rule out scattered thunderstorm activity late Sunday
afternoon and evening, but the overall lack of coverage
warranted leaving mention out of the TAF for now.

OUTLOOK...MVFR/IFR CIGs/VIS possible Sunday night and Monday
morning. Thunderstorms possible Tuesday through Wednesday.

&&

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

&&

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