851
FXUS63 KIND 092314
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
714 PM EDT Sat May 9 2026

.KEY MESSAGES...

- Isolated showers this evening into early Sunday; a few rumbles of
  thunder northeast of Indianapolis this evening

- Additional threat for rain and storms late Tuesday and Tuesday
  night

- Seasonably cool through midweek with much warmer air arriving by
  next weekend

&&

.DISCUSSION (This Evening through Saturday)...
Issued at 143 PM EDT Sat May 9 2026

A strong upper level low south of James Bay will maintain a general
longwave trough across much of the eastern half of the country into
early next week. Ridging aloft will briefly replace the departing
trough prior to another upper low diving into the eastern Great
Lakes by the middle of next week keeping temperature predominantly
near to slightly below normal. Modification of the upper level flow
with more substantial ridging will bring much warmer air into the
Ohio Valley for next weekend and beyond.

Through Sunday

A scattered to broken cu field was present over much of the forecast
area early this afternoon in the wake of the rain from Friday
evening into early this morning. Despite the cu...temps had warmed
nicely with mid and upper 60s across the region at 17Z.

Relatively quiet weather will continue through the rest of the
weekend as the Ohio Valley remains heavily under the influence of
the strong upper level low across northern Ontario. A weak wave
rounding the base of the parent low in tandem with a surface trough
will bring the opportunity for a few showers from late today into
Sunday with the possibility of a couple rumbles of thunder this
evening across northeast portions of the forecast area.

Cu will slowly decrease in coverage through late day as deeper low
level moisture moves away from the region. Convection will develop
across lower Michigan and into the eastern Great Lakes by late
afternoon in the vicinity of an axis of slightly stronger MLCAPE.
There remains the possibility that the tail of the convection may
graze the far northeast part of the forecast area this evening.
Model soundings do show subtle instability and steep mid level lapse
rates that could present a narrow opportunity for a few stronger
cells in the 00-04Z window despite limited low level moisture.

Beyond that the surface trough will sag into the forecast area
overnight but once the lapse rates aloft weaken with the limited
moisture present...hard to justify more than just isolated showers
through early Sunday with most locations remaining dry. Mid and
high level clouds will decrease from the north on Sunday as high
pressure builds in from the upper Midwest and the surface trough
shifts into the Tennessee Valley. Overrunning moisture along the
remnant trough by late day Sunday may enable isolated light showers
to briefly slip back into far southeast portions of the forecast
area into Sunday evening but the overall trend will be towards dry
conditions. Surface flow will veer to northerly late tonight and
persist Sunday.

Temps...with the cloud cover lows tonight should largely hold into
the lower and mid 50s. Low level thermals support highs Sunday
roughly 5-7 degrees cooler than temperatures this afternoon. Expect
mid and upper 60s for much of the forecast area.


Sunday Night through Wednesday

With the departure of the surface trough and associated moisture to
the south...high pressure over the upper Midwest will become the
primary feature influencing weather over the Ohio Valley for Monday
and much of Tuesday. The airmass is cooler behind the surface trough
but not overtly so with low level thermals supporting highs mainly
in the 60s on Monday. The presence of light flow as the center of
the high passes through early Tuesday could enable a patchy frost
risk...perhaps our last of the Spring season based on trends...
focused over the northeast portions of the forecast area. Return
southwesterly flow on the back side of the departing high will
advect warmer air into the region for Tuesday with highs closer to
normal in the upper 60s and lower 70s. A tightening surface pressure
gradient Tuesday in advance of an approaching cold front from the
northwest will provide for a breezy day as well.

Convection will accompany the aforementioned front as it tracks into
the area Tuesday evening...but the lack of substantial moisture
return ahead of the boundary and timing of main impacts during the
evening and overnight will limit overall convective coverage and
intensity across the forecast area. A potent upper wave in tandem
with a 40kt 850mb jet however will likely be sufficient to maintain
convection through the night. Rainfall amounts into Wednesday
morning should be generally at a half inch or less with locally
higher amounts tied to any heavier showers or storms. High pressure
will reestablish Wednesday with temps a shade cooler than Tuesday as
cyclonic flow aloft sets up with a new upper low developing to our
north.

Wednesday Night into Next Weekend

High pressure will shift east across the area Thursday with the
upper low weakening and moving off the East Coast. A warm front will
follow in its wake for late week with a transition to much warmer
air for next weekend. Growing confidence in highs into the lower and
mid 80s would be the warmest daytime temps for the forecast area
since April 23. Cannot rule out isolated diurnally driven convection
for Friday into next weekend.

Beyond next weekend...there appears to be the potential for one more
stretch of seasonably cooler temperatures in the 60s and lower 70s
for 2-3 days during the week of May 18 behind a cold front.
Otherwise...the upper level flow regime is increasingly supportive
of warm and largely dry weather for the Ohio Valley for the latter
half of May with a likely return to multiple days with highs in the
80s.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 714 PM EDT Sat May 9 2026

Impacts:

- Isolated showers possible overnight

- W/SW winds becoming NNE overnight, then returning to NNW Sunday

Discussion:

A weak cold front will pass through the area overnight. The main
impact of this at the terminals will be a wind shift from WSW to NNE
overnight, with winds backing slightly to NNW during the day on
Sunday. Any lingering gusts will come to an end at or just past
valid time of the TAF. Ceilings will become broken around 8kft
overnight, before clearing again Sunday with just a bit of mid and
high cloud.

Isolated showers will be possible tonight with the frontal passage,
but will be very light and of minimal impact if they do happen to
reach a terminal. Will include no mention given the minimal
impact/probability of this.

&&

.IND WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

AVIATION...Nield
DISCUSSION...Ryan