232
FXUS63 KIND 091903
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
303 PM EDT Sun Jun 9 2024

.KEY MESSAGES...

- Unseasonably cool Monday
- Mid-week moderation will bring highs near 90F by Thursday
- Mainly dry past low-chances of showers/t-storms Thu Night-Friday

&&

.SHORT TERM (This evening through Monday)...
Issued at 300 PM EDT Sun Jun 9 2024

The cirrus shield associated with the earlier convective cluster to
our southwest has continued to shift south into the early afternoon
as cloud tops warm and diminish overall. Diurnal cu has formed in
its place especially across the northern half of the forecast area
as the upper trough anchored across the northeast States has begun
to amplify. Temperatures are comfortable this afternoon with mid and
upper 70s common across central Indiana as of 18Z.

The aforementioned upper trough will serve as the main influence
across the region through the short term...with increasing
amplification of the trough tonight and Monday before shifting away
from the Ohio Valley Monday night. With an expanding area of high
pressure at the surface approaching from the northwest on Monday as
well...the stage is set for a brief shot of cooler air before Summer
is set to arrive in earnest later this week. Monday will not only be
the coolest day of the next 7 days...but it very likely will be the
coolest day across the region for the foreseeable future.

Gusty northwest winds will be the primary impact for the rest of the
afternoon as soundings already showing a well mixed airmass up to
about 800mb currently that is likely to mix even higher by the end
of the afternoon. Peak gusts at 25 to 30mph will continue through
the remainder of the afternoon before diminishing this evening. Cu
will persist into the early evening then dissipate near sunset.
Expect highs to peak in the upper 70s and lower 80s over the next
few hours.

Skies will be mainly clear to start this evening but a broad area of
lower stratus and stratocu dropping south currently through the
Great Lakes will advect into the region early Monday associated with
a wave aloft aiding in the mean trough amplification. Model
soundings and RH progs both supporting an expansion of lower stratus
into the northern half of the forecast area Monday morning.

The question then becomes how extensive the cloud cover will be and
how long it will hold on Monday. While cold advection will be
ongoing... broad stratus lingering for a full day in June is
difficult considering that our sun angle is at nearly peak level for
the year. Suspect that as the wave aloft shifts off to the east
Monday afternoon...will see stratus mix out into a cu field with the
greatest coverage over the northeast half of the forecast area where
cold advection will remain strongest. The lingering cu along with a
resumption of breezy winds from the north will make for a
distinctively early Fall feel to the air on Monday.

Temps...cool night expected tonight with lows falling into the 50s.
Could see a few spots make a run at the upper 40s in northern
counties but think the arrival of the stratus late will keep that
from occurring. As mentioned above...Monday is easily set up to be
the coolest day for the foreseeable future. Nudged temps down based
on the expected cloud coverage and cold advection regime with highs
in the upper 60s and lower 70s from north to south. After a chilly
Monday night...temperatures will quickly recover through the week
with heat on the horizon. More on this in the Long Term section
below.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 302 PM EDT Sun Jun 9 2024

Monday Night through Wednesday...

The long term will start on the heels of what may well end up being
the coolest day of the foreseeable future Monday...as the inflection
point between the departing deep H500 trough and arriving short wave
upper ridge crosses Indiana Monday night.  Seasonably strong surface
high pressure (currently over the Canadian interior Plains) will
then cross the local region during Tuesday-Tuesday night...while the
upper ridge crossing the Great Lakes breaks down ahead of
strengthening upstream retracted/zonal flow.

Mostly clear skies will include a period of scattered clouds late
Tuesday under a passing ripple in the building zonal ridge.  This
subtle transition will mark the switch from below to above normal
readings amid the steadily moderating pattern.  Mainly light
southwesterly breezes will bring 80s on Wednesday under H850
temperatures rising to around 15 Celsius.  The western extents of
the slowly departing/weakening surface ridge will keep the CWA dry
through Wednesday night.


Thursday through Sunday...

Very warm to hot conditions will be the rule throughout the late
week and upcoming weekend as the subtropical zonal ridge attempts to
build northward over much of the CONUS.  A short wave trough will
cross the Great Lakes around the Thursday night-Friday night
timeframe...which will bring at least isolated rain chances to
central Indiana, and likely slightly cooler and less humid
conditions around Friday night and Saturday.  Not the greatest
confidence in the late week precipitation forecast with strong to
severe storms likely well to our northwest...which may spill at
least scattered peripheral showers across northern Indiana for maybe
6-12 hours ahead of this late-week cool frontal passage.

Otherwise mid-summer type marginal heat and moderate humidity should
prevail most days, with highs most likely 5-10 degrees above normal
and dewpoints often into the 60s.  A glance into next week shows the
potential continuing for heat...as CPC Max Temp probability of 90F+
at 25-50 percent across the CWA through Day 14...with greatest
likelihood of hot conditions south/west of Indianapolis.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1225 PM EDT Sun Jun 9 2024

Impacts:

- W/NW winds gusting up to 25kts this afternoon
- MVFR ceilings possible mainly at KIND and KLAF Monday morning

Discussion:

Cirrus shield associated with convection over Kentucky and Tennessee
continues to shift south of the region early this afternoon with
mainly scattered high clouds expected for the rest of the day. Some
diurnal cu development is expected as well with overall cloud
coverage diminishing further into the evening as subsidence expands
across the region. With the mixing layer expected to peak at 7-8kft
this afternoon...winds will remain gusty for most of the rest of the
day.

A sharpening of the upper trough over much of the eastern part of
the country tonight and into Monday will enable lower ceilings
currently over the northern Great Lakes to progress south. MVFR
stratus will make it to KLAF late tonight and KIND shortly after
daybreak. Lower ceilings will gradually lift by Monday  afternoon as
drier air advects in from the north with gusty winds likely resuming
as well.


&&

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

$$

SHORT TERM...Ryan
LONG TERM...AGM
AVIATION...Ryan