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727
FXUS63 KIND 150432
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1232 AM EDT Sat Jun 15 2024

.KEY MESSAGES...

- Dry weather and near or slightly above normal temperatures Saturday
- Hot and humid trend starts Sunday...increasing confidence in
  potentially hazardous heat into next week
- Low chance for a few showers or storms Monday and Tuesday

&&

.FORECAST UPDATE...
Issued at 940 PM EDT Fri Jun 14 2024

A pleasant early summer overnight is taking shape across central
Indiana...with northerly winds diminishing as the southern portions
of Canadian surface high pressure continue to slowly cross the
Midwest.  Mainly clear skies will prevail, past a few high cirrus
making it over the upper ridge slowly approaching over the central
CONUS. Winds will veer to northeasterly while becoming light through
the middle of the night, with calm winds likely in protected areas
and valleys towards dawn.  Suspect dewpoints stay low enough to
prevent any fog formation, with any patchy visibility reductions
closer to the Ohio River.  On the heels of Indianapolis again
matching its warmest reading so far this year at 87F, the modest
cold air advection will help drop temperatures about 25 degrees down
to seasonable levels...with generally low 60s expected by dawn.

&&

.SHORT TERM (This evening through Saturday)...
Issued at 248 PM EDT Fri Jun 14 2024

A weak midlevel shortwave passing through the southern Great Lakes
now has nudged a cold front south of our area to near the Ohio
River. Temperature advection is weak so temperatures should be near
daily maximums experienced yesterday. A drier continental air mass
is noted in observations advecting in, and drying is enhanced by
mixing process given particularly dry/subsident layer aloft evident
in water vapor. ACARS soundings show enough residual low level
moisture for some cumulus at the top of the mixed layer but this may
wane later in the diurnal cycle given the drying trend.

No major concerns with a model blend approach to temperatures
tonight, though radiative processes may be strong enough for a few
locations to fall slightly lower. Given that we`re peripheral to the
MSLP high center and light winds should prevail overnight we won`t
adjust downward.

High-level moisture may crest the ridge bringing some cirrus later
tonight and through the day tomorrow. Diurnal cumulus tomorrow
should be minimal as we`re still a couple days away from meaningful
low-level moisture return. The warmer windward side of mid-upper
ridge axis will be positioned to our west tomorrow which will hold
off the onset of anomalous warmth that is to come as the synoptic
pattern shifts beyond the short term period.

&&

.LONG TERM (Saturday night through Friday)...
Issued at 248 PM EDT Fri Jun 14 2024

Saturday night through Next Week

**Increasing confidence in an extended period of very hot and humid
conditions Sunday through much of next week**

The main story in the extended period will be the very hot
temperatures building across much of the eastern CONUS Sunday and
persisting through next week. Upper ridging initially centered over
the Great Lakes region Saturday night is expected to amplify and
become centered over the Northeast by early next week. At the
surface, high pressure should gradually shift east before settling
near or just off the Northeast coast supporting southerly flow back
across the Ohio Valley. Increasing heights aloft combined with
return flow will result in temperatures quickly warming up into the
90s at the beginning of the long term period. In addition, look for
humidity to be on the rise which raises concern for dangerous heat
indices near or above 100F by Monday.

Most guidance shows upper ridging remaining the dominant influence
through much of the period though the ridge may begin to flatten
late next week as a few troughs traverse far northern portions of
the Great Lakes or Canada. Unfortunately, there appears to be little
relief from the heat during this period and overnight lows are only
expected to fall into the 70s. The extended stretch of heat this
early in the season is abnormal so make sure to stay hydrated and
take frequent breaks in air conditioning if you are outdoors.

Increasing moisture from southerly flow combined with daytime
heating supports at least low end chances for showers and storms
most days. The strongest subsidence from the upper ridge/surface
high should be focused further east of the area suggesting capping
should not be an issue. Some models show ridging breaking down late
next week allowing for a system to move in, but diverging model
solutions leads to low confidence for this scenario.

&&

.AVIATION (06Z TAF Issuance)...
-- Changed Discussion --
Issued at 1232 AM EDT Sat Jun 15 2024

Impacts:

- None

Discussion:

High pressure over the Great Lakes will serve as the dominant
feature through Saturday with mainly clear skies and just periodic
cirrus drifting through the region overtop of the expanding upper
level ridge. Light and variable flow overnight will veer to
southeast on Saturday at around 10kts.
-- End Changed Discussion --

&&

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

&&

$$

UPDATE...AGM
SHORT TERM...BRB
LONG TERM...Melo
AVIATION...Ryan