476
FXUS63 KIND 240137
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
937 PM EDT Sun Jun 23 2024

.KEY MESSAGES...

- Tuesday likely to be warmest day of the week.
- More thunderstorms possible Tuesday into Wednesday, with one or
  more rounds of strong to severe storms possible, though uncertain.
- A brief respite from heat and humidity late in the week.

&&

.FORECAST UPDATE...
Issued at 936 PM EDT Sun Jun 23 2024

A tranquil midsummer evening is taking shape across central Indiana
following a rather weak, yet effective cool frontal passage Sunday.
Broad surface high pressure slowly building from the Mississippi
Valley promoted diminishing winds earlier this evening, and
dropped Indianapolis to 79F by 900P for the first time in eight
days. Light north-northwesterly winds and mainly clear conditions
will be the rule overnight and into Monday, with dewpoints only
dropping slightly to the low 60s per the modest advection. Expect
at least minor visibility reductions through pre-dawn hours from
patchy fog focused over western and especially southern counties
along river valleys and low-lying areas. Overnight minimums may
be the lowest in 11 days for some locations, ranging from around
60F along eastern counties to 65F in far southwestern zones...
while typical colder spots in Randolph and Henry Counties may
bottom out in the upper 50s.

&&

.SHORT TERM (This evening through Monday)...
Issued at 306 PM EDT Sun Jun 23 2024

There is a pretty strong dry/subsident signal in 7.3 micron water
vapor satellite imagery in the wake departing shortwave trough. The
synoptic-scale pattern has caused the cold front to lag though, and
a fairly thick stratus layer and shallow convective showers are now
exiting the region. The front will clear the state later today, and
behind it only modest drying is present with cumulus/stratocumulus
gradually thinning. Mixing and momentum transfer has resulted in
wind gusts to around 25 mph, and these should subside early this
evening.

Part of the reason the cold front is lagging is the trend toward a
more amplified flow pattern aloft with somewhat short wavelength and
another upstream shortwave perturbation evident now in water vapor
over northern Minnesota. The front is making progress though and
should clear the state later today. A drier cP air mass will arrive
tomorrow with slightly cooler temperatures and noticeably lower
humidity. The MSLP pattern will favor light winds as surface ridging
is centered over Indiana. Conditions should be pleasant with
temperatures near climo in the mid-80s for highs.

&&

.LONG TERM (Monday night through Sunday)...
Issued at 306 PM EDT Sun Jun 23 2024

Continued warmth is expected throughout much of the long term
forecast, with at least a day or two of highs back in the 90s
appearing likely Tuesday and perhaps Friday. The saving grace will
be that some relief from the recent stifling humidity is expected
late in the work week.

Additionally, a couple of opportunities for thunderstorms are
expected, with some potential for organized severe thunderstorms
late Tuesday into Wednesday, though uncertainty remains significant
given guidance discrepancies and daily dependencies of convection on
the influences of prior days` activity.

Some dying convection may make its way into our northwest around
daybreak on Tuesday into Tuesday morning, and some low chances will
be necessary then. This activity could have an impact upon our
chances of reaching into the 90s, though it appears a lull between
waves of storms will allow for decent insolation during much of the
day.

Additional thunderstorm activity should develop ahead of the front
to our northwest during the day into the evening on Tuesday, which
may then make its way into central Indiana with time. Very strong
instability will likely be in place, with at least modest deep layer
shear, though cold pool organization/thermodynamics should largely
drive the activity and any attendant severe threat, which would be
primarily damaging winds.

Reintensification or redevelopment of strong to severe storms will
be possible Wednesday along the front or boundaries from prior
convection, though degree of destabilization is more in question
given the impacts of this prior activity on insolation and low level
moisture advection. The more likely area for a severe threat
Wednesday may be across our southeast or further southeast out of
the area as time goes on.

Overall, late Tuesday into Wednesday will merit close monitoring for
one or two windows of severe threat, primarily due to damaging wind
potential, along with some heavy rain/localized flooding threat
given fairly significant precipitable water values. Experimental
machine learning guidance continues to support this potential.

The latter portion of the work week will offer some relief in the
form of quiet weather, slightly lower temps, and significantly lower
dewpoints as high pressure traverses the region, though this may be
short-lived as guidance indicates potential for the southwestern
ridge to push back eastward and additional convective potential
along the periphery and ahead of another boundary as we get into
next weekend, though model differences are significant with respect
to ridge amplitude and location, and thus relatively modest chances
remain the forecast. Another welcome respite from the humidity may
come again early in the first week of July as another surface high
follows this next boundary as well.

Moderated NBM numbers a bit at times, especially on the warmest
forecast days, both due to NBM biases and potential convective
influences which may prevent reaching warmest numbers.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 725 PM EDT Sun Jun 23 2024

Impacts:
 - Occasional gusts to 15-20KT through 02Z

Discussion:

VFR conditions will continue to dominate into Monday evening.
Wind gusts exceeding 20KT at KIND as of 23Z will diminish through
sundown. Broad yet weak surface high pressure, approaching from
the Mississippi Valley, will promote light and at time variable
winds tonight, from generally north-northwesterly directions.
Diurnal heating Monday will only return a modest increase in NNW
flow, with sustained winds expected to stay under 7KT through the
period.

&&

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

$$

UPDATE...AGM
SHORT TERM...BRB
LONG TERM...Nield
AVIATION...AGM