Area Forecast Discussion
Issued by NWS Indianapolis, IN

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FXUS63 KIND 241839

Area Forecast Discussion
National Weather Service Indianapolis IN
239 PM EDT Thu Jun 24 2021

.Short Term...(This evening through Friday night)
Issued at 239 PM EDT Thu Jun 24 2021

Satellite imagery depicts a robust MCS over central Illinois,slowly
progressing eastward  and approaching the far NW corner of central
Indiana. Downstream cloud cover of this MCS have filled in skies
early this afternoon, and limiting temperatures gains with highs in
the low 80s.

Most areas will stay dry through 03Z, minus far W and NW locations.
Rain will be associated with the aforementioned MCS, as is moves
eastward. This is supported by a surface low developed within
diabatic cooling of the previous nights convection and moderate warm
air advection within SW flow. 7 C/km lapse rates and a dew points in
the upper 60s, have also allowed for a conducive environment for
convective initiation. However, without any strong upper level
support, this MCS is continuing to sit over the same region,
producing 2-3"/hour rates at times. As this enters central Indiana,
diurnal cooling along with some interaction with an impressive ridge
over the EC will inhibiting its growth, allowing it to decay through
the overnight period. Heaviest rainfall totals will remain in NW
central Indiana, where the MCS could reach prior to decay. Areal
flooding could be of concern if rain rates remain high for prolonged

Scattered light to moderate showers can be expected over most areas
overnight as the dissipating MCS moves through. A brief lull in the
late morning and early afternoon is likely prior to the initiation
of another MCS, this time located within or near central Indiana.
Heavy rain and thunderstorms will be likely at times tomorrow
evening with isolated rainfall totals greater that 2 inches in
northern portions of the CWA.

Severe winds will be possible in the evening as convective mixing
within thunderstorms taps into a 50kt LLJ. Mid level dry air will be
lacking for strong downburst. Light hail could be possible as steep
lapse rates promote strong updrafts and elevated storm tops, but
severe hail should remain isolated.


.Long Term...(Saturday through Thursday)
Issued at 239 PM EDT Thu Jun 24 2021


Throughout early part of the long term, central Indiana will be in
southwest flow aloft with the area in between an upper high over the
Atlantic and an upper trough over the central part of the country.
Southwest flow will be ongoing at the surface as well with a
stalled front to the northwest of the area.

This deep southwest flow will continue to pump in moisture to the
area. Better forcing and more widespread coverage of precipitation
though will mostly remain to the west, closer to the stalled out
front. Any upper impulse moving through the upper flow could trigger
scattered convection though, given the warm and unstable atmosphere
in place. Precipitable water values between 1.5 and 2 inches will
keep the heavy rain and subsequent flooding threat in place.

Will have to watch and see if the upper high can build farther west
as indicated by some models. If it does, coverage of convection
would be less, especially across the eastern forecast area.

By mid-week next week, the upper trough will move slowly east into
the area, bringing more widespread showers and thunderstorms. These
too will have a heavy rain threat as well.


.Aviation...(18Z TAF Issuance)
Issued at 139 PM EDT Thu Jun 24 2021


- Generally VFR conditions, deteriorating to MVFR at KIND by 17z
- Winds around 140-180 early this morning...will veer slightly to
180-200 by 14z this morning...while increasing to around 10-14 kts,
with gusts to 15-24 kts through the midday-afternoon hours
- VCSH will slowly advance eastward this evening...with more
widespread SHRA following Friday morning


Dry conditions will continue through at least midday today, with
slight chances of rain showers returning to KLAF/KHUF early this
evening...and around midnight at KIND/KBMG.  Rain coverage will
increase overnight, with likely chances reaching KLAF/KHUF by 12z
Friday morning...and KIND by the end of the TAF period.  Isolated
thunderstorms will also be present, but confidence is too low at any
specific location to include in TAFs at this time.

VFR will generally prevail through the period, although CIGs will
drop to MVFR at KIND by midday Friday.  Brief MVFR is also possible
in and around heavier showers tonight and Friday morning.  South-
southeasterly winds around 6-7 kts early this morning...will veer to
S/SSW by mid-morning while increasing to 7-12 kts, with gusts as
high as 20-24 kts through the midday-afternoon hours.




Short Term...Updike
Long Term...50
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