000
FXUS63 KIND 251901
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
301 PM EDT Mon Oct 25 2021

.Short Term...(This evening through Tuesday night)
Issued at 300 PM EDT Mon Oct 25 2021

This Evening/Tonight...
Yesterday`s upper low and associated surface low continue to push
northeast of central Indiana.  Nonetheless, GOES16 IR shows a broad
cyclonic rotation around the system with central Indiana on the back
side.  As a result, lingering rain showers continue to drift across
the forecast area at this time and will continue to do so into the
evening.  And, would not rule out light drizzle into tonight.
Meanwhile, winds will remain strong out of the west/northwest into
tonight when the pressure gradient weakens. Sustained speeds have
generally been in the 10 to 15 mph range with gusts up to 30 mph. As
clouds scatter out tonight, overnight lows will dip into the low
30s.

Tuesday/Tuesday Night... A sharp upper ridge will spread over the
Midwest tomorrow with strong subsidence streaming into central
Indiana.  So, any lingering morning clouds will quickly clear out by
Tuesday afternoon.  Nonetheless, the breezy northerly winds will
keep daytime highs below normal in the mid to upper 50s.  A few wind
gusts up to 20 mph could linger into the morning, but sustained
winds will have already dropped to around 5 to 10 mph.

The strong radiational cooling under clear skies Tuesday night,
coupled with the light winds and low dew point depressions will be
conducive to fog formation.  Patchy dense fog could result in
reduced visibilities early Wednesday morning.

&&

.Long Term...(Wednesday through Monday)
Issued at 300 PM EDT Mon Oct 25 2021

Wednesday...

Models suggest strong ridging in place over Indiana within a highly
amplified pattern aloft. A deep trough will be moving through the
plains...but should hold off til late Wednesday night. Thus with
lingering subsidence and weak high pressure at the surface
this should lead to a dry day.

Wednesday Night through Saturday Morning...

A strong negative tilted upper trough is expected to push toward
Indiana and the Ohio Valley on Late Wednesday night before slowly
settling over Tennessee and Kentucky By Friday as a deep and broad
upper level low pressure system. Strong forcing and broad cyclonic
flow will be on place during this period...along with plenty of
moisture within the flow. Forecast soundings through this period show
a saturated column with pwats over 1 inch. Thus will be including
high pops through the period as clouds and showers will be expected
from time to time within this cyclonic flow.

Saturday afternoon through Monday...

The upper low is finally expected to begin to depart on Saturday
afternoon and Saturday Night...pushing associated forcing and
moisture northeast of Indiana with it. Forecast soundings at that
time begin to show the start of subsidence as ridging builds across
Indiana from the upper midwest. Thus will trend toward a dry
forecast by late in the day on Saturday and keep this feature in
place through Sunday.

ECMWF does suggest the arrival of some mid level moisture on Monday
as the flow aloft becomes more zonal as the previous ridge appears
to flatten. Furthermore a warm frontal boundary appears to settle
across Indiana with associated mid level moisture. Confidence is low
with these weaker features at day7...thus will try for a dry
forecast or small pops for now.

&&

.Aviation...(18Z TAF Issuance)
Issued at 139 PM EDT Mon Oct 25 2021

IMPACTS:
- IFR/MVFR through this afternoon, then becoming predominantly MVFR
into tonight.  VFR should return late tonight.
- West/northwest winds of 12 to 15 kts with gusts up to 28 kts
through Tue 06Z.

DISCUSSION: IFR/MVFR conditions expected to linger through this
afternoon with TAF sites still in cyclonic rotation of upper low.
Anticipate predominantly MVFR conditions by this evening and into
tonight with VFR returning late tonight.  Meanwhile, strong
west/northwest winds will be sustained at 12 to 15 kts with gusts up
to 28 kts through Tue 06Z.


&&

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

&&

$$

Short Term...TDUD
Long Term...Puma
Aviation...TDUD