Area Forecast Discussion
Issued by NWS Indianapolis, IN

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000
FXUS63 KIND 290700
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
300 AM EDT Fri Mar 29 2024

.KEY MESSAGES...

- Warmer today

- Rain chances return Friday Night through Wednesday; thunderstorms
  possible at times

- Some uncertain potential for strong to severe storms early next
  week

&&

.SHORT TERM (Today and tonight)...
Issued at 259 AM EDT Fri Mar 29 2024

Rest of the Overnight...

A weak impulse, ahead of a Plains ridge, along with a baroclinic
zone demonstrated, best displace by 925 millibar frontogenesis, from
southern Iowa into northwestern Indiana, has lead to some light
showers and or sprinkles over areas near and north of I-74. This was
hinted at by CAMs which suggest the shower threat will be east of
the area by daybreak.

Today...

The Plains ridge will move to near the Indiana border by 00z
Saturday. Southerly winds on the back side of high pressure over the
southeastern states will allow for a nice warmup today with
temperatures expected to climb back to above normal and into the 60s
during the afternoon.

Although 300K isentropic lift will kick in late today, the dry low
levels per Hi-Res soundings suggest there will only be mid and high
clouds increasing and despite the mixing layer rising to 5K feet,
momentum transfer vectors suggest only a mild breeze with gusts
under 20 knots.

Tonight...

300K isentropic lift on the nose of a southwest to northeast
oriented 40+ knot nocturnal low level jet and overtop a low level
baroclinic zone along with a wave moving along this baroclinic zone
will pave the way for widespread showers and a few thunderstorms
mostly concentrated overnight and along and north of I-70. DESI
suggests the heaviest QPF axis will be north of central Indiana,
however with DESI PWATs increasing to 0.70 to 1 inch, would not rule
out that some northern sections see half an inch and perhaps more in
the stronger cells. Bulk of the instability will be to the west, so
do not expect a lot of lightning around.

High confidence the warm advection and increase in clouds will keep
temperatures from falling lower than the 50s.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 259 AM EDT Fri Mar 29 2024

An active weather pattern is expected for much of the long term
period. Quasi-zonal flow is likely through the weekend as central
Indiana remains on the northern periphery of an upper ridge building
across the eastern CONUS. At the surface, a low pressure system
moving through on Saturday brings the potential for scattered
showers and storms. The cold front associated with this system may
push just south of central Indiana briefly Saturday night before
lifting back north on Sunday as a warm front. Models then show the
frontal boundary meandering over the region through early next week
keeping rain/storm chances in the forecast.

Some uncertainty remains regarding storm coverage during the day
Sunday once the front lifts back north, at least initially. The main
reasons for this are that the upper ridge axis should be centered
near the area and a few models show hints of an EML advecting into
the area. Modest destabilization combined with daytime heating
should eventually allow for storms to fire up late in the day.
Strong deep-layer shear supports at least an isolated severe weather
threat Sunday afternoon into the overnight hours once storms fire
up.

Additional rounds of severe weather are possible Monday into Tuesday
as a deepening low pressure system associated with an upper
shortwave moves across the region. Strong deep-layer shear over a
favorable thermodynamic environment with increasing dynamics from
the approaching surface low suggests more widespread organized
convection is possible. Confidence continues to increase, but
uncertainties in exact details remain due to differences between
guidance. Multiple rounds of convection will also lead to hydrologic
concerns, particularly with the system moving in early next week.

Precipitation chances linger into the middle of next week as
moisture wraps around the departing surface low. Expect dry
conditions to then return sometime Wednesday night into Thursday
once surface high pressure builds in. Temperatures will be above
normal for much of the period before cooler air filters in the
middle of next week.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 1053 PM EDT Thu Mar 28 2024

Impacts:

- KIND and KLAF could see a light shower or sprinkle through
  09z

- Additional showers and possibly MVFR conditions after 05z Saturday
  with the best chances at KLAF and KIND

- Non-convective low level wind shear possible after 07z
  Saturday

- SSW wind gusts to 25+ knots after 05z

Discussion:

High confidence in VFR flying conditions today and this evening,
then shower chances will increase overnight as overrunning ramps up.
Also, KIND and KLAF could see a light shower or sprinkle until near
daybreak today.

A strong low level jet will make non-convective low level shear a
concern Friday night. Otherwise, south and southwest winds will pick
up as well Friday night.


&&

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

$$

SHORT TERM...MK
LONG TERM...Melo
AVIATION...MK


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