888
FXUS63 KIND 191326
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
926 AM EDT Sat Apr 19 2025

.KEY MESSAGES...

- Showers and thunderstorms this morning capable of strong winds and
localized flooding.

- Decreasing rain chance into tonight with more rain and
  potential flooding Sunday night.

- Generally near to above normal temperatures into next week with
periodic shower/storm chances.

&&

.FORECAST UPDATE...
Issued at 9265 AM EDT Sat Apr 19 2025

Active morning continues although the focus has shifted more to the
potential for localized flooding from convection tracking across the
same areas. Heaviest storms are now largely focused across the
southeast half of the forecast area with widespread light to
moderate rainfall over areas further northwest. The frontal boundary
has settled into the southeast counties as of 13Z with temperatures
ranging from the mid 50s in the northern Wabash Valley to near 70
over southeast Indiana.

The overall forecast remains in good shape for the remainder of the
day. A conditional risk for stronger wind gusts remains in play
through midday over the southeast half of the forecast area but
primary severe weather risk should focus closer to the Ohio River
and south where the instability axis will reside closer to the
southward moving cold front. As mentioned above...focus has shifted
to heavy rain and localized flooding concerns especially to the
south of I-70 where multiple areas of convection have produced radar
estimates up to 1.5 to 2 inches from near Terre Haute northeast
towards the Indy metro. Should see this axis of heavier rates
gradually shift south over the next few hours with the cold front.
May see a brief lull in rainfall coverage early this afternoon
before additional showers move in for late day into the early
evening.

Made minor adjustments to high temps based on current obs and
trends. Zone and grid updates out.

&&

.MESOSCALE UPDATE...
Issued at 344 AM EDT Sat Apr 19 2025

A small MCS over central Illinois should reach the Indiana border by
around 4:30am or shortly after. Nocturnal stabilization is weak
owing to warm advection strength, and when paired with a fairly deep
and persistent wind/RIJ structure, will likely not substantially
limit strong to severe wind potential over the next couple of hours.
This MCS should maintain its intensity into central Indiana
progressing through the state between 5:00am and 8:00am, with its
east-northeastward movement at around 60 mph.

&&

.SHORT TERM (Today and tonight)...
Issued at 230 AM EDT Sat Apr 19 2025

The synoptic pattern will feature a progressive northern stream
shortwave trough and a lagging upstream southern stream trough,
along with a persistent anomalous ridge across the east. This
configuration will result in a deep subtropical moisture plume
positioned across our region through the short term period. Neutral
to slowly rising mean heights suggest limited forcing for ascent.
Most of the forcing will be from southward moving remnant cold
front.

With this pattern, boundary-parallel flow and training resulting in
excessive rainfall would be a concern. Two limiting factors exist,
however; (1) limited synoptic-scale forcing, and (2) meager
instability amidst deep saturation and poor midlevel lapse rates.
HREF probability match mean has some >1.00" QPF amounts across
portions of central Indiana, tied to remnant convection currently in
Missouri moving through early this morning. Deep layer shear and
weak instability may be enough for some organization and strong
winds, with a low probability of severe winds in the 5:00am to
9:00am time frame.

Instability should be at a minimum after initial round of weakening
convection this morning and some overturning. Diurnal
destabilization will be minimal at best and preceding morning
remnant convection will have likely helped augment the frontal
position southward, leaving weak anafrontal convection and/or light
midlevel stratiform precipitation periodically into the afternoon.

Lingering light precipitation late in the day into the overnight is
possible, but limited instability and forcing should preclude
widespread coverage or heavier amounts. Coverage could increase by
daybreak as warm advection regime strengthens preceding the next
eastward migrating mid-latitude cyclone.

&&

.LONG TERM (Sunday through Friday)...
Issued at 230 AM EDT Sat Apr 19 2025

The strongest period of forcing in the long term period, and thus
greatest rain chance, will be Sunday night into early Monday. A
frontal band of weakening convection is expected. Subsequent weak
cold advection will bring temperatures down to near normal Monday.
Weakly perturbed westerlies amidst building eastern mean heights
suggests a warming trend to around 5-10 degrees above normal and
limited opportunities for organized/widespread precipitation.

The synoptic pattern indicated in model ensemble data for the 8-14
day period looks to support above normal temperatures with near or
slightly above normal precipitation.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 748 AM EDT Sat Apr 19 2025

Impacts:

- Showers and storms possible through this afternoon with decreasing
  coverage into the evening

- MVFR conditions expected for much of today with improvement to VFR
  likely by this evening

- Mostly quiet tonight with rain likely returning towards daybreak
  Sunday

Discussion:

Numerous showers and storms are likely through the day with decreasing
coverage towards late this afternoon and into the evening. Predominately
MVFR conditions are expected through the day with VFR conditions returning
by this evening. MVFR conditions may linger through tonight near
KBMG and possibly KHUF tonight.

Look for mostly quiet conditions tonight with a low chance for a few
light showers early. Rain then returns towards daybreak Sunday. A
few thunderstorms cannot be ruled out on Sunday, mainly near KHUF/KBMG.
Winds will veer through the TAF period.

&&

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

&&

$$

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