462
FXUS63 KIND 051759
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
159 PM EDT Tue May 5 2026

.KEY MESSAGES...

- Cooler and rainy today with isolated thunderstorms possible.

- Heavy rain could result in localized flooding of low lying and
  agricultural areas.

- Largely below normal temperatures this upcoming week, with
  multiple chances for more rain on Friday Night and again on Sunday.

&&

.FORECAST UPDATE...
Issued at 924 AM EDT Tue May 5 2026

Showers and a few embedded thunderstorms are developing over
southern Illinois. High-resolution guidance is in good agreement
showing this activity expanding in coverage while lifting
northeastward into central Indiana. We`ve adjusted PoPs with more
weight added to CAMs that are handling the current precipitation
well. Though rain chances are high, we`ve kept the thunder chances
fairly low. Though instability looks to be limited, a few hundred
J/Kg should be present this afternoon...especially across southern
portions of the area. As such, thunder is possible throughout the
day with.

Severe weather does not appear likely today given very limited
instability and poor lapse rates. However, model soundings show deep
saturation with relatively high freezing levels. Rainfall production
may be quite efficient at times, especially within any embedded
convective core. Our primary hazard today is localized flooding.

We`ve also cut temperatures down a bit across our northwest as rain
moves in. Temperatures should be fairly steady today for most of the
area, with our southern counties seeing the largest diurnal rise as
rain takes the longest to reach those areas.

&&

.DISCUSSION (Today through Monday)...
Issued at 219 AM EDT Tue May 5 2026

Surface analysis early this morning shows low pressure over MI, with
a cold front extending SW to nrn IL and to Central MO. Radar shows
areas of showers and thunderstorms along and ahead of the front,
stretching across Central Indiana to central IL. Aloft, water vapor
showed deep low pressure over Ontario, providing cyclonic flow
across the upper midwest, but mainly a zonal flow was in place
across Indiana. A short wave pivoting around the upper flow pushing
through the northern plains. Water vapor shows Pacific moisture
streaming across the Rockies into the plains toward Indiana. A more
tropical plume of moisture was found streaming across Baja
California and Texas toward the Ohio valley. These features were
providing ample moisture for showers and storms ahead of the front
and upper short wave.

Today and Tonight...

Models show the cold front will slowly sag southward across Central
Indiana through the course of the day. More showers and storms are
expected through the day along and in the wake of the front, as the
upper short wave continues to approach from the northwest. The
previously discussed flow of upper moisture with embedded
disturbances are then expected pass across central Indiana today and
into the evening. HRRR suggest several waves of showers through
tonight. Forecast soundings through today and into tonight show deep
saturation, with pwats over one inch. Better drying and subsidence
within the column does not appear to arrive until Wednesday. Thus
will use near 100 pops for today and tonight. Although soundings do
not suggest a favorable column for convection, an isolated rumble of
thunder cannot be ruled out.

Given our expected rain today and the arrival or north winds, expect
steady state temperatures today in the mid 50s. Lows tonight will
fall to the mid 40s.

Given all this rain, flooding of low lying and agricultural areas
will be possible, flood advisories along with a few areal flood
warning may occur later today and tonight.

Wednesday through Thursday...

Cooler but drier weather will arrive for Wednesday and Thursday.
Models suggest surface high pressure over the northern plains states
will build SE across Indiana and into the Ohio valley, while the
cold front sags farther southeast.  The steady upper flow of
moisture is also shifted farther south, across the Tennessee Valley
and the Carolinas. Forecast soundings across Indiana during this
time dry out considerably, suggesting subsidence and drying. Some
afternoon CU will be possible, resulting in partly sunny skies on
Wednesday and bit more sunshine on Thursday. Cool northwest flow
will continue to keep temperatures below normals, with highs in the
60s.

Friday through Monday...

Broad upper cyclonic flow will remain in place across Indiana and
the northeastern quadrant of the United States through the weekend
and into Monday. Models suggest a pair of short waves pushing across
Indiana within the upper flow on Friday into Saturday and again on
Sunday afternoon into Sunday Night. Within the lower levels a cold
front is suggested to pass on Friday night into Saturday, and
another low pressure system is suggested to pass on Sunday. Surface
high pressure  will then arrive on Monday. Forecast sounds show most
favorable conditions for precip will be on Friday and Sunday as the
surface and upper features pass. Still due to timing adjustments
between now and then larger windows of pops will be used.

No intrusions of warm air are expected this period as the strong
upper low to the north continues to keep mainly a NW flow of cooler,
Canadian air across central Indiana. This will keep temperatures at
or below seasonal normals.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 158 PM EDT Tue May 5 2026

Impacts:

- MVFR conditions with rain today. An isolated thunderstorm possible.
- IFR ceilings at times through this evening.

Discussion:

Rain has overspread central Indiana and is redeveloping upstream
across Illinois as well. As such, rain is expected to continue at
all the TAF sites this afternoon into the evening hours. As the
lower atmospheric moisture increases, IFR ceilings are likely to
develop this afternoon continuing into the evening. Rain ends around
06z with gradual improvement in sky cover thereafter. There is a low
probability of thunder (under 20 percent) but will not be mentioned
in the TAFs for now.

Winds are becoming northerly as a cold front slowly drops southward
across Indiana. Speeds have been under 10kt so far, but a period of
10-13kt winds is possible for a few hours this evening. Winds
diminish once again overnight into the day Wednesday.

VFR conditions return Wednesday morning although SCT to BKN skies
persist through the day.

&&

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

$$

UPDATE...Eckhoff
AVIATION...Eckhoff
DISCUSSION...Puma