246
FXUS63 KIND 051911
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
311 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.

&&

.DISCUSSION (This evening through Tuesday)...
Issued at 311 PM EDT Tue May 5 2026

Steady rain has overspread much of central Indiana as of 2pm, though
a break in the rain is taking shape towards the Illinois state line.
This should gradually fill in as broad forcing aloft arrives from
the west. Guidance is in excellent agreement showing widespread rain
through the evening and into the overnight. Additionally, some weak
instability may creep far enough north to allow for embedded
convection capable of thunder. Overall, instability is only a couple
hundred J/Kg in the most aggressive solutions...so we will keep the
mention of thunder to a minimum.

Model soundings indicate a fairly deep warm cloud layer (around
10000 feet) with a mostly saturated column. As such, warm rain
processes with abundant moisture (PWATS around 1.25 inches) should
allow for efficient rainfall production today. Any embedded
convective element could allow for rather heavy rainfall rates
despite meager radar appearance. Therefore localized flooding is our
primary hazard today. Flash flooding is less of a concern, as
rainfall rates shouldn`t be high enough for that. Slower inundation
of low-lying areas and roadways is more probable. Most guidance
shows between 1-2 inches of additional rainfall through tonight,
with the highest amounts along and south of I-70.

Tonight

Additionally, winds have turned northerly behind a cold front that
is moving southward this afternoon. Temperatures have dropped around
5 degrees with the frontal passage and a slow drop is expected into
tonight. Lows in the 40s are likely for much of the region by
sunrise Wednesday. Cloud cover will take longer to clear out than
the rain which should help limit radiational cooling. However,
should clearing occur then patchy fog cannot be ruled out.

Wednesday

Partly to mostly cloudy skies prevail on Wednesday within the post-
frontal environment. Temperatures are expected to be cool, roughly
10-15 degrees below average for this time of the year (average highs
in the low 70s). Surface high pressure building in will keep winds
rather light.

Thursday

Surface high pressure is firmly established by Wednesday night, and
ideal radiative cooling conditions look to be present. Clear skies,
light winds, and a subsident atmosphere should promote temperatures
into the upper 30s by sunrise Thursday. Patchy frost and fog may be
possible, mainly in rural areas where cooling potential is greatest.
Light winds and sunny skies will allow for a steep diurnal curve,
with temperatures rebounding nicely to near 60s by the afternoon.

High pressure begins departing to the east Thursday night, allowing
for southwesterly flow to develop. Winds at the surface remain
light, however, under a stable boundary layer. As such, another
night with good radiative cooling potential is likely Thursday
night. Lows in the low 40s appear likely.

Friday onward

Southwesterly flow intensifies on Friday with warmer weather
expected. Highs near 70 return for much of the area. Though low-
level flow is out of the southwest, broad northwesterly upper-level
flow remains in place. Ensemble guidance shows a shortwave trough
diving southeastward late Friday. With little surface reflection,
mass response is limited. Nevertheless, enough moisture should lift
northward to allow for scattered showers and thunderstorms. Model
soundings do not show a lot of instability, a couple hundred J/Kg at
most, but enough for the mention of isolated thunder.

Broad troughing persists into the weekend and potential early next
week. As such, near to below average temperatures are favored.
Ensemble guidance is hinting at a return to a warmer weather pattern
around mid-month, though the signal isn`t very clear at the moment.

&&

.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.
&&

$$

AVIATION...Eckhoff
DISCUSSION...Eckhoff