539
FXUS63 KIND 011818
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
218 PM EDT Fri May 1 2026

.KEY MESSAGES...

- Below normal temps to continue through the weekend with frost
  likely Saturday and possible Sunday

- Milder but still largely below normal next week, with multiple
  chances for rain; heavy rain possible at times

&&

.DISCUSSION (This evening through Friday)...
Issued at 218 PM EDT Fri May 1 2026

The synoptic pattern through the next week will feature an upper
level closed low pinwheeling between the Great Lakes and James Bay,
keeping cyclonic flow in place for the most part across the Midwest
and Ohio Valley. This will lead to generally below normal
temperatures and allow for frequent chances for additional rainfall
next week.

Today through Sunday -

A weak surface low pressure system departing the area has taken this
morning`s showers with it, though a secondary trough axis, steep low
level lapse rates, and some lingering moisture may allow a few
sprinkles to develop this afternoon. Highs will struggle into the
50s across the majority of the area, with stratocumulus continuing
to break up late this afternoon and ample clearing this evening,
particularly northeast.

Some cloud cover may return later tonight as the aforementioned
shortwave trough axis pivots through the region, though the bulk of
this is likely to be confined to southwestern portions of the area,
helping to keep lows up a bit and likely preventing frost issues
outside of the current frost advisory area to the northeast.

A sprinkle or stray shower cannot be ruled out early Saturday
morning with this impulse, and may need to carry either a slight
chance PoP or a sprinkle mention here, but this will be of minimal
impact.

Lows tonight should drop into the 30s to low 40s across the area,
with the low to mid 30s predominant along and northeast of I-74.
These temperatures and light winds will support a threat for areas
of frost, and will maintain the Frost Advisory as is.

Highs tomorrow will again struggle into the 50s under partly sunny
skies after any lingering sprinkles clear out.

Lows Sunday morning will again drop into the mid to upper 30s, which
is a bit more borderline for frost - will forgo any headline for now
rather than confuse the issue with tonight`s headline. Highs on
Sunday under slightly more sunshine and modest warm advection will
rise into the 60s, getting a bit closer but still remaining below
normal.

Sunday night through Thursday -

Much of the work week, particularly early to mid portions of the
week, will be dominated by the effects of an elongated frontal zone
stretching from strong low pressure under the closed low to our
north/northeast back to a leeside low developing as a result of
southwesterly flow over the Rockies ahead of a cutoff low over the
southwestern CONUS, though this cutoff low will fairly quickly be
recaptured by the larger cyclonic flow over eastern North America as
the week wears on.

Large scale deep-layer flow will be significant parallel to this
boundary, making its southeastward progression slow and possibly
presenting opportunity for multiple days with rain chances, as well
as some heavy rainfall as modified tropical moisture is transported
northeast along the front - though GFS Integrated Vapor Transport
progs currently show this maximized to our south early next week.

Experimental machine learning guidance suggests a low chance for a
strong to severe storm Monday into Monday night, but given the flow
orientation and overall pattern, suspect hydrologic concerns might
be slightly more of an issue, though with plentiful shear the storm
threat cannot be entirely dismissed.

Shower chances may linger into the latter part of the work week even
once the aforementioned boundary is through the region, as impulses
pivoting around the larger scale upper low continue to swing through
the area, promoting broad upward motion - these showers would likely
be lighter in the absence of more significant moisture.

Temperatures will remain below normal through the week under the
cyclonic flow aloft, with the possible exception of Monday, when pre-
frontal warm advection may push temperatures to a few degrees above
seasonal normals, which currently sit around 70 for highs and 50 for
lows.

Timing and speed of frontal passage this week will determine the
overall hydrologic impact across the region. With minor flooding
ongoing across lower portions of the main stem rivers in the area,
and plentiful rainfall in the past several days, significant
rainfall could prolong or exacerbate the situation. However, model
differences lead to a fairly wide range of solutions in the
hydrologic ensembles, ranging from a return to flooding to a mere
slowing of river recession. The ultimate situation will turn on
mesoscale details that are to a significant degree unresolvable this
far out.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 134 PM EDT Fri May 1 2026

Impacts:

- Sporadic wind gusts 17-21KT this afternoon

Discussion:

As weak low pressure exits the area, low end VFR stratocumulus will
remain in place this afternoon before gradually breaking up and
lifting a bit this evening. Skies may clear for a time before
additional VFR cloud cover moves back in later tonight.

Through this afternoon, winds will gust to near 20KT at times from
roughly 330-340 degrees, and perhaps slightly either side of this,
as steep low level lapse rates mix down some slightly stronger
momentum aloft. These gusts will subside in typical diurnal fashion
this evening.

&&

.IND WATCHES/WARNINGS/ADVISORIES...

Frost Advisory from midnight tonight to 9 AM EDT Saturday for
INZ021-028>031-035>049-054>057-065.

&&

$$

AVIATION...Nield
DISCUSSION...Nield