Flash Flood Warning 4, NWS Indianapolis, IN

Area Forecast Discussion
National Weather Service Indianapolis IN
257 PM EDT Sun Jul 17 2022

.Short Term...(This evening through Monday night)
Issued at 255 PM EDT Sun Jul 17 2022

Widespread showers and isolated thunderstorms are ongoing across
central Indiana as a surface low associated with an upper trough
moves through. Current surface analysis shows the surface low is
centered over northern Indiana. Rain chances will begin tapering off
this evening and overnight as the low moves into Ohio.

Forecast soundings suggest weak instability and less than 20kts of 0-
6km bulk shear is present across the area. This along with poor
lapse rates will likely inhibit organized thunderstorms. While the
thunder potential has decreased, widespread showers with some
embedded thunder should continue into tonight. An isolated strong
thunderstorm is possible across far southern counties this evening
as the LLJ strengthens.

The flood threat remains across Central Indiana with the greatest
threat south of I-70. High freezing levels, moist adiabatic lapse
rates, and deep moisture may lead to high rainfall rates in some
storms this evening. The potential for training storms along with
high rainfall rates could lead to localized flooding. Upper level
forcing will begin to move east of the region overnight, helping to
taper rain chances. A few showers may linger into Monday morning as
a sluggish cold front associated with the low takes its sweet time
exiting the region.

Dry air filtering in aloft should help to clear out clouds through
the day Monday. The weak front will only lower surface dewpoints
into the upper 60s. Lingering surface moisture in association with
expected daytime heating keeps an isolated shower or thunderstorm
chance for Monday. For the most part, expect a dry and sunny start
to the work week. Look for highs in the low to mid 80s tomorrow with
northwest flow aloft keeping limiting diurnal heating. Lows will be
in the upper 60s as surface moisture limits overnight cooling.

&&

.Long Term...(Tuesday through Sunday)
Issued at 255 PM EDT Sun Jul 17 2022

- Rain chances Tuesday Night and Wednesday
- More rain chances Sunday

Tuesday through Wednesday...

Models depict NW flow in place aloft across Indiana on Tuesday as
strong high pressure aloft will be found across the American
Southwest. A short wave within this flow will approach Indiana on
Tuesday before passing across the Great Lakes on Tuesday Night and
Wednesday. Best forcing with this feature looks to remain well north
of Central Indiana, but an associated cold front will still pass
across Central Indiana on Tuesday Night and early Wednesday. Given
the expected warm and humid air mass across the area, showers and
thunderstorms cannot be ruled out.

Thursday through Saturday...

Mainly dry and warm weather will be expected for the end of the work
week and the start of the weekend. Models show a continued NW flow
in place aloft spilling from the northern plains to the Ohio Valley.
Little in the way of forcing is expected to pass within the flow
during this time. Surface high pressure is suggested to push across
Indiana on Thursday before exiting to the east on Friday and
Saturday. Southerly surface flow will develop by this time, allowing
for warmer and more humid air to push into the Ohio valley. Thus
will try to trend toward a dry and warmer forecast. Models may try
to include some diurnal convection as a more humid air mass will be
arriving, but confidence in that at this time is low.

Sunday...

A second short wave during this period is expected to push to the
upper midwest. An associated surface low over the plains will be
approaching Central Indiana and a lingering frontal boundary will be
lingering in the area. Given the possible forcing along with the
warm and humid air mass in place chances for showers and
thunderstorms appear worthy.

&&

.Aviation...(18Z TAF Issuance)
Issued at 1250 PM EDT Sun Jul 17 2022

IMPACTS:

- MVFR Conditions with brief IFR conditions possible this afternoon.
- IFR Conditions possible overnight.
- A return to VFR by mid-day Monday.

Discussion:

Radar shows area of rain showers over Central Indiana and upstream
over Central Illinois and SE Missouri. This precipitation is
associated with a short wave pushing across our region today and
this evening before it is poised to exit overnight. Forecast
soundings across Central Indiana ahead of the short wave show a
saturated column with high pwats. HRRR suggests precip will advect
across the TAF sites through the afternoon. Instability appears to
be limited this afternoon as clouds and showers in the area will
limit heating. However isolated rumbles of thunder cannot be ruled
out. Thus will use VCTS for thunder mention expect at BMG where
thunder seems most probable.

As the short wave departs tonight a weak cool front is expected to
sag southward across the TAF sites. Forecast soundings dry out and
any precipitation will come to an end. However lingering moisture
and light winds may lead to diurnal fog formation and will include
more IFR Conditions for low Cigs and fog potential at diurnal
minimums.

As heating and mixing resumes on Monday...a return to VFR will be
expected.

&&

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

Short Term...Melo
Long Term...Puma
Aviation...Puma

Hazardous Weather Outlook
National Weather Service Indianapolis IN
409 PM EDT Sun Jul 17 2022

INZ021-028>031-035>049-051>057-060>065-067>072-182015-
Carroll-Warren-Tippecanoe-Clinton-Howard-Fountain-Montgomery-Boone-
Tipton-Hamilton-Madison-Delaware-Randolph-Vermillion-Parke-Putnam-
Hendricks-Marion-Hancock-Henry-Vigo-Clay-Owen-Morgan-Johnson-Shelby-
Rush-Sullivan-Greene-Monroe-Brown-Bartholomew-Decatur-Knox-Daviess-
Martin-Lawrence-Jackson-Jennings-
Including the cities of Delphi, Flora, Williamsport, West Lebanon,
Lafayette, West Lafayette, Frankfort, Kokomo, Attica, Covington,
Veedersburg, Crawfordsville, Lebanon, Zionsville, Tipton, Fishers,
Carmel, Noblesville, Anderson, Muncie, Winchester, Union City,
Farmland, Parker City, Clinton, Fairview Park, Rockville, Montezuma,
Rosedale, Greencastle, Plainfield, Brownsburg, Danville,
Indianapolis, Greenfield, New Castle, Terre Haute, Brazil, Spencer,
Gosport, Martinsville, Mooresville, Greenwood, Franklin,
Shelbyville, Rushville, Sullivan, Carlisle, Shelburn, Farmersburg,
Linton, Bloomfield, Jasonville, Worthington, Bloomington, Nashville,
Columbus, Greensburg, Vincennes, Washington, Loogootee, Shoals,
Bedford, Mitchell, Seymour, and North Vernon
409 PM EDT Sun Jul 17 2022

This hazardous weather outlook is for central Indiana.

.DAY ONE...Tonight.

Scattered thunderstorms are expected at times into tonight. An
isolated strong storm or two cannot be ruled out with strong gusty
winds and small hail. Heavy rain and localized flooding will also be
threats, with lightning a threat from any storm.

.DAYS TWO THROUGH SEVEN...Monday through Saturday.

Thunderstorms will remain a threat into Monday, with isolated storms
possible Wednesday afternoon as well. Severe storms are not
expected.

Peak heat index values over 100 degrees are possible Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated, but spotters are encouraged to
report any significant weather observed, including rainfall amounts
and observed flooding.

&&

More information, along with other weather, hydrological and climate
information can be found at http://weather.gov/ind