Brownsburg, Indiana 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

210
FXUS63 KIND 171019
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
619 AM EDT Thu Apr 17 2025

.KEY MESSAGES...

- Rain showers with perhaps a rumble of thunder this afternoon

- Warmer and breezy tonight

- Warming trend towards Friday with strong to severe thunderstorms
  possible Friday night into early Saturday

- Multiple rounds of rain continue into the weekend with the
  potential for returned river flooding

&&

.SHORT TERM (Today and tonight)...
Issued at 229 AM EDT Thu Apr 17 2025

Surface analysis early this morning shows strong high pressure in
place over the Great Lakes, stretching south to OH and the Smokey
Mountains. Low pressure was found over western KS, pushing eastward.
GOES16 shows area of high CI over IL and MO, advancing toward
Indiana. Otherwise much of the state was mostly clear. Aloft, water
vapor imagery showed moderate ridging in place over the Mississippi
valley, resulting in NW flow across Indiana. Within this upper flow a
steady stream of Pacific moisture was noted, streaming across the
intermountain west to the plains states, eventually reaching the
Ohio Valley. Easterly Surface flow was in place across Indiana.

Today -

The ridging aloft is expected to push across Indiana. This will
allow for the development of southwest flow aloft over Indiana along
with the end of the subsidence that has been present the past few
days. As this occurs, the surface low over the high plains is
expected to emerge, deepen, and move east. An associated warm front
with this feature will surge northward across Central Indiana this
afternoon, shifting the winds toward a more southerly component. As
the front passes. HRRR suggests an thin band of showers, quickly
passing across Central Indiana. Precipitation should be light with
this as deep moisture is limited. In further support of this
feature, the GFS 295K isentropic surface shows lift pushing across
Central Indiana this afternoon with the associated front, with a
surge of specific humidity. Thus confidence is high for a short
period of very light rainfall, particularly across the western half
of Central Indiana. Given the arrival of our warm air advection,
high should be at or above the NBM, in the middle to upper 60s.

Tonight -

The previously mentioned ridge axis will continue moving east of
Indiana, allowing the development of tropical, southwest flow aloft
to begin. That flow aloft is what will be a main player in bringing
rain to Central Indiana this weekend. Moisture will not yet quiet
arrive though for tonight. Continued high clouds are expected to
stream across central Indiana within this flow and forecast
soundings and time heights show periods of saturation aloft as this
occurs. Within the lower levels, strong warm air advection will be
in play on southerly winds. A moderate pressure gradient appears to
be present ahead of the deepening low pressure system to the west,
and this will provide ample mixing across our area through the
night. Precip will not be expected as overall moisture and forcing
is limited. but partly cloudy skies should be expected as mid and
high clouds pass from time to time. Given our warm air advection,
good mixing and gusty winds, temperatures should not fall too much.
Will trend lows at or above the NBM, in the upper 50s to around 60.

&&

.LONG TERM (Friday through Wednesday)...
Issued at 229 AM EDT Thu Apr 17 2025

Friday Through Sunday.

Main focus for the long term period is on the conditional threat for
a few strong to severe storms late Friday night as a cold front
pushes through central Indiana and the potential return to flooding.
Ahead of the front, continued flow from the Gulf will bring high
temperatures to near 80 and dewpoints into the low 60s during the
day on Friday. An EML will limit convective initiation during the
day with a stout cap in place. Showers and storms are expected to
initiate later into the overnight hours across northwest Indiana and
Illinois with a gradual southeastern progression through the night,
but models are increasingly trending towards a drier overnight with
the overall severe threat minimal until early Saturday morning. Some
of the hi-res models try to show some convective initiation during
the evening and early overnight, but those showers look to remain
shallow with widespread cu being more likely. Ahead of the rain and
severe threat, gradient winds of 30-40 mph are likely through the
afternoon with efficient mixing down of LLJ winds.

A few strong to severe storms look likely towards daybreak Saturday
but this quickly transitions into a flooding threat later into the
day as the atmosphere saturates which cuts the instability. Current
focus for any severe weather would be from the 3AM to 9AM timeframe
with both large hail and damaging winds possible, but overall the
threat looks lower than previous model runs. The cold front is then
expected to stall across the Ohio Valley with differing model
solutions on where the front stalls which will impact the axis of
heaviest rain. Rain is expected along the stalled front through the
day Saturday with 1-3 inches of additional rain along that boundary.
Another round of rain is expected Sunday into Sunday night with a
strong upper level low moving in from the southwest which will push
what is left of the stalled front out of the forecast area, but not
before bringing an additional half inch to an inch of rain along
with another shot for low-end severe weather.

While there is uncertainty as to exactly how much rain will fall,
latest model ensembles continue to trend higher for both 2+ and 4+
inch totals between Friday night and Monday with higher end outliers
of 6+. Amounts on the higher end of the potential would bring a
return to widespread minor flooding along area rivers and pockets of
low-end moderate flooding as shown by the latest MMEFS runs.

Monday Through Wednesday.

Quieter weather is expected for the start of the work week with
temperatures returning to near normal Monday with zonal flow aloft.
Small rain chances arrive as early as Tuesday with a weak upper
level disturbance, but confidence in the forecast quickly drops off
past Monday as the global models struggle to resolve the synoptic
pattern in the aftermath of the exiting low.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 618 AM EDT Thu Apr 17 2025

Impacts:

- Brief light rain in the 17Z to 22Z timeframe
- Wind gusts to around 25kt this afternoon

Discussion:

VFR conditions are expected through the period. A front will move
through central Indiana during the afternoon hours today bringing a
brief period of light rain and perhaps a rumble of thunder or two.
Winds will gradually become more southerly through the morning with
gusts to 25kts during the afternoon hours. These stronger winds will
relax after sunset with winds of 9-13kts through the night.

&&

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

$$

SHORT TERM...Puma
LONG TERM...White
AVIATION...White