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000
FXUS63 KIND 121656
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1256 PM EDT Fri Apr 12 2024

.KEY MESSAGES...

- More rain today, especially this morning. Amounts less than a
  quarter of an inch are expected.
- Gusty winds again today with gusts near 40 mph possible.
- Minor flooding continue along main stem rivers continues with isolated
  moderate flooding in smaller creeks
- Active weather pattern continues into next week with numerous
  chances for rain and storms, severe weather threat increase
  Tuesday into Wednesday
- Above normal temperatures Sunday into most of next week.

&&

.FORECAST UPDATE...
Issued at 917 AM EDT Fri Apr 12 2024

- Rain showers exiting late this morning.
- Isolated Thunderstorms/showers possible NE this afternoon (Low
Confidence).
- Mostly Cloudy and Cool.

Surface analysis this morning shows deep low pressure over Ontario,
north of Lake Ontario. This deep area of low pressure was resulting
in a strong pressure gradient across Central Indiana and was
providing cyclonic flow. GOES16 showed extensive cloudiness across
Central Indiana within the cyclonic flow.   Radar shows an area of
light rain showers pushing southeast across Central Indiana within
the cyclonic flow. This feature was focused with a weak upper trough
axis pushing across the region. This weak trough was associated the
deeper upper low over the Great Lakes. Aloft, strong ridging was
found over the western plains, allowing for northwest flow into the
Mississippi Valley.

This afternoon the upper trough is expected to push southeast within
the cyclonic flow aloft. This will push the ongoing precipitation to
move southeast, exiting the area by late this morning. The weak
forcing provided by this wave will be lost by afternoon as it exits
southeast. ACARS soundings this morning show a saturated column, and
forecast soundings show dry air intruding into the sounding this
afternoon after the wave passes. Thus confidence is high for rain to
exit and end across much of the forecast area this afternoon. Time
heights show saturation within the lower levels is expected to
persist through the day, thus mostly cloudy skies.

Forecast soundings across the northeast parts of the forecast area
this afternoon show shallow CAPE amid steep lapse rates favorable
for convection. HRRR shows very isolated TSRA development this
afternoon across the far northeast. Convective temperatures in this
area are in the middle 50s, which may be reached. Thus some chance
pops for isolated showers or a thunderstorm will be included during
the mid to late afternoon hours.  Given the expected clouds  and
neutral advection, highs in the middle 50s to near 60 should be
expected.

&&

.SHORT TERM (Today and tonight)...
Issued at 238 AM EDT Fri Apr 12 2024

The wet pattern will continue this morning across central Indiana,
before dry weather returns to all areas overnight tonight.

This morning...

Additional upper energy rotating around an upper low will bring more
rain to much of central Indiana this morning, as plentiful moisture
remains across the area. Will go likely category or higher PoPs most
areas early to mid morning, but PoPs will diminish from northwest to
southeast from mid to late morning.

Rainfall amounts will be less than a quarter of an inch.

This Afternoon...

Some drier air will try and work into the area from the west,
allowing some decrease in clouds by late afternoon, especially
across the southwest forecast area.

Additional upper energy will rotate around the upper low, but by
this time only the northeast/far eastern areas will be impacted as
the main system moves east. Will keep some chance PoPs in these
areas. Some weak instability will have developed thanks to surface
heating and colder air aloft, so an isolated thunderstorm is
possible.

A decent pressure gradient plus some mixing with the steeper lapse
rates will bring down some of the winds aloft. Ensembles are showing
that odds favor winds remaining below Advisory criteria (45 mph),
but gusts up to 40 mph remain possible.

Temperatures will rise into the middle to upper 50s central and
east. In the west, if clouds break as expected, highs will reach the
lower 60s.

Tonight...

A few showers may linger very early in the period in the far
northeast, then forcing will exit the area. Surface high pressure
will nudge its way into the area late tonight, bringing drier air.
This will allow clouds to decrease during the night.

Clearing skies and diminishing winds will lead to low temperatures
in the upper 30s and lower 40s.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 238 AM EDT Fri Apr 12 2024

Saturday...Hit the pause button for weather systems impacting the
Ohio Valley as the departing trough axis finally pivots east of the
region Sat morning. This will allow a modest height rise in the
500mb layer, with broad anti-cyclonic flow found within the boundary
layer and centered south of the region along the GOMEX. Generally
will see a quasi-zonal flow Sat, which will help with the
progressive flow. Currently guidance is indicating most of Sat will
end up full-sunshine due to the diffluent/sinking motion to the
airmass overhead; however, the concern is that we could see a solid
diurnal cumulus field develop late morning and persist into the
afternoon hours. One scenario that could offer a better solution is
that air will be sinking and could suppress the diurnal clouds from
being much more than Few/Sct coverage.

The southwest flow should be increasing by mid-morning Sat, allowing
warmer air to begin advecting north. Guidance continues to lean on a
modest thermal ridge arriving and helping to push temps into the
upper 60s to perhaps low 70s. But the caveat to how warm the surface
becomes will be the saturated surface conditions, which will likely
require more energy from the sun to warrant a positive response and
see a strong diurnal curve. Mixed layer should also be on the
increase, coupled with isallobaric gradient within the mixed layer
helping to keep breezy conditions in place Sat as well.

Sunday...While the longwave pattern within the mid-levels appears to
be leaning towards a slightly amplified height field upstream,
surface ridging will be drifting east towards the Southeast CONUS.
This will allow the GOMEX to be wide-open with moisture streaming
north. Thermal ridge will continue to be overhead, and combined with
minimal cloud cover should warrant a large diurnal curve with temps
easily into the upper 70s to perhaps 80 degrees.

Monday through Tuesday...Continued southerly flow to kick-off the
week with a quiet weather pattern; however, the middle of the week
will see a turn towards more convective activity to the Ohio Valley.
Upstream a shortwave will be exiting the four-corners region of the
CONUS, and quickly pushing into the Central Plains late Mon into
Tue. The antecedent low-level moist conditions coupled with strong
southerly flow early in the week and an approaching shortwave point
towards potential for convective activity arriving Tue. Temps will
continue to be unseasonably mild.

Wednesday through Thursday...A shortwave will be undergoing a
transition Wed as it phases into a stronger system over the Northern
Plains, with a slight negative tilt to the 500mb wave pattern.
Southerly flow is still progged to linger mid-week, supporting
continued unseasonable warmth and likely humidity given the moist
boundary layer. There may be a brief period or two of quiet weather,
towards the later half of next week the active pattern does return.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1256 PM EDT Fri Apr 12 2024

Impacts:

- MVFR Cigs improving to VFR by 00Z
- Gusty winds diminishing by 00Z
- VFR on Saturday

Discussion:

GOES16 shows the back edge of cyclonic cloud shield over the Wabash
Valley, while clear skies were found over IL. The cloud shield was
making steady progress east, with clearing and VFR conditions
expected to arrive at LAF and HUF within the next few hours. VFR
should arrive at IND and HUF by late afternoon.

Strong ridging aloft over the plains will lead to subsidence along
with a ridge of surface high pressure building across the TAF sites
tonight and on Saturday. Forecast soundings trend toward a dry
column. Thus VFR is expected to arrive overnight, and persist on
Saturday as the surface high dominates at that time.

Gusty winds this afternoon will also diminish as the low to the
northeast departs farther and the pressure gradient gradually
lessens and daytime heating is lost.

&&

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

$$

UPDATE...Puma
SHORT TERM...50
LONG TERM...Beach
AVIATION...Puma