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000
FXUS63 KIND 230211
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1011 PM EDT Mon Apr 22 2024

.KEY MESSAGES...

- Increasing Clouds tonight and Warmer.

- Cloudy with late morning/afternoon rain expected on Tuesday

- Cooler mid-week, with some frost possible Wednesday night

- Active pattern returns late this week into the weekend with above
  normal temperatures

&&

.FORECAST UPDATE...
Issued at 1010 PM EDT Mon Apr 22 2024

Forecast continues to be on track so only minor adjustments for
current observations were needed. Satellite shows that upper clouds
have started to move into the area while surface obs show southerly
to southwesterly surface flow. Lows tonight will be in the mid to
upper 40s. For the rain tomorrow, still expecting an arrive from the
NW sometime late morning into the afternoon.

&&

.SHORT TERM (This evening through Tuesday)...
Issued at 222 PM EDT Mon Apr 22 2024

Synopsis:

Surface analysis early this afternoon shows strong high pressure in
place over Arkansas and Louisiana. A strong surface ridge extended
northeast from the high, into TN/KY/OH and W NY. GOES16 shows clear
skies across Indiana as temperatures were reaching the lower to
middle 60s. A moderate surface pressure gradient was found over IA
and MO on the backside of the departing ridge. GOES16 shows
widespread CI over IA/WI and IL pushing southeast within the flow
aloft. Radar mosaics show limited precipitation over ahead of a cold
front over MN and Eastern NB.

Tonight...

Northwest flow remains prevalent aloft. High clouds as seen upstream
are expected to advance and reach central Indiana this evening and
overnight. Forecast soundings show this through the overnight hours
as they continue to show dry air within the lower and mid levels of
the column, but saturation arrives aloft overnight. Thus increasing
high clouds will continue to invade Central Indiana this evening and
overnight. Ongoing warm air advection is expected overnight as 850mb
temps surge toward 6C. This along with the expected increasing cloud
cover should allow for overnight lows to only fall into the middle
to upper 40s.

Tuesday...

Models shows a quick moving short wave within the upper northwest
flow dropping southeast from the upper Midwest and across Central
Indiana on Tuesday. Best forcing will arrive during the afternoon
and evening hours. Forecast soundings by 18Z show deep saturation
across the area with pwats around 1 inch. The associated cold front
with this upper system is expected to sag southward across central
Indiana, providing lower level convergence. 300K GFS Isentropic
surface shows up glide ahead of the cold front on late Tuesday
morning and during the afternoon. Specific humidifies look to reach
around 5 g/kg. A caveat is that days of subsidence have led to a dry
air mass across Central Indiana and gulf flow really fails to
develop due to the blocking high to the south. Thus forcing seems
quite favorable for precip, but moisture is somewhat limited. Thus a
light rain is expected. So we are looking at high confidence, low
amount type rain event. Furthermore, forecast soundings fail to show
much instability, so any thunder will be minimal to none.

Given the southwest flow, expected precipitation and cloud cover,
highs should only reach the mid to upper 50s.

&&

.LONG TERM (Tuesday night through Monday)...
Issued at 222 PM EDT Mon Apr 22 2024

Tuesday night...

The initial cold front will still be moving through southern
portions of the area during the evening. A secondary front will be
not far behind. Will keep some mainly chance PoPs going south during
the evening with lower PoPs to the north. Overnight, forcing should
be far enough south to go dry across the area.

Wednesday and Thursday...

High pressure will be in control during this period, providing dry
conditions. Temperatures will be below normal for much of the time.
On Wednesday night, low temperatures in the 30s will be common.
Skies will be mostly clear, and winds will be light. In portions of
the forecast area (mainly north) where lows will be in the mid 30s,
some frost looks possible.

Friday and beyond...

A series of systems will eject out of the southwestern USA from
Friday into early next week. This will bring periodic chances for
showers and some thunderstorms through the period. Southwest flow
will bring moisture and warmer air to the area. Temperatures will be
above normal.

Questions remain though on the timing of the systems and best
forcing, so confidence in the timing of the higher PoPs remains low.

Machine learning has indicated a low severe weather threat around
Sunday, and that is not out of the realm of possibility given the
potential instability and wind fields. However, with the low
confidence in the timing of the systems, will just keep an eye on it
for now.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 822 PM EDT Mon Apr 22 2024

Impacts:

- LLWS late tonight at LAF. May periodically impact other sites as
well

- Rain to move through tomorrow, lowering ceilings and
visibilities to MVFR with it

- SW  to W winds tomorrow will be sustained near 15 kts with gusts
up to 30 kts

Discussion:

VFR conditions will persist through the night and into tomorrow
morning ahead of an approaching system that will brings rain, MVFR
conditions, and breezy winds. High clouds ahead of this system have
already started to move into the area. Rain and MVFR conditions will
arrive from the NW tomorrow, reaching LAF near mid-morning and the
other TAF sites by early to mid afternoon.

There will be a threat for LLWS from 06-12z that is mostly expected
to impact LAF but can not rule out that it impacts the other sites
periodically during that timeframe. Winds overnight will be from the
SW near 7-10 kts. Sustained speeds will increase to near 15 kts in
the morning with gusts up to 30 kts possible through much of the
day. Wind direction will become more westerly by the end of the TAF
period.


&&

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

$$

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