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000
FXUS63 KIND 221822
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
222 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

&&

.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 (18Z TAF Issuance)...
Issued at 1252 PM EDT Mon Apr 22 2024

Impacts:

- VFR Conditions expected for much of this TAF period.
- MVFR Cigs/Visibility possible after 231400Z in Rain.

 Discussion:

VFR conditions will persist through the afternoon along with warmer
southwest lower level flow as high pressure moves south of Indiana.
High clouds with an approaching upper short wave over the upper
midwest will advance and spread across the TAF sites this evening.
This will just result in high VFR Cigs through the overnight hours.

An upper level wave is expected to push into and across Central
Indiana on Tuesday from the northwest. This will result in the
arrival of low IFR cigs late on Tuesday morning. Forecast soundings
at that time begin to trend toward saturation as the best forcing
arrives. Some brief MVFR cigs and visibilities will be possible as
the wave passes through mid day and early afternoon across Central
Indiana.


&&

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

$$

SHORT TERM...Puma
LONG TERM...50
AVIATION...Puma