888 
FXUS63 KIND 290211
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1011 PM EDT Tue May 28 2024

.KEY MESSAGES...

- Scattered showers and at least a few storms are possible late in 
  the day and early tonight. Strong wind gusts are the primary 
  hazard. 

- Dry and Seasonable Wednesday through Friday, Rain chances Saturday 
  into Sunday

&&

.FORECAST UPDATE...
Issued at 1012 PM EDT Tue May 28 2024

Convection continues to shift east in tandem with the upper wave 
passing through the region. At 02Z...storms were now across far 
eastern counties and slowly weakening. Temperatures late this 
evening ranged from the upper 50s to near 70.

Storms so far this evening have produced pea hail and gusty winds. A 
cell merger over eastern Marion County led to a brief intensification 
of the storms and penny to quarter hail in a few spots between 
Cumberland and New Pal. As mentioned above...convection is weakening 
but still occasionally producing gusts to near 40 mph and pea size 
hail. Convection should be out of the forecast area by midnight but 
a few showers may pivot back down across far northeast sections of 
the forecast area late tonight as the upper wave shifts east into 
Ohio. 

The remainder of the night will be quiet and cool...with a steady 
increase in lower stratus from the northeast during the predawn 
hours. Expect these clouds to be over much of the northern half of 
the forecast area by 12Z Wednesday morning. Lows will fall into the 
lower and mid 50s by daybreak.

Zone and grid updates out.

&&

.SHORT TERM (This evening through Wednesday)...
Issued at 252 PM EDT Tue May 28 2024

Generally northwesterly flow exists through the depth of the 
atmosphere today as a trough axis resides to our east. A short wave 
embedded within the broader flow is currently diving to the 
southeast out of central Canada. This feature should pass just to 
our north this evening and overnight. Given the cooler air aloft, 
associated with the trough, lapse rates are fairly steep today. RAP 
soundings show 7-8 C/Km with super adiabatic values (up near 10C/km) 
very near the ground. ACARS soundings out of IND do not show this 
super-adiabatic near-surface lapse rates, however. Despite the steep 
lapse rates, instability is modest with values generally between 500-
1000 J/Kg. This is in part due to a lack of moisture within the 
boundary layer.

Enough lift is present within and ahead of the vort max that showers 
and thundershowers are shown by most guidance. Observations tend to 
agree with this, as weak radar echoes are beginning to develop in 
northern Illinois and even into northern Indiana. Continued growth 
is expected through the afternoon with greater concentration nearer 
to the vort max. Given the steep lapse rates and relatively dry 
column, strong downbursts/wind gusts are the primary hazard with any 
shower or storm. Activity should diminish after 00z as diurnal 
heating wanes and the boundary layer stabilizes.

Overnight, expect quiet weather with diminishing winds. Low-clouds 
cover may develop towards morning from the north as the vort max 
swings by. Wouldn't rule out a few light rain showers within the 
area of low clouds either. These low clouds may persist into the 
morning hours but should dissipate as daytime mixing resumes and the 
vort max pulls away. Surface winds should pick up again as well once 
the boundary layer begins to mix. Gusts upwards of 20kt are possible 
at times tomorrow afternoon. Temperatures look to be a bit below the 
climatological average for this time of year due to the broad 
troughing aloft. Typical values at IND are 77/57.

&&

.LONG TERM (Wednesday night through Tuesday)...
Issued at 252 PM EDT Tue May 28 2024

The long term will begin with our first consistent reprieve from wet 
conditions as high pressure moves in from the north. 

Troughing over the Mid-Atlantic region has brought a succession of 
waves through the region, but as of Wednesday, confluence in the 
upper jet stream and broad AVA will aid in raising heights through 
the mid to upper atmosphere. Eventually, the amplifying ridge axis 
will lead to surface high pressure over the Ohio Valley. Initially, 
some semblance  of surface moisture will stick around on Wednesday 
(DP in the low 50s). However, by Thursday, adiabatically warmed 
subsidence should drop surface dew points in the mid to low 40s. 

The combination of subsidence, and drying air will lead to quiet 
conditions Wednesday night through Friday. Highs will begin to 
slightly increase on Thursday and Friday (Mid to upper 70s) within 
well mixed PBLs. Even with deep PBLs, the lack of a LLJ should keep 
winds rather calm; expect winds to top out around 10-12kts Thursday 
and Friday afternoons. 

The next wave of moisture/lift looks to arrive late Friday through 
Saturday. Although the upper wave may arrive Friday night, the dry 
low to mid levels from prior day subsidence should keep any 
precipitation from reaching the ground until sometime on Saturday. 
Overall this system looks to be mostly showery due to poor mid level 
lapse rates, but its still too far out to have high confidence in 
the details. The forecast beyond Saturday becomes much more murky 
due to the relatively elevated surface moisture and remnant 
boundaries and weak surface level waves in the remnants of the 
Saturday upper level system.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 646 PM EDT Tue May 28 2024

Impacts:

- Scattered convection possibly impacting KIND and KLAF early evening
- Gusty winds and temporary MVFR conditions possible in 
  showers/storms
- W/NW wind gusts to 20kt Wednesday
- MVFR ceilings expected Wednesday morning

Discussion: 

Isolated to scattered convection continued across northern portions 
of Illinois and Indiana early this evening in tandem with an upper 
level wave. As this feature pivots southeast through the evening... 
scattered convection will persist and may briefly impact KIND and 
KLAF prior to 02Z. Clouds will scatter and wind gusts will diminish 
into the overnight.

By predawn Wednesday...the upper wave will track into western Ohio 
with lower clouds swinging back down across northern Indiana and 
eventually encompassing the terminals Wednesday morning. Model 
soundings support MVFR stratus with saturation through much of the 
boundary layer. Cannot rule out a stray shower at both KIND and KLAF 
as well in the morning but coverage too low to include at this time.

Ceilings will gradually lift into a broken VFR cu/stratocu field for 
the afternoon before clouds diminish Wednesday evening. N/NW winds 
may periodically gust to around 20kts on Wednesday.

&&

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

&&

$$

UPDATE...Ryan
SHORT TERM...Eckhoff
LONG TERM...Updike
AVIATION...Ryan