433 
FXUS63 KIND 111010
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
610 AM EDT Sat May 11 2024

.KEY MESSAGES...

- Brief period of rain through 8 AM across north central Indiana
- Afternoon wind gusts of 30-35 mph today
- Showers and storms return Monday into Monday night
- Near normal temperatures for next week

&&

.SHORT TERM (Today and tonight)...
Issued at 221 AM EDT Sat May 11 2024

Aurora viewing over the last few hours has been somewhat successful 
across central Indiana as clouds have remained scattered. 
However...starting to see an increase in mid level clouds ahead of a 
cold front currently located across the western Great Lakes with an 
area of showers along it. Rain is most numerous across lower parts 
of Lake Michigan with convection much more scattered south into 
central Illinois. 06Z temperatures were predominantly in the mid and 
upper 50s with light southwest winds.

The frontal boundary is the primary focus in the immediate near term 
as it will sweep southeast across the forecast area during the 
predawn hours into the first part of the morning. Beyond that...much 
of today will be dry with windy conditions developing due to a 
combination of cold advection and a tight surface pressure gradient 
in the wake of the frontal passage. 

Clouds will overspread the northern half of the forecast area over 
the next few hours with a narrow band of showers following close 
behind. These showers will quickly drop southeast across the 
northeast half of the forecast area over the next 4-6 hours as the 
front moves across the region. Rainfall amounts will be light with 
most areas receiving no more than a tenth of an inch. Across the 
southwest half of the forecast area...it will largely remain dry 
with the wind shift from southwest to northwest signifying the 
frontal passage. Showers will be east of the forecast area by 12-13Z.

The rest of the day will be similar to Friday with a mixture of sun 
and clouds as a healthy cu field develops for the afternoon in the 
cold advection and cyclonic flow present aloft. The primary 
difference from Friday will be the winds which will be higher for 
much of the day as the airmass becomes well mixed with dry adiabatic 
conditions up into the 650-700mb layer by mid to late afternoon. 
This should easily enable stronger winds to be drawn to the surface 
with gusts likely to peak at 30-35mph. Gusts will drop off quickly 
with sunset as high pressure expands across the Ohio Valley. Cu will 
diminish with the loss of heating and leave mainly clear skies 
overnight with light northerly flow.

Temps...low level thermals are supportive of highs this afternoon 
ranging from the mid 60s northeast to the lower 70s southwest. With 
ideal radiational cooling conditions developing 
tonight...temperatures will fall into the mid and upper 40s over 
much of the forecast area.

&&

.LONG TERM (Sunday through Friday)...
Issued at 221 AM EDT Sat May 11 2024

A quasi-zonal pattern will dominate through much of the extended 
with a slow moving cutoff upper level low set to bring another round 
of wet and unsettled weather for the first half of next week. 
Another system will impact the Ohio Valley by Friday with another 
chance for rain. With the subtropical jet displaced well to our 
south throughout the extended...severe weather is not expected and 
the lack of appreciable instability will keep even the threat for 
thunderstorms limited through much of the extended. 

Sunday and Sunday Night

Continued high pressure and the arrival of ridging aloft will make 
for a fantastic Sunday with abundant sunshine and temperatures 
recovering into the 70s to potentially lower 80s across the forecast 
area. CAMs beginning to pick up on a weak wave aloft drifting across 
northern portions of Indiana by the afternoon. With a deeply mixed 
airmass up to 700mb and little to no instability...not sure the wave 
will be able to generate much more than a light shower. That being 
said...closer analysis of the model soundings for late Sunday 
afternoon highlight steep lapse rates up through about 8kft which 
might be enough to get locally gusty winds to the surface with any 
isolated shower especially with dewpoint depressions on the order of 
30-35 degrees. Will continue to monitor but most areas will remain 
dry all day Sunday.

A cutoff upper level low will eject out of the Rockies on Sunday and 
move slowly east through the central Plains through early Monday. 
Mid and high clouds will begin to increase Sunday night ahead of 
this feature and the associated surface wave approaching from the 
west. Model soundings show residual dry air and subsidence will 
linger Sunday night and with moisture advection associated with the 
surface wave largely delayed until during the day Monday...dry 
conditions will persist Sunday night.

Monday through Tuesday Night

The upper low and associated surface wave will be over central 
Kansas Monday morning...and will track slowly east through the 
Missouri...mid Mississippi...Ohio and Tennessee Valleys through 
early Wednesday. Showers will gradually increase in coverage 
throughout the day Monday with the best chances for rain to come 
Monday night into Tuesday as the surface low drifts through the 
region. Recent model trends have initiated weakening of the upper 
low more rapidly as it arrives over the Ohio Valley with the 
attendant surface wave tracking further south than previously 
thought. This would result in the locally heavier rainfall rates 
potentially shifting closer to the Ohio River and points south and 
the sounding data supports this thinking as well with less moisture 
present through the depth of the column.

Instability will remain weak throughout much of the period with 
abundant cloud cover limiting heating. CAPE values are subtly better 
on Tuesday in the immediate vicinity of the surface low but expect 
thunderstorms to be isolated to scattered at best. Despite the lower 
moisture levels showing up in the soundings...precip water values 
peak near 1.25 late Monday night into Tuesday. The setup supports 
the potential for non-uniform pockets of moderate to heavy 
rainfall...particularly on Tuesday and likely focused over southern 
portions of the forecast area with any slow moving convection. 
Expect 0.50 to 0.75 inches for much of the forecast area by Tuesday 
night with locally higher amounts confined to southern Indiana in 
closer proximity to the surface low track. High temperatures will 
rise into the 70s both Monday and Tuesday...held down slightly on 
Tuesday with increased rain and clouds over the region.

Wednesday through Friday 

The upper low will weaken and eventually become absorbed by the mean 
flow aloft as it moves away from the region on Wednesday. After a 
cloudy start Wednesday as low level moisture lingers in the wake of 
the upper low...clouds will scatter as ridging aloft builds into the 
Ohio Valley. Temperatures will warm back up into the mid and upper 
70s for Wednesday and Thursday with dry conditions. A surface low 
with an associated frontal boundary will move across the region late 
week with scattered showers and storms focused especially during the 
day Friday.

&&

.AVIATION (12Z TAF Issuance)...
Issued at 609 AM EDT Sat May 11 2024

Impacts:

- Northwesterly wind gusts 23-27KT 15Z to 23Z

Discussion: 

VFR conditions expected through the TAF period. Northwesterly winds 
will occasionally gust to around 25kts through much of the afternoon 
hours before weakening near sunset. Skies will clear through 15Z 
before diurnally driven clouds return mid afternoon.

&&

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

$$

SHORT TERM...Ryan
LONG TERM...Ryan
AVIATION...White