563 
FXUS63 KIND 291659
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1259 PM EDT Sun Sep 29 2024

.KEY MESSAGES...

- Cloudy with occasional showers again today

- Chance of fog Monday and Tuesday mornings, locally dense fog 
  possible Tuesday morning.

- Mainly dry conditions with nearly seasonable temperatures to open 
  up October

&&

.FORECAST UPDATE...
Issued at 1000 AM EDT Sun Sep 29 2024

Forecast is in good shape this morning. A couple of bands of light 
rain continue to rotate into the eastern half of the forecast area, 
with scattered light rain elsewhere. 

Adjusted PoPs to match trends seen on radar. The bands will weaken 
during the day as the remnants of Helene continue to weaken. 
However, additional scattered showers will develop as some heating 
occurs this afternoon. Thus, lowered the coverage of likely PoPs 
this afternoon while keeping chance PoPs elsewhere.

Otherwise, look for mostly cloudy to cloudy skies across the area. 
Temperatures look reasonable so made no changes other than hourly 
forecasts to match recent obs.

&&

.SHORT TERM (Today and Tonight)...
Issued at 258 AM EDT Sun Sep 29 2024

Scattered light showers continue to drift southwest across parts of 
the forecast area early this morning. Cloudy and damp conditions 
persist with 06Z temperatures in the mid and upper 60s.

The remnant surface low that was once Helene continues to fill and 
spin across western Kentucky with deep moisture over the Ohio 
Valley. The surface wave will weaken further today and become an 
open wave as the parent upper low becomes the primary feature. The 
upper low will shift east slowly through Monday morning resulting in 
a continuation of the largely damp and dreary conditions experienced 
since Thursday night while overall shower coverage and intensity 
diminishes.

Expect shower coverage to gradually increase from the east through 
the morning as a deep moisture rotates counterclockwise around the 
remnant low. The loss of stronger forcing aloft however will keep 
showers relatively light into the afternoon. Subtle heating by late 
today will generate weak instability and this is captured well by 
model soundings. May see weak scattered convection develop as a 
result during the second half of the afternoon before diminishing by 
this evening as what limited heating experienced is lost. 

The position of the upper low moving into far eastern Kentucky 
tonight will shift deeper moisture east of the region and allow for 
drier air aloft to work in. This should serve to cut off any showers 
overnight but with a developing inversion trapping moisture within 
the boundary layer...skies will remain cloudy with potential for 
patchy fog as northeast winds relax.

Temps...the diurnal range will again be limited by clouds and 
occasional showers. Low level thermals support upper 60s to mid 70s 
from east to west for highs today. Lows will fall into the 60s 
tonight.

&&

.LONG TERM (Monday through Saturday)...
Issued at 258 AM EDT Sun Sep 29 2024

A return to generally quiet and dry weather is expected during the 
long range period. Before that happens, however, the remnants of 
Hurricane Helene will still be present to some extent Monday into 
Tuesday. By this point, the system is expected to become an ill-
defined swirl. A cold front approaching from the northwest will then 
sweep away whatever remains on Tuesday.

Lingering low-level moisture may lead to patchy fog at times Monday 
and Tuesday mornings.  The overall signal for fog appears better on 
Tuesday morning as surface wind diminish almost entirely. Lingering 
stratus/stratocu is the primary mitigating factor. Should enough 
clearing occur Monday afternoon and evening, then potentially dense 
fog could develop overnight Monday into Tuesday morning.

The aforementioned cold front arrives on Tuesday bringing in cooler 
air, with highs about 10 degrees cooler on Wednesday. Little in the 
way of precipitation is expected with the front despite Helene's 
moisture still nearby. Most of the deeper moisture will have drifted 
east of the region by the time the front arrives. Nevertheless, we 
will carry a slight chance of precip on Tuesday mainly across our 
eastern counties since a stray shower cannot be ruled out.

A progressive quasi-zonal jet stream should keep things moving, 
allowing for a quick rebound with highs returning to the mid and 
upper 70s by Thursday. Continued dry conditions with near-average 
(74/52 for IND) temperatures persist through the end of the period. 
Some members of guidance hint at a secondary cold front arriving 
Friday or Saturday, but this too seems dry and transient.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1259 PM EDT Sun Sep 29 2024

Impacts:

- Some improvement in ceilings likely this afternoon at KLAF/HUF 
  with lower odds of improvement at KIND/KBMG

- IFR ceilings return tonight with gradual improvement on Monday

- Periodic light showers persist through the day then diminish 
  tonight

Discussion: 

Low level moisture will remain across the sites through Monday. 
Heating this afternoon will lift ceilings some. KLAF/KHUF will 
likely return to VFR, while KIND/KBMG likely stay MVFR. During the 
night, ceilings will return to IFR and potentially worse. 

Some fog will develop at KBMG overnight into early Monday.

Gradual improvement will occur on Monday, but MVFR will be 
predominant for much of the day.

&&

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

$$

UPDATE...50
SHORT TERM...Ryan
LONG TERM...Eckhoff
AVIATION...50