National Weather Service Raw Text Product

685 
FXUS63 KIND 160038
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
838 PM EDT Wed May 15 2024

.KEY MESSAGES...

- Scattered showers and a few rumbles of thunder through early 
  evening across the south.

- Fog possible overnight to early tomorrow morning.

- Rain and storm chances return at times late Thursday through 
  Saturday.

- Above normal temperatures for this weekend through the middle of 
  next week.

&&

.SHORT TERM (This evening through Thursday)...
Issued at 259 PM EDT Wed May 15 2024

The low pressure system that has brought ample rain since yesterday 
is slowly making its way eastward leaving scattered showers across 
the southern portion of the forecast area this afternoon. The rain 
should fully exit central Indiana by late this evening. Brief upper 
ridging will then move through, allowing a quick break in 
precipitation before the next system moves in for the end of the 
week. 

Clouds will likely stick around for much of the night tonight with 
model soundings showing persistent saturation at the top of the 
boundary layer, but will have to keep an eye out for any locations 
that do begin to clear as the recent rains will help to 
supersaturate the low levels and may allow for some fog formation. 
The low confidence that things will clear out enough for widespread 
fog makes a Dense Fog Advisory seem a bit overdone at this time, but 
will have to monitor things going into this evening.

Warmer temperatures are expected tomorrow with highs back into the 
mid 70s to near 80. Another upper short wave behind the ridging will 
bring additional rain later in the day tomorrow. Time of arrival is 
still not clear but could arrive from the west as early as the 2 to 
8pm timeframe.

&&

.LONG TERM (Thursday night through Wednesday)...
Issued at 259 PM EDT Wed May 15 2024

Thursday night through Saturday...

An approaching southern stream shortwave will keep elevated rain or 
storm chances in the forecast towards the end of this week. The best 
chance for rain looks to be late Thursday night through Friday 
evening when the best forcing/moisture move across the Ohio Valley. 
Anomalous moisture and warm rain processes could potentially lead to 
another round of locally heavy rain. Considering grounds are already 
saturated from heavy rain over the past 24 hours, there are elevated 
flooding concerns if this scenario plays out. The one caveat to this 
is that a strong MCS will likely move across the Gulf coast states 
late Thursday into Friday morning which could limit deeper moisture 
return further north. A few models have recently trended lower on 
precipitation amounts for this reason.

Rain chances persist into Saturday as the aforementioned system 
should still be centered near the Ohio Valley. Confidence is 
somewhat limited on how long precipitation lingers Saturday due to 
model discrepancies. The GFS is noticeably slower compared to other 
guidance keeping elevated rain chances into Saturday night. Decided 
to stick with the larger suite of models showing a more progressive 
pattern with the system departing Saturday evening and decreasing 
rain chances overnight. 

Sunday onward... 

Brief ridging building in Sunday should provide mostly dry 
conditions, but can't rule isolated diurnal convection, mainly over 
SE counties as there could still be sufficient PBL moisture in 
place. Confidence decreases some towards next week with model 
solutions diverging. However, guidance is in general agreement that 
upper level pattern switch from split-flow to more full-latitude 
troughing across the western CONUS. The pattern looks to remain 
active with multiple embedded shortwaves potentially moving through 
next week. Look for rain chances to return late Monday PM and 
persist through at least midweek. 

At least a low end severe weather threat looks possible 
Tuesday/Tuesday night as increasing instability and deep-layer shear 
ahead of an approaching surface low could support organized 
convection. CIPS Analogs and CSU machine learning are showing 
increasing severe weather probabilities during this period. It is 
still too early for exact details, but this will be monitored 
closely over the coming days. Strengthening southerly flow should 
help to warm temperatures well into the 80s early next week.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 837 PM EDT Wed May 15 2024

Impacts:

- VFR conditions expected this evening.

- IFR or worse visibilities possible late tonight in fog.

- A return to VFR after 1300Z on Thursday.

Discussion: 

Wrap around diurnal clouds were slowly dissipating this evening as 
low pressure east of the TAF sites continues to exit to the east. 
Weak high pressure in place over the middle Mississippi valley is 
expected build across Central Indiana allowing the clouds to 
dissipate.

Low dew point depressions overnight along with clearing skies, light 
winds and residual lower level moisture will allow for some fog 
development late tonight. Have included some MVFR fog mention with 
IFR tempo groups for now.

Fog will dissipate in typical diurnal fashion tomorrow morning, with 
a SCT-BKN low end VFR cumulus deck likely to develop on Thursday. 
HRRR suggests some scattered convection on Thursday afternoon as 
diurnal highs area reached. For now have included a VCSH mention.

&&

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

$$

SHORT TERM...KF
LONG TERM...Melo
AVIATION...Puma