958 
FXUS63 KIND 090616
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
216 AM EDT Thu Sep 9 2021

.Short Term...(Today through Friday)
Issued at 216 AM EDT Thu Sep 9 2021

Skies were mainly clear across central Indiana early this morning 
with a surface ridge centered to the west over the Missouri Valley. 
Pockets of clouds were drifting southeast off Lake Michigan in 
association with a weak wave traversing through the parent upper 
level trough centered over the Great Lakes. These clouds were 
grazing our northeast counties this morning. Comfortable morning in 
progress with 0630Z temperatures ranging from the mid 50s to lower 
60s in most areas.

Very quiet weather is expected to round out the work week as the 
aforementioned surface ridge shifts east and serves as a dominant 
influence for the Ohio Valley. The upper trough will also remain a 
factor at least for today before it begins to lift out to the 
northeast into New England by Friday. The weak waves tracking 
through the trough will remain to the northeast of the region but 
enough cold air aloft will remain across the Ohio Valley on the back 
side of the trough for a decent diurnally driven cu field to form 
for this afternoon over much of the forecast area. 

The clouds will diminish towards sunset with skies returning to 
mostly clear overnight. As the upper trough departs Friday and mid 
level heights begin to recover as a result...expect less cu coverage 
for the afternoon with a broad mid level cap taking over. Northwest 
winds today will transition to more of a southwest direction Friday 
as the surface high passes through and moves into the central 
Appalachians by late Friday. 

Temps...pleasant temperatures and humidity levels by early September 
standards are set up for today and Friday...and frankly will feel 
refreshing with the expected return of the heat by late weekend into 
next week. Low level thermals and the likelihood of greater cu 
coverage this afternoon warrant cooler temps than Wednesday...with 
much of the forecast area in the mid to upper 70s. Temperatures will 
recover a few degrees for Friday. Lows tonight will be cool with low 
to mid 50s. Would not be a shock to see a few of our normal cool 
spots slip into the upper 40s early Friday...especially northeast of 
the Indy metro.

&&

.Long Term...(Friday Night through Wednesday)
Issued at 216 AM EDT Thu Sep 9 2021

Upper level northwesterly flow will moderate and level out Friday 
night into the weekend as the deep trough currently moving through 
continues to push off to the east. Zonal flow then is expected for 
the weekend as a broad ridge builds across The Plains. Southerly 
surface flow will help bring warmer than normal temperatures into 
the area late this week into the weekend with highs generally in the 
mid to upper 80s and lows in the mid to upper 60s. Some areas look 
to into the low 90s Sunday and Monday when the ridge is expected to 
be at its strongest. 

A fairly strong upper level low pressure system will be moving 
through the Hudson Bay area early next week with a strong mid level 
jet streak moving through the Great Lakes Region.  Upper level 
forcing associated with that jet streak may reach as far south as 
the northern counties with small chances for rain Tuesday into 
Tuesday night.  Confidence in this remains quite low with 
significant model spread on both the strength of the jet streak and 
how far south the associated forcing reaches. Will keep small POPs 
across the area with gradually decreasing chances across the 
Indianapolis area and further south.

Better chances for rain arrive Wednesday into Wednesday night as a 
low pressure builds in the lee of the Rockies with a diffuse surface 
front stretching to the aforementioned stronger low across the 
Hudson Bay area.  Weak surface convergence associated with the front 
will help bring those better chances for rain mid-week with perhaps 
a rumble of thunder or two during peak heating with expected CAPE 
near 1000 J/kg.

&&

.Aviation...(090600Z TAF Issuance) 
Issued at 1133 PM EDT Wed Sep 8 2021

IMPACTS:
- Surface winds 310-340 degrees at 8-12 kts by late morning 
Thursday.

DISCUSSION: No significant weather expected at the terminals through 
midday Thursday, as surface high pressure builds in from the 
northwest. 

Some shallow instability cloud based around 040 expected to develop 
towards midday Thursday, under thermal troughing aloft.

&&

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

&&

$$

Short Term...Ryan
Long Term...White
Aviation...JAS