442 
FXUS63 KIND 121850
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
250 PM EDT Tue Oct 12 2021

.Short Term...(This evening through Wednesday night)
Issued at 249 PM EDT Tue Oct 12 2021

Model data suggest upper ridging will reestablish itself across 
the Ohio Valley during this period, as another strong short wave 
trough ejects into the northern Plains by Wednesday night.

Satellite loop indicates the back edge of a low cloud deck currently 
moving into the west central and southwest zones. Extrapolation and 
short term model data indicate the low cloud deck will gradually 
scatter out from the southwest over the course of the rest of the 
afternoon, reaching the far northeast zones this evening.

Some concern for fog development later tonight, as it is possible 
that the low cloud deck may not clear out fast enough this afternoon 
for mixing out of the dewpoints. Will monitor dewpoint trends within 
the clearing zones later this afternoon and evening with respect to 
fog potential.

Otherwise, a warm advection pattern will develop by Wednesday and 
Wednesday night locally, ahead of next Plains trough. At this time, 
it appears the stronger advection pattern/better precipitation 
threat will remain off to the northwest of the local area, closer to 
the axis of the low level jet. Some activity may sneak into mainly 
the western and northwestern zones at times from midday Wednesday 
into Wednesday night, but overall the better precipitation threat 
will hold until after this forecast period. 

Low level thicknesses generally support the GFS MOS temperature 
guidance through the period, so little, if any, changes planned.

&&

.Long Term...(Thursday through Tuesday)
Issued at 249 PM EDT Tue Oct 12 2021

A front will be stalled to the northwest of central Indiana on 
Thursday, with an upper trough to the west. Impulses in the upper 
flow will interact with the front to bring chances for rain Thursday 
into Thursday night. Highest chances will be across the northwest 
half of the area.

A more potent surface low will move along the front on Friday and 
will finally kick the front to the east after it passes. This should 
bring widespread rain to the area. Will go with high PoPs. 

Precipitable water values will be in the 1.50 to 1.75 inch range or 
thereabouts through Friday, so locally heavy rain may be a threat.  

Timing has sped back up again, so now Saturday looks to be dry all 
day. High pressure will then build into the area and provide dry 
conditions into Monday.

Another cold front looks to move into the area around Tuesday. 
Moisture looks limited so go with a dry forecast.

Highs in the 70s through Friday will give way to more seasonable 
readings in the 60s for most areas Saturday through Tuesday.

&&

.Aviation...(121800Z TAF Issuance) 
Issued at 1227 PM EDT Tue Oct 12 2021

IMPACTS:
 - Areas of IFR ceilings, mainly in the KLAF vicinity, until 121900Z.
 - Widespread MVFR ceilings 012-020, scattering out from the 
southwest by late this afternoon.
 - Surface winds 230-260 degrees at 9-13 kts this afternoon,
   diminishing towards sunset. Occasional surface gusts 18-20 kts
   through early afternoon.
  
DISCUSSION: Back edge of an area of widespread MVFR ceilings 
currently approaching southwest Indiana. Extrapolation and short 
term model data suggest these low clouds will gradually scatter out 
from the southwest at the terminals by late this afternoon.

Otherwise, pressure gradient continues to relax with time, in the 
wake of yesterday's surface low. As a result, expecting the surface 
winds to diminish as the afternoon progresses.


&&

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

$$

Short Term...JAS
Long Term...50
Aviation...JAS