550 
FXUS63 KIND 170741
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
241 AM EST Tue Jan 17 2023

.Short Term...(Today and tonight)
Issued at 241 AM EST Tue Jan 17 2023

* Low cloud cover will move back into the area today, with this and 
  cold advection leading to nearly steady temperatures over much of 
  the area except the far south, where some limited warming should 
  occur.

* Strong low level flow will promote gusty winds today.

Low pressure is centered over Wisconsin this morning, moving 
steadily east/northeast. The triple point is moving through central 
Indiana, to be quickly followed by the cold front. Remnant 
drizzle/showers will come to an end rapidly in the next few hours.
Some clearing of skies is occurring in the dry slot behind the 
front, but this will be temporary this morning as low cloud cover 
associated with the upper low expands back into the area today. 
There will be a fairly sharp cutoff to the southern extent of the 
sky cover, and this is a source of uncertainty for today's forecast. 
Cold advection will be ongoing much of the day, and the cloud cover 
will further limit any insolation to counteract this, so expect 
temperatures nearly steady throughout the day, especially across the 
northern half or so of the area. This required some downward 
adjustment to NBM temperatures. Low to mid 40s appears likely 
north/northwest for highs, with low to mid 50s across the 
south/southeast, where some limited sun and warming is likely.

Strong low level flow in the wake of the cold front, along with 
steep low level lapse rates under a developing subsidence inversion, 
will promote gusty winds today. BUFKIT momentum transfer progs 
suggest a few gusts approaching 30KT may be possible at times, with 
the strongest gusts north, and gusts in the low to mid 20KT range 
common. Gusts will weaken in typical diurnal fashion this evening as 
boundary layer mixing subsides.

Cloud cover is likely to persist across much of the area into 
tonight, although mid and high cloud will likely replace dissipating 
low cloud. This will limit diurnal cooling along with the rapid 
onset of warm advection yet again ahead of the mid week system. 
Blend temperatures appeared too cool as a result and were adjusted 
upward - expecting mid to upper 30s for lows across the area.

&&

.Long Term...(Wednesday through Monday)
Issued at 241 AM EST Tue Jan 17 2023

* Active pattern with multiple chances for precipitation

* Locally heavy rainfall possible far south Wednesday night

* After another warmup on Thursday, cooler, but still above normal 
  temperatures, will continue afterward

Wednesday into Thursday...

Deepening upper and surface lows will impact the area through this 
period. On Wednesday, the morning will likely be dry for much of the 
area, but as a low level jet approaches from the south, isentropic 
lift will begin to ramp up across the area during the afternoon. 
Enough moisture will work north during the day for likely PoPs 
southwest by the end of the day and chance PoPs northeast.

The 60kt low level jet will continue to bring lift and moisture into 
the area Wednesday night. Integrated vapor transport and 
precipitable water values will be near their climatological maxima. 
The occluded front will move through the area, with the triple point 
with the warm and cold front moving through southern Indiana.

Plentiful moisture and forcing will lead to categorical PoPs all 
areas Wednesday night. With the warm front remaining across southern 
Indiana, the focus for locally heavy rain will be near and north of 
the front. At the moment, that area looks to be near or not too far 
south of the far southern forecast area. 

One caveat though, is that convection along the cold front to the 
south could rob moisture. QPF numbers are down from previous model 
runs as well. Nevertheless, will continue to mention locally heavy 
rain in the Hazardous Weather Outlook.

Best instability will remain south of the area in the warm sector. 
so any severe weather should remain out of central Indiana.

Wrap-around moisture behind the lows will move in on Thursday, 
mainly in the afternoon behind the dry slot. Will keep some chance 
PoPs around, mainly north.

Temperatures will climb Wednesday into Wednesday night, and then 
perhaps some more on Thursday in the dry slot before the colder air 
arrives and brings falling temperatures in the afternoon. Breezy 
conditions will develop as well.

Friday and Saturday...

High pressure will bring dry conditions and cooler temperatures 
during this period (highs mainly in the 30s, lows mainly in the 20s).

Sunday into Monday...

An upper shortwave, as well as a surface trough extending northwest 
from a surface low in the southeastern USA, could bring some 
precipitation to the area. However, questions remain on the path and 
timing of the system, so confidence is low. Will just go with some 
chance PoPs, with PoPs ending for now by Monday afternoon. Highs 
will warm into the upper 30s to middle 40s.

&&

.Aviation...(06Z TAF Issuance)
Issued at 1206 AM EST Tue Jan 17 2023

Impacts:

* IFR/low end MVFR ceilings improving overnight before returning to 
  MVFR during the day Wednesday.

* Drizzle and a few lingering showers early.

* Southwesterly-westerly wind gusts 18-22KT during the day Wednesday.

Discussion: 

A low pressure system is currently moving through the Great Lakes, 
with the triple point moving through central Indiana. Widespread low 
ceilings ahead of the boundaries appear likely to clear out 
significantly in a few hours, with just some scattered mid cloud 
likely. With the onset of diurnal heating Wednesday, expect mixing 
to produce both wind gusts of 18-22KT and the redevelopment of MVFR 
ceilings across most of the area except perhaps BMG.

Some lingering drizzle and a few showers are possible early in the 
period, mainly at IND, before the area dries out. This will likely 
be the only significant obstruction to visibility, although will 
have to monitor for rapid fog formation depending upon how quickly 
we clear out overnight.

&&

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

&&

$$

Short Term...Nield
Long Term...50
Aviation...Nield