651 
FXUS63 KIND 231055
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
555 AM EST Thu Jan 23 2020

.UPDATE...
The AVIATION Section has been updated below.

&&

.SYNOPSIS...
Issued at 321 AM EST Thu Jan 23 2020

Active weather is expected over the next 72 hours as an upper
level low pressure system moves through the area. Precipitation
will initially begin as rain today and tomorrow with some snow
mixing in tomorrow night and Saturday. Little to no snow
accumulations are expected at this time. High pressure will move
in Sunday with dry conditions for much of next week before small
chances for precipitation return for the later half of the work
week.

&&

.NEAR TERM /Today/...

Issued at 321 AM EST Thu Jan 23 2020

Much of the period will be dry with some small chances for rain 
during the latter portions of the day as a strong upper level and 
associated surface cold front approach the area. Latest radar 
images show a few areas of light precipitation across central 
Illinois with some mixed precipitation falling. Over central 
Indiana, air near the surface remains too dry for anything to 
reach the ground. Saturation is expected across the western 
counties by mid morning and will reach the eastern counties by 
late this afternoon. In addition to the dry low level air, little 
upper level forcing is expected over the area today which will 
further limit precipitation chances. Overall, a few snowflakes may
mix in this morning across the western counties, but otherwise 
rain is expected to be the dominant precipitation type with little
precipitation accumulation.

Fairly strong warm air advection will be in place today which will
allow temperatures to rise into the upper 30s and lower 40s even
with little to no breaks in the clouds.

&&

.SHORT TERM /Tonight through Saturday Night/...

Issued at 321 AM EST Thu Jan 23 2020

Active weather will continue into the short term period as a 
strong upper level low pressure and associated surface cold front 
move through central Indiana. By tonight, the atmosphere will be 
fully saturated with stronger upper level forcing in place as the 
upper low nears. This will lead to widespread light rain over the 
area through much of the night. The LLJ will be strongest further 
east into Ohio which is where the best moisture advection and 
highest rain amounts are expected. Confidence in rain tonight is 
very high and trended POPS near 100 to account for the high 
confidence.

Rain will continue off and on into the day Friday as the dry slot
works its way into central Indiana. Confidence in rain tomorrow 
is high with lower confidence in rain at any given point. A few 
snow showers may begin to mix in late Friday night as colder air 
works its way in on the back end of the system. Models show a good
flow of moist air originating from the Atlantic Ocean and 
wrapping around the low to arrive in central Indiana by Saturday. 
Confidence that the moisture makes it this far is fairly low and 
if it does, it should remain light. Thermal profiles show that 
there may be a brief period where accumulating snow is possible 
Saturday morning, but will be strongly dependent on surface 
temperatures which confidence is low in at this time. 
Precipitation will end by Saturday night with dry weather for 
Sunday.

Overall rain amounts will be around a half inch with some locally
higher amounts in the eastern counties. Snow accumulations are
expected to be less than a half inch with low confidence in any
accumulations occurring. Temperatures will be above average 
through the period with highs in the upper 30s to lower 40s and 
lows in the low to upper 30s.

&&

.LONG TERM /Sunday through Thursday/...

Issued at 231 AM EST Thu Jan 23 2020

The national blend was accepted for most items. 

Starting Sunday, surface high pressure will build in from the west 
in the wake of the previous low pressure system, and will stick 
around for most of the Long Term. This will keep central Indiana 
dry, blocking moisture from the south. Afternoon high temperatures 
will be near to above average, with a slight uptick in temperatures 
towards midweek. 

Aloft, ridging out west will lead to a multitude of weak short 
waves, initiating in the interior Canadian Plains, and progressing 
southeast over the Midwest. Weak dynamics over the Midwest and a
lack moisture will limit precipitation chances as these waves
pass. By Wednesday, the surface high pressure weakens, allowing 
for more moisture to advect over central Indiana. For now, PoPs 
are kept low for Wednesday, as confidence remains low. The next 
best chance for precipitation remains Thursday as a more aligned 
upper- level trough and surface low develops over the Midwest. 

&&

.AVIATION /Discussion for 23/12Z TAF Issuance/...

Issued at 537 AM EST Thu Jan 23 2020

VFR conditions expected for much of the morning. MVFR ceilings 
will start this afternoon. IFR ceilings likely late tonight into 
tomorrow morning.

A low pressure system will progress eastward over central Indiana
during the day. Snow showers are possible this morning at KLAF.
Otherwise, precipitation will start for all sites later this
evening with a gradual drop in ceilings throughout the night.
Visibility will drop to MVFR as precipitation begins, and will
continue for the rest of the TAF period. Winds will start out the
southeast and will gradually shift eastward as the low 
approaches.



&&

.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SYNOPSIS...White
NEAR TERM...White
SHORT TERM...White
LONG TERM....Updike
AVIATION...Updike