FXUS63 KIND 111421

Area Forecast Discussion
National Weather Service Indianapolis IN
921 AM EST Mon Dec 11 2023

.Key Messages...

- Clearing and Cold today

- Dry weather for the upcoming work week


.Forecast Update...
Issued at 921 AM EST Mon Dec 11 2023

GOES-16 visible satellite and surface obs were showing that the back
edge of the stratus was near a Terre Haute to Indian Springs line
this morning. The clearing was continue to progress northeast
through the afternoon. The clearing has allowed temperatures to drop
to the lower 20s over this area while areas within the stratus were
in the upper 20s to lower 30s. In addition, a weak trough in the
northwest flow aloft was producing patches of AC from northern
Missouri to southern Illinois.

At the surface, a ridge of high pressure extended from the Great
Lakes to the southern states. This feature will move off to the
Appalachians late in the day which will allow winds to shift to the
southwest. Clearing trend and the southwest winds should allow
temperatures to top out near seasonable in the mid 30s to lower 40s.


.Short Term...(Today and tonight)
Issued at 256 AM EST Mon Dec 11 2023

Surface analysis early this morning shows a strong ridge of high
pressure stretching north from the eastern TX and lower Mississippi
River Valley to Minnesota and Wisconsin. Cool westerly flow remained
in place across Central Indiana.  Water vapor imagery aloft shows a
broad, elongated upper trough in place stretching from the east
coast to Appalachia, then west to the plains and eastern Rockies.
GOES16 shows a stratocu cloud shield east of the surface ridge axis.
The back edge of the clouds were found along a SW MN, NE IA, E IL to
Central KY Line, still engulfing much of Central Indiana.


Models keep moderate northwest flow in place aloft as the broad
trough remains in place over Ontario and Quebec. Little in the way
of upper support will pass. This will allow for ongoing subsidence
across the Mississippi and Ohio valleys today and tonight. The
surface high pressure system is suggested to slowly push east today,
allowing the ridge axis to build and pass across Indiana today. The
925 MB RH fields suggest the current stratocu found across Central
Indiana will also advect eastward, along with the passing ridge
axis. This will allow for a gradual clearing this morning. Forecast
soundings and time heights are on board, showing a dry column by 18Z
with subsidence through the day.

Slight warm air advection is expected to begin today, but a cold air
mass still remains over Central Indiana. 850mb temps near -4C will
only allow highs to push into the upper 30s and lower 40s.


Little overall change is expected in the sensible weather tonight.
Forcing dynamics aloft will not be present as the NW flow of Pacific
air remains. The surface high is expected to drift farther east as a
secondary, albeit dry cold front approaches Central Indiana from the
upper midwest. Forecast soundings and time heights remain dry
through the night. Thus we will expect mostly clear and cold
conditions tonight. Southerly winds ahead of the approaching dry
cold front will provide some slight mixing as a pressure gradient
will remain across the area. Given the southerly winds and weak warm
air advection tonight, look for low temperatures to fall to the
upper 20s and lower 30s.


.Long Term...(Tuesday through Sunday)
Issued at 256 AM EST Mon Dec 11 2023

Upper level ridging building in during the work week combined with
dominant surface high pressure will keep weather conditions quiet
through Friday. Weak warm air advection should help temperatures
warm well into the 40s Tuesday, but a dry cold FROPA should return
temperatures to seasonal midweek. While no precipitation is expected
with the front, enhanced cloud cover cover is possible Tuesday night
into Wednesday. Heights aloft will then begin to increase late week
as the aforementioned upper ridge builds eastward. This along with
return flow should help temperatures warm back up. Temperatures will
likely be above normal for the latter half of the period.

Guidance shows a shortwave trough approaching the region over the
weekend leading to increased cloud cover. At this time,
precipitation looks unlikely as a a secondary upper trough centered
near Texas should limit gulf moisture return. Rain chances cannot be
completely ruled out though due to the large spread in model
solutions by this period. Model trends will continue to be
monitored, but latest guidance has shifted precipitation further
south and east. Will stick with a dry forecast during the weekend
for now given the latest trends.


.Aviation...(12Z TAF Issuance)
Issued at 558 AM EST Mon Dec 11 2023


- MVFR ceilings clearing today, leading to VFR conditions.


GOES16 shows the back edge of a widespread stratus deck over eastern
IL and far Western Indiana. HUF has lost its ceiling, while the
other sites remained under the cloud shield.

The surface high to the west will continue to build east today,
pushing the cloud shield farther east. Ultimately this will lead to
VFR conditions and overall decreasing cloudiness. Forecast
soundings show slow drying through the lower levels of the column
this morning. Anticyclonic flow is expected to arrive as the high
builds. Thus have trended to VFR conditions by late morning. VFR
will continue tonight as as the high pressure system remains across
our area.




Short Term...Puma
Long Term...Melo