713 
FXUS63 KIND 260651
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
251 AM EDT Sat Aug 26 2023

.Short Term...(Today and tonight)
Issued at 251 AM EDT Sat Aug 26 2023

- Cooler but still warm today.
- Cooler and less humid tonight.

Surface analysis early this morning shows a broad, poorly organized, 
weak trough stretching from the northeastern United States to the 
middle Atlantic states, before turning west to WV, Nrn KY and 
southern Indiana. Convection was found early this morning over 
southern Central Indiana near the trough, but this feature was 
quickly diving southeast. Radar trends also show a weakening trend 
with the system. A large and broad area of high pressure was found 
over the northern plains. This feature was helping to push the 
trough farther south along with the hot humid air. This pattern was 
setting up for weak north or northeast surface flow across Central 
Indiana. Aloft, water vapor showed strong ridging in place over the 
Rockies, with NW flow aloft stream across the upper midwest into the 
Great Lakes and Ohio Valley. Strong Subsidence was found over MN and 
WI.

Today...

Models today show the high pressure to the northwest pushing east 
across the Great Lakes, keeping NE surface flow across Central 
Indiana. This in turn will help to continue to push the disorganized 
weak trough farther south, and away from Central Indiana. Aloft, NW 
flow remains prevalent and little in the way of forcing dynamics 
appear to push across Central Indiana. After this early morning 
convection exits, forecast soundings trend toward a dry column 
through the day and strong mid level subsidence over WI is shown to 
push SE toward Central Indiana. Forecast soundings show convective 
temps in the upper 80s, so a few CU could be possible this 
afternoon, but overall, a partly cloudy day will be in store.

Cold air advection is in place today. 850MB temps are falling about 
3C to near 15C today and this is much cooler than Friday. Thus highs 
in the middle to upper 80s will be expected.

Tonight...

The models continue to show slow cold air advection from the 
northeast overnight and this looks to continue into Sunday. 
Northwest flow aloft on the lee side of the strong ridge over the 
Rockies looks to continue also and little in the way of forcing 
dynamics appear to pass. Forecast soundings show a very dry column 
with strong mid level subsidence shown creating a very dry mid 
level. Thus will continue with a mostly clear sky as any diurnal CU 
will be lost in the evening. Given the less humid dew points in the 
lower 60s arriving across the area, lows in the lower to mid 60s 
will be expected.

&&

.Long Term...(Sunday through Friday)
Issued at 251 AM EDT Sat Aug 26 2023

* Quiet and seasonably pleasant through the coming week.

Despite typical model suite disagreements, particularly with the 
handling of possible tropical remnants late in the week, broad 
agreement can be found in the overall thrust of the long term 
forecast that conditions should be fairly quiet and seasonably 
pleasant through the week.

The primary upper level ridge that brought the intense heat and 
humidity to the area in the last several days is expected to 
continue to weaken and retreat westward, leaving central Indiana 
largely under the influence of cooler northwest flow aloft and 
multiple areas of surface high pressure, with the primary baroclinic 
zone reinforced well to our south much of the week.

If there were a window for precipitation chances, it would most 
likely be Tuesday afternoon and evening with the passage of a very 
weak cold front, although the upper level forcing is displaced to 
our north over the Great Lakes, and guidance generally keeps us dry.

Later in the week, large disagreements are noted in model handling 
of possible tropical remnants, but even the far more westerly GFS 
keeps the precipitation associated with this system to our east and 
southeast, thus a dry forecast will remain throughout the long term.

Temperatures and particularly dewpoints will be significantly more 
pleasant for the last week of climatological summer, with highs 
generally in the mid 70s to mid 80s, and dewpoints as much as 10-25 
degrees below their highest readings in recent days.

&&

.Aviation...(06Z TAF Issuance)
Issued at 1253 AM EDT Sat Aug 26 2023

Impacts:

* Thunderstorms will impact the BMG Taf site for the first few hours 
  of the TAF period.
* Otherwise VFR Conditions will be expected.

Discussion:

Radar shows convective cluster over SW Central Indiana, pushing 
southeast within the flow aloft along an axis of instability near 
the surface trough. These storms are projected to push southeast 
across the BMG TAF site through the first hour of the TAF period. 
HRRR suggests this convection should exit BMG and weaken with its SE 
propagation through 09. Thus have used a prevailing TSRA at BMG for 
the first hour, but trended to VFR conditions after 07Z-08Z.

Cooler temperatures on northerly winds associated with high pressure 
is expected to arrive on Saturday. Forecast soundings and time 
heights show a dry column through the rest of the TAF period as mid 
level subsidence is show to build across the Taf sites through the 
day. Some VFR afternoon CU will be possible, but any CIGS will 
remain VFR.


&&

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

$$

Short Term...Puma
Long Term...Nield
Aviation...Puma