214
FXUS63 KIND 201838
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
238 PM EDT Sat Jul 20 2024

.KEY MESSAGES...

- Dry through the day on Sunday

- Chances for rain/t-storms and increasing clouds next week will
  likely help keep temperatures slightly below to near normal

&&

.SHORT TERM (This evening through Sunday)...
Issued at 237 PM EDT Sat Jul 20 2024

Rest of This Afternoon...

Scattered to broken coverage of cumulus will continue along with
some high clouds, resulting in partly cloudy skies for much of the
area. Temperatures will peak in the 80s.

Tonight...

A weak upper wave will drift toward the area, but at the surface,
lingering high pressure will remain in control. Mid level moisture
will increase with southerly flow there. The resulting mid level
cloud deck will result in mostly cloudy skies.

Some weak isentropic lift may sneak into the far southern forecast
area late tonight, and this may result in a sprinkle given the dry
low levels. Not confident enough though to introduce any sprinkles
at this time.

Clouds will help keep temperatures a little warmer than previous
nights. Lows will be in the 60s.

Sunday...

The mid and high clouds will stick around well into Sunday, and some
cumulus may pop up. Skies will overall be partly to mostly cloudy.

Some weak lift will continue south of the forecast area. With the
lift staying south of the area, will go with a dry forecast.
However, if the lift were to get a little farther north, a light
shower or sprinkle would be possible in the far southern forecast
area.

High temperatures will be in the 80s.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 237 PM EDT Sat Jul 20 2024

Upper Levels:

Ensemble guidance continues to show a tight height spread in regards
to the stagnation of a deep upper level ridge over the western CONUS
this weekend through most of next week. This will further reinforce
general troughing over the Mississippi and Ohio Vallies, with some
amplified troughing possible as the quasi-stationary Bermuda high
builds westward towards the end of the extended forecast period.
There has been a trend towards a weak wave passing through the Ohio
Valley late Tuesday into Wednesday

Low Levels and Surface:

Currently, surface ridging remains over the Great Lakes region,
thanks to efficient CAA earlier this week. This high pressure will
slowly erode, with troughing aloft. Upper level diffluence will
prevail early next week, with most of the Ohio Valley out of the
influence of low level high pressure by late Monday. Greater
southerly flow ahead of a surface wave next weekend could alow for
a warmer airmass shift towards the end of the long term.


Temperatures:

Upper level troughing above strong low level high pressure will help
continue the sub-seasonal temperatures for portions of this weekend,
but temperatures will approach seasonal by tomorrow as deep PBLs
will aid in mixing and greater surface warming. Monday onward,
surface high pressure will become weaker, but increased cloud cover
and moisture will inhibit diurnal temperature gains, with highs
remaining in the mid 80s. Greater southerly flow next weekend should
give a subtle boost to temperatures, but uncertainty still remain on
the more mesoscale related influence. Still, the overall pattern
next weekend supports highs likely reaching the upper 80s.

As mentioned, surface moisture will increase rapidly late Sunday
through Tuesday as the surface ridge breaks down, and a weak mid to
upper wave develops over the Ohio Valley. Current expectations are
for surface dew points to push into the 70s once again by mid week,
returning the summer-time feel to the air. Surface winds will remain
very light through the extended period due to the lack of any
significant low level disturbance.


Precipitation:

Upper level diffluence within a destabilizing atmosphere beginning
on Monday will lead to an increases in diurnal thunderstorm chances
throughout next week. Lapse rates are consistently greater than 6
C/km throughout he troposphere next week, further aiding in deep
convective instability. The combination of deep instability and deep
moisture will allow for very efficient rainfall rates within any
thunderstorms. With storm motion expected to be very slow (Weak
steering flow), pockets of 1-2" over short periods are possible.
Outside of this, the flooding threat looks low outside of a low
potential for mesoscale boundaries to help organize initiation.

Without much shear, thunderstorms will have a difficult time
organizing next week, limiting the overall severe threat. Still,
given 3-4k CAPE and a high EL, updraft may be rather strong even in
these brief windows of growth. This could lead to isolated hail and
wind threats next week. There is some uncertainty on the amount of
available mid level shear Late Tuesday and Wednesday, of which could
increase the severe threat slightly during this 36 hour stretch.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1251 PM EDT Sat Jul 20 2024

Impacts

- No impacts expected

Discussion:

Scattered to broken VFR cumulus along with some high clouds will
continue into the early evening hours. For the overnight, mid and
high clouds will increase across the area, and these will continue
into the day Sunday. Some cumulus may return on Sunday as well.


&&

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

$$

SHORT TERM...50
LONG TERM...Updike
AVIATION...50