Area Forecast Discussion
Issued by NWS Indianapolis, IN

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097
FXUS63 KIND 200213
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
1013 PM EDT Fri Jul 19 2024

.KEY MESSAGES...

- Dry and pleasant into this weekend

- Seasonable warmth and increasing humidity returns by late this
  weekend

- Chances for rain/t-storms and increasing clouds next week may help
  keep temperatures slightly below normal

&&

.FORECAST UPDATE...
Issued at 1013 PM EDT Fri Jul 19 2024

No changes needed to the forecast this evening. Generally calm
conditions and clear skies expected overnight. The only forecast
challenge we will have overnight is the potential for patchy fog.
Given the anticipated clear skies and light winds, radiational
cooling potential optimal. The best chance for patchy fog is near
rivers, in low-lying areas, and over fields/farmland. The most
probable locations appear to be across the northern parts of our
forecast area.

&&

.SHORT TERM (This evening through Saturday)...
Issued at 237 PM EDT Fri Jul 19 2024

Rest of This Afternoon...

Scattered to broken coverage of cumulus will persist this afternoon,
with some decrease expected late. Mild temperatures will continue
with temperatures in the 70s to lower 80s.

Tonight...

Cumulus will dissipate this evening with loss of heating, but some
cirrus will drift across the area. Overall though the night will be
mostly clear. Winds will be light with high pressure still nearby.

The combination of light winds and mostly clear skies could allow
for some isolated fog, especially northwest. However, coverage is
not expected to be high enough to include in the forecast at this
time.

These conditions will also allow temperatures to fall into the upper
50s to around 60 for lows.

Saturday...

Another quiet day with high pressure remaining in control is
expected. Some high clouds plus some cumulus development will lead
to partly cloudy skies for much of the area.

With some gradual modification of the airmass occurring, highs will
get into the lower 80s for much of the area.

&&

.LONG TERM (Saturday night through Friday)...
Issued at 237 PM EDT Fri Jul 19 2024

Upper Levels:

Ensemble guidance is in agreement on the continuation 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.

Low Levels and Surface:

Currently, surface ridging is robust over the Great Lakes region,
thanks to efficient CAA earlier this week. This high pressure will
take time to erode, even with troughing aloft. However, eventually,
upper level diffluence will prevail, with most of the Ohio Valley
out of the influence of low level high pressure by early next week.

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 Sunday 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 later in the week
should give a subtle boost to temperatures, with highs by next
weekend likely reaching the upper 80s.

As mentioned, surface moisture will increase rapidly next week as
the surface ridge breaks down. 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
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. Currently it is too far out to pinpoint any
specifics on timing and location of severe potential

&&

.AVIATION (00Z TAF Issuance)...
Issued at 734 PM EDT Fri Jul 19 2024

Impacts

- Low probability of fog at KLAF near sunrise

Discussion:

Scattered cumulus will dissipate shortly after sunset. Clear skies
and light winds then prevail through morning. Light north to
northeasterly winds and redevelopment of diurnal cumulus is expected
after sunrise.

With light winds and mostly clear skies, cannot rule out some fog at
KLAF late tonight. However, confidence is not high enough to include
at this time.


&&

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

&&

$$

UPDATE...Eckhoff
SHORT TERM...50
LONG TERM...Updike
AVIATION...Eckhoff