IND issues Area Forecast Discussion (AFD) at Sep 10, 2:47 PM EDT511
FXUS63 KIND 101847
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
247 PM EDT Wed Sep 10 2025
.KEY MESSAGES...
- Gradually climbing temperatures through the week with near 90
degree highs by Saturday
- Mostly dry weather outside of breif rain chances this weekend
may lead to continued expansion of drought conditions into next
week
- Dry fuels and low RH values each afternoon may lead to an elevated
fire threat, but light winds should limit the overall threat
&&
.SHORT TERM (This evening through Thursday)...
Issued at 247 PM EDT Wed Sep 10 2025
A combination of near surface high pressure and the passage of mid
level shortwaves will make for a somewhat uncertain evening forecast
of portions of central Indiana. This afternoon should remain rather
mundane with a well mixed PBL and temperatures in the low 80s.
However, focus shifts towards the passage of an amplified mid level
shortwave this evening. Overall moisture content is lacking, but
there is a narrow layer between 800-600mb of moisture convergence
over southern IL and IN that could be enough for sporatic showers
and even an isolated thunderstorm to develop after 22Z. This should
generally be defined to the Vincennes, Shoals, and Washington
regions with overall QPF below a tenth of an inch.
Even with a small sub-region receiving rain chances, the wave
arrival should lead to broken mid level cloud cover over much of
central Indiana this evening. These clouds will become more diffuse
over NE central Indiana later tonight into tomorrow morning, of
which could lead to a diurnal cooling boundary with NE portions of
the area falling into the mid 50s and SW portions remaining in the
low 60s.
Tomorrow will begin the arrival of longwave ridging from the west,
of which will bring a warming trend and dry weather through at least
early Saturday (more on this in the Long Term Section). Low RH
values tomorrow afternoon and dry fuels will support an elevated
fire threat. More details on this threat can be found below in the
fire weather discussion.
&&
.LONG TERM (Thursday night through Wednesday)...
Issued at 247 PM EDT Wed Sep 10 2025
Saturday Through Tuesday.
Forecast confidence remains low this weekend into early next week
with a wide range in potential outcomes, well depicted by model
spread in the 3 major ensemble guidances. The general synoptic
pattern has a building ridge across the Central US, but the variance
is associated with the potential for for ridge-riding diabatic
shortwaves. While there will be some moisture return into the Ohio
Valley by Saturday, instability values will be fairly meager, but a
strengthening jet across the Upper Midwest will increase shear and
create a favorable environment for thunderstorm organization. At
this point, confidence is fairly high in at least some thunderstorms
across the Great Lakes region, but confidence is low that any reach
as far south as central Indiana.
The lack of confidence in Saturday to Early Sunday's forecast
provides cascading impacts for the rest of the long term, and
therefor forecast confidence continues to decrease Sunday into
Monday. General consensus in the overall airmass will remain warmer
than normal, with the potential caveat of lingering upper level
cloud cover. Currently leaning towards a more persistent pattern
with the upper level ridge helping to push the aforementioned low
pressure further east into the Northeastern states, but will have to
continue to monitor forecast trends.
&&
.AVIATION (18Z TAF Issuance)...
Issued at 107 PM EDT Wed Sep 10 2025
Impacts:
- None
Discussion:
VFR conditions are expected through the period.
An mid level wave will be moving through the Ohio Valley later today
through tonight providing scattered to broken cloud cover between 10-
15kft. There is a low chance that some 4-6kft clouds reach KBMG this
evening.
Winds will be less than 10KT through the period, starting off
easterly, before turning more southerly Wednesday.
&&
.FIRE WEATHER...
Issued at 247 PM EDT Wed Sep 10 2025
The lack of any significant rainfall since late August has resulted
in abnormally dry and minor drought conditions to develop across
Indiana. With little to no rain in the forecast for the next 7 days,
confidence is increasing in an slightly elevated fire weather danger
each afternoon as daily min RH values fall into the 25 to 35% range.
The major factor keeping the fire weather threat lower is the lack
of wind. Despite deep mixing, very weak low level flow should keep
winds under 10 mph through the period. If no appreciable rainfall is
observed this weekend, the fire weather threat may continue to
increase and persist into mid month. Will continue to monitor the
extended forecast for increasing fire weather concerns.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Updike
LONG TERM...White/Updike
AVIATION...Updike
FIRE WEATHER...White
Source:
IND issues Area Forecast Discussion (AFD) at Sep 10, 2:47 PM EDT---------------
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