883
FXUS63 KIND 060159
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
959 PM EDT Sat Oct 5 2024

.KEY MESSAGES...

- Elevated fire weather risk Sunday afternoon

- Dry and warm weather continues tonight and Sunday.

- Early next week will return to seasonable temperatures, but warmer
  air will return later in the week

&&

.FORECAST UPDATE...
Issued at 959 PM EDT Sat Oct 5 2024

Southerly breezes tonight will hold central Indiana temperatures
well above normal despite clear skies.  A potent baroclinic system
continuing to cross southern Canada...will drag its cold front
eastward across the Middle Mississippi Valley and towards Indiana by
dawn.  Warm advective flow will increase slightly amid approaching,
rather modest gradient ahead of this boundary...while winds veer
slightly to south-southwest into pre-dawn hours.

Expecting gusts to reach 20 mph for most locations north of I-70 in
the wee hours...with downward temperature trends of only another 5
or so degrees promoting lows of 60-65F across the CWA. The record
high minimum for October 6 at Indianapolis is 71 (1941)...the
current forecast low is 65F...which would be in the 94 percentile
for the date.

&&

.SHORT TERM (This evening through Sunday)...
Issued at 232 PM EDT Sat Oct 5 2024

Synopsis:

Surface analysis early this afternoon shows strong high pressure in
place over Lake Erie and Southern Ontario. This high was in firm
control of the weather across Indiana and the region. A surface
ridge extended southwest from the high, stretching across the Ohio
Valley to Arkansas. GOES16 shows mostly clear skies across Indiana
as morning mid level clouds have dissipated. Some mid and high
clouds were found across MN and the Dakotas associated with a cold
front. Aloft, water vapor showed riding in place over Indiana and
the Great Lakes and strong subsidence was shown across Illinois and
Indiana. Southeasterly lower level flow was in place and dew points
were mainly in the 50s.

Tonight -

Dry weather is expected tonight. The high pressure system and
ridging across the area is expected to depart to the east this
evening, allowing the cold front over the northern plains to arrive
in Indiana toward 12Z. This will result in mostly clear skies and
warm conditions tonight in the warm sector, across Indiana. The
arrival of some high clouds will be expected late tonight as the
front reaches our area. This front is moisture starved as southerly
gulf flow never develops ahead of this system. Forecast soundings
and time heights fail to show deep saturation. Thus overall, we
expect mostly clear skies this evening, partly cloudy skies toward
daybreak, with lows in the lower to middle 60s. Also, a moderate
pressure gradient across the area with the approaching front will
allow winds to remain around 5-10 mph overnight, providing some
mixing.

Sunday -

Models show the dry cold front will push across Central Indiana and
exit to the east through the course of the day. Strong high pressure
is expected to build across Indiana in the wake of the front from
the northern Plains. Aloft, ridging over the high plains is expected
to redevelop, allowing for more lee side northwest flow aloft and
subsidence spilling into the Ohio Valley. All of this will add up to
partly cloudy skies as forecast soundings remain dry through the
day. The strongest cold air advection does not begin until later in
the afternoon and strong mixing is expected as a moderate pressure
gradient will still be in play. Winds may gust to 20-25 mph. This
may continue fire weather concerns with highs in the middle 80s and
low afternoon RH values.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 232 PM EDT Sat Oct 5 2024

A prolonged dry spell can be expected at least through this week, as
strong high pressure dominates the region throughout the period,
bringing pleasant autumn weather but potentially enhanced fire
danger concerns, as well as potentially deteriorating drought
conditions after a brief improvement due to rainfall from the
remnants of Helene late last month.

Normal highs and lows for the time of year are currently right
around 70 and 50, though steadily declining with time as we push
inexorably toward the cool season - by mid month we lose another 4-6
degrees on average.

Dry conditions will likely lead to enhanced diurnal temperature
ranges, with lows near to a bit below normal much of the week, and
highs near to a bit above normal. Temperatures will be on a modest
warming trend through the week, coolest early and warmest late as
broad upper level ridging over the western CONUS gradually nudges
toward the region later in the week.

Will likely adjust blend guidance dewpoints downward during the
afternoons many days this week, as despite relatively light winds,
it will require only modest mixing in a very dry column to produce
potentially substantial dewpoint drops in the afternoons. This is an
area where NBM is known to struggle, often significantly. The
aforementioned light winds will mitigate fire concern somewhat, at
least with respect to reaching red flag conditions, but continually
drying fuels and afternoon RH values potentially nearing critical
levels will present at least some concern.

Longer term guidance does suggest some potential for precipitation
near or just beyond the end of the forecast period with another
quick moving upper low and cold frontal passage late next weekend
into early the following week, but long term outlooks remain fairly
strongly warm and dry, and prevailing westerlies look to remain
displaced well poleward for most of the next couple of weeks at
least. CPC 6-10 and 8-14 day outlooks are strongly indicative of
below normal precipitation and nearly as strongly indicative of
above normal temperatures, and this is well-supported by long term
guidance, including the CFS.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 739 PM EDT Sat Oct 5 2024

Impacts:
 - Winds veering from southerly to west-northwest by late day Sunday
 - Low level wind shear at KLAF 08-12Z tonight
 - West to west-northwesterly winds gusting to 16-22KT Sunday

Discussion:

VFR conditions will continue over central Indiana terminals into
Sunday evening.  A potent cyclone crossing southern Canada will drag
its dry cold front across the region Sunday morning.  Sustained
winds ahead of this passage will slowly increase within mainly a 7-
12KT range tonight, except at KBMG where lighter flow will be
present...while veering slightly over all terminals to 210-230
degrees by dawn.

Winds will continue to veer Sunday through westerly direction with
the frontal passage, while gusting to mainly 16-22KT...before
diminishing late in the day.

&&

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

$$

UPDATE...AGM
SHORT TERM...Puma
LONG TERM...Nield
AVIATION...AGM