249
FXUS63 KIND 081943
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
243 PM EST Fri Nov 8 2024

.KEY MESSAGES...

- Above normal temperatures will likely continue through next
  Wednesday but near normal temperatures could return late
  next week.

- Rain expected Saturday night and Sunday.

- Slightly cooler temperatures but still above normal next week.

&&

.SHORT TERM (This evening through Saturday)...
Issued at 243 PM EST Fri Nov 8 2024

The latest surface analysis was showing a broad area of high
pressure extending from the upper Midwest and Missouri Valley to the
Great Lakes and Ohio Valley. The nearest frontal system was
meandering across the southern Plains and Deep South. Meanwhile, H20
vapor imagery was revealing a vigorous upper low that has been
responsible for an epic early season snow storm over parts of
eastern Colorado and northeastern New Mexico.

Various perturbations, associated with the southwest upper low, were
being ejected northeastward toward and over an upper ridge, that
extended from the northern Plains to the Tennessee Valley. This has
brought increasing an increasing cirrus shield into central Indiana.
More high and eventually middle clouds will be moving across central
Indiana tonight and Saturday. This and a slightly tightening low
pressure gradient should keep fog from being a big issue tonight,
although can not rule out a few locales to see some light fog at
times toward and just after daybreak, especially if the cirrus is
more on the thin side. Winds will be fair light and veer from
northwest to east Saturday morning and finally southeast Saturday
afternoon. As the complex southern front gets closer late Saturday
afternoon and evening, the showers could make into the Zincennes
area but confidence is low. With instability lacking, will not
include thunder.

With the center of the high moving off to the northeast, winds will
shift to the east. In addition, with the increasing cirrus should
add some insolation. Thus, look for overnight lows not quite as cold
as last night. DESI grand ensemble interquartile lows in the upper
30s to lower 40s look good. Meanwhile, the southeast, increasing
winds, should allow temperatures to once again reach slightly above
normal readings in the lower to middle 60s, Saturday afternoon.

&&

.LONG TERM (Saturday night through Friday)...
Issued at 243 PM EST Fri Nov 8 2024

Ensemble spread has lessened with this weekend`s mid-latitude system
and rain event. Several ensemble members were too fast initially,
especially within the GEFS camp, and have since slowed. Alignment is
good enough now for fairly high confidence in a Saturday evening
through Sunday morning window for rain. With the eastward branch of
the warm conveyor belt containing the most anomalous moisture, the
heaviest QPF is confined to near/south of the Ohio River. There is
fairly good clustering around 0.75 inch storm total QPF across the
southeast portion of our forecast area, tapering to around or just
below 0.50 inch QPF across the northwest portion. There are a few
ensemble outliers of 1.00+ inches, but this seems only possible if
convective elements are more intense given the relatively weak
forcing for ascent on the southern periphery of deamplifying/lifting
trough. Given the trough`s path, cooler midlevel temperatures will
be displaced to the north, limiting instability and mostly
precluding thunder for central Indiana.

In the wake of the departing system, quasi-zonal flow is expected
with generally positive mean height anomalies. This will support
slightly above normal temperatures for much of next week and dry
conditions until late Wednesday or Thursday. This trough may have a
lower latitude intrusion and colder post-frontal air mass than
recent systems for at least a short period late next week, but there
are signals for building anomalous ridging after that once again.
So, the Day 8-14 period should be above normal based on current
medium-range model indications. One or more transient systems within
an indicated progressive pattern should keep precipitation at least
near normal, if not above, during this period.

&&

.AVIATION (18Z TAF Issuance)...
Issued at 1141 AM EST Fri Nov 8 2024

Impacts:

- Low chance of fog overnight with the best chance at KLAF after
  09z

Discussion:

A slightly tighter low pressure gradient and increase in high clouds
tonight should lessen the chance of fog.

Winds will veer from northwest to northeast and finally east through
Saturday as a low pressure system approaches from the west. Upper
ridging and a dry lower column should keep the showers away until
closer to Saturday night.


&&

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

$$

SHORT TERM...MK
LONG TERM...BRB
AVIATION...MK