982
FXUS63 KIND 200702
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
302 AM EDT Fri Sep 20 2024

.KEY MESSAGES...

- Above normal temperatures continue into the weekend

- Isolated to scattered thunderstorms this afternoon and
  evening

- Cooler temperatures early next week with increasing rain chances

&&

.SHORT TERM (Today and tonight)...
Issued at 302 AM EDT Fri Sep 20 2024

An upper trough will pivot from the upper Midwest to northern
Ontario through tonight as a dome of high pressure remains parked
over Texas. Meanwhile, a weak cold front will move into the Wabash
Valley this evening spread into southern Indiana by Saturday
morning. MRMS reflectivity was showing widespread convection across
Wisconsin with more scattered activity southwest into Iowa along and
ahead of this front.

As the front reaches central Indiana, it will have limited low level
moisture and weak to moderate instability to work with after
examining Hi-Resolution soundings. In addition, lapse rates will be
weak. So confidence in anything other than isolated late day and
evening convection is low. That said, with marginal 30-35 knot deep
shear to go with the weak to moderate instability and a curved
hodograph, would not rule out marginally severe hail and or
thunderstorm gusts per the SPC Day1 Severe Weather Outlook. Best
timing and highest chances will be after 19z and over the upper
Wabash Valley.

Once again, deep mixing, diurnal heating and light breezy southwest
winds should result in well above normal temperatures in the upper
80s and lower 90s today. Meanwhile, the frontal passage should have
little effect on temperatures tonight with lows in the 60s. Normal
high temperatures for this time of year are in the upper 70s and
lower 80s and normal lows are in the 50s.

&&

.LONG TERM (Saturday through Thursday)...
Issued at 302 AM EDT Fri Sep 20 2024

Some relief from the recent hot and dry conditions appears to be on
the way for next week, with growing chances for enough of a soaking
rain to at least prevent worsening of ongoing drought conditions,
and perhaps offer some improvement.

Guidance is generally in agreement on a weakening of the persistent
subtropical ridge that has kept us dry and hot in recent days and
weeks, allowing for multiple upper level disturbances to impinge
upon the area late in the weekend into early next week. Model
precipitable water values are anomalously high well into next week,
which should allow for rainfall as modest forcing moves through the
region.

Model spread increases from mid week onward with respect to
evolution of the synoptic pattern, which will significantly impact
resultant conditions, but broadly speaking, expect the first
significant rainfall chances in quite some time Sunday into Tuesday,
along with a fairly substantial cooldown to much nearer
climatological normals, followed by continued milder conditions and
perhaps some low rain chances late in the week into next weekend,
depending upon the degree to which the upper level ridge reasserts
influence near the region.

Model QPF is likely a bit overdone given the relatively modest
forcing, but WPC 7 day QPF of an inch or two total is certainly
reasonable and would put a substantial dent in the monthly deficit,
were it widespread enough.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1008 PM EDT Thu Sep 19 2024

Impacts:

- Isolated convection possible late Friday afternoon and
  evening

- Winds 210-230 degrees with gusts less than 20 knots

Discussion:

Would not rule out some late afternoon and evening thunderstorms as
a cold front moves in. However, chances are too low to put in the
TAFs. Otherwise, good confidence in VFR flying conditions through
the TAF period.


&&

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

$$

SHORT TERM...MK
LONG TERM...Nield
AVIATION...MK