689
FXUS63 KIND 092349
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
649 PM EST Sat Nov 9 2024

.KEY MESSAGES...

- Rain expected tonight into Sunday

- Above normal temperatures will likely continue through Wednesday

- Rain chances return late Wednesday into early Thursday

&&

.SHORT TERM (This evening through Sunday)...
Issued at 137 PM EST Sat Nov 9 2024

CIRA satellite-derived layered moisture products shows high-level
moisture overspreading our region, and lower tropospheric moisture
lagging, just now entering the mid-Mississippi Valley region.
Meanwhile, weak perturbations on the windward side mean ridge is
acting with the initial moisture to result in light precipitation
which is mostly virga given the residual lower tropospheric dry
layer.

This is all in response to an upstream cut off mid-upper low in
Nebraska, migrating eastward. It appears the window for rain (0.25-
0.75 inch totals per HREF mean), will be late tonight through
tomorrow morning. The QPF maxima in the models are aligned with the
eastward bending branch of the warm conveyor belt and associated +2-
3-sigma PWAT anomalies, south of the Ohio River. Higher QPF within
high-resolution models is apparent where peripheral DCVA/forcing may
align with the northwestern fringe of the warm conveyor belt across
the southern portion of our forecast area tomorrow morning. Locally
up to around 1.00 inch is possible there, and this will be near and
south of a Bedford to Columbus to Greensburg line. It is possible
that northwest of this line precipitation amounts will under-
perform, as stronger forcing for ascent passes north and deeper
moisture is relegated to the south, with dry conveyor belt moving in
during the morning.

To summarize our expectations with the precipitation, we expect
virga to increase for the rest of the day and perhaps sprinkles at
times, followed by a more contiguous area of rain showers mid-late
evening onward mostly moving out by mid morning. Lingering rain
showers across southern portions of the area will continue until
early afternoon.

There may be just enough instability present for an isolated
thunderstorm or two, but in general the steeper midlevel lapse rates
will be confined to our northwest limiting thunderstorm potential.

The post-frontal environment will feature weak cold advection and
still seasonally warm conditions, with clearing and deep enough
mixing into momentum aloft for gusty winds tomorrow afternoon. Gusts
of 25-30 mph will be common.

&&

.LONG TERM (Sunday night through Saturday)...
Issued at 137 PM EST Sat Nov 9 2024

Sunday Night Through Wednesday.

A dry slot associated with the system that is expected to impact
central Indiana on Sunday will move through Sunday night which will
allow for skies to quickly clear out as drier air moves in aloft.
Temperatures will stay warmer than average through the night as the
flow remains westerly, but by late Monday the near surface flow is
expected to briefly turn northerly before becoming more easterly as
central Indiana becomes more influenced by a broad ridge across the
Ohio Valley. Temperatures will remain slightly above average through
the middle of the week with mostly clear skies.

Wednesday Night Through Saturday.

The next impactful weather system is expected to move through
central Indiana Wednesday night into Thursday as a broad but strong
open trough moves eastward across the Northern United States.  There
remains a fair amount of uncertainty in the timing of a front
associated with this system as ensembles are showing a 12-18 hour
spread with general clustering towards midnight Wednesday night into
Thursday. The better lift with the system is more towards the Great
Lakes with fairly weak near surface convergence ahead of the front.
Thus, will be continuing the trend of lower QPF into the forecast
with growing confidence that this won`t be the 1+ inch system that
it looked to be a few days ago. Thunder potential with this system
looks low with meager lapse rates leading to near zero instability.

Quieter weather is expected for the rest of Thursday into the
weekend with broad ridging across the Central United States.
Temperatures will remain slightly above normal with mostly clear to
clear skies through the rest of the week.  Looking beyond next
weekend the pattern looks to become much more active with multiple
chances for rain with some models showing the potential for portions
of the Ohio Valley to see greater than an inch of rain.

&&

.AVIATION (00Z TAF Issuance)...
Issued at 649 PM EST Sat Nov 9 2024

Impacts:

- IFR ceilings and rain showers late evening through late morning
- Gusty SW winds tomorrow afternoon

Discussion:

Latest satellite and radar imagery show extensive cloud cover
stretching from the Gulf Coast to the Great Lakes ahead of an
occluded front. ACARs soundings from around the region though still
show quite a bit of dry air in the lower troposphere and a 15 degree
dew point depression at the surface. It will take some time for the
atmosphere to saturate enough to create sub VFR conditions this
evening. Keeping cigs and vis VFR through at least 06z this evening
for TAF sites across Central Indiana. Observations further south and
west do show the low levels saturating with IFR cigs on the backside
of the front from Iowa to Arkansas. Expect cigs and vis to
deteriorate after 06z with heavier and more widespread showers
moving in. Expect MVFR to IFR conditions through late morning before
clearing pushes in from the west.

Southeasterly winds this evening will become southerly overnight
around 7-14kts. As the occluded front pushes through, expect a few
hour period of southwesterly winds with gusts 25+kts Sunday
afternoon.

&&

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

$$

SHORT TERM...BRB
LONG TERM...White
AVIATION...CM