772
FXUS63 KIND 050817
AFDIND

Area Forecast Discussion
National Weather Service Indianapolis IN
317 AM EST Wed Feb 5 2025

.KEY MESSAGES...

- Precipitation arriving this afternoon. Brief Freezing rain
possible north

- All precipitation changes to rain late this evening with rain
ending overnight

- Minor ice accumulations possible Lafayette to Muncie, mainly on
elevated surfaces

- More precipitation likely Fri night through Sat night, brief
wintry precipitation possible Fri night into early Sat AM.

&&

.SHORT TERM (Today and tonight)...
Issued at 317 AM EST Wed Feb 5 2025

Synopsis:

Surface analysis early this morning shows strong high pressure in
place over the upper midwest, with a ridge axis extending southeast
across MI to PA and the middle Atlantic states. This was resulting
in dry easterly flow across central Indiana.  GOES16 shows an
abundance of cloud cover across central Indiana. Aloft, water vapor
shows weak ridging in place over the plains states, with a plume of
moisture over the plains streaming into the the Ohio Valley and
points east. Temperatures were mainly in the upper 20s and lower 30s.

Today and Tonight -

After a relatively quiet morning and early afternoon, active weather
is poised to arrive late this afternoon and into the evening.

As we start the day, the ridging aloft over the plains will push
across Central Indiana, continuing to provide a stream of mid and
high clouds across the area. No significant forcing is expected
through early afternoon and this will result in dry weather through
that time.  However across KY and TN a warm front will be setting
up, and this will be a feature that helps bring precipitation to
Indiana tonight. Thus in the meantime, we will expect just mostly
cloudy skies and easterly winds. Temperatures will rise into the at
least the lower 30s north, with mid and upper 30s more prevalent
central and south.

Late this afternoon and evening, the upper ridge is expected to
depart to the east as a short wave within the flow aloft arrives
over the plains and begins to push toward Indiana. This will provide
ample forcing for precipitation late this afternoon and evening.
Through the evening, the warm front to the south will be a focus for
lower level convergence along with isentropic lift. The 295K
isentropic surface shows good lift with specific humidities greater
than 6 g/kg.  Forecast soundings late this afternoon and tonight
show a saturated column, suggestive of an overrunning type pattern,
Thus overall confidence for precipitation is quite high. Thus high
pops, particularly this evening, will be used. However a few caveats
remain.  Forecast soundings are suggestive of a freezing rain
profile, and surface temperatures, mainly across the northern parts
of the forecast area, may be near freezing at precipitation onset.
Several models suggest above freezing temps at that time, while a
few outliers do not. Thus confidence for freezing precipitation is
low, but it cannot be ruled out. Some elevated areas, where
temperatures may be more likely to be slightly colder, may have a
better favor-ability for this. Thus will plan on keeping a few hours
of freezing rain mention across northern parts of Central Indiana
late this afternoon and early evening. Any icing that should occur
will be quite limited along with impacts.  As the evening
progresses, warm air advection is expected to continue as the warm
front to the south nudges northward. Here models suggest that
temperatures across Central Indiana will rise into the middle and
upper 30s by mid evening, ending the freezing rain threat.
Thereafter, any precipitation will should mainly just be rain and
any icing that occurred should also melt. Road temperatures across
Central Indiana are in the middle 30s early this morning also.

Models suggest the forcing and associated short wave pushing east of
Indiana after 09Z tonight. After that precipitation is expected to
end, leading to just cloudy skies. At that point, pops will be
ramped down. Warm air advection through the night suggests steady or
slowly rising temperatures with values in the mid to upper 30s north
to around 40 south in a non-diurnal fashion.

&&

.LONG TERM (Thursday through Tuesday)...
Issued at 317 AM EST Wed Feb 5 2025

The long term period will see a cool down as an expansive trough
steadily sets up aloft this weekend and next week.

Thursday could start off with lingering light precipitation before
tapering off from NW to SE once surface high pressure builds in
behind the exiting system. Forecast soundings show a shallow
saturated layer which could support light rain, but there is a
noticeable subsidence inversion developing due to increasing large
scale subsidence. This along with weak forcing limits confidence on
how long precipitation lingers Thursday or how widespread it will be.

After a quiet weather day Friday, a quick moving low pressure system
is set to move over central Indiana, bringing good confidence in
additional precipitation throughout the day Saturday. This precip
will potentially start off as snow or a rain snow mix, especially
across the northern half of the forecast area where below freezing
temperatures will be probable, before changing to all rain by the
afternoon as the associated warm front pushes through. Rain is
expected to end late in the day Saturday and may finish off with
additional snow mixing in as the cold front takes over. Should there
be any snow accumulation, it is expected to be minimal.

Behind this Saturday system, near normal temperatures will settle in
for the first couple of days of the new week. Another surface low
could bring more precipitation to the area but variances in where
the low will track leads to a lack of confidence in PoPs next week.
Keeping with guidance on PoPs for now due to the uncertainty, but
there is a possibility that the band of moisture could stay south of
the forecast area. However, there is higher confidence in even
cooler temperatures behind this system for central Indiana, with
slightly below normal temps expected for the end of the forecast
period.

&&

.AVIATION (06Z TAF Issuance)...
Issued at 1132 PM EST Tue Feb 4 2025

Impacts:

- VFR through 20-23Z.
- Deterioration to MVFR and IFR after 23Z.

Discussion:

A steady stream of mid clouds within the flow aloft will persist
overnight. This will lead to VFR conditions across all of the TAF
sites. Microphysics channel showing an area of lower VFR cigs over
Central IL, poised to push in to HUF and BMG overnight. Have
included these lower Cigs at those locations.

Light rain showers are expected to push in tomorrow afternoon as a
warm front sets up south of Indiana as a short wave passes aloft.
This could lead to brief FZRA or a light ice glaze on elevated
surfaces. However confidence and potential impacts should be low as
warming temperatures through the evening should allow any
precipitation to quickly change over to rain. As the precipitation
arrives, MVFR ceilings are expected with an eventual trend toward
IFR through the evening.


&&

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

$$

SHORT TERM...Puma
LONG TERM...KF
AVIATION...Puma