IND issues Area Forecast Discussion (AFD) at Feb 7, 9:43 AM EST
774
FXUS63 KIND 071443
AFDIND
Area Forecast Discussion
National Weather Service Indianapolis IN
943 AM EST Fri Feb 7 2025
.KEY MESSAGES...
- Rain returns Friday night into Saturday, brief freezing rain
possible Saturday morning
- Additional chances for wintry precipitation next week
&&
.FORECAST UPDATE...
Issued at 943 AM EST Fri Feb 7 2025
Quiet start to the morning so far with high pressure across the
region. Broad area of mid and high clouds drifting across the lower
Great Lakes producing a thin deck across the northern half of the
forecast area with mainly clear skies further south. 14Z
temperatures were generally in the 20s with a few spots into the
lower 30s across south central Indiana.
The primary focus for the morning update is to bring cloud cover
into the region faster than previously expected as a thick mid level
cloud deck focused to our southwest expands into the region
throughout the day. Expect the leading edge of the mid clouds to
make it into the lower Wabash Valley shortly and certainly by midday
at the latest. Clouds will expand northeast and likely will
encompass most of the region along and south of I-70 by late day.
Low level thermals support highs ranging from the mid 30s over far
northern counties to the lower 40s south of Interstate 70. Zone and
grid updates out.
&&
.SHORT TERM (Today through Saturday Night)...
Issued at 218 AM EST Fri Feb 7 2025
Central Indiana will be rather active over the next 7-10 days as a
strong SW to NE oriented baroclinic zone will be centered over the
Ohio Valley.
Initially, this baroclinic zone has shifted southward, in
conjunction with the arrival of northerly winds and the eastern
side of a low level high early this morning. A renewed shot of
cold air advection will accompany the shift in winds, with
temperatures falling into the mid to low 20s by dawn. During the
day, a strengthening low over the mid Mississippi Valley will lead
to modest frontogenesis upstream, leading to a return of easterly
winds, curtailing the push of cold air. This should result in
near seasonal temperatures for central Indiana today with highs in
the upper 30s to low 40s for most areas. Clouds will begin to
increase again this afternoon as high pressure exits eastward and
a mid-level system approaches from the west.
Lift and moisture associated with this low level wave will arrive
tonight, mostly along an elongated warm front. This moisture looks
to be contained in the lowest 2km of the atmosphere, removing any
chances for snow with no ice nuclei present in the clouds. The
antecedent dry air mass and weak northward push of the warm front
should keep any precipitation initially over southern portions of
the state. However, as the low strengthens beneath the LLJ, greater
frontogenesis, and gradual northward movement of the front should
lead to scattered rain showers over most of central Indiana be 6A-8A
Saturday morning. There is some uncertainty on when precipitation
will begin in far southern central Indiana Friday night, of which
could begin as drizzle due to the lack of deep low level saturation.
Surface temperatures will be at to just below freezing during
precipitation onset Saturday morning, leading to some concern for a
brief 2-4 hour period of freezing rain from a Bloomington to
Columbus line on northward. Luckily, the saturation along this
frontal boundary is vary shallow, keeping light precipitation rates,
and therefor any ice accumulation minimal. Greatest freezing rain
amounts should remain below 0.05", mitigating many impacts, but
isolated slick spots on low traffic roads, bridges and overpasses
are possible Saturday morning.
As we reach midday on Saturday, a surface low should begin to
develop increasing the overall lift in the atmosphere. This should
also strengthen the temperature and wind gradient over the state
pushing surface temperatures above freezing in all locations, even
nearing 50 degrees in far southern central Indiana. This greater
source of low level lift is expected to lead to showers with periods
of moderate rainfall rates at times Saturday afternoon and evening;
greatest coverage would be along and south of I-70. By Saturday
night, all rain is expected to be east of central Indiana, with a
shift back towards NW winds and a subsequent drop in temperatures.
Expect lows in the mid to low 20s once again Saturday night.
&&
.LONG TERM (Sunday through Thursday)...
Issued at 218 AM EST Fri Feb 7 2025
Sunday through Monday:
As mentioned in the short term, a strong baroclinic zone will be
present across the Ohio Valley over the next week. By Sunday, this
will once again be pushed southward, removing precipitation chances
through Monday morning. This baroclinic zone will still be active,
but ensemble guidance is in agreement with the rain remaining along
and south of the Ohio River. North of this baroclinic zone (central
Indiana), temperatures are expected to be near seasonal, leading to
highs in the mid 30s to low 40s both Sunday and Monday.
Monday Night through Tuesday Night:
A more substantial upper level system looks to impact the Ohio
Valley late Monday through Tuesday night with models continuing to
show agreement in the overall synoptic pattern. This pattern
consists of a relatively deep surface low moving somewhere across
the Tennessee Valley to southern Ohio Valley with central Indiana
remaining in the cold sector of the system, including modest
northeasterly surface flow. This area is known as the cold conveyor
belt, and with enough moisture, should lead to periods of snow.
Although there is good general ensemble agreement, variances in
specifics like QPF and timing is leading to a wide range in
potential outcomes for central Indiana regarding specific snowfall
amounts with this system. There is also potential for shifts in the
overall track, of which would change snow expectations. Keep
monitoring forecast updates in the coming days as details become
more apparent, and plan on the potential for Tuesday travel hazards
in the event moderate to heavy snowfall comes to fruition.
Wednesday through Friday:
Ensemble members continue the active pattern along the baroclinic
zone with another wave developing and passing through the Ohio
Valley sometime Wednesday through Thursday. At this time, ensemble
variance is too high to resolve much more than chances for
precipitation, but this will be another system to keep an eye on in
the coming days. Also, given the large temperature gradients within
this baroclinic zone, slight shifts in the overall pattern could
result in large forecast temperature swings. As of this forecast
update, the expectation is for seasonal temperatures late next week,
but this could change depending on how the aforementioned systems
evolve.
&&
.AVIATION (12Z TAF Issuance)...
Issued at 509 AM EST Fri Feb 7 2025
Impacts:
- Deteriorating flying conditions in rain after 09z-15z Saturday
and a small chance for brief freezing rain near the onset
Discussion:
Rain is possible toward 12z Saturday at KHUF and KBMG and after 15z
at KIND. Otherwise, good confidence in VFR flying conditions through
tonight with deteriorating conditions with the arrival of the rain
Saturday.
Winds will be less than 10 knots today and tonight and shift from
north and northwest to east and southeast late.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...Ryan
SHORT TERM...Updike
LONG TERM...Updike
AVIATION...MK
Source: IND issues Area Forecast Discussion (AFD) at Feb 7, 9:43 AM EST (https://mesonet.agron.iastate.edu/p.php?pid=202502071443-KIND-FXUS63-AFDIND)
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