ILN issues Area Forecast Discussion (AFD) at Jan 22, 2:25 AM EST519
FXUS61 KILN 220725
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
225 AM EST Wed Jan 22 2025
.SYNOPSIS...
Cold and dry weather is expected today as surface high pressure
moves east of the Ohio Valley. Another weak front on Thursday
will bring additional chances for flurries or a few light snow
showers. Temperatures will remain below normal until we get to
this weekend when seasonable air finally returns to the region.
&&
.NEAR TERM /THROUGH TODAY/...
The coldest temps of this entire cold stretch are expected
through sunrise given the favorable setup, but this is not
necessarily translating into significantly colder wind chills
than what we have already experienced given the light/calm winds
that have evolved area-wide.
With the ~1038mb sfc high traversing srn parts of the region,
do think that most, if not all, areas have (or will) experience
subzero air temps through early this morning. In fact, sheltered
and low-lying areas are experiencing air temps around/below -5F,
with -10F air temps likely in rural/sheltered spots in parts of
central/south-central OH. The fly-in-the-ointment, however, is
going to be that as the sfc high pulls E of the region toward
daybreak through early this morning, return flow on the backside
will allow for winds to begin to increase to around 5-10kts
across parts of EC IN and WC OH between 09z-15z. This may not
seem like much, but with air temps between -5F and -10F
degrees, any light wind will have a significant impact on the
wind chill. But it may also help nudge the air temp up a few
degrees once the wind picks up, too. Either way, minimum wind
chill values are going to be very close to warning-level
criteria (-20F N and -15F S) for a large portion of the area
through the early morning hours, but there is still not enough
confidence to support an upgrade to a warning given the
uncertainties in the ever-delicate temp/wind dance that will
unfold toward daybreak and beyond. It is going to be very cold
no matter the circumstances, even if wind chill values stay in
advisory criteria due to lighter/calmer wind.
Breezy conditions are expected during the day today amidst a
tightening pressure gradient, with temps rebounding rather
abruptly past sunrise from the 0F to -10F range into the upper
teens to mid 20s by the afternoon. The stiff SW breeze will be
in response to the approach of the next weak system, which
should bring additional low-end light snow chances to the area
by late Thursday. Skies will be mostly cloudy by this afternoon
for the majority of the region.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM THURSDAY/...
Light SW flow will be maintained tonight amidst mostly clear
skies. Temps will still be cold, even by seasonal standards, but
will be quite a bit warmer than we've experienced very recently.
Expect that lows will bottom out in the mid/upper single digits
above zero in central/south-central OH and NE KY where winds
will be lightest and skies will be clearest. Further to the W,
particularly near/W of I-75, the maintenance of some light
southerly flow and increasing clouds late should keep temps
generally in the teens. While there is still the expectation for
wind chills near, or slightly below, zero tonight into early
Thursday morning, advisory criteria thresholds are not expected
to be met for the majority, or all, of the ILN FA.
For the daytime Thursday, the longwave trof entrenched across
the ern CONUS will dig back into the OH Vly once again by the
afternoon, with another reinforcing shot of cold air set to
filter back into the region by Thursday night into Friday. This
disturbance, given the seasonably cold air in place, should
provide just enough forcing amidst a meager moisture profile to
generate additional scattered flurry or very light SHSN activity
for the afternoon and evening along the eastward-advancing
front. This will especially be the case across parts of
central/south-central OH and NE KY mid afternoon, where a
dusting to perhaps a few tenths of an inch will be possible.
Highs on Thursday will top out in the mid 20s near/N of I-70 to
the mid 30s S of the OH Rvr.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
On Thursday evening, the ILN forecast area will be in a regime of
cold westerly flow, just behind a somewhat-ill-defined cold front.
Some light snow or flurries may be possible Thursday evening, ending
after 06Z. After that occurred, cold advection will continue into
Friday -- and the overall model trend has been in the colder
direction for Friday. Max temps are now expected to be in the lower
to mid 20s.
Conditions will change a bit over the weekend, as high pressure sets
up over the southeastern states, leading to deeper and stronger
southwesterly flow into the Ohio Valley. This will bring
temperatures above freezing (lower 30s to lower 40s) for the ILN CWA
on Saturday, though maybe a couple degrees cooler on Sunday. By
Sunday into Monday, attention will turn to the deep south, as the
surface high drifts a little further to the southeast and moisture
advection begins heading northward from the Gulf of Mexico. The
chances of this moisture reaching the Ohio Valley, however, have
decreased somewhat based on latest model guidance. The overall flow
pattern aloft is appearing likely to remain very flat and zonal,
with little of the amplification that would be necessary to bring a
surge of theta-e this far north. As a result, PoPs have been limited
to the 20-30 percent range, primarily focused on Monday, and the
southern sections of the ILN forecast area. This may be a mix of
rain and snow, depending on timing, but snow appears favored right
now due to the suppressed nature of the system and the colder air
remaining in place. No significant accumulations are expected either
way.
The pseudo-zonal flow will continue into the first part of next
week, with no clear signs of any large chances for precipitation.
High temperatures will likely remain in the 30s -- notably warmer
than the preceding week, but still slightly below normal for late
January.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions will prevail through the TAF period. Clear skies
and calm light/VRB winds are expected through daybreak as the
center of high pressure positions itself over the Ohio Valley.
Mid level clouds are expected to overspread the area during the
daytime before clearing once again toward the end of the period.
Southerly winds will increase to around 10 kts before subsiding
once again past 00z. Some SW LLWS on the order of 40kts will
evolve toward/past 06z Thursday.
OUTLOOK...MVFR CIGs are possible Thursday into Friday, and again
on Sunday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...Cold Weather Advisory until 10 AM EST this morning for OHZ026-
034-035-042>046-051>056-060>065-070>074-077>082-088.
KY...Cold Weather Advisory until 10 AM EST this morning for
KYZ089>100.
IN...Cold Weather Advisory until 10 AM EST this morning for INZ050-
058-059-066-073>075-080.
&&
$$
SYNOPSIS...KC
NEAR TERM...KC
SHORT TERM...KC
LONG TERM...Hatzos
AVIATION...KC
Source:
ILN issues Area Forecast Discussion (AFD) at Jan 22, 2:25 AM EST---------------
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