ILN issues Area Forecast Discussion (AFD) at Jan 11, 6:27 PM EST747
FXUS61 KILN 112327
AFDILN
Area Forecast Discussion
National Weather Service Wilmington OH
627 PM EST Sat Jan 11 2025
.SYNOPSIS...
High pressure will pass east across the Ohio Valley tonight. A
cold front will then move through Sunday night into Monday,
followed by an Arctic front on Tuesday. Bitterly cold weather
can be expected by mid week.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
A surface ridge of high pressure will traverse east across the
middle Ohio Valley tonight. First off, cloud cover will be a
little tricky, especially through early morning. It appears at
least our eastern zones may go partly cloudy to mostly clear for
a period, while our western zones see partly to mostly cloudy
skies due to low level moist ascent/weak WAA advection taking
place on the backside of the ridge. Where winds drop off briefly
and skies remain partly cloudy to mostly clear, some patchy fog
may develop, along with temperatures dropping off fairly
quickly due to snow cover. Thus, although we are forecasting
lows in the lower teens east to the upper teens west,
temperatures in the east could dip further a little more if the
right conditions set up.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY/...
A clipper system is forecast to pass east across the Great
Lakes and Ohio Valley Sunday through Sunday night. While the
surface low stays to our north, its attendant cold front is
poised to move through our region Sunday night. On Sunday,
southerly flow ahead of the front will allow for some warm up
after cold morning lows. Highs will range from the lower 30s
north to the mid 30s south. Cloud cover will vary, but should be
highest west and lowest east.
For Sunday night into the first part of Monday, the cold front
will cross east through our CWFA. Models depict a fairly
saturated but shallow column of moisture through about 2 kms.
Thus, although there will be a lack of deep moisture, models
show some appreciable low level forcing along and ahead of the
front such that some pcpn will be possible. How much measurable
it will be is somewhat uncertain at this point, and thus only
slight chance PoPs have been placed in the forecast. P type will
be in question as well, being based on surface temperatures and
the potentially lack of ice nuclei in the saturated column
(saturated column is forecast to be warmer than -10 C which is
an indicator of low ice nuclei activation). As a result, will
mention a slight chance of light snow and/or drizzle/freezing
drizzle as potential p types. The good news is that once the
front passes by, the threat for pcpn will come to an end. On
Monday, we will see some CAA behind the front, so some
temperature drop may occur from morning lows. Highs on Monday
will not be too far off from Monday morning lows.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
On Monday evening, a regime of generally westerly flow aloft
will be in place over the Ohio Valley, with a trough over the
northern Great Lakes gradually moving east-southeast. Cold air
will remain in place, with even colder air coming in on Tuesday,
and thus the main concern through the extended forecast period
will be the continued run of temperatures below normal through
Thursday.
On Tuesday, a mid-level wave and a surface cold front will both
be moving into the area. With some weak and transient forcing
aloft also coinciding with these features, there could be some
snow on Tuesday, though the chances for anything measurable look
small. The bigger concern will be behind the cold front, as a
strong area of high pressure moves into the region associated
with this arctic air mass. This will likely lead to Wednesday
morning being the coldest of the period, with a solid chance for
min temps dropping below 0F across the majority of the forecast
area.
Wind chill values on the mornings of Tuesday, Wednesday, and
Thursday will be dangerously cold -- with Wednesday being the
coldest. This is already highlighted in the Hazardous Weather
Outlook and may require Cold Weather Advisories as these days
get closer.
Once the surface high has moved east of the area on Thursday,
the pattern will switch to warm advection -- which will finally
bring temperatures (slightly) above freezing on Friday. There
are indications that another storm system will bring
precipitation to the area by the weekend, with timing,
intensity, and precipitation type all still very unclear this
far out.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Although there are relatively clear skies entrenched across the
region locally for the start of the period, do think that some
BKN borderline MVFR/VFR clouds will work back in from the WSW
through the first part of the TAF period, particularly by/after
06z through daybreak. This lends itself to uncertainty
regarding the potential development of patchy BR/FG, but do
think that the presence of SCT/BKN CIGs should keep BR/FG
somewhat limited in both time and space, especially between
06z-12z. That being said, cannot rule out some brief MVFR/IFR
VSBYs should skies clear and winds subside for long enough in
any one spot.
Light WSW at 5-7kts will go more southerly after 06z, increasing
to out of the SSW past 15z or so to 10-12kts with the
occasional gust to 15-18kts. There should be a
clearing/scattering trend by 12z-14z from SW to NE, although
there remain some uncertainties in just how much clearing is
expected during the daytime. Do think that, given the setup,
that the borderline MVFR CIGs early morning should go more
FEW/SCT in coverage for most of the daytime for most of the
area.
OUTLOOK...MVFR/IFR conditions are likely Sunday night. MVFR
CIGs will linger into Monday. MVFR CIGs are possible at times
Monday night through Thursday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Hickman
NEAR TERM...Hickman
SHORT TERM...Hickman
LONG TERM...Hatzos
AVIATION...KC
Source:
ILN issues Area Forecast Discussion (AFD) at Jan 11, 6:27 PM EST---------------
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