Later this evening and tonight it will snow in Kentucky while Indiana remains cloudy. Today is the last day in the mid 40's so enjoy it if you can. Starting tomorrow we will enter a much colder pattern that will last until about February 6 and then it will be warmer than average after that. So here we are; perhaps the last two weeks of winter. For #BOTS fans, it has to happen in the next two weeks.
Here is a very long discussion from the National Weather Service Office out of Indianapolis:
Area Forecast Discussion
National Weather Service Indianapolis IN
1233 PM EST Wed Jan 19 2022
...Updated Aviation Discussion...
.Forecast Update...
Issued at 1000 AM EST Wed Jan 19 2022
900 AM observations across central Indiana indicated a cold front
crossing the southeastern third of the state, with temperatures in
the subsequent frontal zone ranging from the mid-40s along the East
Fork of the White River to near 32F in far northwestern corners of
the CWA. Dry conditions were continuing under at least BKN post-
frontal mid/high cloud that was continuing to advance into and over
the region from the west.
A broad arctic air mass will build into the region today. Winds
will continue to veer to northwesterly this morning before
increasing this afternoon with gusts as high as 15-20 knots for most
locations. The 32F isotherm will slowly cross the northwestern
portions of the region through this afternoon, before quickly
advancing southeast of the I-70 corridor late today. Plummeting
readings will already be in the mid 20s across northwestern zones by
early this evening. Latest guidance is continuing to indicate
chances of light rain to snow for far southern counties this
afternoon, although confidence is low in any accumulations exceeding
a thin coating by late day. Any lake-effect snow flurries that may
reach our north-central/northeastern zones would not start until at
least late this evening.
&&
.Short Term...(Today through Thursday)
Issued at 255 AM EST Wed Jan 19 2022
Highlights...
*Falling temperatures throughout today from NW to SE. Overnight lows
in the teens with wind chill values near 0.
*Scattered showers transitioning into snow in far southern central
Indiana. Confidence in snow amounts is low, but only minor
accumulations expected at this time.
Today and Tonight..
Currently, temperatures are still unseasonably high across central
Indiana as SW flow continues to advect warm air over the region.
With some mid to upper level moisture increasing, cloud development
will become likely overnight with broken to scattered upper level
clouds by the morning.
To the north a deepening surface low will move off to the east,
opening a elongated channel of NW flow to approach central Indiana.
This will drop throughout the day as a cold front passes through
from NW to SE. With the front displaced from the surface low, the
temperature gradient will not be quite as steep as a typical
wintertime cold front, but gradual temperature decreases within
moderate CAA will occur this afternoon following frontal passage.
Also of note is the significantly drier air within the cold air
mass. This will create a steep moisture gradient across central
Indiana with dew points ranging 15+ degrees by Wednesday evening.
A second disturbance will approach from the SW throughout tomorrow,
increasing chances for precipitation over far southern central
Indiana the afternoon through tonight. As the low deepens, a
strengthening southerly LLJ will push higher low level moisture into
the Ohio Valley. This will eventually saturated the PBL, leading to
scattered showers. The strengthening southerly flow will work against
the advancing frontal boundary, keeping the mid to low level drier
air from reaching portions of southern Indiana. The opposed systems
will also develop a strong deformation zone, of which will be the
primary threat for increased QPF.
Although moisture will stay elevated north of the secondary low,
cold air will still move over south central Indiana, aided by
diurnal cooling. This should drop temperatures below freezing
leading to chances of snow. Snowfall will be likely within the
deformation bands this evening and overnight, but where these bands
are positioned is still in question. To add to the uncertainty is an
enhanced 850-700 moisture boundary, that will create steep QPF
gradients over southern Indiana. Current expectations are for
minimal accumulations over south central Indiana, but this could
change is the deformation bands develop further north. Observational
analysis will be paramount in future updates today.
Eventually, the secondary low will move off to the east, with dry
air encompassing central Indiana. Residual mid-level clouds could
inhibit some diurnal cooling in southern and southeastern central
Indiana, but a majority of central Indiana should see significant
temperature drops overnight with lows in the teens. This in
combination with sustained winds around 10-15mph will lead to wind
chill values near or below freezing. Elevated low level moisture
down stream of Lake Michigan should lead to some cloud development
over NE central Indiana overnight. This should lead to some
scattered flurries as the saturated layer interacts with
the cold air mass.
Tomorrow...
Much quieter weather will be in store for tomorrow as surface
pressure increases beneath the CAA. Skies should be mostly clear,
although some lake effect clouds will still be ongoing in northern
portions of the region. A stay flurry is will still be possible
within this cloud cover. Temperatures will remain bellow normal with
highs in the mid 20s.
&&
.Long Term...(Thursday night through Tuesday)
Issued at 255 AM EST Wed Jan 19 2022
The long term will see several waves move through the area within
fast northwest flow aloft. That said, deep moisture will be lacking,
so confidence in anything more than low coverage light snow showers
or flurries at any one time is lacking. Confidence is much higher in
below normal temperatures each day.
Thursday Night through Friday Night.
A strong expansive high pressure ridge will extend from the southern
Plains to the Great Lakes late this week into the early weekend.
Meanwhile, a broad upper trough embedded within the northwest
flow aloft will move across on Friday followed by a quick moving
ridge Friday night. With only modest boundary layer flow off Lake
Michigan becoming northeasterly overnight Thursday night, do not
expect any lake effect snow showers to make it in our northwestern
counties. Meanwhile, aside for some thin low level moisture per
model soundings and rh time sections, the atmosphere will be way too
dry on Friday for any precip associated with the elongated upper
trough. Finally, even a more dry column combined with the
quick moving ridge will keep it dry Friday night as well.
Very cold boundary layer with 850 millibar temperatures to 16
degrees below zero Celsius, weakening winds and clearing skies
should allow overnight temperatures to bottom out in the teens
Thursday night and Friday night. Meanwhile, light winds will keep
wind chills from falling below zero. Afternoon highs will struggle
to reach the middle and upper 20s on Friday. Normal high
temperatures this time of year are in the 30s and normal lows
around 20 degrees.
Saturday through Tuesday.
Saturday should only see a very slight warmup as the broad surface
ridge well move over the southern states and block return flow from
the Gulf. This will also serve to keep the mid and low levels bone
dry ahead of another upper trough in the northwest flow aloft and
approach of a cold front from the northwest. Thus, will stick with
a dry and slightly warmer forecast for Saturday.
The aforementioned cold front will move through Saturday night and
another upper wave will follow Sunday. This should reinforce the
cold weather with only an increase in high clouds.
Will keep the remainder of the long term dry with less confidence of
timing on any waves in the northwest flow aloft and no tell tale
signs of a moisture influx.
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