Monthly Archives: January 2021

A little more snow

Sun. Jan. 31, 2021  6 P.M.

A weakening storm system which created large snowfalls over northern IL and IN yesterday gave us the overnight rain.  Today a very weak surface low (the remains of yesterday’s stronger storm) has been very slowly moving east over southern IN.  The  passage of the low has changed our winds to a westerly flow and brought in colder air.  As we’ve seen today, not much happens in the center of a low pressure system – especially a weakening one.

As the upper air system moves eastward to merge with the developing “Noreaster” along the east coast, we should see the added influx of energy allow the noreaster to become a major winter storm from the mid-Atlantic states to New England.  Very slow movement will keep this storm active over New England into Tuesday.

Meanwhile, as the upper air system moves east the so-called backlash part of the storm moves over us.  Basically, some of the moisture (from southerly winds) ahead of a storm becomes trapped in the lower atmosphere.  The counterclockwise flow around the storm takes this moisture northward, then pushes it westward, and finally southward again.  This wrap around effect takes the small supply of moisture into the colder air following the storm.  The cold air then squeezes the moisture out of the air.  Whether it’s rain or snow depends on temperatures.

Around a developed low pressure area the northwest quadrant pretty much promises two things.  1).  there will be precipitation, and 2). the amount of precipitation will be light.  Precipitation totals usually run about .02″-.03″ inches per six hours.

All that background to lead to tonight’s forecast…

Periods of light drizzle/rain this evening will change to light snow before midnight and continue overnight.  Temperatures will be slowly dropping to about 32 for the morning rush hour.  By that time, grassy areas will have less than an inch of snow.  Roadways will have little or no accumulation, so roads should be in good shape, mostly.  Possible exceptions, as always, will be bridges and overpasses.  If any icy conditions develop those areas are the most likely spots.

Additional light snow/flurries are possible tomorrow into tomorrow night.

COLD February!?

The U.S. has a forecast model, the coupled forecast system, version 2 (CFSv2) that is designed to detect weather/climate trends out to about six months ahead. For the past few months it has continuously predicted the whole country to have above  to much above normal temperatures for February.  As recently as last Tuesday, the warm February forecast covered most of the U.S.

Then, something strange happened.  Wednesday, the forecast changed to “near normal”.  Thursday, the forecast changed again.  Below normal temperatures covered about 2/3 of the country.  Just the southwest part of the U.S. stayed at near-to-above normal.

Today’s forecast continues the cold projection.  This model normally changes very little on even a weekly basis.  Even when it does, changes are slow.  But, a total forecast reversal in two days just doesn’t happen.  Until it does!

There has been some sudden fundamental change in the atmosphere that the CFSv2 has picked up on.  Could be a cold and stormy month lie ahead.  That would be fun for a change!

Snow has arrived!

4 P.M. Wed., Jan. 27, 2021

Best snow of season, so far

Fast-moving upper air disturbance is moving over lower Ohio Valley now.  Highest energy with the system is now streaking over TN.  North of the jet streak the air is cold enough for some light snow.  Over central Kentucky temperatures are still above freezing, so that’ll cut our accumulation a bit.  Colder areas north and west of Louisville should see the heaviest accumulations from this storm.  However, the rapid eastward movement of the upper support will limit the duration of snowfall so no major accumulations are likely.

Snow will gain intensity quickly and then fade quickly on the other end.  Heaviest snow should fall between roughly 5 P.M. and 8 P.M. in Louisville.  During that time, accumulations should run about one-half inch an hour – mostly on grassy areas.  Roadways will stay wet for most of the evening rush hour, so major problems are not expected.  However, temperatures are expected to drop to 32 between 6 and 7 P.M.  So, some of the later commuters will probably experience some slick spots – especially bridges and overpasses.

Overall, the Louisville area should expect 1″ – 2″ on grassy areas.  Roadways will most likely see less than an inch of snow.  Major roads around the area should be fine by morning, but, as usual, untreated roads will be icy.

Outside of Louisville, conditions will be different.  West and north of Louisville, colder air I expect will bring higher accumulations.  Most of southern Indiana should expect 2″ – 3″ of snowfall.  Wouldn’t be too surprised to see some reports over 3″.

Also, east of Louisville, most of the snow will fall after dark, which also favors higher accumulations.  From Oldham, Shelby and Spencer Counties and east,  2″ – 3″ of snow is likely.


The official definition of “heavy snow” varies across the country.  In snowier areas the threshold is six inches to use  the term heavy snow.  Our area’s threshold is four inches, so it’s not likely we’ll see that this time.  But winter’s not over!

Snow update

Tue., jan. 26, 2021

Afternoon model runs have been upping the snow forecast for late tomorrow.  Latest idea is for the snow total to be in the 1″ – 2″ range.

Another small snow on the way

Tuesday, Jan. 26, 2021  3:30 P.M.

The long term weather situation continues to strongly emphasize a mild weather pattern to continue over North America.  Had a little hope last week as the central Canadian upper low shifted eastward.  If the shift had held we’d be a a “cold” pattern for awhile.  But, the trough is re-intensifying over western Canada.  That signifies above normal temperatures along with wet conditions over the eastern U.S. for the next two weeks, at least.

Meanwhile, colder air is slowly shifting south over the central U.S. and we’ll see the results tomorrow.  A fairly strong upper air system is digging in over the midwest today and will move over the southern U.S. tomorrow.  Most of the system will be rain – from TN to the Gulf states.  However, the northern part of the precipitation will be snow.  Areas like MO, IL and western IN could see several inches of snow tomorrow because they will have more cold air and moisture.  As the system moves quickly eastward tomorrow, the primary energy will be streaking across the states to our south.

That leaves us in a situation with weakening upper energy and decreasing moisture.  Thus, nothing very exciting will be happening here.  But, with the way things have been this winter, even a small snow can be pretty exciting.

Tomorrow will be cloudy and cold – temperatures remaining in the mid (maybe upper) 30’s.  Light snow should move over the area from about 4 P.M. until 8-9 P.M.  As temperatures should remain above 32, roads should be wet for the rush hour although some bridges/overpasses could ice over.  So, no major road problems are expected.  Snow accumulation is likely on grassy areas.  Up to one inch of snow is likely there.

Active weather continues.

Saturday, Jan. 16, 2021  6 P.M.

The upper air disturbances keep coming our way.  It was nice to actually watch the snow today…seems what little snow we’ve had this winter has fallen at night.

Afternoon flurries will fade away tonight.  No problems are expected in the metro area as temperatures are expected to stay above freezing.

Another upper air system will move across the region tomorrow.  Louisville’s weather should be much the same as today – periods of light snow but no accumulation.  The snow will be a little heavier in southern Indiana where some minor accumulations are possible.

At least  we’ll get to see it snow again!

Light snow tonight and…

Friday, Jan. 15, 2021

Situation is developing pretty much as described in yesterday’s post…check that for more details.  Meanwhile…

Tonight:  periods of light snow.  accumulations range from “a dusting” up to one inch by morning.

Tomorrow: a few flurries possible while Friday night’s snow melts away.

Late tomorrow night/Sunday:  another round of light snow begins (especially north of the Ohio River).  Little or no accumulation in Louisville area.  However, 1″- 2″ possible over south central Indiana.

That possible storm around 1/24 has dropped out of the models…too warm for snow.  But we will get colder air for the last week of January.

Our atmosphere’s cranking up some storms

Thursday, January 14, 20216 P.M.

Lot’s of activity, but still lacking cold air

Temperatures have been mild this winter so far.  The short cold spell around Christmas is about the coldest we’ve been.  And, overall, the weather here has been rather quiet.  But, part of that equation is about to change.

Weather patterns are really expected to pick up over the next ten days as a major upper air trough over central is expected to expand and slowly move eastward.  That eastward shift opens up the opportunity to push some significant cold air south over the eastern U.S., but not until about 7-10 days from now.

Meanwhile, upper air patterns are going to start moving quickly across the country.  The first one will move over the northern Ohio Valley tonight and tomorrow.  Some scattered light showers will be likely this evening, but they will be of little consequence since the Gulf of Mexico is shut off from this system.  As colder air arrives tomorrow a few rain and/or snow showers will be possible.  Best chance for snow showers will be tomorrow night with accumulations up to one inch on grassy areas.  Temperatures should remain above freezing, so no major road problems are expected.   Some flurries could continue Saturday.

Sunday another disturbance will float over the area.  Once again Gulf moisture will be missing, so snow potential will be on the low side – probably up to a half-inch or so.

At least a couple more disturbances will hit the area next week, but there won’t be enough cold air to make snow…just cold rain.

It’s a long way off, but a storm expected next weekend should be quite strong and offer a rain-changing-to-snow situation.  It might be strong enough to push us into a “colder than normal” weather pattern.

Deja Vu

Monday, January 11, 2021  6 P.M.

It’s happened again!

Yesterday’s post was about a little “pet peeve” about the National Weather Service’s failure to update forecasts when they go bad.  For details, read yesterday’s comments.  Well, it really surprised me to see the same situation again today.  Only this time, the forecast also hit upon another one of may pet peeves.

Today’s forecast called for mostly cloudy skies this morning with skies becoming partly cloudy during the afternoon.  A late morning look at the situation showed that clearing, if any, would be very slow this afternoon.  So a forecast update then should have been a downgrade to at least “mostly cloudy” or , even better, “cloudy.” But, since midday updates aren’t required anymore, nothing happened.

My second pet peeve of the day is this…many times the morning forecast contains messaging for “this morning” and “this afternoon” rather than “today.”  That’s good.  After all, weather does change.  To me, it seems like a sensible idea that around Noon the forecast should be reissued removing the “this morning” wording.  Makes sense to me.  But, I can’t tell you how many times I’ve gone to the NWS forecast during the afternoon and the first phrase of the forecast contains the words “this morning.”  It’s just common sense.


One of my favorite quotes…Common sense isn’t.

The “good old days”

Sunday, January 10, 2021  12:30 P.M.

One of things I miss from the old days is the updated forecasts issued by the NWS around 11:30 A.M. and P.M.  Forecasts were not as accurate in those days, so the updates to the “prime” morning and evening forecasts were sometimes needed.

Somewhere along the line it was decided that the morning and evening forecasts were all that was needed.  Updates became hard to find.  Today’s forecast is a perfect example why that may not be such a good thing.

When I got up this morning, my radio told me “sunny skies today with a high near 40.”   But it wasn’t sunny, so I went to the NWS site to see what they were saying.  There I found a forecast for Jefferson County of “partly cloudy with a high in the upper 30’s.”  Ok, that was still in play.  Later, however, taking a little closer look at the actual weather data and satellite imagery, I noticed that the models predicted the sunnier part of the day to be during the morning with clouds increasing again during the afternoon.  A quick look at satellite views shows increasing clouds advancing eastward from western KY.

So, now the morning forecast no longer seems to be “in play.”  In the old days, the 11:30 A.M. update would (should?)  have put the forecast back on track.  But, at last glance, the incorrect forecast still stands.  Surely someone at the NWS would want to correct it (and drop the “high” to the mid 30’s).


The music for the song, Twinkle, Twinkle Little Star, is the same tune that is used in the ABC song we use to teach children the A, B, C’s.

The composer of that music was Mozart!