Category Archives: forecast

Snow chances getting higher

6 P.M. Sat., Feb 13, 2021

Models in closer agreement

Another day without sunshine and we probably won’t have much, if any, tomorrow.  Temperatures will probably remain in the 20’s all day.  But after that, snow enters the picture.  A  strong upper air system over the southwest today will cross the Rockies tonight and become better organized south of the Texas coast by late tomorrow.  Then it heads northeastward.  What the final path will be is still uncertain, but we should have a better idea tomorrow.

Currently, the GFS predicts a 4″-6″ snowfall for our area – higher over eastern KY.  The NAM has a 6″-8″ prediction.  Snowfall should begin before the Monday morning rush hour and continue through the day.  There is disagreement about when the snowfall ends.  Estimates run from Monday evening to Tuesday morning.  The longer duration of snowfall most likely would produce an even higher snow total.

The second storm expected next week has undergone more model changes.  Best guess now favors a freezing rain to rain scenario on Thursday.

Some doubt

Although at least some snowfall is likely Monday, the amounts are uncertain.  While most of the U.S. models are big on snow, the Euro, Canadian and Navy models carry everything farther east.  As a result, our snowfall totals would be much lower.

For now, I’ll go with a forecast somewhere between the two major themes  Let’s say something like 2″ – 4″ for the Louisville area.  Either way, higher snow totals east of Louisville, especially east of I-75.

I’m hopeful I’ll have a better handle on this tomorrow.

Icy night ahead

Wed. Feb.10, 2021  6 P.M.

Biggest ice threat stays south of Louisville

Situation is playing out pretty much as discussed yesterday. Freezing rain will be the biggest concern for the Louisville area tonight, but sleet will mix in at times.  Primary precipitation will be over before Midnight, but a few periods of  light sleet and or snow will hang around until daybreak.  Any accumulations will be very small. In addition, ice accumulations (.1″-.2″) will fall short of the damaging range.

Southern Indiana will see an earlier end to the icy mix and, compared to Louisville, will have less freezing rain, sleet and snow.

Biggest concern remains the central third of KY.  (Far southern and SE Kentucky now appear to have a much reduced icing threat than mentioned yesterday.)  The central third – E-town, Leitchfield, Lebanon, Bardstown, Frankfort, Lexington, etc – will see freezing rain tonight continuing at least until Noon tomorrow.  Ice accumulations should run  .25″ to .50″.  That much ice can do a lot of damage to power lines and trees/shrubs.

Snow?

Earlier this week I mentioned how the GFS model seemed to be so much different from other models when it predicted more than a foot of snow on the ground here on Sunday.  Since then, the GFS has come into closer agreement with other models, but not total agreement.  The big Sunday “snowstorm” for the Ohio Valley  has disappeared from the GFS.  It never existed on other models.

Now the GFS is predicting a major winter storm to hit the Ohio Valley Monday night – significant snow possible!  Other models are also “seeing” this storm, but are moving it northward along the eastern side of the Appalachians.  That would only give us minor problems, if any.  The GFS pulls the storm up along the western side of the mountains.  That brings back memories of January 1978.  Could it happen again?

Stuff

Bob Gibson, the Hall of Fame pitcher for the St. Louis Cardinals who recently died,  played a season with basketball’s Harlem Globetrotters before moving to baseball full time.

6:15 update

Just saw the NWS forecast. WOW!!!

 

Models still can’t agree

Tue., Feb 9, 2021  6 P.M.

Storm potential downgraded

Models are still having a debate at how the upcoming wintry weather system will play out.  In the short term a solution seems to be stepping forward.  But the GFS is still out on its own for the weekend.

Meanwhile, the models seem to be converging on an idea that the ice storm expected tomorrow will have its major impact over the southern two-thirds of KY.  Louisville area will have just a small amount during the day, but could see an increase in intensity tomorrow night.  I was happy to see the Weather Service downgrade Louisville’s threat assessment.  Outside of ever-slippery bridges/overpasses, tomorrow shouldn’t be too bad.  Even fewer problems over southern IN.

As colder air continues to slide southward, warmer air aloft will melt any snow trying to fall, so most of us will see freezing rain (some sleet also possible) probably beginning by mid morning.  Daytime heating should keep most of the roads wet with icy spots on the aforementioned bridges and elevated spots.  Wires, tree limbs, railings, sidewalks will probably get icy.  Luckily ice accumulations will be less than .1″

Freezing rain should pause during the afternoon, but resume again tomorrow night.  Once again, accumulations of ice should be small locally.  Also, the freezing rain should change to snow early Thursday.  Snow could accumulate an inch or two.

Although icing conditions are expected to be minor locally, this will be a MAJOR ice storm for the southern two-thirds of Kentucky.  Damaging ice conditions could accumulate to as much as .25″ to .50″.  That would be very damaging.

 

Week of wintry weather

Mon., Feb. 8, 5:30 P.M.

Snow, sleet, freezing rain, and rain all likely this week

1).  The GFS model predicts we’ll have over 12″ of snow on the ground by Sunday afternoon.

2).  No other model has a prediction scenario anywhere near the GFS  ideas.

3).  We’ll see several chances for a variety of precipitation types this week…tonight, Wednesday into Thursday and Sat/Sun.

We’ll take a look at tonight and save the rest for later.  A weak upper air disturbance will pass over the region tonight and the Ohio River seems to be about the dividing line between rain/snow.  The Louisville area will be on the southern edge of the system.  We’ll most likely see some light rain/snow mix beginning late this evening.  The system will be bringing colder air, so a change from rain to snow should occur later tonight.  By morning, another light accumulation is likely.  Less than one inch here with even less snow south of town.

Meanwhile, over Indiana it’ll be mostly snow and more of it.  As you travel north of I-64 in IN and about 10-20 miles north of Louisville and north of eastern Oldham Co., Trimble and Carroll Cos., you’ll see rapidly increasing amounts of snow. Most of southern Indiana can expect 1″ to 3″ of snow by morning.  That 1″-3″ total also holds for northeastern KY.

Currently, Wednesday’s storm looks like it’ll be mostly ice.  More tomorrow.

Another little snow tonight

Sat.,Feb. 6,2021  5:30 P.M.

Another weak upper air disturbance system crosses the Ohio Valley tonight.  Once again, the Gulf is cut off from the flow, so producing much moisture will take a valiant effort from the upper air contribution.  It doesn’t appear likely to happen.

As a surface cold front pushes through overnight, it’ll probably produce some flurries and snow showers for a few hours, especially around Midnight.  Models are in agreement that one-half inch accumulation (on grassy areas) should be the upper limit.  So, not much to hope for.

Colder tomorrow with a high near 30.

The “big Blast” of cold air is still on track for next weekend.  Sat/Sun should be very cold followed by a quick warming.  Current GFS says this should be a one-time deal with no significant follow-ups expected.

Stuff

Popular myth says that sharks can detect one drop of blood in an Olympic-sized swimming pool. NOT TRUE   While sharks, and fish in general, have good smelling abilities, they don’t came anywhere close to that claim.

Another popular shark myth is that once they get a taste of human blood, they will continue to search for more humans.  These are called “rogue sharks.”  Research, however, has shown that there are NO rogue sharks.  They much prefer a seafood diet.

Don’t believe everything you hear on “Shark Week.”

Waiting on the cold air

Friday, Feb. 5, 2021  4:30 P.M.

Models keep delaying arrival date

Early this week the forecast high for Super Bowl Sunday (Feb. 7) for Louisville was 20 degrees.  Now the forecast is 32 deg. Yes, that’s cold.  But around here a high of 20 is quite a different situation.  So, what’s going on?

What’s going on is a common habit of the GFS model.  It (often) foresees a major pattern change or shift, but predicts it to happen too soon.  Such is the case this time.  Originally, the GFS brought the bitter cold air into the Ohio Valley tomorrow.  By midweek, the big arrival was pushed back until next Wed/Thu with only a small chunk of the colder air arriving Sunday.

Current thought is that another small surge of wintry air arrives about Tue/Wed.  Finally, the much anticipated “coldest air of the winter” makes it’s appearance Fri/Sat.

With the “Big Chill” still a week or so away,  the smaller air masses will still keep us in below normal temperatures next week.  Daytime highs will run from the upper 20’s to the 30’s.  Several weak upper air systems will probably bring some more small snows during that time.  The first chance will be tomorrow night into early Sunday.  Then, very light snow/flurries should be an almost daily occurrence next week.  Best chance for meaningful snowfall will be with the really cold air arrival late next week.

 

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.

Stuff

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.