Wed. Jan 10, 2018  5 P.M.

Heavy snow likely near Louisville

Today’s latest from the GFS products department…

Forecast for 12 hours ending at 7 A.M. Saturday.

Unfortunately for local snow fans, this is probably a little too optimistic for Louisville.

Yesterday there was a very wide range of computer solutions for the storm late this week.  Confidence is higher now as two changes have occurred in the past 24 hours.  First, the various models have converged in their solutions.  Second, the very unusual (and snowy) solution by the operational GFS has faded into a much more realistic-looking forecast today.

In general, my current expectation goes like this:  strengthening low pressure will develop over the northwest Gulf of Mexico and move northeastward tomorrow.  It will accelerate quickly along the spine of the Appalachians tomorrow night.  That storm track will be very important.  A little farther west than expected and we’ll see almost all rain with just a little snow at the end.  If the track moves a little east of current thought, we could be in for a heavy snow (5″-10″).

The highest probability, though, would be for the storm to follow the current projected path OR to the left (west) of the current prediction.  As usual, the NAM is a little more rambunctious with this system.  It almost always is more energetic than the GFS 48 hours in advance, but the GFS is almost always better in the end.

So, here’s what I expect – rain showers become likely by afternoon tomorrow. Rain continues tomorrow night and Friday morning.  Temperatures turn colder by Friday afternoon and the rain changes to snow by mid-to-late afternoon.  Temperatures will drop rapidly as the rain transitions to snow.  A “flash freeze” of roads will be possible.  Snow diminishes after midnight.  Total snow accumulation for the Louisville area:  1″ – 3″  Less snow will fall east of Louisville.  For instance, Lexington should see little more than flurries.

Note:  Very heavy snows are expected west and north of Louisville.  A swath of snow should fall over western TN, western KY, southwest and central IN.  Paducah, Evansville, and Indy could get as much as 6″-12″ Friday afternoon and night.

Saturday, Nov. 18, 2017  2 P.M.

Cold Front approaching rapidly

A strong cold front is pushing rapidly (about 50 mph) southeastward across the lower Ohio Valley. Currently, is is stretched from about Indy southwest to near Paducah.  That pushes the front through the Louisville area between about 4:00 and 5:00 this afternoon.  The front has become active with a narrow line the showers/thunderstorms along it.

The Storm Prediction Center has issued a Severe Thunderstorm Watch for all of southwestern Indiana WEST of I-65 and most of KY west of Louisville.  Louisville is not in the Watch.  Nevertheless, the front is already beyond it’s severe weather.  A couple of severe winds reports came from southern Illinois as the system developed (often the case in marginal situations), but over the past hour or so the energy has become more evenly distributed along the cold front.  Thus, the threat for severe weather in Louisville area is very low.  Strong winds, yes; severe winds, probably not.

What to expect:  Winds will be quite gusty as the front approaches.  Wind gusts of 35 to 45 mph will be likely.  The cold front will bring a narrow line of showers and thunderstorms through the local area between about 4:00 and 5:00 P.M.  During that time we may see gusts reach 50 mph.

Temperatures will remain in the mid 60’s before the rain.  An hour later they should be in the lower 50’s.  After the rain departs, strong winds will continue for a few more hours.  This time they will be from the northwest around 30-40 mph.

NOTE:  Yesterday I was hoping the cold front would arrive around 3:30 so that the UL-Syracuse game start would be delayed, but played straight through after that.  Now, it looks as though the game should start but still be in the first quarter when the thunder hits. Then a delay of 60 minutes to 90 minutes before resumption..

Friday, Nov. 17, 2017

Strong storm system will move through the area tomorrow.

A  storm system will form tonight over MO/AR and develop rapidly as it races across Illinois and Indiana into Ohio by late tomorrow.  Two active fronts will move across our area by tomorrow evening.

First, a warm front will push northward through the area tonight.  This should produce widespread showers over KY and so.IN after midnight.  A few scattered elevated thunderstorms will be possible along the front.  If you hear thunder in your neighborhood, there’s a good chance you’ll get some small hail mixed in with the rain.  Rain connected with the warm front should be out of the Louisville area by 8 A.M.

Then we’ll have a period of 4-7 hours of mostly dry weather as the winds increase dramatically.  By late morning into the evening, winds will become quite strong thanks to that strong storm passing to our north.  Southerly winds should gust into the 30-40 mph range during that time.

Second, the cold front associated with the storm system.  That should arrive between 2 P.M. and 5 P.M.  It will sweep rapidly through the area from northwest to southeast.  Ahead of the front will be a narrow line of gusty showers and possible thunderstorms.  Winds could briefly gust to 40-50 mph during this time.  Rain should last only a short while, probably less than one hour.  During this time, temperatures will tumble quickly from the sixties before the rain down to near 50 as the rain ends.

Then back to colder weather by Sunday.

I realize the scenario looks bad for UL’s game with Syracuse.  Lamar Jackson’s possible (probable?) last game in Louisville will be played with a wet field (which has very good drainage, by the way) but it looks to me as though most (maybe all) of the game will be played in dry weather.  It all depends on the cold front’s ability to create thunderstorms.  When the front arrives, if thunder is in the area the game will be delayed.  When the thunder leaves the area, the game will start or resume with dry weather the rest of way.  But, they’ll still have to contend with those strong winds.

Sunday, Nov. 5, 2017  8 P.M.

Good news from earlier update.

1).  Storms have weakened faster than expected.  Still an outside chance for some near severe storms over south central IN – more than 30 miles north of Louisville.

2).  Winds locally will probably average a little below the values mentioned earlier, but 40-45 mph wind gusts will still be likely for many of us.

3).  System is a little faster than mentioned earlier.  Now looks like the line/area of storms will pass through the metro area between 9:30 P.M. and 12:30 A.M.

5 P.M. Saturday, Oct 7, 2017

Turns out we don’t need Hurricane Nate to get some much-needed rainfall.  A weak cold front entering the lower Ohio Valley has been squeezing out some brief light showers around the Louisville area this afternoon.  So far, the rain has not been enough to ease any soil dryness.  However, from 7 P.M. until Midnight they should become more numerous.  Some spots could get as much as half an inch this evening.

Rains from Nate should reach us tomorrow morning and continue through the afternoon.  Models have shifted Nate’s path slightly west again so my earlier prediction for Nate’s rains will have to pushed up somewhat.

My latest estimates for the Louisville area:

This evening:  about .25″ to .40″  of rain (higher amounts west and north of Louisville)

Sunday:  about .35″ to .80″

NOTE:  Sunday’s rainfall totals will rapidly increase as you head southeast from Louisville.  Southeastern KY may see as much as 6″+ of rain.