5:25 P.M. Tuesday April 2, 2024

Activity has acted as suspected. Heaviest storms are over southern IN – along and north of I-265 in Floyd Co, – moving rapidly ENE. Over KY a narrow line of storms is moving ENE onto Louisville area. Strong winds are biggest threat, but the threat is certainly much less than SPC’s Watch of a few hours ago led me to believe. Storms will be generally weakening as they cross our area over the next two hours.

Some mostly minor damage can be expected.

Tuesday, April 2, 2024 3:50

The Storm Prediction Center is about to Issue a Tornado Watch for southern IN and central KY. Louisville is right in the middle of the Watch.

The main focus for severe weather today was expected to be mostly eastern Kentucky, but clouds from this morning’s storms have held temperatures down to levels where it has been hard to generate instability.

Meanwhile, the weak cool front/dry line crossing western IN southwestward into Tennessee has been slowly trying to generate thunderstorms. The area has the advantage of warming sunshine to induce greater instability. The upper winds are very strong, so severe weather can be expected from any thunderstorm that can form. The wind fields are conducive to tornado formation. Any supercell that manages to develop in this situation could easily produce strong (F2 or higher) tornadoes. Instability required to manufacture strong thunderstorms is somewhat limited, but if supercells can form, we’re in for trouble.

At this time (4 :15 P.M.) the strongest storms are over southwest IN moving northeast at 50-60 mph. That puts southern IN under the greatest threat of damaging weather now. In this case, damaging weather should stay 30-40 miles north of the Ohio River. Primary time for storms to arrive in Louisville area will be 5:30 P.M. until 7:30 P.M.

Currently, thunderstorms in western KY are having a tough time developing. If that trend continues, the threat for damaging weather over the Louisville area will be low.

More later.

Feb.27, 2024 11 PM

Southern part of system has been slow to develope, but should become quite active in the next few hours. 1st round of storms mentioned earlier will not be a factor. Activity will be concentrated on both sides of the cold front scheduled to arrive in area around 6 AM.

Thus, 4-7 AM looks to be “prime time” for severe weather. This system is packed with energy, so strong to very strong winds (50-75 mph) will be possible. In addition, hail will be possible. Some tornadoes are likely to be scattered across the area.

Tornado Watch until 6 AM. Storm Prediction Center puts us at a moderate risk for high winds, hail, tornadoes and strong tornadoes (EF 2 or higher). Widespread power outages are expected

Keep alert for possible warnings late tonight.

Atmospheric conditions are lining up in a familiar pattern. It’s a pattern that often wreaks havoc over the Gulf Coast states during winter nights.

This time, the system is farther north and seems to have its sights along the Ohio River later tonight. The moisture component is weak, but the dynamic wind patterns are very strong. That should easily overcome the moisture problem

A storm system developing over IL will send a strong cold front into the Ohio Valley overnight. As that encounters somewhat wetter air to our west, I expect two lines of thunderstorms to form tonight. A prefrontal line should in the area about 2-4 AM. Strong wind gusts are possible (50 mph+) as they pass over.

The cold frontal line should be here roughly 5-7AM. It should be even stronger. The Storm Prediction Center says wind gusts could reach as high as 75 mph. In addition, due to the enhanced wind fields, some tornados will be likely.

At the least, I expect we’ll see widespread power outages.

Keep alert tonight!

5 P.M. Friday, Feb. 14, 2024

Forget much of what I said yesterday and earlier today. There’s been a development recently that looks like it’ll change the snow forecast.

The overall large scale picture remains the same, however, there’s a fly in the ointment. A wedge of dry air has appeared to our west and will push up the Ohio River over the next few hours. That will split the precipitation into two sectors – one north of the Ohio River and one to the south. Roughly 20 miles (or so) either side of the river will see less snow than earlier thought.

Another change is that we’ll probably see more sleet than expected. I had pretty much written off sleet as a brief interval during the rain to snow transition. Models are now pointing to a longer period of sleet. So, less snow.

Current thinking: We are now in a lull of precipitation due to that dry wedge. The sleet to snow transition should occur between 6 P.M. and 7 P.M. Any significant snow should be over by 8 P.M. and any lingering flurries will be gone by 9 P.M.

Snow accumulation for Louisville area should be small…up to one inch on grassy areas. Slick spots should develop (mostly) around bridges and overpasses.

Friday, Feb.16, 2024 12:30 P.M.

A few minor tweeks to yesterday’s post…

1). Faster timing. Now looks like rain should start about 4 P.M. with change to snow about – 6-7 P.M. then snow ending by about 9 P.M.

2). Stronger system. Rain/snow totals have been increased by most models.

3). Slight shift south? The GFS still holds firm to the 1″ snow line right along I-64 with four other models pushing it about 20-30 miles south.

4). Snow forecast. Greater confidence in about a 1″ accumulation for most of Jefferson County on grassy areas this evening. Areas north of I-64, could see 1″-2″ snowfall on grassy areas and possibly more over southern Indiana. Slick spots develop on area highways after 6 P.M.

Thursday, Feb.15, 2024 6 P.M.

A weak upper level disturbance over Nevada now will race eastward and deposit some rain and snow over the area by late tomorrow afternoon. Temperatures will begin to drop tonight and northeasterly winds will keep the colder air over us tomorrow. Nevertheless, temperatures will reach the lower 40’s tomorrow before falling when rain starts.

Westerly upper level winds over the southern U.S. will keep inflow of Gulf moisture very low, so the disturbance will not have much moisture with which to work (My high school English teacher would be so proud.). So, total precipitation will be low, probably less than .20″.

Current timing has rain beginning around 4-5 P.M. tomorrow and quickly mixing with snow. Most likely it’ll be all snow by 6-7 P.M. and be gone by 9-10 P.M. The temperature should remain above freezing until close to the end of the event.

Soil and road temperatures should remain above freezing throughout the rain/snow. Roads will remain wet EXCEPT some bridges and overpasses near the end of the snow. Grassy areas may see snow accumulations of up to an inch.

Note: Snow accumulations up to an inch only for areas along and north of I-64. Areas south of I-64 will get little or no accumulation.

STUFF The Super Bowl was the most-watched television show ever in the U.S. Estimated audience was 123.4 million viewers.

Monday, Feb. 12, 2024 Noon

Yesterday’s post described the various ideas the models were proposing for our area for tonight’s snow probabilities. By today, models have pretty much come into agreement. Heavy snows still remain a possibility, but not for the Louisville area. The developing snow storm will move faster than expected. So, the snow/rain situation won’t spread northward fast enough for any concern here.

So, Louisville area should expect to see increasing cloudiness this afternoon with rain developing around 5 – 7 P.M. Rain will briefly change to snow during the late evening. The wet snow should end around Midnight with little or no snow accumulation. So, no luck here.

However, the southeastern part of KY should see a big, sloppy wet snow, Areas along and south of a line from about Leitchfield to Lexington to Ashland are expected to see roughly 2″-4″ of snow with some areas getting to 6″ or more tonight!

Sunday, February 11, 2024 4 P.M.

After bringing lots of rain to the southwestern states last week, all that’s left is a small cutoff upper level disturbance left behind as the major system moved on. The system is now being re-absorbed into the primary jet stream flow as it ejects toward the Tennessee Valley. A small surface low will develop tomorrow over TN and move over southeastern KY tomorrow night. That’s a classic snow situation for us! However, the big questions are exactly where the snow will fall? and will cold air arrive in time?

The models have been ignoring this development for the past few days, but are now paying attention. Unfortunately, they can’t seem to agree on the exact details. One area for agreement is that it’ll be a rain changing to snow situation. That change depends on the arrival of colder air that is expected tomorrow evening.

This morning’s GFS for the area has the rain/snow line along the Ohio River with accumulations of 2″ to 6″ inches of heavy, wet snow over the southern quarter of Indiana by Tuesday morning. Meanwhile, the KY side of the river should see an inch of snow or so – mostly on grassy areas. On the other hand, the NAM places the northern edge of the snow along the river. That puts about the northern third of KY (Including Louisville area) into the area of heaviest snowfall. That could mean about 2″ to 4″ of sloppy, wet snow for us but little snow for Indiana.

Now, however, the afternoon run of the NAM paints another take on the situation. This forecast pushes the whole situation about 60 miles south of it’s earlier solution. That means extreme southern Indiana and the KY counties touching the Ohio River will see rain tomorrow afternoon and evening with little or no snow on the tail end.

The afternoon GFS hasn’t arrived yet. It’ll be interesting!

STUFF: If the 49ers win tonight, they will tie the Pittsburgh Steelers and New England Patriots for the most Super Bowl victories. 6 each.

Sat. July 29, 2023 12:30 P.M.

National Weather Service has an 80% chance for thunderstorms this afternoon. It would be nice to get some rain, but an 80% chance? Where did that come from?

Scan of various models and derived data puts the chances lower than 20%. Even the Storm Prediction Center only goes to 40% chance this afternoon.

The 80% chance forecast looks like a big gamble. Let’s see how it plays out!

Also, for the past few days the longer range outlook for next week has kept our daily highs in the upper 80’s. Most recent model runs put daily highs back into the 90’s. Will our August end up being hotter than July? (Just guessing here, but I’d go with yes.