Be sure to check out John Belski's blog to see the pics he and Kevin took of the damage in Indiana. I am sure Kevin will be posting soon on this too.
As many of you know, Henryville was ruled an EF-4. It touched down as an EF-3 in Pekin, IN. Went to a 4 in Henryville...then back down to an EF-3 for Chelsea, IN and Milton, KY. But it is more complicated than that. There was a 2nd supercell behind the big one...and it likely produced another tornado too. So survey teams have to sort through all the damage to figure out which tornado did what. Takes time.
Below are some of the radar images from StormCutterHD showing the 2 main supercells as they tracked through Indiana/N Kentucky.
PEKIN, IN TOUCHDOWN
HENRYVILLE, IN TOUCHDOWN..... 2nd SUPERCELL HITS PEKIN, IN
1st SUPERCELL HITS MILTON, KY .... 2nd SUPERCELL HITS HENRYVILLE, IN
As you can see, all of this unfolded in just 30 minutes time. These supercells were very fast...60-70 mph. In fact, the West Liberty Tornado was moving over 70 mph and likely will become one of the fastest moving tornadoes in U-S history.
Stay tuned as we continue to go over data from this event.
Now let's get to the snow. Sigh. Normally I love snow...I think everyone knows that. But not now. We need nice weather for the crews and recovery.
While we have flurries/snow showers out there this morning...the main event will be tonight. That is when a Winter Weather ADVISORY takes effect.
This is a clipper system...and those can be tricky when they make the "turn" through the Ohio Valley.
NAM/GFS still vary on snow amounts and the exact path. That remains the biggest challenge.
NAM shows how the clipper drops through the Midwest today. Pretty weak overall.
By tonight, the clipper enhances...and the snow rate picks up quite a bit.
Here is the radar by 10pm this evening according to the NAM:
By 1am, an area of moderate to heavy snow shows up.
Here is the NAM SNOWMAP: you can see how some spots will see a trace..and some several inches if you get caught under that narrow band.
The GFS is less dramatic with this event.
Here is the energy this afternoon. Mostly weak.
By tonight, unlike the NAM---the GFS keeps the clipper fairly weak as it swings through.
Therefore, the GFS SNOWMAP is less dramatic. Lack of heavier snow means the warm ground will help melt most of the snow.
SUMMARY: This reminds me of the clipper we had back in December I believe it was. When Bardstown picked up 4-5" of snow. It was a narrow band of moderate/heavy snow. I have seen clippers many times make the turn from tracking SE to due E over KY and enhance themselves as they may that turn. That has me leaning toward the NAM. However, the warm ground temps does make me feel melting is certainly likely. So I decided to split the difference of the two and below is my map of thinking. The key to accumulations will not only be temps of 32 or lower..but the snow rate. If it snows hard...it will stick...even on a warm ground. If the snow stays light---it will struggle to accumulate...and even then, limited to grassy areas only.
---- NOTE: Snow did fall after the April 3-4, 1974 Outbreak. Louisville recorded a TRACE of snow on April 5th.
Make sure to check back in for updates from Lauren this evening as she should have more data to work with on the track and snow rates. Plan extra time in the morning just in case the NAM solution verifies.