Hated to see the Balloon Race unable to lift off (winds too strong aloft + wet ground) ...but at least the Marathons went well this morning!
Now we watch to see how things unfolds, weatherwise, this afternoon and tonight.
First off..the SETUP:
Warm front to our south with the main low out in the Plains.
It will be that warm front tahat will act as the "train tracks" for the storms to follow along this afternoon and evening. So its eventual placement today is crucial in determining the track of thunderstorms.
Since this is a pretty short term event, I plan to take advantage of some of the good short-term models we have to try to nail down this afternoon's event.
We already know we need to nail down the placement of the warm front, but we also need to track the dewpoints. They remain low this morning in the upper 30s to around 40. Several models bring it closer to 60 or so this afternoon---which would be enough for severe storms.
SPC does forecast dewpoints up to 4 hours out..so this is the dewpoint map for midday:
You can see how they are pushing north toward the Ohio River at that time. The bump "upward" across IL still suggests they will see the first round of storms fire there.
CAPES are also forecast to climb quite a bit toward midday south of the front. Nearing 3000 or so to our west. However, notice the areas of light blue. That is where the CAP is weak. There is a decent solid area of white south of the front which tells us storms likely will not fire in that zone--even with the high CAPES. SO the storms will be right on the northern fringe...which there is light blue showing up. Also, you can tell that area of weak CAP is pretty narrow..so the line of storms will not be overly wide in nature.
The RUC has an enhanced model called the HRRR.
Here it is for 2pm today: all quiet
4pm today: few pop ups possible...storms fire in IL too
6pm this evening: few pop ups locally...storms continue to build in MO/IL
8pm this evening: pop ups remain in area..esp b/w Louisville and Lexington. Main cluster in IL.
EHI's are up in spots...so while large hail is the main issue--damaging winds and perhaps a brief tornado cannot be ruled out. Not a tornado outbreak however. The winds are mostly uni-directional (less twisting) so any rotations look brief.
So here is the end result from SPC :
SLIGHT RISK
Tornado % High Wind % Large Hail %
Storm Chance Timing:
12noon to 3pm: 10%
3pm-5pm: 40%
5pm-9pm: 50%
9pm-1am: 30% (showers)
SUMMARY: Anytime we deal with dewpoint changes...it makes forecasting storm placement a challenge. We have had some bad luck on warm front timings this season. Given the current data, the storms look to be clustered in nature and not wide-spread. If they can form into a line (likely horizontal), the tornado/hail threat will get reduced some. However, if a rogue cell can become isolated---that would be the type to watch for severe weather potential. It is hard to pinpoint when the storms will clear out this evening as they will be weakening to spotty showers and may just linger around in spots. We will just trend this for the day and keep you all updated as we get more of a handle on the warm front timing/placement.
Looking ahead---highs in the 80s next week with several storm chances---although the models are trying to trend a bit drier for Oaks/Derby. We shall see.
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