April 10 chase log; Plains forecast update for April 11
Despite unidirectional wind profiles, speed shear thanks to a 60-knot midlevel jet overhead coupled with modest instability and a cold front to initiate storms meant it was at least a marginal severe weather chase day in the St. Louis metro on Monday evening. After several left-split-dominant clusters of storms struggled during the evening, a few supercells finally evolved at sunset. I grabbed one of these just south of home at Venedy, IL where the RFD gust front pushed a rounded base outward with a nice show of frequent lightning.
A descending blob of precip produced a tornado look-alike in about the right spot for one:
I encountered a few downpours of dime-sized hail, but otherwise didn't come away with any "keeper" imagery. It was nice to have only a 25-minute drive home after a chase.
Plains forecast update for April 11
The Plains system I had been watching for next weekend and beyond has - not unexpectedly - vanished completely from model-land. A few marginal (weak instability) setups on the dryline appear possible over the coming 10 days, but certainly not anything I feel will be worthy of spending spring chase funds (and vacation days) on for a trip. With nothing of interest showing up on medium-to-long range models either, I'm fairly confident in no chase expeditions happening for at least the next 10 days.
The following table charts the probabilities for a Plains chase expedition taking place for the date ranges shown:
|2017 Plains Chase Expeditions - Probabilities as of April 11|