Chase forecast update 4, for March 31
The first month of meteorological spring this year has been a quiet one. While the system last weekend brought many chasers their first Plains tornadoes (me included), they were fairly low-quality events. Aside from the great lightning I was able to score in the Texas Panhandle, March in the Midwest and Plains has been mostly devoid of any photogenic storm phenomenon. Unfortunately, medium-range models show that this trend will likely continue into at least the first 10 days of April, as quality Gulf moisture struggles to make it very far north and the upper pattern fails to develop any chasing-favorable western troughing. A few southern-stream shortwaves are indicated beginning late next week, but are shown pretty far south with the best parameters on the lower-end on the scale in terms of instability in the chasing-friendly regions of the Plains and Midwest. One wave manages to bring 50s dewpoints into Oklahoma on Wednesday, which looks a little similar to last weekend: maybe enough for supercells, hail and lightning, but meager for tornadoes.
Last weekend's "lightning only" trip was a one-off to test the new camera, so no more long trips of that nature are planned. It's back to watching for systems that offer prime tornado and supercell conditions to arrive.
Again, what I look for in the models for signs the chase season is getting ready to go active is the Gulf really "charging up" with dewpoints well into the 70s, with favorably-timed and oriented western troughing systems pulling that deeper moisture north to at least the Kansas/Oklahoma border. Models show the Gulf air might be juicing up sufficiently toward the end of the current 10-day period, but indicate very little of that making much farther north than the coast.
Though we really can't put much stock in models beyond 10 days, none of the long-range ensembles or operational runs that I use have been showing any hint of a favorable pattern for storm chasing showing up on the extended range out to mid-April. We'll just need to keep waiting - they'll show up eventually.
Speaking of long-range forecasts, a new resource for medium-to-long range tornado outlooks worth checking out is Victor Gensini's ERTAF site, you can view that here.
The following table charts the probabilities for a Plains chase expedition taking place for the date ranges shown:
|2019 Plains Chase Expeditions - Probabilities as of March 31|