2020-03-18 EVENT: TX/OK

[Jeff House]

If I still lived in DFW this is a chase day, thankfully mainly well west of the Metroplex. ARW version of WRF is close to town. Fortunately I agree with the NAM version and HRRR several counties west of the Metroplex.

Outflow boundary is near US-287 at 10 am Central. It may lift a little. I figure cells go toward 22-00Z out in northwest Texas. Native Texans are cringing now I know. I mean along 287 east of the Panhandle (PH is West Texas, east of it is North TX). Could start west of SPS tho.

Most models do have strong cells into the DFW Metroplex this evening. Hopefully they are not tornadic that point.

CAMs may continue to disagree on placement of initiation. They are trying to find the triple point of the OFB, DL in northwest Texas. Fortunately we humans can track surface charts and visible satellite.

LLJ may be just-in-time around 00Z, but it's Daylight time. Should be no trouble for an hour or two of daylight. Chase safely and keep social distance other than your chase vehicle partner(s).

 

[James Gustina]

I didn't realize how rusty I am with writing forecast discussions but winter always takes its toll. Pretty good clearing across North Texas and into the Big Country with some juicy dewpoint temps for this time of year. 68° isodrosotherm is already well clear of DFW and inching northwest per mesoanalysis.

A handful of CAMs including the 16Z HRRR and 12Z NAM3K are pointing towards initiation in the vicinity of San Angelo to Abilene for a few discrete cells which seems plausible given the location of the jet max currently and the timing of it running through eastern New Mexico. The HRRR in particular has been consistent with a long-lived, discrete cell skirting just west and north of the Metroplex through Wise County and Denton County.

MLCAPE values look to possibly to exceed the ~2600 j/kg progs the NAM flavors had on the 12Z run and assuming shear ramps up a bit before sunset with the LLJ, could get a solid tornado or two out of any discrete cell before the boundary layer decouples after sunset.

 

[Warren Faidley]

Part of south-central Arizona under a 2% tornado risk. I can still chase this year from home!

 

[Nick Dewhirst]

The HRRR in particular has been consistent with a long-lived, discrete cell skirting just west and north of the Metroplex through Wise County and Denton County.

Well, the HRRR nailed this one. As I type this, a damaging tornado associated with that long-lived, discrete supercell is ongoing in northern Wise county and will move into northern Denton county soon.