FORECAST
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Late afternoon into the evening
MODERATE CONFIDENCE
A Supercell or Two in W. Oklahoma Today
Hail is the main threat, but damaging winds will also be possible.
Storm coverage will be highest over N/NW Oklahoma this afternoon and evening.
The Stakes
It will be a day where a storm or two will become supercells amidst a larger crop of multicells and even single cells. Hail is the main threat.
The Setup
Water vapor imagery shows an upper trough over the central/southern High Plains lifting northeast this morning, with a smaller upper jet slicing across the TX Panhandle into Oklahoma. A lee trough keeps southerly low-level flow (and modest moisture, dewpoints in the low-to-mid 60s) streaming across the region. This morning's scattered storms should fizzle, with the real action holding off until 21-23 UTC as low-level lapse rates steepen and the cap erodes.
The Ingredients
- Where: Widely scattered to scattered storms develop from south-central KS through western OK and into west/northwest TX by mid-afternoon.
- Shear: Deep-layer shear is strong enough for storm organization, and modified soundings show extensive veering with height, enough for a supercell or two later today into the evening.
- Threats: Isolated large hail and severe gusts, mainly 22z-02z, with the risk lingering overnight rather than shutting off at sunset.
The Question Marks
- Timing is everything: The HRRR is late on initiation, holding off until just before sunset. If storms fire earlier than that, the severe threat locally increases with any supercells that form; if it verifies late, the window to watch shrinks.
- Surface-based or not: Whether storms can stay surface-based is the other half of that same question, and it's tied directly to when they form.
- The sunset window: SPC's 22z-02z timing lines up with where I'd put the highest-risk stretch too. This is basically the hours surrounding sunset for those of you who can’t read Zulu time.
- The tornado question, again: After yesterday's surprise tornado in eastern New Mexico, it's fair to wonder if strong low-level shear and high streamwiseness near sunset could produce another surprise in Oklahoma. Same answer as yesterday: you can never say never, but the tornado threat is extremely low. Supercells, yes. Tornadoes, probably not but yet...