1AM Day 3 Convective Outlook for Wednesday, January 7. NO SEVERE THUNDERSTORM AREAS FORECAST
SUMMARY
General thunderstorms are possible along the coastal Pacific Northwest on Wednesday and across parts of the southern Great Plains to the Ozark Plateau Wednesday night.
Coastal WA/OR
A shortwave trough should reach the coastal Pacific Northwest by midday/early afternoon Wednesday, before amplifying inland into the Great Basin by 12Z Thursday. Cold mid-level temperatures of -30 to -35 C at 500 mb in conjunction with onshore low-level flow should yield scant surface-based buoyancy along the immediate coast by late morning. Sporadic lightning flashes are possible through the afternoon amid widely scattered low-topped convection near and in the wake of trough passage.
West TX to the Ozarks
In response to the aforementioned amplifying upper trough, a low-latitude shortwave trough will accelerate east-northeast from west of Baja CA. How far downstream this trough reaches by 12Z Thursday remains uncertain. The 00Z EC-AIFS has been quite consistent with a slower ejection and appears more reasonable given typical guidance biases. It is an outlier along with the 00Z GFS in holding the trough over northwest Mexico, while the majority of guidance has it ejecting onto the southern High Plains. This will impact the initial amplitude of cyclogenesis over the OK/northern TX Panhandles vicinity through Wednesday night.
Modified low-level moisture return from the western Gulf will initially be modest beneath an elevated mixed layer. Forecast soundings also suggest weak lapse rates with nearly saturated upper-level profiles well downstream of the low-latitude trough. As such, elevated buoyancy should increase but remain weak. Guidance also has pronounced differences in the degree of convective development prior to 12Z Thursday, likely related to the degree of preceding MUCIN and timing of strengthening large-scale ascent. Opted to broadly aligned with the low 03Z SREF calibrated thunderstorm probabilities pending potentially greater guidance consistency in later outlooks.