The document linked above states that the development of these systems is typically preceded by the flow of cold air from Canada towards a warmer airmass over the Great Basin, creating unstable conditions. Indeed, The 18z GFS indicates a pronounced flow of cold air at 850mb from British Columbia into Nevada in the wake of an upper-level trough.
The same page goes on to list three other conditions that may contribute to the strengthening of the Tonopah Low:
1. A wave on a west-east oriented front.
2. A secondary low in an unstable air mass follows the passage of a frontal low.
3. Beneath a cut-off low, or at the tip of a long wave trough, which has a jet maximum over the area.
I don't see much in the way of the first two today, but note the intense jet max rounding the base of the upper-level cut-off low centered over the Sierra at 500mb.
1. A wave on a west-east oriented front.
2. A secondary low in an unstable air mass follows the passage of a frontal low.
3. Beneath a cut-off low, or at the tip of a long wave trough, which has a jet maximum over the area.
I don't see much in the way of the first two today, but note the intense jet max rounding the base of the upper-level cut-off low centered over the Sierra at 500mb.
These conditions have led to the development of a low pressure system in south/central Nevada today, which is forecast to move east overnight...
...spawning the issuance of winter storm warnings from central Nevada through the southern Wasatch, where 6-12" of snow is expected at higher elevations. As for those east-facing slopes of the Sierra, a few inches are in the forecast, but nothing big this time.
No comments:
Post a Comment