Closed low and the tour de West Coast

Posted Saturday, March 14th, 2020 by Andy Park

TL;DR
Pretty cool to watch this closed low amplify off the coast of the PNW the last few days. Current ensemble models show agreement that this system will slide along the western seaboard before ejecting up through the inter-mountain west sometime mid week. Snow likely tonight and mild temperatures until midweek.

Short Term:
This system doesn’t look that exciting; warm, windy, and a few inches of snow in the higher terrain. This event will primarily be driven by flow interaction with terrain as there is not a strong signal of dynamics for the SLV Wasatch Front. Take a look at the time heights from the weather.utah.edu tools:

Some “deeper” moisture through tonight but becoming shallow tomorrow.
SREF and NAEFS plumes show strong disagreement of snow totals:

SREF
NAEFS

So NAEFS is indicating a few inches for the top of Collins with one ensemble member going for 15 inches. For the SREF plumes are more… diverse. What this means that while there is a very small statistical probability for around a foot we are more likely to receive around 4-6 inches of snow overall. Given the lack of dynamics, the lack of strong temperature gradients, and southerly wind, I feel more confident in the half of a foot outcome in select locations with 3-4 inches for most areas. Still enough to get some nice turns tomorrow and Monday.

Long Term:
This closed low is really taking the long way around with GEFS model runs indicating that the center of the low will reach as far as the Catilina Islands by Wednesday. A consequence of this process will be southerly flow impacting the region for the forecast period. These winds, combined with higher clouds lingering overnight, should keep temperatures warm throughout the week until this closed low decides to tour Utah.

Cheers everyone! Thanks for reading, see you in the mountains!
Andy

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