Thursday, January 26, 2017

Strong East Winds This Weekend

Frosty morning view of Catalinas above - temp on campus indicated as 32 F. Morning low here was 24 F with moderate frost.

For the last two days the WRF model forecasts from Atmo have been indicating strong easterly winds for the weekend. The forecast below is from the 06 UTC WRF-GFS run on the 1.8 km grid and is valid at 11:00 am MST on Saturday morning. Many mountains and lee areas indicated to have steady winds in the 30 to 40 mph range with several spots south of the border even stronger.

Shown here are high-resolution grid-box forecasts for: above - Tucson airport; below - Mt. Hopkins RAWS site; and second below Kitt Peak. The wind gusts at airport are forecast to exceed those on Mt. Hopkins, which is not going to happen. Kitt Peak has a forecast for winds over 40 mph - strongest of the three series shown.

Here are two forecast soundings for Sonoita from the 06 UTC WRF-GFS, upwind from the Santa Ritas - above is valid at 01:00 am on the 28th and below is valid at 01:00 am on the 29th. Model time series indicates an extended wind event for Mt. Hopkins, with gusts of greater than 40 mph beginning tomorrow afternoon, reaching high speeds of 60 to 80+ mph at times from middle of Friday night into Sunday. The last time I tried to forecast severe winds for Mt. Hopkins, the model forecasts were overdone and I had a bad forecast. Forecasts have remained consistent as this event approaches in time, so I'm trying again.

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