Wednesday, October 30, 2019

Continued Dry With Some Wind

Above view shows steam fog this morning over the Snake River at Irwin, Idaho (east of Idaho Falls). At bottom is view of snowy Loveland, Colorado, yesterday afternoon (from son Jason's house).

Fair and dry weather continues here, with cold mornings and mild afternoons. The low here this morning was 36 F (coldest so far this Fall, after 37 F yesterday) - freezing or below tomorrow morning?

At 500 mb (above for 12 UTC) this morning a sharp, positively tilted trough extends southwestward from northwestern Minnesota across Arizona. Behind the trough surface temperatures are very cold (teens to -25 F and colder from the Front Range westward across the Great Basin. Surface high pressure over the Basin is producing continued strong east winds and high wildfire threats over southern California.

The morning sounding at TWC (above) indicates light winds at present below 700 mb, with a PW of 0.66 cm (slightly over a quarter of an inch). Below is the sounding from Flagstaff, where winds are very strong just behind the trough and PW is extremely low (.04 cm or .02 inches - values so low that accurate measurement is difficult).

The 10-m wind forecasts from the 12 UTC run of the WRF-RR. Above forecast is on the 5.4 km grid and is valid at 9:00 am MST this morning; while below is on the 1.8 km grid valid at 10:00 am tomorrow. Note the strong east winds over southern Arizona as front from southern Plains backdoors across our region.

Cooler and dry tomorrow - the last rain here at house was back on September 26th, and it looks like our dry spell will continue on well into November.

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