UWFPS 2017 daily cold-air pool forecast valid Wednesday 02/01/2017 1:00 MST (1:00 pm local time)

Summary: The most significant cold-air pool episode of the 2016-2017 winter continues. The decay phase of the cold-air pool has begun earlier than expected, with top-down erosion beginning in the Salt Lake Valley this morning.  High uncertainty exists on the mix-out of the cold-air pools over next 3 days. Mix-out is looking more likely on Friday night in the Salt Lake and Utah Valley but still uncertain in the Cache Valley.

Current weather synopsis and short-term forecast for Wednesday 1 February:

A very shallow and pronounced temperature inversion continues on day 6 (Wednesday) of the cold-air pool. High clouds have moved in near 600 mb and prevented cooling at the surface and stratus formation. 

KSLC Sounding  1200 UTC1 February 2017

Ceilometer imagery in Salt Lake Valley over last 2 days. White represents cloud. Note the decrease in the depth of the red colors (pollution) over the last 2 days from 600 m to near 300 m.

Ceilometer imagery in the Cache Valley over last 2 days. White represents cloud. Note the constant depth of the yellow colors (pollution) over the last 2 days ~350 m.

Visibility/ceiling/clouds: 3-5 miles in haze. No clouds or fog expected.

Winds: Southerly 10-15 knots above 200 m AGL in Salt Lake and Utah Valley. 3-8 knots elsewhere.

Thursday 2 February

Cold-air pool episode continues to weaken but expected retains its grip on all Valley locales. A weak weather system will cross northern Utah on Thursday. 30% chance of light rain or freezing rain in the Cache Valley is possible, starting mid-morning on Thursday. The cold-air pool will continue to weaken and the polluted layer will continue to erode some in the Salt Lake and Utah Valleys as southerly winds increase. Little change in pollution layer expected in Cache on Thursday. 

Visibility/ceiling/clouds: 3-5 miles in haze. 10% chance fog at Salt Lake Valley, 20% Cache Valley.

Winds: Southerly channelled flow 15-20 knots above 200 m AGL in Salt Lake and Utah Valley. 5-10 knots southwesterly elsewhere.

Friday 3 February

Partly cloudy. Cold-air pool episode continues to weaken but expected to likely retains its grip on all Valley locales through Friday evening. 

Visibility/ceiling/clouds: 3-5 miles in haze. 10% chance fog at Salt Lake Valley, 20% Cache Valley.

Winds: Southerly channelled flow 15-20 knots above 200 m AGL in Salt Lake and Utah Valley. 5-10 knots southwesterly elsewhere.

Saturday 4 February

80% chance of rain. 70% chance of complete mix-out of cold-air pool in Salt Lake and Utah Valley, 50% in Cache Valley.

Sunday 5 February:

Partly cloudy. If Cache, Utah, or Great Salt Lake did not completely mix out yet, opportunity for sampling.

Monday-Tuesday 6-7 February:

Rain likely. Clean air expected at this time.