1. Uintah Basin Weather Discussion 01-02-2012 Uintah Basin Applied Tech College Vernal Utah 1 January 2013 ~11:30 am

2. Topics Snow cover analysis Weather analysis of last few days Weather forecasts for next week

3. MODIS Visible Imagery Last 3 Years 31 December 2010 31 December 2011 31 December 2012 --Widespread snow cover this year similar to that observed 2 years ago

4. NOHRSC Snow Analyses 1 Jan 2011 1 Jan 20121 Jan 2013 NOHRSC snow analyses show less snow in mountains and Uintah foothills this year than 2 years ago but similar snow cover in lowlands this year (4-8”).

5. However, current snow depth from limited COCORAHS observations in basin are currently about half that observed at the same time 2 years ago Dec 31 2010: Snow depth ~11-13” Dec 31 2011: Snow depth ~0.0-0.5” Dec 31 2012: Snow depth ~5-7”

6. 5-day Temperature Trends from MesoWest in the Uintah Basin Cold air from nocturnal drainage pooling has become established in the basin the last few days.

7. UU2DVAR Surface Analysis 2:30 pm 1 Jan 2013 Shallow cold pool as observed By UU2DVAR the afternoon of 1 Jan 2013. Temperatures around 20 F cooler in Uintah Basin than On surrounding slopes.

8. PM2.5 has Been on increase Last 3 days Persistent inversion With valley temps Remaining below 20F

9. 1-week forecast Numerical guidance (NWS bufkit) suggests surface temperatures between -3 and -15 ⁰C in the Uintah Basin with strong inversions remaining in place through the next 7 days…i.e. insignificant melting of snow expected through January 8th. NAM 72 hr forecast at Vernal Near-surface temperature ~ -12 C

10. Forecast Soundings for Vernal Models predict inversions (these are typically under- done in models) 12 UTC Thurs 3 Dec00 UTC Saturday 5 Dec

11. 12 UTC Saturday 5 Jan: Ridge Axis Centered over Western US. Very strong inversion conditions

12. Monday 7 Jan: Ridge weakens but stagnant conditions and inversions persist

13. Cloud Cover? Patchy low clouds over basin 11 am 1 Jan 2013

14. NWS Grand Junction going for ‘patchy fog’ next 5 days…

15. Cloud Cover? Given the stagnant conditions and dew points near saturation (and the previously observed low cloud episodes on satellite during other years), more widespread low cloud coverage is likely next week, particularly if there is minor melting of snow cover later next week.

16. What about beyond Jan 8 th ? Week 2 CPC forecast: below average temps