Uintah Basin Weather Discussion01-02-2012

Uintah Basin Applied Tech College Vernal Utah 1 January 2013 ~11:30 am

Topics

• Snow cover analysis• Weather analysis of last few days • Weather forecasts for next week

MODIS Visible Imagery Last 3 Years31 December 2010

31 December 2011

31 December 2012

--Widespread snow coverthis year similar to that observed 2 years ago

NOHRSC Snow Analyses1 Jan 2011 1 Jan 2012 1 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”).

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”

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.

UU2DVAR Surface Analysis 2:30 pm 1 Jan 2013

Shallow cold pool as observedBy UU2DVAR the afternoon of1 Jan 2013.Temperatures around 20 F cooler in Uintah Basin than On surrounding slopes.

PM2.5 hasBeen on increaseLast 3 daysPersistent inversion With valley temps Remaining below 20F

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

Forecast Soundings for VernalModels predict inversions (these are typically under-

done in models)

12 UTC Thurs 3 Dec 00 UTC Saturday 5 Dec

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

conditions

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

Cloud Cover?

Patchy low clouds over basin 11 am 1 Jan 2013

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

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.

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