Dust event D6-WY2014 is increasingly likely next Tues/Weds — Colorado Dust-on-Snow Program (original) (raw)

This morning's (Friday, April 18) Grand Junction National Weather Service 0323 AM "Forecast Discussion" product includes the following language in the Long Term section:

BY TUESDAY...THE RIDGE BREAKS DOWN AS A STRONG COLD FRONT APPROACHES FROM THE PAC NW. AS EARLY AS TUE AFTN WE SHOULD FEEL THE EFFECTS AS THE GRADIENT TIGHTENS AND SOME GUSTY WINDS ARE FELT ACROSS THE CWA. THESE WINDS WILL CONTINUE TO STRENGTHEN AS THE FRONT AND UPPER LEVEL SUPPORT CONTINUE TO APPROACH THE AREA. LATEST GUIDANCE HAS GFS COMING AROUND TO EC THINKING OF KEEPING THE HEAVIEST PRECIP WELL TO OUR N WHILE SPOTTY PRECIP WILL BE POSSIBLE TUE AFTN THRU WED AFTN. H7 WINDS STILL SHOW 55 TO 60KTS WHICH WILL LIKELY MIX TO THE SURFACE SO DO ANTICIPATE PLENTY OF WIND ADVISORIES...IF NOT HIGH WIND WARNINGS FOR SOME SPOTS...ALONG WITH BLOWING DUST ADVISORIES FOR SOME AREAS AS WELL. WITH THIS MUCH WIND...WE CAN ALSO EXPECT PLENTY OF DUST ON SNOW WHICH WILL INCREASE SNOWMELT FOR MOUNTAIN LOCALES...THINKING SAN JUANS ATTM. THIS IS NOT ETCHED IN STONE HOWEVER AS WE REMAIN 5 DAYS OUT SO PLENTY OF TIME FOR SOME MODEST TO MAJOR CHANGES IN THE FORECAST.

Furthering the thoughts in our Wednesday, April 16 Update, a D6-WY2014 dust-on-snow event now appears even more likely, and this event may be 'dry' for some areas, without accompanying snowfall. If the next dust event is dry in your watershed, and falls on an extensively re-emerged D4 layer, the additional reduction in snow albedo would only accelerate any streamflow surging already in progress. If D4 had not yet re-emerged, a dry D6 event would initiate a surge that could soon accelerate as D6 merged with D4.

As always, the NWS will continue to interpret and weight their many models and iteratively refine the forecasts over coming days. I recommend reading these discussion products routinely, for their insights into the short term (2-day) forecast and for their analyses of uncertainty in model outcomes for the "long term" (day 3-7). You can click to the Forecast Discussion products in the "About This Forecast" and "Additional Forecasts and Information" portions of a seven-day forecast page for your locale.

More soon,
Chris