Raindown, Snowup: Advisories Issued

6:30 am

First the good news. This should say Hesperus above 8,200 feet in my opinion.

URGENT - WINTER WEATHER MESSAGE  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
348 AM MST SAT FEB 2 2019  
  
COZ018-019-022200-  
/O.UPG.KGJT.WS.A.0001.190203T0700Z-190204T0100Z/  
/O.NEW.KGJT.WS.W.0002.190203T0700Z-190204T0100Z/  
NORTHWEST SAN JUAN MOUNTAINS-SOUTHWEST SAN JUAN MOUNTAINS-  
INCLUDING THE CITIES OF TELLURIDE, OURAY, LAKE CITY, SILVERTON,   
RICO, AND HESPERUS  
348 AM MST SAT FEB 2 2019  
  
...WINTER STORM WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 6 PM  
MST SUNDAY...  
  
* WHAT...HEAVY SNOW EXPECTED. TOTAL SNOW ACCUMULATIONS OF 8 TO   
  16 INCHES EXPECTED. WINDS GUSTING AS HIGH AS 50 MPH.  
  
* WHERE...NORTHWEST SAN JUAN MOUNTAINS AND SOUTHWEST SAN JUAN   
  MOUNTAINS.  
  
* WHEN...FROM MIDNIGHT TONIGHT TO 6 PM MST SUNDAY.  
  
* ADDITIONAL DETAILS...TRAVEL COULD BE VERY DIFFICULT. PATCHY   
  BLOWING SNOW COULD SIGNIFICANTLY REDUCE VISIBILITY. GUSTY   
  WINDS COULD BRING DOWN TREE BRANCHES.  
  
PRECAUTIONARY/PREPAREDNESS ACTIONS...  
  
A WINTER STORM WARNING FOR SNOW MEANS SEVERE WINTER WEATHER  
CONDITIONS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE. IF YOU  
MUST TRAVEL, KEEP AN EXTRA FLASHLIGHT, FOOD AND WATER IN YOUR  
VEHICLE IN CASE OF AN EMERGENCY.

“Gusty winds (and wet snow/ice) could bring down tree branches” That is a concern and I am glad they mentioned it but I wanted to repeat it.

A series of storms and or pieces of storms are going to dominate our weather at least through Thursday. The timing of these waves is going to be very difficult to predict. With so much uncertainty, I am going to do my best take these systems one at a time because there is a high degree of uncertainty in the pattern.

Sunday storm

All I can say is yuck. This first system is what old school residents would call the pineapple express, these days it is known as an “AR” event. The models have been pretty consistent indicating the higher snow levels. This indicates the airmass is “thick” with warmer air. With a “normal” storm there is noticeable cooling in the airmass and I can interpret snow levels by the projected pressure levels from the weather models. For example 6,500′ versus 8,000′ is clearly indicated by weather models. With these AR events there are times when there is very little difference in temperatures between these elevations, so you don’t know what you are going to get. Normally a strong storm like this on its own would lower snow levels in the most intense portion of the storm (tomorrow morning), but this subtropical tap (AR) may keep this from happening.

If I just interpret the pressure levels on the models it is an easy call to say snow levels will drop from 8,000′ to 6,500′ between 5 am and 11 am tomorrow. I have another data source I use that indicates snow levels will hover around 7,500 feet throughout the event, that would disappoint a lot of people but the concern is that it also shows surface temperatures around 30-32 after midnight for areas between 7,000′- 7,400′. If that happens the warmer precipitation could freeze on contact. Which could cause some very dangerous conditions on elevated areas of 160 west of Lightner and Bayfield to the east. Also of course 501 and Wildcat, and 550 north of the train bridge curve. Please keep this in mind during the morning “race” to Purg.

Snow forecast

Sometimes I wish I only dealt with Ski Resorts, that would be a lot easier.

The dividing line definitely seems to be around 7,500′ with this storm. There is no doubt in my mind that certain areas of the same elevation may get different precipitation amounts.

Throughout the day I may revise these snowfall amounts and this does not take into consideration melting. These amounts are between tonight and first thing Monday morning.

7,000′ and Below 0-2″

Mid Elevations Rafter, Dwest, Shenandoah, Forest Lakes, Edgemont, Dhills 2-5″

Vallecito, Lemon, Hesperus&DRR at or above 7,800′ 4-6″

Mayday, Purgatory, Telluride 6-10″

Wolf Creek 10-15″

As I said I will be revising things throughout the day so check back. Here are the models, remember earlier in the week I was posting multi-day totals, this is just for this storm.

GFS overnight

226zgfs