12/27/24 Friday 3:30 pm
The storm’s remnants snuck in a little earlier and a little further south than expected. This week has been a big miss for the European model.
Over the last few years, my observations are that the European deterministic model, which updates four times a day, gets stuck during periods of extended patterns.
When we are in a dry pattern, which we are, it continues to forecast warm and dry conditions. When some residual moisture tries to work in, it minimizes the accumulations. When we are in a wet pattern (which I hope we will be transitioning into in the next two weeks), the model fails to see drier patterns coming.
Late this morning, the Southwest San Juans were added to the advisory for 4 to 8 inches of snow.
This afternoon they doubled down.
COZ019-280900-
/O.CON.KGJT.WW.Y.0036.000000T0000Z-241228T0900Z/
SOUTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF SILVERTON, RICO, MAYDAY
308 PM MST FRI DEC 27 2024
...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 2 AM MST SATURDAY
ABOVE 9000 FEET...
* WHAT...PERIODS OF MODERATE TO HEAVY SNOW EXPECTED ABOVE 9000 FEET.
ADDITIONAL SNOW ACCUMULATIONS BETWEEN 3 TO 7 INCHES WITH LOCALLY
HIGHER AMOUNTS. WINDS GUSTING AS HIGH AS 40 MPH ABOVE 10000 FEET.
* WHERE...SOUTHWEST SAN JUAN MOUNTAINS.
* WHEN...UNTIL 2 AM MST SATURDAY.
* IMPACTS...ROADS, AND ESPECIALLY BRIDGES AND OVERPASSES, WILL
LIKELY BECOME SLICK AND HAZARDOUS. PLAN ON SLIPPERY ROAD
CONDITIONS. THE HAZARDOUS CONDITIONS COULD IMPACT THE FRIDAY
EVENING COMMUTE.
Also added new wording for the Northern San Juans
COZ009-018-281145-
/O.CON.KGJT.WW.Y.0036.000000T0000Z-241228T1300Z/
GRAND AND BATTLEMENT MESAS-NORTHWEST SAN JUAN MOUNTAINS-
INCLUDING THE CITIES OF SKYWAY, TELLURIDE, OURAY, AND LAKE CITY
308 PM MST FRI DEC 27 2024
...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 AM MST SATURDAY
ABOVE 9000 FEET...
* WHAT...ADDITIONAL SNOW ACCUMULATIONS BETWEEN 3 TO 7 INCHES WITH
LOCALLY HIGHER AMOUNTS. WINDS GUSTING AS HIGH AS 45 MPH.
* WHERE...NORTHWEST SAN JUAN MOUNTAINS AND GRAND AND BATTLEMENT
MESAS.
* WHEN...UNTIL 6 AM MST SATURDAY.
* IMPACTS...ROADS, AND ESPECIALLY BRIDGES AND OVERPASSES, WILL
LIKELY BECOME SLICK AND HAZARDOUS. TRAVEL COULD BE VERY DIFFICULT.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
In both cases, these are additional accumulations because, as I mentioned, the storm tracked a little further south.
Temps in the lower and middle elevations were lower than forecast leading to consistent snow at or above 7,400 feet today. Today’s snow was mostly associated with an earlier wave passing through while the main energy is still off to the west.
Additional accumulations seem likely in the mid-elevations. I will not throw a dart at the forecast, but I would not be surprised to see more snow.