So here we are, it’s Thursday we are supposed to have more model agreement and run to run consistency but we have not, things are flipping back and forth, timing and placement of the jet streak associated with the southern branch of the jet stream are not initializing well with the morning hi-res NAM model run. And that initial moisture surge is the key for accumulating snow west of Pagosa, the passage of the Front on Friday will just be a technicality for most of us, it will be a “was that it?” storm.
I think the only area safe for the good snow we would expect with a decent storm is Wolf Creek where the moisture will get bottled up before Friday’s frontal passage.
Below is the current surface map
You can see the jet streak and associated moisture streaming in from SE Colorado to the Baja. You also see the “storm” coming onshore in Northern California, unless something changes, that storm is going to be a brief moderate snow and high wind event that won’t stick around most areas for very long. Basically, it would have to dig deeper into the west and find some more moisture to bring with it to affect us differently. At this time the models don’t see that happening. But the models are inconsistent, so we will see.
That moisture is supposed to be streaming up and on the increase this afternoon, increasing late day and this evening before scouring out on Friday.
We have had a change to the wording for the Winter Storm Advisory, which they have upgraded to a Warning. The only thing I hate more than these 2 phase systems (split flow systems) is when the NWS issues a blanket advisory. I call it a blanket advisory because they list a couple of towns down here, then in the wording, they extend the coverage area so it is actually outside of their forecast coverage area. Here is the warning then I will explain what I mean.
INCLUDING THE CITIES OF SILVERTON, RICO, AND HESPERUS
245 AM MST THU JAN 16 2020
…WINTER STORM WARNING REMAINS IN EFFECT FROM 2 PM THIS
AFTERNOON TO 5 PM MST FRIDAY…
* WHAT…HEAVY SNOW EXPECTED. TOTAL SNOW ACCUMULATIONS OF 6 TO
12 INCHES WITH LOCALLY HIGHER AMOUNTS UP TO 18 INCHES POSSIBLE
ALONG THE EASTERN PORTION OF THE SAN JUANS. WINDS GUSTING AS
HIGH AS 60 MPH.
* WHERE…SOUTHWEST SAN JUAN MOUNTAINS.
* ADDITIONAL DETAILS…WHILE ACCUMULATING SNOW WILL FALL
THROUGHOUT THE ENTIRE SAN JUAN RANGE, THE HEAVIEST SNOW TOTALS
WILL FALL ALONG AND SOUTH OF THE US 160 CORRIDOR IN THE
SOUTHERN SAN JUAN MOUNTAINS.
* WHEN…FROM 2 PM TODAY TO 5 PM MST FRIDAY.
It is that last highlight under “Additional Details” that is a problem, how many people around here will read that and assume that since they mention Hesperus in the headlines and “the heaviest snow will fall south of the US 160 corridor in the Southern San Juan Mountains” in the additional details, that it means areas south of 160 in La Plata County?
That is not at all the case, they are referring to this area south of the 160 corridor.
What they are referring to is the area of the San Juan Wilderness south of Wolf Creek and east and southeast of Pagosa, pretty much where nobody lives.
I am sure it made sense to the person who wrote it, but this is another reason that I think it is a mistake to include areas that are outside their forecast area, which it is.
As far as the rest of the Warning, it is not a big deal to pick up 6 inches of snow between Purgatory and Red Mountain, you don’t even need a storm just a little moisture and lift and you can hit the 6″ or more. The Warning portion comes in because of the wind, a couple fresh inches of snow with wind gusts to 65 mph creates a dangerous situation and if you are caught in a squall of blowing snow on 550 during the frontal passage tomorrow you are going to feel like you are in a major storm.
I am not trying to nitpick, I just want to make sure people understand what they are reading and to understand the meaning.
So where does that leave us? All of the models are expecting the majority of the snow to fall in the 18 hour period between 11 am today and 5 am tomorrow, then the snow will increase as the front goes through tomorrow and ends fairly quickly after that.
Based on what I am seeing this morning here is what I am thinking for accumulations.
Wolf Creek 10-18″. Purgatory, Mayday, and an area from Vallecito southeast over to Pagosa 4-8″. Telluride 3-6″. Mid-elevations 2-5″. Durango, Bayfield, Aztec, Bloomfield 1-3″. Farmington, Cortez and Mancos trace to an inch. Based on what I see later today I may split up the mid-elevation areas and bump things up for the eastern portions of La Plata County.
I will be updating a couple of more times today, stay tuned.