Blue skies and warm temps (10-15 degrees above normal) today with another storm on the way arriving on southwest flow with increasing clouds and wind throughout the day. Tonight through Tuesday the San Juans will see steady & intermittent snowfall with a cold front arriving late Monday/early Tuesday that should increase precip rates, but it’s all timing … Wednesday dries out then the unsettled pattern continues into the weekend with hopefully another storm (southwest flow) on the way.
A large trough of low pressure birthed in the Gulf of Alaska has moved south into the Great Basin and has stretched/elongated west into the warm subtropic Pacific entraining good moisture. This is a slow moving storm with all the dynamics necessary for good snow production. Convection, orographic lift, vorticity, supported by a 120 kt jet all converging Monday afternoon/evening & hopefully performing like the Dave Brubeck Quartet.
This storm looks similar to our last storm with the elongated trough reaching back into the warm Pacific waters along with the NW cold front which helped create decent snow especially to southwest aspects above TL. If all dynamics pan out we should see 8-12″ on the average above 11,000′ with higher amounts possible, up to 24″ in those special places we all dream about. This storm and the next week potential may put a small dent in our H20 starved southern mountains.
GFS – US – 500mb – Loop
The forecast below is for Red Mountain Pass, and Wolf Creek looks similar. Most lines (forecast models) agree on a forecast of about 20 inches.
As our last storm exits the area we have another entering the San Juan on SW flow with decent moisture, a 140 kt subtropical jet mixing with a cold front (polar jet to our north). We should see light snow flurries later today in the high country then tonight the storm kicks in as the trough of low pressure moves just upstream (southwest) of our mountains … We could see 8-12″ (more in some places) of snow on southwest aspects above 11,000′.
The large trough sliding down the West coast will bring in warm subtropical Pacific moisture and when mixed with the cold front and orographic lift from the windy conditions should bring good snow fall tonight through mid day Thursday.
We’ll then have a brief clearing Friday and Saturday before the next disturbance arrives late Sunday or early Monday morning. The european model shows a impressive storm with a strong jet that will track further south than two other models show. This would put the San Juans in the bullseye on Monday/Tuesday but it’s too far out to have any confidence.
GFS – US – 500mb – Loop
Yesterday’s storm totals…
These 4 full depth avalanches in upper Gov. were triggered with 1 shot. Speed Miller
Evidence of a fragile snow pack!
Yesterday’s storm has exited on SE flow & we are now seeing the beginning cirrus formation moving into our mountains on WSW flow setting up for the next storm beginning in the high country late tonight/early Monday morning. A large low pressure trough is moving into the Great Basin today and by tomorrow morning it will spin warm subtropical Pacific moisture into the SJ’s. This first portion of the storm could bring 4-8″ to the southwest facing terrain above TL.
Late Monday the trough pinches off into a closed low and moves back towards California (retrogrades) with a resulting split flow (A upper level high pressure positioned over a low pressure beneath or to the south forming a Rex Block that directs winds from east to west). The location of this block puts the San Juans in good position for more snow possibly between 5-10″ into Tuesday. Winds decrease a bit with the split flow so it’s difficult to forecast exact snow totals for a given time and region but maybe we should be feeling lucky the next few days.
A large scale low pressure trough will visit the San Juans later today on northwest flow. A cold front will also push in from the north later in the afternoon bringing a good shot of snow with high precip rates in a short period of time … 8 -12″ above TL and lesser amounts in the valleys. The North San Juan (Uncompahgre Gorge) will be favored.
Seems like most of the activity will be between 3 to 10 pm today. Good storm dynamics but short lived and the storm will move southeast of our mountains by mid-day Sunday with clearing Sunday evening when another storm system will move into the area later Monday.
This storm which has three models agreeing will dive SW out of the Great Basin as a cutoff low stretches from California to the 4-corners. These storm are very unpredictable (when/where/how much) so i’m not even guessing yet…
Monday evening through Tuesday world view with closed low