Tuesday, April 15, 2014
A couple of weak waves will move through the area tonight and tomorrow with some cooling but little or no precipitation expected for our area. The first wave is mostly north of us tonight while the second wave is mostly south of us tomorrow and should produce light precipitation for central and southern Colorado.
Thursday will start cool but warm up nicely as a transient ridge moves over our area. Friday will be warmer, though there may be rain showers in the afternoon as the warm southern portion of a split trough is forecast to bring moisture into Colorado. The storm is fairly disorganized, and what cold air there is should bring our best precipitation Saturday afternoon or evening, though snow accumulations will be limited to the higher elevations.
There may be afternoon convection Sunday and Monday afternoon, though the warming and stabilizing airmass will limit those showers on Monday. Tuesday should be warm and dry before another major storm is forecast to enter the west coast around then. There is a lot of model uncertainty on how this energy interacts with the west coast ridge, as the European ECMWF keeps the wave progressive while the American GFS cuts this off to our southwest and brings it over our area midweek. Details will evolve in future model runs as our active spring weather continues.
Monday, April 14, 2014
The storm forecast for closing day was indeed interesting! The Steamboat ski area reported 2” mid / 3” top at 5 am as some convection ahead of the cold front brought rain to the valleys and snow to the hill. Then we were affected by 3 pulses of energy, though the first or these was limited in impact as there was only 4” of snow at 1 pm up top. However, at this time, the second pulse delivered good snow and was quickly followed by a TROWAL (TRough Of Warm air ALoft), which is evident on the IR satellite loop shown on the right (first image at 10:11 am MDT and last image at 5:45 pm MDT on 13 April 2014). This is seen as convective plumes generated over the southern Front Range propagated northwestward over the Continental Divide and into our area. The powdercam at the top of Sunshine Peak showed 6” of snow fell between 1pm and 3pm, with 3.5” falling between 2 pm and 3 pm!
The intense snowfall rates also brought snow to the valleys with over 6” of snow falling in the 5 hours between 11:30 am and 4:30 pm. Additionally, temperatures at Storm Peak Lab near the top of Mt. Werner fell from about 23F around noon to 14F at 4pm, and kept falling through this morning until the temperature reached a mid-winter -1F!
Ski conditions moved from good to great to outstanding, and as advertised in earlier forecasts, the last run of the day was the best, with 10” of snow shown on the powdercam and over a foot measured in the favored areas. The mountain was also relatively sparsely populated due to the events at the base, though I’m sure the mid-winter storm skiing also discouraged those expecting spring conditions!
Saturday, April 12, 2014
The interesting storm advertised earlier this week looks to be a significant snow maker for much of Colorado Sunday. A cold front currently draped across central Montana has entrained some cold air from the Hudson Bay vortex and is forecast to move across our area early tomorrow morning, probably around report time. There may be showers ahead of the front after midnight, but the bulk of our snow will come with and behind the front. There might be an inch or two on the morning report, but moderate to localized heavy snows should be occurring in rapidly falling temperatures by sometime in the early morning and continuing until sunset before tapering off and ending around midnight.
I would expect to be skiing in 4-8” of powder by the time the lifts stop spinning for our season tomorrow afternoon, though only some of that will be reflected on the official noon report. Probably another 2-4” on top of that after lifts close would make for great skiing on Monday were it not our first closed day.
A chilly start for Monday that will make the day feel cool, though temperatures are forecast to rise in the beautiful sunny weather that lasts until Tuesday. Models are once again in disagreement as to the strength of a storm forecast for Wednesday. The American GFS model insists on another significant snowstorm lasting through Thursday while the European ECMWF has a much flatter and faster moving storm. Interestingly, the GFS entrains another lobe of cold air from the Hudson Bay vortex while the ECMWF is less generous with that interaction. I would guess the Wednesday storm will behave similarly to tomorrow’s storm and would lean towards the GFS forecast.
Nonetheless, skies should be clear by Friday for a return of spring weather. Current forecasts have storms moving well north and south of us for the weekend, leaving us in very pleasant weather.
Thursday, April 10, 2014
After beautiful almost summer-like weather, our very active spring reasserts itself with storms timed for closing day on Sunday and midweek. Similar to yesterday, there may be some showers this afternoon that will enhance gusty winds, though no accumulations are expected.
Friday will be warmer and drier, and Saturday will start similarly, though changes are afoot by the afternoon in advance of a complicated and interesting storm system. A low off the southern California coast affects our area by Saturday afternoon with a another round of afternoon convection. Concurrently, a lobe of energy from the still present Hudson Bay vortex will phase with some cold air from the Siberian vortex over western Canada and bring a strong cold front into our area late Saturday night or early Sunday morning.
There is disagreement among the models as to the western extent of this storm, but the possibility exists for significant snowfall during the day and perhaps the evening as well before the storm moves east of our area by Monday morning. Snowfall forecasts will have to wait until model uncertaintly is resolved.
A transient ridge will bring spring-like weather back to our area by later Monday and Tuesday before another storm affects our area starting Wednesday. The American GFS model has the storm closing off and stalling over Colorado as another lobe of energy from the Hudson Bay vortex brings cool air into this system. Conversely, the European ECMWF model does not show this interaction and keeps the storm fast-moving and weak.
Both models show additional energy for the end of next workweek that will keep the weather active. Bases will likely continue to build through at least next week, and it’s a shame that the Steamboat ski area does not consider extending their season like many of the surrounding resorts. Lifts could be limited to the gondola, Storm Peak Express and Elkhead, with Burgess Creek being a convenient addition, but not necessary. Credibility as a skier’s mountain could only help Steamboat’s marketing efforts, not to mention the increase in seasonal snowfall averages.
Unsettled weekend with significant snow for Monday followed by our first week of true spring weather
Friday, April 4, 2014
After a beautiful morning today, the atmosphere moistens and destabilizes ahead of a splitting trough just entering the west coast. Clouds should increase today and there may be some showers near the end of the day.
Most of the cool air will be shunted to our north as the trough splits, so precipitation will likely fall as rain or a rain / snow mix at lower elevations and snow higher up on the hill. Showers will likely redevelop early Saturday and grow heavier and more numerous in the afternoon, though accumulations will likely remain light and localized before decreasing after sunset.
Sunday will also be unsettled, though a productive cool and moist trailing wave from the northwest will influence our area by the afternoon. Showers will be much heavier than today and Saturday by Sunday afternoon, and there will likely be accumulations on the hill by the end of they day.
Snows will increase after sunset Sunday and become moderate to heavy by midnight as cooler air is dragged across the region. Though this is a quick moving wave, we should see 4-8” by Monday morning with the possibility of some Steamboat magic after the report.
Showers will taper off through Monday, with periods of sun, especially in the valley. Winter-weary people will welcome the strongly warming temperatures and beautiful spring weather starting Tuesday and likely lasting through much of the workweek. Thursday may be a bit cooler and cloudier as models have a Pacific wave battling the ridge over our area and eventually passing to our north.
The result of this battle may allow additional Pacific energy to influence our area for closing weekend, though there is model disagreement on how this may happen.