THUNDER 'N' LIGHTNING

 

TL;DR: THUNDER 'N' LIGHTNING

Nowcast:

Unsettled Morning in Salt Lake City - Light rain transitions to snow at Parley's Summit. City Cam: https://home.chpc.utah.edu/~u0790486/wxinfo/cgi-bin/uunet_camera_explorer.cgi?cam=WBBW

UDOT Road Weather Cam via http://udottraffic.utah.gov/ 

Moderate temperatures to start the day before a cold front pushes in this afternoon. Risk of thunderstorms! 

Short term: 

Forecast loop showing surface temperatures and surface winds. A blob of blue brings wind and cold air out of the northwest today. https://www.pivotalweather.com/model.php?m=hrrr&p=sfct_b-imp&rh=2023041800&fh=gif&r=conus&dpdt=&mc= 

Straight model output (HRRR) below shows minimal snow for the Wasatch, however a Winter Weather Advisory is calling for 6-12" up high. https://www.weather.gov/slc/WWAmap?id=https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.c3d190f7fc7acf8bbab9322a00d7ac789a683999.001.1#ACTIVE. Brush off the Mountain Biking pads and get that jacket out, temps dropping below 20F in the mountains overnight. 

Point Forecast in the Wasatch Mountains showing 0.20" of precip... "woohoo".. and temps dropping below 20 overnight. Via https://spotwx.com/products/grib_index.php?model=hrrr_wrfprsf&lat=40.65272&lon=-111.64633&tz=America/Denver&label=

Long term:

Cooler temperatures to persist after the current round of instability. There's a possibility of some early-week precipitation (3-4") to start Sunday overnight through Monday. 

Maybe a couple of inches Sunday overnight into Monday. TBD! 

Backcountry comments: 

If you will be traveling in the backcountry make sure you have the proper equipment and know before you go. For the whole avalanche forecast and all things avalanche head over to our friends at the Utah Avalanche Center here: Utah Avalanche Center

SURVIVED? SNOW AND COLD

TL;DR: SURVIVED YESTERDAY? LIGHT SNOW ALL WEEKEND, COLD TEMPS CONTINUE

Nowcast:

Current conditions 9am MTN 2023-03-25 via https://www.wrh.noaa.gov/map/

Looks like a cold front came through and temps are below freezing in the city and down to single digits above 9,000 ft in the Canyons. Right now, winds are mostly from the west at 5 mph gusting to 11. 

Surface weather map shows high pressure parked east of Utah as it exits the state. Mountain-snow showers to weaken during the day as the system heads eastward. 

Surface Weather Chart via https://www.weather.gov/zid/surface

Short term: 

The GFS shows continued west/northwest flow as a low closes over southern Idaho. Looking at the 500 mb upper air chart to see steering flows: 

60 hr forecast from the GFS via https://www.pivotalweather.com/

Cold temperatures will continue and wring out some light snow showers through the day Saturday and Sunday through Monday morning. A couple of inches expected each day to continue building our record snowpack: 

Point-model output from the GFS for a spot in the Wasatch Mountains. Cold temps persist with cloudy conditions and light snow through Monday afternoon. A shift in conditions for Wednesday will bring more moderate temps and another pulse of snow. Via www.spotwx.com

Long term:

Jumping ahead to Wednesday - a low comes onshore around Northern California and this changes the flow pattern to come from the southwest. Warming temps could be a relief for those looking to thaw out and a mid-week snow-treat for the skiing and snowboarding crowds. 

Wind barbs showing a shift to SW flow over Utah starting Wednesday. With it, warmer temps and precipitation. 

Backcountry comments: 

LOTS of wind overnight and LOTS of snow caused havoc in the Canyons and the resorts yesterday. Big impact to the snowpack and expect increased hazard with the rapid change. 

If you will be traveling in the backcountry make sure you have the proper equipment and know before you go. For the whole avalanche forecast and all things avalanche head over to our friends at the Utah Avalanche Center here: Utah Avalanche Center

Here. We. Go.

TL;DR:

    With favorable conditions shaping up, buckle down for lots of snow through the first half of this week. HERE, WE, GO!

Nowcast:

    With only 7" so far from this storm we are off to a slower-than-expected week, that being said, fear not there is more snow on the way. It has been snowing throughout the day today in the cottonwood canyons with temperatures in the low twenties, dipping to the upper teens around the mountain tops. Winds are blowing out of the West around 20-30 mph, keep an eye out for blowing snow as the storm rages on. The snow will continue through tonight until around midnight when the storm will settle.

Through today and into this evening a trough is digging off the west coast. As a result of the orientation of the trough, the westerly upper-level flow will prevail. Accompanying that flow is a strong band of moisture that lies slightly south of Utah. 

Short Term:

    Tuesday will bring a slight break in the storm with moisture being the limiting factor. Northern Utah may see some scattered showers but nothing significant. Down in Southern Utah however, some snow may fall with the injection of moisture as well as some strong vorticity advection creating an optimal environment for snow.  

    Yet, you Northern Utah dwellers get ready as the storm will start back up Tuesday afternoon and evening as the moisture surge will reach into the Northern stretches of the state. Snow totals range up to an additional 5-8" by midnight before the storm really starts to kick. 

U of U Atmospheric Science

    The maps above are valid at 1500 UTC Tuesday (11:00 am). This is just prior to when the storm will kick back into action. In the bottom right and bottom left the moist and dry areas are highlighted. Note that southern Utah will be significantly moister, this will be favorable for the La Sal Mountains along with those Southern ski areas. In the top right map take note of the significant area of strong upper-level vorticity and the location of Utah relative to the trough. Note that as a result of this orientation significant vorticity advection will be brought to Utah, accompanying the cool temperatures will make for excellent upper-level dynamics to be in place for Wednesday. 

Long Term:

    Looking to Wednesday the upper-level flow will shift to a more Southwesterly flow helping to bring more significant moisture levels helping to classify this as a low-level atmospheric river event (AR 1/2 along the Wasatch front). The moisture accompanying the cool temperatures and favorable upper-level dynamics will result in some significant snow totals. Areas of the Wasatch Front could receive nearly 2 feet of snow with isolated areas in the upper alpine receiving nearly 2.5-3 feet. In Southern Utah similar totals are possible by the end of the storm.

U of U Atmospheric science

If you plan to travel in the backcountry know before you go and have the proper equipment. Avalanche conditions will be heightened this week with the addition of lots of snow and a prolonged period of wind that will have the ability to blow snow. Consult our friends over at the Utah Avalanche Center for the full avalanche forecast and observations.

Bluebird powder day, with more on the way

 TL;DR: Bluebird says for the weekend with another storm moving through next week. 

Nowcast:

It is a spectacular bluebird day today. With around a foot of new snow and colder temperatures, the snow quality should be great today. It is colder than it was yesterday with highs in the teens and low 20s. There wont be a cloud in the sky today. If you are planning on going out remember to ring some sunscreen.

                                                                High Rustler, Alta

Short Term:

It should remain clear through the weekend with temps slowly rising but still only reaching the mid 20s. There could be accouple low level clouds that settle into the canyons, but there will be no precipitation associated with them. The snow that fell yesterday should stick around through this weekend, but there might be a bit of crust that forms due to solar radiation and low temperatures.

Long Term:

    It looks like there is another system that will role through early next week. There is a large low pressure system that will be moving across the wester US starting Monday. It looks like the brunt of the storm will hit midday Tuesday and carry through into Wednesday. Curranty, the NAEFS is predicting around 30 in from Monday to Wednesday, but it might be a little optimistic due to the uncertainty of the models. 

POW. WEDNESDAY.

Nowcast:

09:42 MTN / 15:42 UTC Camera Display looking EAST from the Neil Armstrong Academy in West Valley. Via https://home.chpc.utah.edu/~u0790486/wxinfo/cgi-bin/uunet_camera_explorer.cgi?cam=NAA

Current Temperatures and Wind Direction around I80 and the Cottonwoods. Via https://mesowest.utah.edu/cgi-bin/droman/mesomap.cgi?state=UT&rawsflag=3

Overcast skies with cloud layers at 5500 ft, 12000 ft, and 14000 ft according to the KSLC METAR (KSLC METAR) for 1454z. Winds are from the south at 16 mph at the airport, consistent with ridge top winds at Hidden Peak blowing 25 mph with gusts to 40 mph. 

Temperature is in the low 50s in the valley and just below freezing (low 30) up at the ski hills. 

Satellite / Infrared imagery shows a 'big red lobster' i.e. the remnants of an atmospheric river heading our way from the southwest. This atmospheric river brings moisture, and unfortunately warmth, to the region. 

Infrared imagery with the incoming atmospheric river as an 'angry lobster'. Via https://weather.cod.edu/satrad/?parms=regional-southwest-14-24-1-100-1&checked=map&colorbar=undefined

Short term: 

Snow is expected to start late this afternoon bringing 3" before midnight and another 15" by sunrise tomorrow. Winds are expected to be ripping during this event with consistent gusts exceeding 40 mph. 

Snow continues throughout Wednesday with another 12"(ish) to fall during the day. 

Freezing levels should remain above 7000 ft until a cold front barges through Thursday morning. 

Ensemble plumes showing the bulk of the precip to happen overnight Tuesday and throughout Wednesday. 

This incoming storm has prompted a Winter Storm Warning from NWS/NOAA with 'Significant Mountain Snow Accumulations'. 

Sounds like a POW day to me! 

Tuesday afternoon through Wednesday Morning - expect mountain snow courtesy NWS/NOAA https://www.weather.gov/slc/ 

 
Long term:

The cold front will turn off the tap until shortwave troughs move through this weekend, potentially bringing precipitation on Saturday or Sunday. 

Backcountry comments: 

Winds and loading contribute significantly to snowpack instability. Changing temps as they increase or drop with the cold front will increase the likelihood of natural and human triggered avalanches. Be mindful of the intense winds and dense upper snow layers as they can be a bed surface for the new storm snow to slide on.  

If you will be traveling in the backcountry make sure you have the proper equipment and know before you go. For the whole avalanche forecast and all things avalanche head over to our friends at the Utah Avalanche Center here: Utah Avalanche Center

Spring who?

TL;DR: We will have a quiet start to the week as we wait for a shortwave system with favorable upper-level dynamics and moisture transport to hit Wednesday morning. 

NOWCAST: Alta has gotten 4" in the past 24 hours and is currently 21 F at the base with light WNW winds. High pressure currently dominates the region.

(Alta Ski Weather: https://www.alta.com/weather) 

Short-Term Forecast: Wednesday morning a shortwave trough will barrel through the region coupled with good IVP from an atmospheric river penetrating through California. Winds at the 700mb level (~11,000 ft) will be positioned from the SW during the arrival of this storm. Storm snowfall totals range from 30"-50" at Alta. 

(University of Utah NAEFS, https://weather.utah.edu/) 

Long-Term Forecast: After the trough passage on Wednesday, slightly high pressure will build into the region for the rest of the week. Smaller feature shortwaves are possible throughout the rest of the week but none will bring considerable snowfall. Our weather pattern seems to stay very progressive and this next ridge will be quickly pushed out by a deeper trough early next week. 

(500mb Geopotential Height Anomaly, Tropical Tidbits: https://www.tropicaltidbits.com/)

Snow today; Bigger storm mid-week

TL;DR: Light snow showers today will bring a light refresh to the mountains. A bigger storm with lots of moisture will impact the region starting Tuesday afternoon and lasting through Wednesday.

Nowcast: After the sun briefly made an appearance yesterday, snow has returned to the Wasatch today. Most resorts are not reporting any new snow for the past 24 hours, aside from 2" at the BCC resorts, and 1" at Deer Valley. Light showers are falling throughout the region now, and visibility appears to be a challenge per Alta Ski Area's Superior webcam.

Source: Alta Ski Area

Short-term Forecast: Today's storm is not an exceptional one, but it should provide a few inches of fairly low-density snowfall in the Wasatch. By this afternoon, the University of Utah's GFS-derived forecast for Alta calls for 5" of new snow - a nice Colorado powder day :).

Source: University of Utah Department of Atmospheric Science

Fortunately, winds are not too strong today, with peak gusts around 30 mph from the west at the highest elevations.

Mid-Long Range Forecast: A bigger storm is on tap for mid-week, but it won't contain light, dry powder. Just like our system on Friday, this storm is associated with an inland penetrating atmospheric river with southwesterly flow. This can be seen clearly in the 0600 UTC valid for early Wednesday morning.

Source: University of Utah Department of Atmospheric Science

In the bottom right panel of the above four-panel plot, we can notice the yellow and orange colors penetrating the interior western United States, signifying high moisture transport into the interior from the Pacific. Unfortunately, this is once again a pretty warm system, with 700 mbar (crest-level) temperatures at right around -2 °C (red dashed contour in bottom left panel). This would mean that we could see rain at resort-base level. Expect fairly high precipitation rates in the 0.25-0.5 in. in 3 hr range (upper right panel). With snow-to-liquid ratios around 7 to 1, though, this won't translate to the most impressive snowfall rates. The GFS calls for just over 1.5 inches of liquid precipitation equivalent for the upper Cottonwoods, which would translate to about a foot of heavy snow.

By late Wednesday, we clear out into next weekend.

Snowfall Forecast:

For today expect 1-4" at the resorts with maybe more if one does particularly well.

For the warm mid-week storm, we'll be looking at 10-20" of new snow for the mountains.