Wasatch Weather Weenies

With 29 days in the bag for the month, the average temperature at Salt Lake City for this June is 77.3ºF, just 0.2ºF behind 2015 for the hottest of all-time. Source: NOAA Regional Climate Centers I've run some quick numbers using the last night's minimum temperature (74ºF) and the forecast maximum for the day (91ºF).  Those will bump this June up about .15ºF, which will put us very close to 2015 (and within the roundoff uncertainty of the monthly mean data I have access to, which is rounded off to the nearest tenth of a degree).  Much will depend on today's maximum and whether or not we get some dramatic cooling from precipitation to lower the minimum.  In either event, 2015 and 2016 will stand as back-to-back Junes of unusual warmth compared to past Junes in the historical record. Meanwhile, here in the Northeast, yesterday was an "excursion" day at our conference, allowing us to get out into the Adirondack Mountains and climb Giant Mountain.  The day sta...

With four days left in the month, the race is now on for the hottest June on record.  The average temperature so far for this June puts us in 2nd place all time in Salt Lake City, 1.2ºF behind 2015. Source: NOAA Regional Climate Centers And the forecast calls for triple digit scorchers today and tomorrow and 90s for the last 2 days of the month with above-average minimum temperatures. Source: NWS It's gonna be close.  Although it's unclear which year will end up number one, it's clear we're going to go #1 and #2 for the past two Junes.  Yes, you have bragging rights.

Looks like Salt Lake has gotten some much needed relief from the heat as I just pulled up the 2 PM MDT observation from the airport and it's only 77ºF with a dewpoint of 19ºF and winds from the northwest at 12 mph gusting to 18.  That must feel so good. I'm currently in New York visiting family in advance of the American Meteorological Society Conference on Mountain Meteorology, which will be held in Burlington, Vermont next week.  Although we are warming up here and are expected to hit 90ºF tomorrow, it's been pleasant for my stay so far. Today I did a hike up Snowy Mountain, which is not so snowy by Utah standards, but at 3899 ft, is the highest peak in the southern Adirondacks and requires about a 2000 vertical foot ascent.  Most of the trail is fairly easy, but the last several hundred vertical feet is your classic Adirondack knee breaker, basically a steep creek bed requiring the occasional "vegetable belay," especially on the descent.  A red trail marker...

Here are two ways to look at the temperature for June so far.  In the first, we compare the mean temperature for June 1–22 to similar periods in the past.  This year stands as the hottest such period on record, 0.1ºF warmer than June 1–22, 1918. Source: NOAA Regional Climate Centers In the second, we compare the mean temperature for June 1–22 to that of prior Junes (i.e., June 1-30).  The mean temperature for June so far would rate as the 2nd warmest on record, behind only last June. Source: NOAA Regional Climate Centers Although there's a cool down on tap for Friday and Saturday, we look to rebound again for the remainder of the month.  It looks like a two horse race for hottest June on record between 2015 and 2016.  My money is on the latter.

Here are a few temperature "highlights" from yesterday: The Salt Lake City Airport hit 100ºF, the first triple digit reading of the summer.  Was it a record?  Nope.  June 20, 1936 hit 101ºF.   The Salt Lake City Airport also set a record high minimum for the day of 77ºF, trouncing the old record of 69ºF set in 2003 Alta hit 79ºF, breaking the old record for the day of 75ºF set in 2007 Numerous daily record maximum and high minimum temperatures were set in SoCal, including:  122ºF in Palm Springs, which was 1ºF off their all-time record (123ºF) and also equates to 50.0ºC, precisely half way between freezing and boiling.  111ºF at Bob Hope Airport (Burbank), tying their June record 125ºF in Needles, setting a new record for June and tying their all-time high (set in 1925 and 2005) 126ºF in Death Valley, a record for the day People often ask me if such heat waves are what we will be facing with global warming. This heat wave is not the future. ...

Although Arizona got some attention in the lead up to the current southeast heatwave, SoCal felt the heat yesterday too. Source: Penn State The temperature contrasts along the coast can be quite remarkable in patterns like this.  This morning at about 10 AM PDT, it was 98ºF at USC and 79ºF in Inglewood.  Out at Oxnard, with a decent onshore flow, it's a cool 69ºF.  Location, location, location. Source: MesoWest But perhaps the most remarkable temperature goes to Avalon Catalina Airport on Santa Catalina Island.  The airport is 1578 ft above sea level and above the marine layer.  The 11 am temperature was a whopping 101ºF.  Check out their temperature trace over the last 5 days.  Simply nasty. Source: MesoWest In case you are wondering, the average high at Avalon Catalina Airport in June is 67.6ºF.

I often joke that there's no reason to go to Utah County, but really there's one, and that is the opportunity to hike (or ski) some truly spectacular peaks.  In fact, a credible argument can be made that the peaks of Utah County are more spectacular and beautiful than those of the central or northern Wasatch as they tend to be more isolated, have huge prominence, and have spectacular geology and ecology. Today we hiked Box Elder Peak from Granite Flat Campground via the north ridge route.  The entire hike is spectacular, although much of the approach is south facing and hot.  Making it more tolerable are the tremendous views of huge ski lines that require full commitment. Although it is only mid June, the hike is nearly entirely snow free.  The patch below was the largest we crossed on the north ridge and it was about 20 feet long. Although steep, the north ridge has no real technical concerns, other than this highly intimidating class 2 Hilary Step that ...

I've been hoping we would avoid extreme heat next week in northern Utah, but the latest model runs are not optimistic. Below is the 0600 GFS forecast of 500-mb heights from this 1200 UTC this morning through 0000 UTC 22 June (1800 MDT Tuesday).  Pretty much a worst-case scneario for us as the ridge over central North America builds westward across the U.S. Southwest and then northward into the Intermountain West.   The forecast for Tuesday afternoon shows a core of 700-mb temperatures at or above 20ºC across southern Utah, with Salt Lake City around 18ºC.   GFS 500-mb height and 700-mb temperature forecast valid 0000 UTC 22 June (1800 MDT Tuesday) Such temperatures would be a record for that date and time (based on the Salt Lake City area upper-air sounding record) and near the all-time record for the month of June of 19.0ºC. Source: SPC Based on what I'm seeing in the extended model forecasts, I think we have a solid shot at the hottest June o...

Some impressive winds were reported around northern Utah yesterday and I think it's safe to say that they exceeded forecast expectations.  Peak gusts at valley locations reported to MesoWest include the following: Sherwood Hills: 82 mph (0210 UTC/2010 MDT) SR201 at I-80: 80 mph (0130 UTC/1930 MDT) Syracuse: 76 mph (0120 UTC/1930 MDT) Great Salt Lake Marina: 73 mph (0136 UTC/1936 MDT) Many mountain sites, especially in the northern Wasatch, also reported strong gusts. The setup for the event was very similar to many other strong southerly wind events in the spring.  With a developing surface trough extending from the southern Sierra Nevada across central Nevada and northern Utah. RAP sea level pressure analysis, surface observations, and GOES IR satellite imagery at 0100 UTC 16 June 2016 In such situations, strong surface heating typically has two effects.  One is to contribute to the intensification of the surface trough and the associated low-level pressure...

Over the next several days, portions of the southwest U.S. will experience a warming trend leading to fry-an-egg-on-the-sidewalk conditions as a high amplitude ridge sets up over the region.  The 500-mb heights look to be about as high as they get, exceeding 6000 meters (6 km) near the center of the ridge.  For example, in the GFS forecast for 0000 UTC 20 June (6 PM MDT Sunday), 500-mb heights exceed 6000 meters at a few locations in Arizona, New Mexico, and Colorado.  Temperatures at 925-mb, roughly 750 meters above sea level, exceed 40ºC (104ºF) across most of Arizona (Note: this level is below ground for high-elevation regions, but illustrates the extreme heat for lower elevation portions of the state). 0600 UTC 15 June GFS 500-mb height and 925-mb temperature forecast valid 0000 UTC 20 June The National Weather Service has issued an excessive heat watch for much of southern California and Arizona. Source: NWS Excessive heat in that part of the world means ...

After doing a post yesterday on some of the subtleties of convection during the morning and early afternoon yesterday (see prior post The Unusual Distribution of Cumulus Clouds Today ), Mother Nature decided to crank things up and give us some strong storms later in the day. The afternoon sounding from the Salt Lake City International Airport sets the stage.  With daytime surface heating and abundant atmospheric and soil moisture, the surface-based convective available potential energy (CAPE, a theoretical measure of the amount of energy a parcel of air would have if lifted vertically) was 2277 J/kg, a remarkably high value for northern Utah.  Mixing out the shallow surface layer gives lower values, but this is a sounding consistent with deep convection and strong updrafts. Source: SPC And we got some strong storms, some of which were long lived.  Perhaps the most impressive was the cell that tracked from the West Desert, across I-80, over the Great Salt Lake, and...

As far as cumulus clouds go, to day was pretty unusual in the Wasatch.  Usually during the summer, we have a deep surface-based mixed layer driving thermals that produce clouds with bases well above mountain-top level.  Under such conditions, there's usually only one layer of cumulus clouds and cloud bases are at about the same elevation over the valley and mountains. That wasn't the case today.  While on Mt. Raymond, we observed shallow cumulus clouds to the northeast in the area around the lower terrain north and east of Mill Creek Canyon.  Presumably this caused some overcast if you were in that area, or at least partly to mostly cloud skies, but for us, it was undercast.  Meanwhile, at higher elevations, a completely distinct layer of cumulus with higher cloud bases formed over the central Wasatch. Here's another perspective a bit later, although by this time, the lower clouds wer beginning to burn off. What made today unusual was the complex l...