Tuesday, June 30, 2015

June Temperature Record Will Be Obliterated

With the intense warmth of the past few days, this June is now in uncharted territory for the highest mean temperature in Salt Lake City.

With one day remaining (today), the average temperature for June 2015 now sits at 77.1ºF, well ahead the record of 75.7ºF n June 1988.

Source: NOAA Regional Climate Centers
The overnight minimum was 77ºF and the high today is expected to once again eclipse 100, so the mean temperature for the month will increase further.  Although there's a slight chance of a thunderstorm today, which could lower the minimum temperature a bit below the 77ºF recorded this morning, it looks like we will obliterate the June temperature record.

Monday, June 29, 2015

The Hottest June Day Ever

In all likelihood, today will be the hottest June day on record in Salt Lake City.

The Salt Lake City International Airport recorded a minimum temperature of 78ºF overnight, tying the all-time high minimum for the month.

As of 10:30 am, it's already 92ºF and it looks like we are on pace for a max even higher than yesterday's 102ºF, which would put us at 103ºF or 104ºF.  If we hit 103ºF, our average temperature for the day, assuming we don't drop below 78 before midnight tonight, will be 90.5ºF.

On June 28 and 29, 2013, the Salt Lake City airport reported maximum temperatures of 105ºF, but the minima were 71ºF and 74ºF, yielding averages of 88ºF and 89.5ºF, respectively, lower than what I'm anticipating for today.

In addition, during that stretch of hot weather in late June 2013, the temperature sensor at the Salt Lake City airport was clearly reading high (see What's Up @ KSLC from August 20, 2013), so the books during that period are essentially cooked.

The bottom line is that you will experience the hottest June day ever in Salt Lake City today.

I say YOU because I have been happily ensconced in southeast Alaska since the Salt Lake heat wave began and haven't seen a temperature above 71ºF in over a week.  Note the rain jackets and smiling faces.

Heading home soon and not looking forward to it...

Saturday, June 27, 2015

June 2015 Now in Driver's Seat for Hottest on Record

After yesterday's minimum of 68ºF and maximum of 99ªF, June 2015 is now in the driver's seat for the hottest June on record in Salt Lake City.

Source: NOAA Regional Climate Centers
The mean temperature for the month is now 75.8ºF, 0.1ºF ahead of 1988.  The lead will be extended further today and the final three days of the month.  The Heat Miser is in total control.

Friday, June 26, 2015

More Records Will Fall

With five days to go (including today), it looks like this June will go down as the hottest on record in Salt Lake City.  

The average temperature for the month currently sits at 75.4ºF behind only 1988 (75.7ºF) and tied with 1918 (75.4ºF), with the latter observation likely collected in town rather than at the airport. 

Source: NOAA Regional Climate Centers
In all likelihood we will break the record by a sizable margin.  The NWS forecast for Salt Lake shows that the next few days will be the hottest for the summer so far.  In case you are wondering, the all-time record high temperature for June at the Salt Lake Airport is 105ºF set on June 28 and 29, 2013. 

Source: NWS
The heat is on.  Ick. 

Wednesday, June 24, 2015

Great Graphic: What's Caused Recent Warming

Source: Bloomberg
Eric Roston and Blacki Migliozzi of Bloomberg have put together a great info graphic based on research from NASA/GISS illustrating the various human and natural drivers of climate change and their influence on warming since the late 1880s.  One of the great myths concerning climate research is that we only focus on carbon dioxide.  Nothing could be further from the truth as considerable effort has gone into understanding and quantifying the role of various natural and anthropogenic factors and their influence on climate change.  Their graphic, available here, allows you to examine each of these factors, as well as their combined influence.

Monday, June 22, 2015

100 Denied

In our post on Friday (When Will We Hit 100?), we discussed the possibility of hitting 100 yesterday (Sunday), but also that it was going to be close due to an approaching surface trough that was forecast to push across northern Utah.  Specifically, we said that "if the trough is a bit slower than currently progged, then a high of 99–102 seems likely.  Knock that down a couple of degrees if it's a bit faster."

The latter verified and indeed yesterday's high only reached 96ºF.  The time series below shows this well.  Through about 1 PM yesterday the flow war from the south with peak gusts of just over 30 mph.  Then the trough went rhgouth and the wind shifted to NW-N.  Note how the temperatures flattened out and decreased slightly following the frontal passage, resulting in a maximum temperature at about 1 PM.  In contrast, the previous day, which didn't have such an airmass change, saw temperatures rise to a maximum at about 5 PM.

I'm sure you feel cheated out of your 100.

Saturday, June 20, 2015

Green Is Good

While up in the hills the past couple of weeks, I've been blow away by how green and lush it is.  I did short hike in Albion Basin this morning and it's really lush up there.  Here are a few photos.

Mt. Superior is nearly snow free.  In a big year, you can ski it in mid June.
Green Greeley.  Late summer turns in gunsight will be very difficult this year.
Devil's Castle looms white over green meadows.
Looking down the remarkably green slopes of Albion Basin.  Not many wildflowers yet, but there are a few blue ones out there.
And now for something completely different, pink (a.k.a. watermelon) snow.  The color is caused by a snow algea, chlamydomonas nivalis.  

With the Albion Basin road closed, it's far less crowded up there than it is in July and August and well worth a trip. 

Friday, June 19, 2015

When Will We Hit 100?

Yesterday's high at the Salt Lake City International Airport was 98ºF.  The only temperature that I hate more than 98 is 99ºF.  If we must be stuck with US units and it is going to be that hot, it should hit 100.  Will we finally get there in the days ahead?

It won't be today.  We've had a weak trough passage and the air behind it is a smidge cooler than yesterday.

Through the weekend, our best chance may be Sunday, but it's going to be close.  There is a weak trough approaching from the west and if it comes in late in the day or in the evening so that we're in the warm southerlies, we'll make a run at 100.  The NAM and GFS forecast 700-mb temperatures for 6 PM Sunday are 16.8ºC and 16.5ºC, respectively, which is a bit higher than it was yesterday afternoon.  Both models put the trough over northern Utah (GFS) below at that time.

It's gonna be close.  If the trough is a bit slower than currently progged, then a high of 99–102 seems likely.  Knock that down a couple of degrees if it's a bit faster.

In case you are wondering, the extended range forecasts show nothing but hot and dry for the next week and beyond.  Steel yourself for full bore nuclear summer.  It's against my better judgement to icon-based extended forecasts (see Ten-Day Icon Based Forecasts Are Bogus), but The Weather Channel forecast for Salt Lake City pretty much tells the tale.

Source: The Weather Channel

Thursday, June 18, 2015

Temperature Records Are Falling

The National Centers for Environmental Information has released the latest climate numbers for May and they are smoking hot.  In fact, last month represents the hottest May in the instrumented record.
Source: NCEI
And the Northern Hemisphere spring (March–May) was also the warmest on record.

Source: NCEI
And globally, January–May was the warmest on record.

Source: NCEI
And also globally, June–May was the warmest on record.

Source: NCEI
In 1979, the National Academy of Sciences issued a report entitled Carbon Dioxide and Climate: A Scientific Assessment.  Some snippets from the executive summary seem appropriate today.
"For more than a century, we have been aware that changes in the composition of the atmosphere could affect its ability to trap the sun's energy for our benefit. We now have incontrovertible evidence that the atmosphere is indeed changing and that we ourselves contribute to that change. Atmsopheric concentrations of carbon dioxide are steadily increasing, and these changes are linked with man's use of fossil fuels and exploitation of land. Since carbon dioxide plays a significant role in the heat budget of the atmosphere, it is reasonable to suppose that continued increases would affect climate."

"These concerns have prompted a number of investigations of the implications of increasing carbon dioxide.  Their consensus has been that increasing carbon dioxide will lead to a warmer earth with a different distribution of climatic regimes."

"If carbon dioxide continues to increase, the study group finds no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible."

"However, the study group points out that the ocean, the great and ponderous flywheel of the global climate system, may be expected to slow the course of observable climate change. A wait-and-see policy may mean waiting until it is too late."

Wednesday, June 17, 2015

The HRRR Has Arrived

I'm pleased to announce that forecasts from the 3-km High Resolution Rapid Refresh (HRRR) are now available on weather.utah.edu.  Here's the 6-hour forecast valid at 0000 UTC (1800 MDT) this afternoon.  No showers or thunderstorms in the Salt Lake Valley.  Apply the sunblock liberally!

The HRRR is the highest-resolution operational model run by the National Weather Service.  Employing radar and other data assimilation wizardry, it produces 15-hour short-range forecasts every hour.  For now, I'm downloading a subset of HRRR output for the western United States and providing a couple of surface diagnostic loops, one that includes 10-meter winds and model-derived radar reflectivity, the other that includes 10-meter winds and 1-hour accumulated precipitation.  The loops on weather.utah.edu also include analysis frames going back into the past as knowledge of the past is always handy for predicting the future.

More information on the HRRR is available here.  It should be handy for ski forecasting this coming winter.

Tuesday, June 16, 2015

May Was Wet, But Summer Aridity Starts Today

The National Centers for Environmental Information (formerly the National Climatic Data Center) has released the Utah climate data for May.  It was a wet one.  On a statewide basis, it ranks as the 2nd wettest with a total of 3.03", behind only 1995, which recorded 3.06".

For all intents and purposes, the two years plus 1898 (2.97") are essentially indistinguishable given the sparseness, quality, and uncertainties of the precipitation observations.  Basically, it was really wet, but you didn't need a meteorologist to tell you that.

In fact, it was so wet that the January-May precipitation is now a touch above average, despite the tremendous precipitation deficits observed from January-March.

For the October-May water year, however, we're still below average.

We were granted one final burst of thunderstorms yesterday, which was quite enjoyable, but all that rain is in the rearview now.  Summer aridity starts today.

Monday, June 15, 2015

The Summer Bake Begins

We have a slight chance of a thunderstorm later today and if we get it, be thankful.  The summer bake begins tomorrow.  The GFS time-height section for Salt Lake City International Airport shows bone dry conditions for the next week after midnight tonight.  Temperatures will be at or above seasonal averages during the period.  

The mountains were spectacularly green and lush this past weekend.  Get out and enjoy before everything dries out. 

Friday, June 12, 2015

El Niño Likely for the 2015-16 Winter

The National Weather Service Climate Prediction Center issued their latest El Niño/Southern Oscillation (ENSO) Diagnostic Discussion yesterday went mostly (but not quite all) in for El Niño to reign for the rest of the year and through the 2015-16 winter.
There is a greater than 90% chance that El Niño will continue through Northern Hemisphere fall 2015, and around an 85% chance it will last through the 2015-16 winter. - NOAA/NWS/CPC ENSO Diagnostic Discussion, 11 June 2015
An ongoing and strengthening El Niño is already in place over the equatorial Pacific Ocean.  Anomalously warm sea surface temperatures extend from the coast of South America across the Pacific to the dateline.
Source: CPC
Most of the climate models call for El Niño to strengthen over the next few months.  The plot below shows their projected sea surface temperature anomalies in the tropical Pacific from 120–150W and most are calling for strenthening anomalies through the fall, persisting into winter.  Some are calling for a strong El Niño., although there are a few that go for moderate to weak.

Source: CPC
All of this sounds exciting, but for the central Wasatch, there's very little correlation between El Niño and snowfall.  The graph below shows the relationship between 3-month snowfall and an index of El Niño/La Niña strength.  Nothing really to bank on here.

Three month (NDJ, DJF, JFM, FMA) accumulated snowfall at Alta–Guard vs. the corresponding ONI (labeled ENSO index). 
Courtesy Jeff Massey.
For the southwest, however, El Niño loads the dice for a wetter than normal winter, for the northwest, warmer than normal (and drier in the interior, but not necessarily the Cascades, although the warm temps often cause problems there for snowfall at temperature sensitive elevations during El Niño due to a greater fraction of precipitation falling as rain), as reflected in the seasonal outlooks produced by the CPC for Dec–Feb.

Source: CPC
Source: CPC
Personally, I hope a strong El Niño comes through.  The southwest could use some action and an active southern branch of the jet will give me some new blogging material next winter.

Thursday, June 11, 2015

Salt Lake Skunkage

Much of Utah saw shower and thunderstorm activity yesterday, but the Salt Lake Valley was largely skunked except for a brief shower that affected the west valley during the late afternoon.  Rainfall totals yesterday included 1.44" at Joe's Valley Reservoir and 1.26" at Bryce Canyon airport.  Some strong winds were found near storms, including a gust of 70 mph on Flattop Mountain in the northern San Rafael Swell area and 69 mph at Laketown near Bear Lake.

The HRRR forecast through 8 PM tonight shows a very active day in central, southern, and northeast Utah, but less activity over northwest Utah.  The Salt Lake Valley is on the fringes of activity.  We'll have to hope we get something so I can keep my sprinkler-free spring going.

The NWS has a flash flood watch out for southern Utah through this evening.
Source: NWS
Warnings were issued last night for a number of drainages and slot canyons, including Spooky and Peakaboo, two of my favorites.  If the remains of the cow that got lodged in the latter during winter haven't already been removed, hopefully Mother Nature did the job last night.

Wednesday, June 10, 2015

Blanca Pays a Visit

Former Hurricane Blanca is "spreading her ashes" over the southwest U.S. this week, with help from a weak upper-level trough camped off the California coast.

Some interesting tidbits from this event so far:

  • Several stations in SoCal reported measurable precipitation yesterday, including 0.30" at the Santa Barbara airport.  Average rainfall for the month at that location is 0.07".   They are now covered for the next four Junes.
  • The dewpoint at the Boulder City municipal airport in southern Nevada peaked at 61ºF this morning and currently sits at a still muggy (by Nevada standards) 59ºF.  No word on if Las Vegas is considering extracting moisture from the atmosphere to meet future water needs...
Source: MesoWest
  • But it's a dry heat in Arizona right?  Peak dewpoints so far for include 72ºF in Yuma, 70ºF at Buckey municipal airport west of Phoenix, 67ºF at Sky Harbor airport in Phoenix, and 73ºF at Tucson Ryan Field.  Steamy!
  • Although it is not uncommon to find high integrated water vapor levels (a.k.a., precipitable water) over the southwest during the monsoon, the value measured yesterday afternoon at Tucson (1.62", black square below) appears to be the highest in the measurement record so early in the season. 
Climatology source: NOAA/SPC
Blanca began to spread her ashes over Utah last night and there's a good chance of showers and thunderstorms statewide today.  Time will tell if she decides to leave a deposit at your place.  

Addendum @ 12:45 PM:

I just noticed on the Madweather blog that the integrated water vapor yesterday morning in Tucson was even higher than it was yesterday afternoon (latter plotted above).  

Monday, June 8, 2015

Another Rare June Tropical Cyclone Remnant Visit

The passage of tropical cyclone (TC) remnants across the southwest U.S. is rare, but not unprecedented in June.  As illustrated by Ritchie et al. (2011),  rainfall events associated with TC remnants are most common over the southwest U.S. in September.  Action in June is more limited.  During the 1992–2005 period examined by Ritchie et al. (2011), there were only 2 rainfall events associated with TC remnants in June.

Number of eastern Pacific tropical cyclones, number of tropical cyclone remnants that brought rain to the southwest U.S., and number of tropical cyclone remnants that did not bring rain to the southwest but had other impacts.  Study period 1992–2005.  Source: Ritchie et al. (2011)
We've already had one this year associated with TC Andres, and now we'll have another associated with TC Blanca.  Blanca was a category 4 hurricane, but as of this morning had weakened to a tropical storm centered near the Isla Santa Margarita off the west coast of the Baja Peninsula.  High clouds in advance of Blanca were already streaming into southern Arizona.

As can be seen in the contours above, Blanca is accompanied by a slug of high integrated water vapor (a.k.a. precipitable water) and preceded by a surge of high integrated water vapor up the Gulf of California.  This moisture is expected to push into southern California and Arizona today and stream into southern Utah late tomorrow.  At the same time, moisture from the midlatitude Pacific also pushes into the Intermountain region from the west.

Thus, although we're in a bit of a break today and tomorrow, with just some isolated mountain showers and thunderstorms, the action should be on the increase after Tuesday with a good chance of showers and thunderstorms statewide on Wednesday and Thursday.

After nearly turning on my sprinklers in April, I still haven't run them and if we can get more rain midweek, I'll likely make it to at least the middle of the month.

Friday, June 5, 2015

The East Pac Is Jacked!

Sea surface temperatures in the tropical and subtropical eastern Pacific are running generally at least 1ºC above average and 2–3ºC above average west of Mexico (lower panel below).  A warm tongue of warm water off the coast of South America and along the equator is indicative of El Nino conditions.

Source: NOAA/CPC
El Nino years are typically associated with above average hurricane seasons in the east Pac and we've already had two names storms, Andres and Blanca, both of which have reached Category 4.  Andres has dissipated, with the last remnants of its cloud mass near 23 N and 123 W.  High clouds extend northeastward from the Andres remnants and into the southwest US.  Blanca is still churning away.  Although it has weakened to Category 2 strength, having attained Cat 4 earlier, it represents the earliest second major hurricane on record in the east Pac.

Source: NOAA/NHC
The showers that came through the Salt Lake Valley this morning can be traced to a surge of moisture originating in the subtropical eastern Pacific just to the east of Andres.  The loop below, which covers the past 2 days and includes contours of integrated water vapor (a.k.a., precipitable water) and 850-mb winds shows this surge nicely.  Note how the moisture tongue pushes across Arizona and wraps across eastern Utah into the northern part of the state.  

If you are wondering if this is a trend for this summer, it's tough to say.  An above average hurricane season in the east Pac seems to have a good chance.  Monsoon precip from July–September?  Less clear for our part of the world.  El Nino stacks the deck in Arizona for below average monsoon precipitation, but not so much northern Utah (our monsoon precipitation is fickle here to begin and can be hit or miss, making all these statistical inferences "dicier").  Based on a variety of factors, the Climate Prediction Center is giving us slightly better than chance odds of above average precipitation.  I wouldn't bet the farm on this (or even a small side wager), but I'll hope it verifies and I'll enjoy anything that falls from the sky the next few days.  

Thursday, June 4, 2015

Secrets for a Great Price!

If you haven't already purchased a copy of Secrets of the Greatest Snow on Earth, you can get it now from University Press of Colorado for 50% off.  Direct link is http://www.upcolorado.com/utah-state-university-press/item/2390-secrets-of-the-greatest-snow-on-earth.  Enter promo code 50FOR50 at checkout as noted below.  They have other great books too for the same killer deal.  

I wonder if they will have 100% off for their 100th anniversary?

Wednesday, June 3, 2015

The Bear Lake Boating Tragedy

On Monday night, strong winds and waves on Bear Lake capsized a small boat killing one adult and three children.  It sounds like a terrible tragedy and my thoughts and prayers go out to the friends, family, and all involved.

Bear Lake straddles the Idaho/Utah border and is roughly 30 km long and 10 km wide.  The accident apparently happened in the Idaho portion of the lake.  

Although details are still fuzzy, the Salt Lake Tribune reports that winds gusted to 76 mph, with waves reaching 10 feet in height.  Seven people were on board when the boat capsized, all with life jackets on.  The water temperature, however, was only 53º.  It is likely that the victims died from exposure or downing before they could reach the lake shore.  

I've taken a quick look at the weather contributing to this tragedy and it provides a cautionary tale about just how quickly disaster can strike on Utah waters (and elsewhere) seemingly from nowhere. 

The strongest wind gust I could find near Bear Lake from observations collected by MesoWest was  48 mph at the Bear Lake County Airport, just north of the lake.  The meteograms below show that at 1655 MDT (~5 PM), the temperature was 79ºF with sustained winds of 14 mph.  Then things changed dramatically for the worse.  At 1755 MDT (~6 PM), the temperature was 60.3ºF with sustained winds of 35 mph and gusts to 48 mph.  The tempest continued for another hour and and by 1855 MDT (~7 PM) winds were still gusting to 46 mph and the temperature had dropped to 54ºF.  

In addition, satellite and radar imagery shows that Bear Lake was on the edge of most of the thunderstorm activity (the lake is just west of the UT-ID-WY triple point), which was associated with a weak cold front that was moving through the area.

Source: NCAR/RAL
Source: NCAR/RAL
Although there were some weak radar returns in the vicinity of Bear Lake, the strength and duration of the strong winds strongly suggests that a mesoscale outflow boundary (a.k.a. gust front) produced by precipitation and thunderstorms to the north and west likely propagated through the area.  
Indeed, numerous sites in the area reported strong winds during this period, including the Grace RAWS station just northeast of Bear Lake, which hit 65 mph.  There probably were some clouds and showers in the vicinity of Bear Lake ahead of the gust front, but the change in wind, temperature, and waves experienced by the boaters would have been abrupt and severe.  Further, the persistence of strong winds and waves combined with a further drop in temperature following the gust front passage greatly increased the likelihood of drowning or hypothermia before the boaters could reach shore.   I suspect the boaters were hit by something that they never saw coming, or had little time to respond to, and were cast into a nightmare situation.  

This sort of weather situations is, however, not all that uncommon in Utah, highlighting the need for boaters to remain vigilant for rapidly changing conditions when storms are around.  It's especially important to recognize that the strong winds and rapid temperature changes associated with outflow boundaries can sometimes propagate well away from the generating storms, in some cases into areas experiencing clear skies.  

Tuesday, June 2, 2015

The Snow Is Going Fast

Although we had a stay of execution for most of May, the snow is going fast now that the heat is on.  Snow melt at the Snowbird SNOTEL went into overdrive in late May with the snowpack water equivalent dropping from 9.5 inches on May 27th to 0.3" yesterday, a mean melt rate of about 1.5" a day.  0.3" rounds to 0, so I'm officially calling an end the snow-cover season at this site.
Source: CBRFC.  
The snow depth at Alta Collins has similarly been plummeting and is now down to 52 inches.
Source:  MesoWest
The Alta Lodge web cam shows patch cover at the base of Alta.  If you want a top-to-bottom run, you'd better get on it ASAP.

Source: Alta Lodge
The end is near.  Much work will be needed to earn turns after this week.