The Catastrophic Carr Fire

Thermal anomalies (red) and smoke from the Carr Fire as seen from Aqua/MODIS 26 July 2018

A catostrophic situation is unfolding in northern California where the Carr Fire is threatening communities in and around Redding.

The latest incident information from Cal Fire indicates that as of 9:17 AM this morning (27 July), the Carr Fire has burned 44, 450 acres, destroyed 65 structures, and damaged 55 structures.  Only 3% contained, the fire is currently threatening almost 5,000 structures, with numerous evacuations and road closures.  News reports indicate that the fire has now claimed the lives of two firefighters.

News footage of the fire is simply unbelievable.  Below are a couple of perspectives on rotating updrafts associated with the fire.

No, this is not a tornado. The Carr Fire in Shasta County created this rotation updraft. #CarrFire #California pic.twitter.com/CVvcafJBGK

— ABC10 (@ABC10) July 27, 2018

Timelapse video shows the #CarrFire approaching #Redding, California. https://t.co/cZHrZOS53i
[Video: Cody Markhart] pic.twitter.com/x2gg1RL50Y

— NBC Bay Area (@nbcbayarea) July 27, 2018

The rotation was clearly evident in Doppler velocity imagery from the Beal Air Force Base, posted by U of U mountain meteorology alum Neil Lareau.  In this image, red indicates flow away from the radar, which is to the south, and blue flow towards the radar.  In this case, the radar is sensing ash, not precipitation. 

Here is a summary of the radar observed cyclonic circulation within the #CarrFire pyro-plume over #Redding @ 9:45 PDT. Clear couplet of inbound/outbound flow. This radar sweep is about 2 km AGL...surface circulation likely MUCH stronger! Yikes! #CAwx #CAfire Credit to @WxMattt pic.twitter.com/U6yibE5hQm

— Neil Lareau (@nplareau) July 27, 2018

Redding is a hot place in summer, but the situation right now is inferno like.  The average high for yesterday and today is 100ºF at the Redding airport a bit southeast of the fire.  Yesterday it hit 113˚F, a new record for the day, with a relative humidity that dropped below 10%.

Winds have not been as insane as they were during the Tubbs Fire that affected Santa Rosa, but looking at stations around the area, I can find locations with wind gusts to 20 mph yesterday afternoon.

Forecast highs for Today through Monday are 110˚F, 110˚F, 109˚F, and 107˚F. 

Smoke in Salt Lake, Misery in California

This morning dawned with smoky skies and a fairly orange sun that wasn't well captured by my cell phone camera while looking up City Creek Canyon from the Bonneville Shoreline Trail. 

Although the perspective is a bit oblique, I love looking at the beautiful GOES-16 imagery from CIRA.  Smoke covers a large portion of central and northern California, northern Nevada, southern Oregon, and southern Idaho.  There's some that has snuck into northern Utah as well. 

GOES-16 imagery from CIRA at 1507 UTC 26 July 2018

The purple air network shows moderate or worse air quality across much of that area (sadly with few observations in Nevada). 

Source: PurpleAir, 9:35 AM MDT 26 July 2018

Those of us in northern Utah shouldn't complain.  The misery index in California is off the scale.  In addition to smoke and associated poor air quality, high temperatures in the Central Valley are expected to be anywhere from 106 to 112˚F. 

Hideous.

Threats from Ensign Peak Fire Continue

Yesterday afternoon, a grass fire quickly burned 100 acres above Victory Lane just north of the Utah State Capitol, threatening homes in the area. 

Source: Rich Bowmer | The Associated Press | The Salt Lake Tribune

Smoke from the fire sent a chill up my spine as it emerged from Capitol Hill, illustrating that this was a very serious situation. 

Kudos to the Salt Lake City Fire Department, which responded quickly and got the situation under control.  According to the Salt Lake Tribune, only one home was damaged.  Three firefighters were, however, hospitalized, two for heat exhaustion and smoke inhalation and one for a leg injury.  We wish them speedy and complete recoveries. 

The origin of the fire remains unknown, but was almost surely human caused.  The threat of a similar fire remains, with caution, vigilance, and taking steps to protect your home the keys to reducing risk.  Below are recommendations of the National Fire Protection Association. 

Some neighbors in the Avenues hired goats to consume grasses on the slopes below their homes a couple of weeks ago, and I thought that was looking like a really good investment yesterday.  

Although the Ensign Peak Fire is contained, the area is denuded of vegetation and will be prone to erosion and potentially debris flows during precipitation events.  Threats from wildfires continue even after the last ember is extinguished. 

A Beastly July Ridge Dominating Southwest Weather

Take a gander at the GFS 10-day forecast below, especially the top frame, which illustrates the evolution of the winds on the dynamic tropopause (jet-stream level).  Note the slow westward movement, or retrogression, of a very strong upper-level ridge across the southwest US and northern Mexico during the period. 

The intensity of this ridge over the southwest US and northern Mexico is quite unusual for this time of year.  For example, the NAEFS mean 500-mb height forecast for 1800 UTC today shows values that are outside climatological values for the 1979-2009 period.  In other words, we are dealing with unusually strong ridging at those latitudes for July.

Source: NWS

In general, people associate high pressure with fair weather, but the #1 weather-related killer nationally is heat and a strong ridge this time of year over the southwest makes for extreme heat.   As can be seen in the NWS forecast below, excessive heat warnings extend across much of southern Arizona and California, and up the lower Colorado River Valley to portions of Nevada and southern Utah. 

Source: NWS

I'll provide the NWS infographic below as an example of forecasts for today's max temperatures, which include everything from 123˚F in Thermal to 96˚F in Los Angeles. 

Source: NWS

With the ridge moving so slowly, this is going to be a multiday event.  Riverside, for example, is currently 102˚F (1:15 PM PDT), with a high expected to be near 110˚F today, tomorrow, and Thursday.  Riverside is inland enough that it is typically warmer than Los Angeles, but still, the average high this time of year is about 94˚F, comparable to the average for Salt Lake City.  

Source: NWS

We should all feel fortunate that we're on the periphery of this ridge and only running in the mid 90s here in Salt Lake.  

Temperature Oddities as We Enter "Hump Week"

The climatologically hottest week of the year begins today.

There is a 7-day stretch from 23-29 July during which each day the average temperature is 80˚F at the Salt Lake City airport, the warmest of the year.

Call it hump week.  After this, we are on the downward slope to winter!

It's worth a look back at the summer so far.  We've done this once or twice already, but let's dig a little deeper. 

The period from 1 June - 22 July ranks as the 4th warmest on record based on average temperature.  Technically, we are tied for 4th with 2007.

Source: NOAA Regional Climate Centers

Curiously, this warmth has been achieved with only one day with a maximum temperature of 100˚F or greater (102˚F on 6 July).  Indeed, for average maximum temperature, the period only rates as the 15th on record with 90.6˚F, nearly 3˚F behind 1961 (93.5˚F).

Source: NOAA Regional Climate Centers

However, for minimum temperature the period is the 4th warmest on record behind only, drumroll please, the three previous years (2017, 2016, and 2015).  

Source: NOAA Regional Climate Centers

We also had a 13 day run from 5-17 July during which the temperature did not drop below 70˚F.  That represents the 2nd longest streak on record (tied with periods during July 2007 and 2013), but lies short of the 22 day run we experienced last year.  

Disgusting.  

In case you are wondering, the warmest day of the year exhibits significant geographic variability.  The earliest is in extreme western Texas, New Mexico, and Arizona where temperatures peak in June or early July and temperatures later in the summer are damped by the monsoon.  Northern Utah and the greater northwestern U.S. with the exception of coastal areas, sees an average warmest day of the year in late June or early August.  Locations along the Pacific Coast have a much later maximum, some in September, since it is very difficult to get warm, offshore flow at those locales in June and July.  

If you wish to extend your misery, consider a trip to the Gulf Coast of Texas and Louisiana where the average warmest day of the year is in mid to late August and you can double down the heat with brutal humidity.  

Blast from the Past

The past few decades have been quite exciting for meteorologists as our field, like many others, has been transformed by massive technological change. 

Today I took some time to go through my personal archives from graduate school and finally pitch some stuff that's been collecting dust for years.  It was a good reminder of just how far we've come in the past 25 to 30 years. 

As an undergrad in the late 1980s, the Internet wasn't really yet a thing.  I don't recall using it and I certainly didn't have an e-mail account.  We did not look at weather observations, satellite imagery, radar imagery, or model forecasts online.  That information came via DIFAX charts and you were happy to get what you got.  If you wanted to forecast the weather, you had to go somewhere that had these charts, such as a University "map room", so named because the maps were simply hung on the wall. 

Through the 1990s, DIFAX remained a thing and I spent a lot of time in graduate school in the map room trying to figure out the ski weather in the Cascades.  Here's an analysis from 06Z 20 January 1993, a day that will live in infamy in Seattle.  Note the tightly wound cyclone just offshore, which would continue to deepen, eventually generating damaging winds across the Puget Sound.

A portion of my dissertation examined the fine-scale structure of that storm and why it was so damaging, but I have two strong memories about that day.  The first is that one of my fellow graduate students surfed the Puget Sound.  The second is that we tried to go night skiing after the big blow and it was pretty much a disaster trying to get up to the ski area.  I have no recollection of whether or not the skiing was any good, but it probably wasn't.  It sowed heavily in advance of the cyclone, but as it moved through, marine air flooded into the Cascades and likely created even mankier conditions.  Yet another reason to live in Utah. 

When I started at the University of Washington in the summer of 1989, the first job I was assigned involved plotting cross sections.  This involved plotting profiles of wind and temperature by hand from alphanumeric upper-air sounding data, something that nobody has done in ages.  There was no computer program that could do this at the time.  Below is an example, with a manual analysis of temperature (solid lines) and wind speed into/out of the cross section dashed). 

My oh my how things have changed and for the better.   Eventually the bots will probably take over, but for now, this really is a great time to be a meteorologist.  I don't long for the old days, although I would take my 25-year-old body again in a heart beat.