An Early but Brief Start of the Monsoon

The North American Monsoon got an early start in northern Arizona this year with copious amounts of precipitation over the San Francisco Peaks and surrounding areas. Unfortunately, we are now experiencing an extended monsoon break with mostly clear skies and hot temperatures.

Here are some photograph taken during that wet period.

A partial rainbow over Upper Lake Mary near Flagstaff, Arizona.
A partial rainbow over Upper Lake Mary near Flagstaff, Arizona.
The rainbow is gone but sunset colors are seen in the clouds and the reflection in the lake.
The rainbow is gone but sunset colors are seen in the clouds and the reflection in the lake.
A partial rainbow over the grasslands of Wupatki National Monument.
A partial rainbow over the grasslands of Wupatki National Monument.
A zoomed-in segment of the rainbow showing supernumary bows.
A zoomed-in segment of the rainbow showing supernumary bows.
Sunset at Wukoki Pueblo in Wupatki National Monument.
Sunset at Wukoki Pueblo in Wupatki National Monument.

Here are the June rainfall totals from the Flagstaff rain gauge network.

June rainfall totals for the Flagstaff raingage network.
June rainfall totals for the Flagstaff raingage network.

Monsoon–July 2023

A double rainbow arches above Wukoki Pueblo in Wupatki National Monument.
A double rainbow arches above Wukoki Pueblo in Wupatki National Monument.

The North American Monsoon (NAM) has been slow to get started this year. A general rule of thumb is it gets going around the 4th of July and is considered late (but still normal) by mid-July. Likewise an early start can occur as early as mid June–as it did last year.

Composite image of late afternoon lightning strikes over the grasslands of Wupatki National Monument.
Composite image of late afternoon lightning strikes over the grasslands of Wupatki National Monument.
A segment of a rainbow over Wukoki Pueblo in Wupatki National Monument.
A segment of a rainbow over Wukoki Pueblo in Wupatki National Monument.
Several lightning clusters that occurred during twilight at Wupatki National Monument.
Several lightning clusters that occurred during twilight at Wupatki National Monument.

During the month of July the GFS weather forecast model consistently showed the NAM getting started “Real Soon Now.” But the target was always several days away. Finally, late in the month the rains arrived as an inverted trough (IVT; def. 2) moved across Arizona.

Lightning over the San Francisco Peaks with Marshall Lake in the foreground.
Lightning over the San Francisco Peaks with Marshall Lake in the foreground.
Lightning touches down deep in Grand Canyon.
Lightning touches down deep in Grand Canyon.

There have been some photogenic storms. A little over a week ago I traveled to the South Rim of Grand Canyon hoping to get some lightning. Although there were some flashes they were far away. On the other hand, the sunset was pretty good. A band of clouds just above the horizon effectively blocked the Sun at my location while beams of light were getting under the clouds and into the canyon farther to the west. The alternating beams of light and shadow were pretty nice.

Beams of light and shadow filter deep into Grand Canyon.
Beams of light and shadow filter deep into Grand Canyon.
Beams of light and shadow filter deep into Grand Canyon.
Beams of light and shadow filter deep into Grand Canyon.

The following day I went to Wupatki National Monument in hopes of lightning and rainbows. There was a late afternoon storm that moved towards the Monument and produced a lot of lightning. As it got closer it weakened but was still dropping rain and a short time later a beautiful, full double rainbow appeared. All I needed to do was position myself so that I could get the rainbow arch to frame Wukoki Pueblo.

Time lapse of convection developing over the San Francisco Peaks with Marshall Lake in the foreground.

A new storm formed to my southeast as twilight came on and began to produce a lot of lightning. This was the 3rd act of the day and it was a good one.

Later in the week I took a short drive to Marshall Lake near Flagstaff to time lapse the early stages of convection over the San Francisco Peaks–and with some reflections in the waters of the lake. A few lightning bolts landed near the peaks adding to the show.

A few more trips to Grand Canyon rounded out the month.

And, now, the monsoon is on hiatus again.

Sunrise, Sunset, Rainbows, and Fog

The North American Monsoon continues to bring convective activity to much of northern Arizona on a daily basis. There have been plenty of opportunities for colorful sunrises and sunsets as well as rainbows and even some fog.

Light rain showers are illuminated by the rising sun over Anderson Mesa.
Light rain showers are illuminated by the rising sun over Anderson Mesa.
A partial rainbow appears right after sunrise over Mormon Mountain.
A partial rainbow appears right after sunrise over Mormon Mountain.
Early morning light on Upper Lake Mary.
Early morning light on Upper Lake Mary.
Sunset colors illuminate a thunderstorm near Twin Arrows.
Sunset colors illuminate a thunderstorm near Twin Arrows.
The setting sun briefly illuminates heavy rain falling on the San Francisco Peaks.
The setting sun briefly illuminates heavy rain falling on the San Francisco Peaks.
Light rain from a dissipating thunderstorm is illuminated by the setting sun.
Light rain from a dissipating thunderstorm is illuminated by the setting sun.
The almost daily rainfall has resulted in many opportunities for morning fog.
The almost daily rainfall has resulted in many opportunities for morning fog.

The rainy season should continue for at least a few more weeks so there should be additional opportunities for colorful photographs.

Lightning and Rainbows

Twilight lightning over Kendrick Park. The north flanks of Kendrick Peak are illuminated by the bolt.

We are in the midst of the “Transition Season” where the summer monsoon pattern fades away and the mid-latitude westerlies and low pressure systems move across the area. Another of these events is in progress as a weak closed-low moves across the southwest bringing showers and thunderstorms to the area.

Thunderstorms begin to develop over the San Francisco Peaks.
Thunderstorms begin to develop over the San Francisco Peaks.

Saturday afternoon we set out for the north side of the San Francisco Peaks hoping that thunderstorms would form over the higher terrain and then move northwestward across Kendrick Park. A few storms did form over the peaks and some of them were briefly photogenic but there was very little in the way of lightning. Eventually, approaching rain chased us from Kendrick Park to the northwest where we set up near Slate Mountain in a large meadow with good views of the peaks.

Distant lightning under the rainbow.
Distant lightning under the rainbow.
A multi-pronged lightning strike under the rainbow.
A multi-pronged lightning strike under the rainbow.
Twilight lightning over Kendrick Park.
Twilight lightning over Kendrick Park.
Twilight lightning over Kendrick Park. The north flanks of Kendrick Peak are illuminated by the bolt.
Twilight lightning over Kendrick Park. The north flanks of Kendrick Peak are illuminated by the bolt.
Twilight lightning over Kendrick Park. The north flanks of Kendrick Peak are illuminated by the bolt.
Twilight lightning over Kendrick Park. The north flanks of Kendrick Peak are illuminated by the bolt.

These slow-moving storms continued to move towards the northwest and this time we got lightning and rainbows—and rainbows with lightning. As the sun dropped lower in the west the rainbow quickly faded and rain was again approaching our location. We retreated back to Kendrick Park—this time with the thunderstorms located to our northwest with light from the setting sun still illuminating some clouds. Lightning stikes were frequent and close enough to fill the field of view of the 17-mm focal length lens. Several of these lightning bolts struck the northern flanks of Kendrick Peak. About a half-hour after sunset it was over and the storms quickly dissipated.

Another fun day of storms and lightning.

250-mb height/winds at 0000 UTC 26 September 2021.
250-mb height/winds at 0000 UTC 26 September 2021.
24-hour lightning plot with a lightning cluster near the San Francisco Peaks.
24-hour lightning plot with a lightning cluster near the San Francisco Peaks.

A Winter Rainbow in Flagstaff

Over the weekend we had an extended period of rain in the Flagstaff area. Normally we would see snow at this time of year—it is, after all, the middle of winter. Rainfall amounts were sufficient (1.35 inches at Flagstaff airport) to cause large increases in the flow of Oak Creek where gauges recorded a rise from ~2.4 feet (30 cfs) to 9.6 feet (6900 cfs). Other streams were running high as well.

A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.
A winter rainbow in Flagstaff.

I though it might be interesting to look at Lake Mary and Mormon Lake to see if lake levels were increasing as a result of the runoff. Indeed, they were, but not quite as much as I had hoped. Still, water rushing down Newman Canyon, a normally dry wash, into Upper Lake Mary was impressive.

Newman Canyon, a normally dry wash, is filled with runoff pouring into Upper Lake Mary.
Newman Canyon, a normally dry wash, is filled with runoff pouring into Upper Lake Mary.

Back in December 2004, we had a much bigger rain event. Lake Mary was frozen and the water rushing down the hillsides flowed across the top of the ice. The immense weight of the water caused the ice to break with thunderous booms. That is what I was hoping to experience. Didn’t happen because there was no ice this time.

Stream gauge for Oak Creek showing the rapid rise in stream flow.
Stream gauge for Oak Creek showing the rapid rise in stream flow.

My next stop was Mormon Lake. As I drove towards it the sun was able to break through the thinning clouds to my south. I took a quick look in the rear-view mirror to check for rainbows.

And, there it was. A winter rainbow in Flagstaff. Not rare, but certainly not common.