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.
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.
These slow-moving storms continued to move towards the northwest and this time we got lightning and rainbowsâ€”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 Parkâ€”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.Â About a half-hour after sunset it was over and the storms quickly dissipated.
Over the weekend we had an extended period of rain in the Flagstaff area. Normally we would see snow at this time of year.â€”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.
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.
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.
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.
A previous post displayed photographs of storms and weather that occurred during July of this year’s North American Monsoon. Here are photographs from August (plus the first day of September).
Cumulus and Cumulonimbus
A search for wildflowers and thunderstorms brought me to Rogers Lake west of Flagstaff. It’s a lake only ephemerally during springs with heavy snow runoff.Â But it makes a grand place for photographs when a wide-open vista is desired. Earlier convective storms were pushing an outflow boundary southward with new convection developing on the boundary.
There was just enough vertical wind shear on this day to allow some storms to briefly exhibit supercell characteristics and deviate to the right â€”which brought this thunderstorm near the edge of the North Rim of Grand Canyon.
Fog and Smoke
Sometimes the unexpected can be magical. When fog forms in Grand Canyon the visitors may be disappointed but there is the potential for amazing photographs.
The last few days have provided opportunities for photographing lightning and moonbows. A moonbow, of course, is nothing more than a rainbow that is lit by the light of the moon rather than the sun. Although not rare, I’ve never had an opportunity to photograph a moonbow before. Even better, it was a double moonbow. And, to make it even better, there was lightning to go along with it.
A short time-lapse video is available. The video covers a period of 24 minutes compressed into 8 seconds.
The previous evening I was also shooting lightning in Sedona and was able to capture this beautiful cloud-to-ground lightning bolt adjacent to Cathedral Rock. (Minor problem: it wasn’t in sharp focus. Oh, well.)
The summer thunderstorm season got off to a slightly early start this year with moisture flowing northward into northern Arizona in late June. A more typical start would be the first or second week of July. However, you won’t get complaints from most folks about the early start as it signals the end of wildfire season.
The highlight this early in the season is this rainbow seen from Yavapai Point on the South Rim of Grand Canyon National Park. The rainbow spans nearly 3/4 of a full circle and contains bothÂ primary and secondaryÂ bows. Rainbows typically are at least 50% hidden owing to the horizon. Only when the horizon is lower than the observerâ€”e.g., from a mountaintop or over a canyonâ€”will more than 50% be visible.