Is the Monsoon Over Already?

An early-season trough of low pressure moved across the west on Wednesday and Thursday disrupting the winds associated with the North American Monsoon. As the trough moved across the area, copious amounts of sub-tropical moisture surged northward across Arizona and surrounding areas. Widespread rain with embedded thunderstorms occurred across the area with areas of heavy rainfall and localized flash flooding.

Water vapor satellite imagery for 0210 UTC 20 August 2021.
Water vapor satellite imagery for 0210 UTC 20 August 2021.
500-mb analysis for 0000 UTC 20 August 2021 (image courtesty NCAR/RAL).
500-mb analysis for 0000 UTC 20 August 2021 (image courtesty NCAR/RAL).

But now the trough has moved northeastward across the Rocky Mountains and into the northern Plains states. The moisture across the southwest has been swept away. This can be seen in the water vapor satellite image. The warm colors are associated with a drier air mass and this has overspread the southwest.

Medium range models such as the GFS (Global Forecast System) suggest that moisture and showers will not return to the area before the end of the month leaving us with an extended break in rainfall.

Hurricane Grace at 1800 UTC 20 August 2021. (Image courtesy TropicalTidbits.com)
Hurricane Grace at 1800 UTC 20 August 2021.
72-h forecast for the remnants of tropical cyclone Grace.
72-h forecast for the remnants of tropical cyclone Grace. (Image courtesy TropicalTidbits.com)

But there are always some features that can result in different outcomes. For example, Hurricane Grace is moving westward across the Gulf of Mexico and is expected to make landfall in Mexico. The remnants of this tropical cyclone will continue to move to the west and may emerge in the Pacific south of the Gulf of California. If this happens, there might be a surge of moisture moving northward toward Arizona that could bring a return of showers and thunderstorms sooner than models currently suggest.

Sunset Convection and Lightning

It was a pleasant evening in Sedona watching thunderstorms as the sun sank lower in the western sky. It was mostly clear in that direction allowing sunlight to illuminate storms in the east. This is one of my favorite setups: clear in the west and stormy in the east.

Early evening sunlight illuminates thunderstorms and Cathedral Rock in Sedona.
Early evening sunlight illuminates thunderstorms and Cathedral Rock in Sedona.
Early evening sunlight illuminates thunderstorms.
Early evening sunlight illuminates thunderstorms.
Lightning from a distant storm after sunset.
Lightning from a distant storm after sunset.
Lightning from a distant storm after sunset.
Lightning from a distant storm after sunset.

The setting sun produced wonderful pastel colors on the clouds and occasionally illuminated the rock spires and buttresses in the middle distance. And after sunset, distant storms showed large anvils along with occasional bolts of lightning.

Wildflowers Along the Arizona Trail

Two recent trips to different sections of the Arizona Trail (AZT) resulted in these wildflower photographs. First, we have a beautiful pincushion cactus seen along the section of the AZT south of Pine Grove Campground on Lake Mary Road. We were on our mountain bikes and as we passed then in the morning the flowers were closed. On our return a few hours later, the flowers were wide open and beckoned for us to stop and admire them for a few minutes.

Pincushion cactus seen along the Arizona Trail.
Pincushion cactus seen along the Arizona Trail.
Pincushion cactus with a bee.
Pincushion cactus with a bee.

Next, we have wild iris on the section of the AZT near Snowbowl Road. Many of the iris that day were already starting to wilt and most had only pale colors. This one had such vibrant colors that it was worth stopping in the middle of our trail run to grab a few photos.

Wild iris along the Arizona Trail.
Wild iris along the Arizona Trail.

We’re still in the midst of our dry period with the North American Monsoon season still at least a month away. Once that starts, wildflowers should blossom everywhere.

Conjunction of Venus and Mars

As mentioned in the previous post, the planets Venus and Mercury passed very close to each other in the evening twilight sky a few nights ago. In fact, this conjuction is the closest conjunction of these two planets until 2033. I chose to photograph the two planets the night before closest approach as I was interested in getting a bit of separation of the two in both the sky and their reflections in the water.

Venus and Mercury in evening twilight (2025 MST 27 May 2021).
Venus and Mercury in evening twilight (2025 MST 27 May 2021).
Venus and Mercury in evening twilight (2037 MST 27 May 2021).
Venus and Mercury in evening twilight (2037 MST 27 May 2021).

The first image was taken at 2025 MST 27 May 2021 with an 85mm focal length. The second image was taken a short time later at 2035 MST with a focal length of 120mm.

In the first image, there is a very nice and long reflection of Venus in the water; the reflection of Mercury is also present but is faint and diffuse. In the second image, the planets were just a few minutes away from dropping below the ridge to the northwest. In this image, the reflections of both planets are easily seen.

The weather cooperated nicely with light winds allowing reflections on the smooth water of Upper Lake Mary.