Tuesday, July 31, 2012

Salt Lake to Get Some?

Monsoonal thunderstorms caused some flash flooding in southern and central Utah, southern Nevada, southeast California, and northwest Arizona yesterday.  The Salt Lake Tribune reports this morning that flooding damaged multiple homes near Fountain Green and the Wood Hollow Fire burn scar.

Source: Sanpete County Sheriff's Office
Overnight, monsoonal moisture spread northward and precipitable water increased over Salt Lake City as can be seen in the analysis loop below.

and in the GPS precipitable water observations from the Salt Lake City International Airport.

At issue is whether or not the high clouds presently in place will break up enough to enable sufficient surface heating to get things going.  Although rain would be appreciated by most of us, flash floods and debris flows are a concern if heavy rains fall over wildfire scars near Alpine, Saratoga Springs, and elsewhere.

A continued threat of showers, thunderstorms, and flash flooding lingers in portions of Nevada, southeast California, and western Arizona as well.  In fact, flooding in the Imperial Valley of California this morning forced the closure of I-8 and SR-98.


  1. There is a fairly compact cyclonic circulation centered north of Imperial, surrounded by deep convection and dew points of 70-75 F. This may generate extremely impressive rain totals in the CA deserts. It looks to me like the circulation is most apparent near 700 mb, perhaps some sort of hybrid between an upper-level system and a warm-core feature? How would you classify this thing?

    1. I haven't thought about it much. I figured it was a tropical easterly wave, but an analysis of the origins and structural evolution would be interesting.

  2. The more I look at it in the satellite and radar imagery, I think it is entirely warm core, basically a very organized tropical wave. The type of system that would likely develop into a tropical storm or hurricane very quickly if it were over the warm ocean.