A tropical low pressure system has moved northward the past several days and is now south of the tip of Baja. This system has a large area of strong convection associated with it this morning - see IR image above from 1330 UTC (6:30 am MST). Such systems and large MCS events over the GoC can trigger strong surges of low-level moisture up the GoC - so that's the first thought I had when I saw this image.
The blended PW analysis (below for 1300 UTC) from CIRA at Colorado State University indicates that PW values of over an inch extend northward up the GoC for about 2/3rds of its length and the same is true for the western mountain slopes of Sonora. PW values of a half to near an inch cover most of the Sonora/Arizona borderlands.
I have taken a look at today's early run of the WRF-NAM model from Atmo with an eye toward the model's forecast of the evolution of the PW field through mid-week. This is best done with the 5.4 km grid version of the model - as shown above valid at 7 am MST tomorrow morning (June 24th) and below valid at 11 pm MST on June 25th. The forecasts indicate a serious battle between the very dry air that covers most of the forecast domain and the very moist, mT air trying to move northward. The forecasts indicate that the dry air prevails for the next several days over most of Arizona, but with pushes of moisture making it into Cochise County at times. The model continues to forecast some thunderstorms over there, but with limited coverage.
Once the week is over we'll be approaching the first week in July and will watch to see if the Pacific anticyclone weakens and shifts a bit westward to give the mT air a chance to move further north.
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