Minor Update - 07_03_2023

 Overview:

Dry air continues to dominate the region even though surface dewpoints have increased overnight and are a few to several degrees higher than this time yesterday. The increase in dewpoints have spread overnight from west to east and seem to be associated with a modest and very shallow moisture surge from the Gulf of California. This pattern will look to continue over the next 48 hours with the moisture slowly getting deeper over time. In spite of this modest increase in moisture, convection still appears unlikely before this weekend when deeper southerly flow sets up as heights fall in the Pacific and the center of the high-pressure system dominating our area shifts eastward. This should allow for higher precipitable water values that are currently confined to the Baja peninsula and the Gulf of California to start working its way into southern Arizona. Keep in mind that moisture is still not well established in Mexico, with most of the eastern states remaining dryer than climatology.


Moisture:

The above image shows the evolution of the surface map. The green line is indicative of greater than 40 F dewpoints in AZ and NM (ignoring California). Note that dewpoints north of the Gulf of California had reached 61 F by 18 Z this morning. Meanwhile, shallow moisture advection is competing with mixing further east. This has resulted in any moist instability so far today being confined to the Gulf region and locations south of the border as seen in the mesoanalysis map from SPC below. Currently any instability is being capped and is further inhibited by an unfavorable synoptic-scale pattern.


Currently, any cloud development is confined to the higher elevations of the Mogollon Rim (weather.cod.edu)



The lack of any significant deep moisture is evidenced by the following low-level water vapor image (weather.cod.edu)


The following upper-level water vapor image (weather.cod.edu)


The upper-level water vapor loop indicates a relative minimum in moisture in the region of anticyclonic vorticity advection stretching from New Mexico southwestward toward the Baja peninsula.

This axis corresponds to the lower precipitable water values in the mesoanalysis (spc.noaa.gov)


Looking Ahead:

The earliest that I can see anything more than isolated dry convection is this weekend. The upper-level high moves eastward concomitant with a weak trough establishing itself along the West Coast as can be seen in the 500 hPa height anomaly map from tropicaltidbits.com.

This should have the effect of creating a less hostile environment for ascent, as well as increasing the moisture available. However, moisture will not likely be well established in the area before Monday.






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