More Interesting Day Today

Last night's large MCS in Sonora redeveloped northward to the border, but without significant outflows coming into Arizona (other than out at Yuma this morning, where there has been a shallow surge of low-level moisture - see KYUX VAD above). So, once again, my forecast in the post below did not pan out very well - having a tough summer. Moisture values over southeast Arizona have increased into PW range of 1.50 to 1.75" - perhaps with a bit of help from the MCS.

The MCS has left behind a very large MCV that is spinning away to the northeast of Hermosilla (see the visible image above from 1430 UTC this morning). There is no sounding from Guaymas this morning, which would have been very helpful. Showers to the north of the MCV have built northward into Arizona around Bisbee this morning. A side issue is that of whether the circulation over Sonora is an MCV or a larger-scale vorticity maxima that has been enhanced by the nighttime MCS? I tend toward the later answer. Regardless, the large mass of chaotic cloudiness that attends the circulation will affect much of southern Arizona today.

This morning's sounding remains similar to those of past week. A bit more moisture and instability are indicated by the SPC diagnostics this moring (above). The wind field below 300 mb remains chopped-up with very light wind speeds - perhaps this situation will improve during the next 48-hours. The models have somewhat different forecasts this morning. The NAM analyzes the 500 mb vorticity maxima as being near the border. However satelitte loops seem to indicate that NAM has this feature a bit far north. By midnight the NAM forecasts a significant circulation and vorticity maxima to be over the southeast corner of the state. The NAM has forecast significant rains by midnight along the border and extending northward over the much of the southeastern part of the state. Most rain in the NAM forecast for many days.

In contrast, the U of A Atmo, high-resolution version of the WRF-GFS model forecasts today's most significant rains to remain south of the border (above is WRF-GFS forecast rainfall through midningt tonight - usual precip void over metro Tucson. So, today will be an interesting day as the models come up with differing solutions for the day. Note - that I have no idea whether the 1200 UTC runs of WRF-GFS will converge toward the morning NAM forecasts.