Quick Look At Morning Products Sunday July 10th

The morning Tucson sounding (above, from the SPC sounding page) looks a bit strange. There is little structure in the vertical and there are two elevated, old boundary layers, but neither has expected Td structure. The PW, however, is quite close to the GPS value this morning. Winds aloft are mostly light and predominantly with a southerly component. Quite a blah sounding. With considerable morning cloud cover and probably lots of anvil cloud this afternoon, I don't have much confidence in estimating what a late afternoon sounding will look like. But regardless of how I look at the sounding, it's hard to forecast that there'll be much CAPE at low elevations. So, today will probably play out like yesterday - heavier storms on the mountains with some drifting off to low elevations, but no way to predict just where and when.

The above graphic is the NCAR 500 mb analysis this morning. Of interest is the apparent weak trough off to west of San Diego - this feature may have wobbled back and forth from east to west, and west to east, last few days. Another weak trough is over southern Texas. Stronger wind speeds around the anticyclone remain mostly east of the Contiental Divide. Of great concern is the continuing, massive data void over Mexico - meaning that the models continue to mostly use their forecasts to initialize next run.

The NAM 500 mb analysis indicates an elongated string of vorticity maxima running north up the Sierra Madre in the data void. Are these there, or might they be model-generated, convective-related feedbacks in the model's previous forecast? The model does analyze the features west of San Diego and in Texas.

Finally, the NAM forecast for midnight tonight pulls several of the maxima northward, while bringing a weak feature into Arizona from the west. The vorticity maximum, that results over southern Arizona, appears to be associated with a model predicted area of significant rainfall over south-central Arizona. I have little confidence in forecasting within a sloppy, weak synoptic environment as we have - best approach is to sit back this afternoon with a beer and watch what happens.