Tuesday, June 30, 2015

TWC Special Sounding Today

First - a storm chase photo from Mike Olbinski www.facebook.com/mikeolbinskiphotography
taken last night. Specifics of where and when exactly not known.

The NWS Forecast Office did take a special sounding at 18 UTC today - above. The sounding shows a new BL developing with considerable low-level moisture and CAPE. But it appears that the new BL will also have considerable CIN (Convective INhibition). Note that at 2:00 pm the surface ob for TUS is 96/54 versus 104/54 at this time yesterday. So, it will probably take a considerable convergence zone to force storm development at low elevations locally. The PW has also been falling since the early morning max. The 18 UTC analysis of blended PW from CIRA (below) shows a pocket of drier air sneaking into southeast Arizona. 

The GPS estimates of PW (above for Bisbee and below for TWC) have been showing the drops also.

It appears that once again it will be a duel between the drier air and very moist air to the west. The added hitch for today is that substantial low-level convergence will have to develop to get storms in the low elevations of eastern Pima County. Plot below (from MesoWest for 1:00 pm MST) shows most light winds currently in play.

1 comment:

  1. Anonymous7:25 AM

    Shortly after you wrote this, the situation changed as the winds really picked up from the WNW and the IPW began to increase. We know what happened next.