PW Bouncing Around This Afternoon

The precipitable water (PW) has been bouncing around some today - Tuesday, June 24th. The CIRA blended PW analysis for 19 UTC this afternoon (above) indicates that dry, midlatitude air from the Pacific dominates over most of the West and Southwest U.S. However, subtropical, mT air dominates over much of western Mexico. The GPS time series below indicate PW varying substantially on campus and also out at the community college in Sells (where values have dropped to as little as 1/10 inch at both sites). Unfortunately, the site at Douglas (closest to the airmass over Mexico) appears to be out-of-service.

The graphic below is this morning's forecast of PW from the WRF-GPS at Atmo and it looks pretty good for Arizona. However, model forecast appears a bit too dry over northern Mexico, parts of the Texas Big Bend, and parts of New Mexico, where some thunderstorms have developed.