PW Increases Across Southern Arizona

The plot above shows the trend of PW observed via GPS at the University of Arizona site. There was an initial increase last Thursday related to the northward push of moist air associated with Cosme. Since then the PW has increased steadily due to continuing weak advection northward from western Mexico and the GoC. There has been an increased component due to recycling mid-level moisture into the boundary layer by cool, moist downdrafts, particularly yesterday. The large MCS over Sonora last evening has pushed more moist air into southwestern Arizona. The CIRA blended PW product for 13 UTC this morning is shown below (bright green to gold colors indicate 37 to 50 mm of PW). The push into southwest Arizona is pronounced and well indicated by this product. TS Dalila is now a player also as it is located off Cabo Corrientes this morning.

Of interest today -

A large MCV was left behind by the MCS and it is over northern Baja this morning and may bring some thunderstorm activity to southern California this afternoon.

The morning sounding at Tucson indicates 35 mm of PW and a bit of CAPE above 600 mb for lower elevations. Temperatures are cooler in low levels and the high will be down from yesterday's 111 F. The winds aloft are fairly chopped up and the degree to which they recover will affect propagation of afternoon storms.

Yesterday's storms produced strong wind gusts and some spotty severe reports around the city. The airport had a gust to 68 mph (59 kts), while DM AFB had gusts to 54 mph. I estimated gusts here at the house at 50 mph or a bit higher. Just a spit of rain here; 0.03" at TUS, but 0.36" at DM. No rain indicated at atmo and gusts there on the roof were an anemic 37 mph. Across the ALERT network 33 of 92 stations reported rainfall for the 24-hours ending at 6 am this morning, mostly in the east and southern portions of the network.

The WRF model runs at Atmo are providing conflicting forecasts for this afternoon. The WRF-GFS early run forecasts another round of severe thunderstorms and a very strong outflow across the metro area at around 5 pm. This run over-forecast early morning activity and may have been impacted by this. The morning run of the WRF-NAM has much less activity over eastern Pima County this afternoon - which is what I would expect given cooler afternoon highs and the limited CAPE.

The upper-level flow appears very difluent over southeastern Arizona this morning, which is a positive aspect of today's large-scale setting.

Finally, June ended with every day having high temperatures over 100 F at the airport - a first since records have been kept here. Precipitation for June was a Trace here at the house.