Totally Down Day

Yesterday was a totally down day across almost all of southeastern Arizona, except for right along the border. Lot of debris cloud at sunrise today from nighttime MCS and storms in northern Sonora. The morning sounding looked favorable for at least mountain storms yesterday, but there were few clouds any where during afternoon. The evening Tucson sounding appeared more favorable for storms (see sounding below) than conditions obviously were. The WRF-GFS at Atmo had forecast a down day yesterday, starting with the midnight Saturday run - so excellent forecasts. Although the 500 mb anticyclone was nearly overhead at 0000 UTC, I don't see any signatures of strong subsidence in the TUS sounding (below - which was a couple of mm too dry in PW). I also checked the RAWS mountain top observations - theta was 6 to 10C higher than at TUS observation site and mountain surface parcels were quite unstable. So, if anyone has thoughts on why it was so dead yesterday, let me know.

The 0000 UTC IR image (above) shows a huge, cloud-free hole over almost all of southeastern Arizona.

The early run of the WRF-GFS indicates another down day for southeast Arizona, even though it remains very moist locally. The WRF brings in much drier low-level air from the northwest and drops PW by 10 mm, before it rebounds late in the evening. As a result, WRF-GFS forecasts CAPE only along the border during midafternoon. Will have to watch to see how the situation evolves. The WRF-GFS forecast 1200 UTC TUS sounding (above) is considerably drier than the actual observed sounding (below from SPC). The NAM appears to forecast some mountain storms today in the southeast part of state. The 500 mb mb anticyclone has moved off to the north of El Paso, and the vertical wind profile is reasonably good. So, the am observations again appear more favorable for storms than the WRF forecast indicates.