Saturday, August 31, 2013

Labor Day Weekend Begins

Labor Day weekend brings the end of meteorological summer, which has been extremely dry here in northwest Tucson, but very wet in most of southeast Arizona. The weekend started with middle clouds (above) drifting over the Catalinas this morning (Saturday, August 31st) and clear skies east, with clouds west. Precipitable water is trending slowly down after two days with values holding around 2 inches. Even though it was wet, there was marginal CAPE, so thunderstorm activity has been relatively suppressed. There was considerable old anvil cloud over the Tucson area yesterday, and only some lightning strikes on the north slopes of the Catalinas (below is CGs through 6 am MST this morning). A light anvil rain here late in the afternoon produced 0.01" in the gauge. Across the ALERT network only 23 sites had mostly very light rainfall - these were almost all at higher elevations in the Catalinas, Redington Pass, and the Rincons - in the Catalinas White Tail had 0.55" and Marshall Gulch had 0.43".

All the models forecast little of interest today and the early runs of the WRF forecast isolated showers over the Catalinas. There is still CAPE present and there may be more activity over higher elevations than models forecast. At 7:15 am (below) the clear/cloudy boundary is hanging right overhead, so there'll be abundant sunshine over much of southeast Arizona, with more heating than there has been in several days.

Finally, another tropical depression has formed west-southwest of the south end of Baja - TD 11-E. The NHC forecasts it to move little and to be quite weak (below). If it were to become a storm, it would be named TS Kiko.

1 comment:

  1. Anonymous9:09 AM

    Interesting contrast in your clouds W and clear E (towards here).

    Today's sky is so transparent in El Paso, but the humidity still up. But the last 4 days were amazingly humid, especially Thursday...dewpoints got near 70F here a day after .25" of rain. Amazing. I wonder if the drying will finally work it's way down, but my guess is no, since this is a high ridging in from the NE.