Stagnant, Weak Pattern Continues

Storms Over Catalinas at Noon on Tuesday Sept. 8th

Storms developed very quickly yesterday late morning yesterday and by early afternoon we anviled out here at the house. At dark there were several cells just to the west that produced a good lightning show but only a spit of rain at house. Measurable rainfall occurred over about 50% of eastern Pima County during last 24 hours. Nine stations within the ALERT network had half an inch or more and 3 stations measured over an inch.

The weak flow continues today with a large ridge over the Southwest and northern Mexico with embedded features drifting around. Thermodynamics a bit more stable today with more heating required for storms to develop at lower elevations. Surface pressures this morning are up about 3 mb relative to yesterday, when they'd fallen 3 to 4 mbs. Precipitable water remains around 1.25" over south central Arizona. All-in-all not much to say about this stagnant pattern except that NAM forecast indicates interesting changes by Friday, as a large complex cyclone becomes embedded in the ridge, while pushing main anticyclone north and west.