Friday, August 30, 2013

Tropical-Like Conditions Continue



It was an interesting day yesterday with many of the convective towers, especially in the afternoon, having a very tropical-like appearance, i.e., somewhat small and some not deep enough to produce anvils. Rainfall during the day was quite limited (at 5 pm MST only 28 of the ALERT sites had measured rain). However, during the night showers occurred over many parts of the network. This morning at 5 am the number of sites with rainfall during past 24-hours had increased to 68 (74% areal coverage). Amounts were better than yesterday with 36 sites having 1/4" or more rain and 14 sites exceeding 1/2". I've cropped two sectors of the ALERT network - above and below - to focus on the Tucson metro area. These two illustrate well that the showers avoided the lowest elevations and most of the city - we had a couple of sprinkles here, so another Trace day.



The lack of CG lightning strikes over Pima County during past 24-hours ending at 6 am MST this morning (above) indicates the dominance of warm rain processes locally. Visible satellite image below from 7:15 am today shows that widespread cloudiness continues. PW remains very high across all of southern Arizona.



The 12 UTC 500 mb analysis from NCAR RAL (above) shows that a weak piece of the IT has embedded itself in the anticyclone and now lies west-to-east across central Arizona. All of the models this morning shift the most significant storms and rainfall into the northern half of the state today, with much diminished shower activity across the south half.

The morning sounding for Tucson (below) continues to indicate some CAPE, especially for the high elevations, and heavy rain potential if strong storms develop. There is essentially no steering flow and stronger winds are limited to the upper levels of the troposphere.

I'm sure folks with swamp coolers are eagerly awaiting a dry out!


No comments:

Post a Comment