MTW Discussion

August 2009 has reached 100º or greater 9 times out of the 9 days that have passed so far this month. The high at the San Antonio International Airport yesterday was 101º. This also marks the 44th time San Antonio has recorded triple-digit temperatures; the most times of any summer (the previous record was 36 times in 1998). In addition, it was the 97th time San Antonio has topped 90º this year. Summer 2009 is on track to being one of the hottest — if not the hottest — summer on record to date. The forecast for the week does not show much relief from the 100º heat throughout the foreseeable future.

A few isolated showers and thunderstorms are possible mainly to the south and east of San Antonio during peak afternoon heating. These storms are a result of a southerly flow aloft due to ridging over the Eastern United States. However, most of these storms will be small and few and far between. Rainfall totals should remain relatively light across an overwhelming majority of the region. Otherwise, expect generally partly cloudy skies with temperatures reaching 100º or greater across South-Central Texas.

Tomorrow, the upper level ridge will shift westward over Texas and eliminate any probability for precipitation. Temperatures will again soar into triple-digit territory. However, by Wednesday, the ridge will shift far enough to the west to allow for a return to the Northerly/Northwesterly flow aloft. This will allow for isolated afternoon storms with overnight storm complexes traveling south/southeastward across South-Central Texas. At this time, it appears most of the activity should pass east of San Antonio, but current rain chances in the city remain at 20%. A frontal boundary may pass through South-Central Texas Wednesday night into Thursday ushering in a slightly drier and cooler air mass. Temperatures, however, should hover near the century mark.

So far in 2009 there have been no named tropical cyclones in the North Atlantic. This should change soon as activity in the tropics is on the increase and at a rapid rate. The National Hurricane Center has flagged a region off the coast of Africa just south of the Cape Verde islands for a moderate risk of tropical cyclone formation. This storm has shown signs of organization through the past 24 hours and has continued to organize through the overnight and morning hours. Satellite and microwave imagery indicate a clear and well defined low-level circulation with most of the convection located symmetrically near the storm center. Several computer models develop this system into a tropical storm fairly soon and move it west-northwest through the Atlantic. Behind this storm are several disturbances over Central Africa, which will eventually make their way into the Atlantic. Models also develop a few of these disturbances into tropical cyclones.

The Edwards Aquifer is holding relatively steady, but should be on a downward trend the next few days unless rain falls this afternoon. The Stage 3 Water Restrictions Trigger at the J-17 Well in Bexar County is 640 feet above mean sea level. San Antonio has avoided the onset of Stage 3 restrictions at least 3 times so far this summer due to last minute rains. We will continue to monitor the latest levels. Stay tuned for further developments.