Today's Update

Winds again are on the weak side at the surface this morning, with a land breeze evident along Galveston Bay. Winds further south in Texas City and Galveston are stronger out of south, indicating that the land breeze is localized over Galveston Bay only. Profiler data shows winds are stronger aloft (20-30 kts from 0.5 to 3 km), and they are more easterly than yesterday (from ESE). I expect the same evolution of winds as in the past few days, with the exception of them being more easterly light/calm in morning, picking up from the southeast near noon, with sea and bay breezes along coasts developing by noon or 1 p.m.; east-southeast winds during the middle and late afternoon. Looking at the background levels, Galveston is quite high with a 63 ppb and Texas CIty is reporting 32 ppb of ozone. With the land breeze over Galveston Bay, a return flow event of early morning emissions will cause ozone levels to be quite high this morning. By 1 p.m., ozone levels of 140-160 ppb (hourly averages) are probable along Galveston Bay and the Houston ship channel. This morning's LCH and CRP soundings, along with higher surface dewpoints, suggest that thunderstorms will develop along the early afternoon gulf/sea breeze. Chances that a thunderstorm will occur over the surface observing network is 60%. Therefore, it will be an early show for high ozone values. By 1 p.m., thunderstorm development, increased vertical mixing, and higher wind speeds at the surface will help to dissipate the plume.

Max T 97-99 F (37 C)

Clouds scattered cumulus early, building to broken stratocumulus by late morning, and scattered towering cumulus/Cb this afternoon. Anvils from the convection will stream to the west and west-northwest, building a broken ceiling aloft by evening.

Roughly similar to today. Light winds overnight will change to east-southeasterly winds by afternoon. Because of mixing that will take place today, expect ozone levels to be lower tomorrow (due to lower background levels). Thunderstorms again are likely to develop along the sea breeze by early afternoon.

A ridge building over the southeastern US will bring unsettled weather with possible widespread showers. Prevailing winds will be from the east-northeast. Dirtiness of air mass will depend upon extent of upstream and local showers, but it could be quite dirty. Lighter large-scale winds than in the past few days would favor high ozone. The urban plume would be advected toward the northwest, most likely toward Austin. By Monday, a watchful eye must concentrate on the path of Hurricane Debby. Currently, the strength of the high over the SE US, combined with the lack of any strong shortwave approaching in the models, leads me to suspect that Debby could very well visit the Gulf by early next week.