Sunny days headed to the Lower RGV to end September, 2008 Clear nights with developing fog to end September, 2008
Here Comes the Sun!
After Wet Mid to Late Summer, Drying Closes September

Here Comes the Sun...
After a late spring and early summer drought that ranged from severe to exceptional, followed by a complete U turn with one of the wettest July through September periods on record, a "well earned" spell of pleasant weather will finish September, starting with a fine weekend featuring plenty of sunshine each day and clear skies at night. High pressure at the surface, expected to set up shop across the western Lower Rio Grande Valley and Rio Grande Highlands, will provide a light to moderate north to northeast breeze each day, bringing lower humidity to the region, and holding daytime temperatures near or a hair below seasonal averages. Calm winds at night will allow readings to drop through the 60s, with perhaps some upper 50s in normally cooler locations away from the coast. After the summer swelter, mixed in with clouds, rain, and the occasional threat from tropical cyclones, this weekend - in fact the rest of September - will be a treat, indeed! A great time to enjoy outdoor activities in the Valley, this is your weekend.

...But Watch for Fog
The combination of clear, calm conditions, with lengthening nights, and plenty of residual ground moisture, will set the stage for locally dense ground fog each morning through the weekend and perhaps into early next week. Persons planning to drive late at night and during the early morning hours should remember to heed the following safety precautions:

  • Be alert to rapidly changing visibility, especially in rural or low lying areas.
  • Use low beam headlights, and fog lights if available, when encountering dense fog.
  • Slow down, and maintain a safe distance between your vehicles and others on the road.
  • If the fog is too thick for you to drive safely, pull well off the road into a safe location and wait until conditions improve.
The best prospects for fog are in low lying and preferred rural areas, starting around or a little after midnight and continuing through early to mid morning. Conditions should clear out between 8 and 10 AM each day.


Rainfall: The Story So Far
September, 2008 completes a trifecta of wet months to close out the warmest part of the year. Indeed, preliminary rain totals at Brownsville since July 1st (25.42 inches to date) rank third all time, since records began in the late 19th century; at Harlingen, 25.12 inches ranks 2nd all time since 1911, with only the notable hurricane year of 1933 having more rain. Preliminary rain totals for September, 2008 to date rank in the top 15 all time at Brownsville (9.57 inches), and in the top 20 all time at Harlingen (8.34 inches). Highest storm totals were found at the coast, where at least 10 inches fell (more than 11 inches at Laguna Atascosa National Wildlife Refuge, northeast Cameron County), on top of eroded shorelines from Ike and Gustav. The image below shows a rainfall estimate for September, 2008, through the 25th. A monthly, and seasonal, summary will be posted in early October.

Rainfall estimate based on observed and radar data, September 1-25, 2008
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