Peak wind gusts across Deep South Texas and Adjacent Gulf and Bay waters, Dec. 24 2009 (click to enlarge)

Santa Blows in with the Wind in 2009
Gusts early and late cause minor damage in Valley

An intensifying cyclone, which moved across North Texas into Arkansas (below) before turning northward and easing up the Mississippi Valley, pushed a vigorous front through Deep South Texas during the pre dawn hours of Christmas Eve. As the storm deepened, a low level northwesterly jet developed on its southern and western flank, with wind speeds ranging from 50 to more than 60 knots (60 to 75 mph) not too far above the earth’s surface from central Oklahoma south to the Rio Grande Valley. These winds would concurrently produce a bona fide blizzard (below, and box at right) in Oklahoma, where more than a foot of snow was blown by sustained winds peaking near 50 mph and gusting over 60 mph at times!

Across Deep South Texas, two wind peaks were noted: First, along and just behind the early morning cold front, where northwest winds gusted briefly between 40 and at least 50 mph, causing the bulk of the initial minor damage; later, when low level warming (from compression of the air) mixed down some of the 50 to 60 mph northwesterly winds associated with the developing jet. Afternoon surface gusts mainly between 1 PM and 5 PM ranged from more than 50 mph in Kleberg County, to 35 to 45 mph across nearly all of Deep South Texas. Mariners in the offshore waters beyond 20 nm did not experience the same daybreak lull; Gale or near Gale force sustained winds prevailed from the pre dawn hours until near sunset.

The pulsing wind gusts did not leave the Lower RGV unscathed. While there were no reports of significant damage, the estimated 50 mph gusts helped to uproot a 40 foot tall oak tree in Pharr between 330 and 4 AM, blew off shingles from older apartments near the intersection of Price Road and Old Port Isabel Highway in Brownsville at around 430 AM, and blew down a 50 foot section of fence in north Brownsville at around the same time. Dozens of palm fronds and a few mesquite branches were also blown down in Brownsville. The second wave of strong winds blew down a parking lot light pole in McAllen, causing damage to vehicles parked nearby.

National Snowfall Map, December 25th 2009 (click to enlarge)
National snowfall map analysis, Christmas Day 2009. For more snow analyses, go to NOAA’s NOHRSC National Snow Analysis Page

White Christmas for Winter Texans?

For those who left the chill of the Northern Plains, Upper Midwest, and Canadian Prairies for milder weather in the Rio Grande Valley, you also left your dreams of a White Christmas behind. While snow is on the ground most of the time on Christmas Eve and Christmas Day, rare is the case when a full blown blizzard slams the Great Plains corridor, and heavy snows fall during the period from Iowa to Minnesota, on Christmas Eve and Christmas Day. Even North Texas, including parts of the Dallas/Fort Worth Metroplex, got a taste of White Christmas. Most notable was the central and eastern Oklahoma Blizzard. Blowing snow is not unusual one or twice each winter, but combine the blowing snow with 14.1 inches, as best could be measured, along with drifts higher than 4 feet, was quite an event.

National Weather Map, December 25th 2009 (click to enlarge)
National weather map, Christmas Morning 2009. White hatched area denotes continuing heavy snow and blizzard conditions across the Plains and Upper Midwest.
Peak wind gusts across Deep South Texas and Adjacent Gulf and Bay waters, Dec. 24 2009 (click to enlarge)

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