Snow and palm trees at local golf club in Brownsville, December 25, 2004
The Valley's White Christmas!
Miracles Happen as Snow Accumulates Christmas Morn’

The Rio Grande Valley of Deep South Texas experienced one of its most memorable Christmas Holidays ever. A rare combination of weather events developed in late December that produced several inches of snowfall, which in itself is quite rare in this region. However, to have snow fall on Christmas Eve and morning is a historical first according to the more than 150 years of weather data. This White Christmas is certainly one for the record books.

Meteorology, 12/22-24
The freezing temperatures and snowfall were expected in South Texas and National Weather Service Offices were talking about the arrival of unseasonably cold temperatures prior to the holiday. Snowfall was mentioned as a possibility and as Christmas drew closer, snowfall became more likely as the weather forecast became more focused.

We need to look back to the week before Christmas in order to recap the details of this historic event. Signals from the numerical weather forecast models suggested a strong cold front and arctic air mass would move southward along the Rocky Mountains into Texas and eventually over the Lower Texas Coast. This cold front moved through Brownsville, Wednesday afternoon (12/22/2004). A second reinforcing surge of arctic air followed the initial front, dropping temperatures into the 30s and low 40s late Thursday (12/23/2004). Maximum temperatures on Friday (12/24/2004) were in the upper 30s to low 40s across the Rio Grande Valley. Widespread moderate rain covered much of the area with most locations reporting one half of an inch to nearly one inch of liquid precipitation (Figure 1, below). The cold rain began to taper off on Christmas Eve as temperatures began to fall below freezing.

Doppler radar animation snippet, early morning Christmas Eve, 2004, Brownsville (click to animate)
Figure 1. Base reflectivity, NWS Brownsville Doppler Radar, 6 AM to 703 AM December 24, 2004 (click for animation)

Meteorology, 12/25
With the cold air trapped at the surface and wedged against the foothills of the Sierra Madre Oriental, an upper level low with Pacific moisture was moving east across Northern Mexico. The moisture and upward vertical motion generated by this upper level system caused snow to begin falling across Deep South Texas after 10 PM CST. The snow fall persisted through midnight (Figure 2) into Christmas morning and eventually ended around 4 AM on (12/25/2004) leaving behind the first White Christmas ever recording in the Lower Rio Grande Valley of Texas, and most likely the first White Christmas ever in extreme Northeast Mexico. Click here for a detailed meteorological study of this event.

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The National Weather Service Office in Brownsville began talking about the potential for freezing temperatures and a winter mix of precipitation as early as Monday December 20, nearly 5 days in advance of the storm. Forecast Discussions, Hazardous Weather Outlooks, and Special Weather Statements were consistently mentioning the potential for a winter blast in Deep South Texas by Christmas Eve.

Doppler radar animation snippet, early Christmas Eve near midnight, 2004, Brownsville (click to animate)
Figure 2. Base reflectivity, NWS Brownsville Doppler Radar, 1101 PM December 24 until 130 AM, December 25, 2004 (click for animation)

As the event began to unfold, the meteorologists at NWS Brownsville refined the precipitation forecast to account for rainfall changing to sleet or a rain/snow mix, and eventually changing to all snow for the overnight hours between December 24th and 25th. The first in a series of winter weather warnings and advisories - Freeze Warnings - were issued by the National Weather Service at 230 AM December 23rd. Around noon on Christmas Eve, the Freeze Warnings were upgraded to Winter Weather Advisories, which were subsequently upgraded to Winter Storm Warnings later that evening for Heavy Snow, continuing until the morning of December 25th when the snowfall finally ended.

Table 1: Regional Snowfall, Coastal Bend and Lower Rio Grande Valley
Location
Total Snowfall (in inches)
Brownsville
1.5
Harlingen
1.5
San Benito
1.5
La Joya
1.5
South Padre Island
2.5
Port Isabel
3
Rio Grande City
3
Sarita
3
McAllen
3.5
Raymondville
3.5
Hebbronville
5
Corpus Christi
4
Victoria
11
Brazoria
13

All in all, the snowfall was greeted with joy and excitement since it has been almost 110 years since the last measurable snow fell in the city of Brownsville - and for that matter, much of the Valley! Numerous spotters and weather watchers, and just plain curious folks stayed alert until the early morning hours taking photographs and video footage of this “once in a lifetime” event. Click here for photos taken by office staff.

Isopleths of snowfall for Deep South Texas and the Lower Rio Grande Valley, Christmas 2004 (click to enlarge)
Figure 3. Isopleth map of snowfall totals across Deep South Texas and the Lower Rio Grande Valley (click to enlarge)
 
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