A discussion of the Texas Christmas Snow Miracle of 2004.

[Ed Lizard]

BTW, Robbstown, TX, one of the towns that picked up near a foot of snow, a poor agriculural town whose football team is named 'The Cotton Pickers', is the hometown of Mr and Mrs. Ramiro Romo, parents of Dallas QB Tony Romo. As if this story needed any more flavor.

On 24 and 25 December 2004, much of south

Texas received a record snowfall. Measurable

snow was reported from the Galveston/Houston

region, southward to Corpus Christi, Brownsville

and into Northeastern Mexico (Fig. 1). Embedded

within the larger snow field was a narrow, heavier

snow band. This band had maximum snow

depths of 33 cm (13 inches), a half width (distance

between maximum snowfall and half that amount)

of approximately 48-64 km (30-40 miles), and a

total length of more than 320 km (200 miles).

Although Figure 1 reveals only one heavy snow

band, a composite of the radar data from Weather

Surveillance Radar-1988 (WSR-88D) sites across

south Texas indicated that there were at least two

distinct bands that formed during this event. The

entire snow event occurred between the hours of

0000 and 1200 UTC 25 December, with the

heaviest snow falling between 0200 to 0800 UTC.

Maximum snowfall rates of 5 to 10 cm h

-1 (2 to 4inches h-1) were observed within the heavy snow

band region.

To put this Christmas 2004 snow event into

historical perspective, the last time many locations

across south Texas had recorded snowfall

amounts greater than or equal to those received in

this storm was back in the late 1800s. For

example, Corpus Christi (not in the heavy snow

band) and Victoria had not received such a

snowfall since February 1895. It was also the first

ever recorded Christmas Day snowfall for Victoria

(Wilk et al, 2007). Many locations from the

Houston/Galveston area, southward to the lower

Rio Grande Plains and northeast Mexico, recorded

their first white Christmas since local records

began (NCDC Storm Data, Dec. 2004). The

February 1895 snow event also produced a

narrow band of snow across south and southeast

Texas, but the snow totals were nearly double (10-

20 inches) those of the current case (Griffiths and

Ainsworth, 1981). Snowfall amounts were likely

higher with the 1895 storm simply because it

lasted much longer (three days) than the 2004

event, which persisted for only 8 to 12 hours.

The primary motivation for this study was to

diagnose the potential cause(s) for the narrow

heavy snow band, which was not predicted by any

of the operational numerical models, even up to

the time of the event. Since such a winter event

requires the presence of a deep, sufficiently cold

environment to produce frozen precipitation, a

brief investigation into the origin and maintenance

of the deep cold air mass was also included.

Overall, it is expected that this study will reveal

that, despite the rare snow totals and deep cold air

mass across low latitudes, the associated

dynamics were not necessarily unique when

compared to other more northern, narrow heavy

snow band events.

Corresponding author address: Ronald F.

Morales Jr., National Weather Service, 300

Pinson Dr., Corpus Christi, TX 78406;

e-mail: [email protected]

You have to read the whole paper, but to drop a hint, lightning detection and local residents confirmed CG strikes during the event.

[nrgjeff]

Upright and slant-wise convection for the win. Believe theta-e charts are not used enough in the operational community. People are kind of locked into constant pressure charts cause that's what they are used to. The switch to theta-e is not that hard. In fact conceptually it is easier as parcels like to follow the theta-e surface. Plus the theta-e charts make so much sense after doing the cross-section analysis. Suppose if one scored high on those spatial analysis tests, a big help for any Met, either set of charts works.

I remember forecasting and watching that from Wichita, KS; clients in South Texas. The lightning network showed the occasional flash as we played catch-up on accumulation forecasts. Even from a professional distance, it was hard to not get caught up in the storybook Christmas Eve for a place that hardly ever sees snow any day of the winter. Years later in 2009 I lived in DFW, and saw a much lighter but still magical Texas white Christmas.