Overnight on December 7th and continuing into the 8th, an embedded upper level disturbance descended the back side of a growing upper level trough that would soon stretch across the entire eastern two���thirds of the nation. The disturbance provided several critical pieces of the atmospheric puzzle that would change miserable biting rain into a snowscape that brought impromptu celebrations of the season on a Friday, less than three weeks before Christmas. Light rain mixed with sleet and snow before changing to all snow, from northwest to southeast, during the pre-dawn hours of the 8th. The initial changeover occurred across the Rio Grande Plains of Jim Hogg and Zapata County between midnight and 2 AM, and would quickly scoot through the remaining ranch country before 4 AM, and reach much of the populated Valley before 6 AM. Because the low levels of the atmosphere were marginally conducive to snow, the highest accumulations were seen in stronger bands that fell before sunrise at the slightly higher elevation of the ranchlands, which allowed temperatures to fall to 32 or 33��F for the duration of the band. In locations where the bands tapered off, or where bands were less intense, snow accumulation was limited and often the snow mixed with rain again. Highest accumulation, ranging from 3 to nearly 6 inches, fell in a stripe from southwest Zapata County through northwest and northern Starr, southern Jim Hogg, and western Brooks County, extending northeast to areas west of Kingsville and ultimately to the Corpus Christi metro area, where 4 to 6 inches piled up before daybreak. Multiple bands developed or re���developed between 5 AM and noon, with additional snow for the aforementioned stripe from Zapata through Brooks but also sliding into the more populated Rio Grande Valley, mainly along and north of Interstate 2. Much of these bands fell after daybreak, which allowed low���latitude daylight to counter the moderate snow and hold accumulation down to around an inch. The final band exited southeast Cameron County (Brownsville to South Padre Island) soon after noon.

Heavy Snow in JIM HOGG, TEXAS
From 08-DEC-17 00:00:00 to 08-DEC-17 10:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Fire Department/Rescue

At least one ranch owner near Agua Nueva, as well as occasional reports from Jim Hogg County dispatch - with data blended from satellite observations, found snowfall ranging from around 0.5 near Hebbronville (close to the Duval County line) ranging to more than 4 inches across the southern third of the county. From radar estimates, the heaviest snow fell between 1 and 4 AM and again between 5 and 7 AM. In general, between 2 and 5 inches fell across the primary ranch areas with the least amount of snow near Hebbronville.  The snow, falling overnight, created slushy accumulation along elevated bridges and an inch or more on unimproved ranch roads.

Heavy Snow in STARR, TEXAS
From 08-DEC-17 01:30:00 to 08-DEC-17 11:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Multiple snow bands between the pre-dawn hours and mid morning dropped  1 to 3 inches of snow across most of Starr County early on the 8th. Much of the heavier snow across the northwest half of the county fell between 1 and 4 AM, with more widespread coverage between 7 and 9 AM favoring the northeast portion of the county. A Rio Grande City Fire and Rescue worker, also a ranch owner, reported 2 inches near Santa Elena; another ranch owner reported 1.5 inches near El Sauz. Elevation may have made some difference in accumulation, as locations along the Rio Grande reported less snow, in some cases below heavy snow criteria (<1 inch).

Heavy Snow in ZAPATA, TEXAS
From 08-DEC-17 00:00:00 to 08-DEC-17 09:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Emergency Manager

Emergency management, social media, and other contacts reported between 2 and 3 inches of wet snow across most of Zapata County, with the heaviest amounts falling from the Rio Grande near Falcon, northeast across ranchlands along the Starr and Jim Hogg County line (south third of the county). The snow, falling overnight, created slushy accumulation along elevated bridges, including US 83, where there was at least one accident involving a sliding car and school bus (no injuries or deaths).

Heavy Snow in BROOKS, TEXAS
From 08-DEC-17 00:00:00 to 08-DEC-17 10:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Social Media

A single moderate to heavy snow band between midnight and 3 AM, followed by lighter snows during the post-daybreak hours, dropped a whopping 3 to 6 inches of heavy wet snow across the northern half of Brooks County, with an estimated 2 to 3 inches across the southern half based on satellite, radar, and proxy observations on the King Ranch in neighboring western Kenedy County.  A fair measurement of 5.5 inches was received just southwest of Falfurrias, with 4.8 inches nearby. The snow, which fell at a rate of 1 to 2 inches per hour during the post midnight period, covered untreated rural roads with up to 3 inches of snow around the Falfurrias area. The snow also covered the US 281 bypass around Falfurrias, slowed traffic, and caused at least one tractor trailer to jackknife.  No injuries or fatalities were reported.

Heavy Snow in WILLACY, TEXAS
From 08-DEC-17 07:00:00 to 08-DEC-17 11:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Emergency Manager

While several moderate to locally heavy snow bands persisted through the ranchlands of Brooks, Jim Hogg, Starr, and Zapata County, snow arrived late (mainly after sunrise) in most of Willacy County after periods of light rain overnight.  Several reports of 1 inch of snow was reported across the northern half of the county, including the most populated city of Raymondville.  At one point between 9 and 10 AM, SR 186 west of Raymondville was covered with a coating of slush during the heaviest band. There were no known significant accidents despite the quick coating.

Heavy Snow in COASTAL WILLACY, TEXAS
From 08-DEC-17 08:00:00 to 08-DEC-17 11:00:00 (CST-6)
Crop damage: 0.00K
Reported by: Emergency Manager

While several moderate to locally heavy snow bands persisted through the ranchlands of Brooks, Jim Hogg, Starr, and Zapata County, snow arrived late (mainly after sunrise) in coastal Willacy County after periods of light rain overnight.  A report of 1 inch of snow was reported across the northern coastal area, in Port Mansfield.

Winter Weather in CAMERON, TEXAS
From 08-DEC-17 08:00:00 to 08-DEC-17 12:30:00 (CST-6)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Light rain changed to snow latest in Cameron County, Texas, on December 8.  By 9 AM, light snow was falling across the county, with a small area of 1 inch accumulating over and north of Harlingen by 11 AM. Two thin bands of snow affected the county; the first band across the northern half between 8 and 10 AM, and a second across the southern half between 10 and 1230 PM.  Heaviest accumulations on grassy areas occurred during the early morning hours, but the official report at the NWS office in Brownsville (east side of the city) of 0.25 of snow occurred around noon during a short-lived band of moderate snow.

Heavy Snow in KENEDY, TEXAS
From 08-DEC-17 06:00:00 to 08-DEC-17 10:30:00 (CST-6)
Crop damage: 0.00K
Reported by: COOP Observer

A single moderate to heavy snow band developed across the Kenedy County King Ranch around daybreak on December 8th, continuing in waves until 1030 AM before precipitation ended.  Cooperative observers 7 miles east of Sarita and 4 miles southeast of Armstrong (northern and central portions of the county) reported 2 inches each. County-wide, proxy data from Brooks and Willacy County suggested fairly widespread 2 inch totals, with the exception of the northwest corner between Sarita and Falfurrias, where 3 inches may have fallen. It was unknown whether slush accumulated on the elevated portion of US 77 around Sarita.

Heavy Snow in HIDALGO, TEXAS
From 08-DEC-17 07:00:00 to 08-DEC-17 10:30:00 (CST-6)
Crop damage: 0.00K
Reported by: Emergency Manager

While several moderate to locally heavy snow bands persisted through the ranchlands of Brooks, Jim Hogg, Starr, and Zapata County, snow arrived late (mainly after sunrise) in most of Hidalgo County after periods of light rain overnight.  A sliver of the Brooks/Starr/Jim Hogg band covered the northern fifth of Hidalgo, where 2 inches likely accumulated.  Elsewhere, mainly from Alton to Edinburg and Elsa-Edcouch, around an inch fell in a fairly short period of time (8 AM to 1030 AM) with accumulation primarily on grassy surfaces and trees as surface temperatures largely remained above freezing -
and daylight was able to melt some of the snow on contact. There were no known reports of significant accidents from slick roads due to the snow.