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Winter weather is rare in South Texas, but occurs from time to time. A wintry mix of rain and snow occurred over South Texas from the morning of December 7th to the early morning of December 8th 2017. This was the first wintry precipitation event in South Texas since the icing event on January 23rd-24th 2014, and the first measurable snow event since the Christmas Snowstorm of 2004. Below is a summary of this snow event.
A strong cold front, located over South Central Texas early on the morning of December 5th moved slowly southward into South Texas during the afternoon. The boundary stalled over the area during the late afternoon, before pushing southward by early evening. Scattered showers and a few thunderstorms developed over eastern portions of South Texas ahead and along the boundary. Heavy rainfall and minor flooding was observed in the city of Corpus Christi, with a rainfall observer reporting 4.19 inches of rainfall. Most other areas saw much lower amounts as the boundary moved through (see rainfall amounts with the front here.
Behind the frontal boundary, colder air gradually seeped farther south into the area, and the frontal boundary intensified. As a result, temperatures continued to fall over the region. A coastal trough developed on Wednesday December 6th. This, along with an upper level trough, provided additional lift, and brought periods of rain to essentially all of South Texas.
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After the clouds cleared, snow cover remaining into the early afternoon was visible on satellite imagery.
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By the early morning of December 7th, the cold air was becoming entrenched over South Texas. Temperatures had fallen into the upper 30s and lower 40s over much of the area, as seen by the morning surface map. On top of that, the atmosphere continued to cool substantially, as indicated by comparing the Corpus Christi sounding at 6 AM December 5th with the soundings at 6 AM December 7th from Corpus Christi and Del Rio TX. Note that the Del Rio sounding showed much cooler air in the lower levels of the atmosphere, as well as being nearly saturated in the mid levels of the atmosphere, with temperatures around and above the 500mb level colder than -10 degrees Celsius. With a strong upper level jet streak adding more large-scale lift (and even more cooling of the atmosphere), rain began to turn to snow over the Western Brush Country and Rio Grande Plains. Some of the heavier bands of snow moved over portions of Webb and La Salle Counties during the late morning, and visibility at Cotulla was reduced to less than 1 mile at times due to the snow. As a result, portions of La Salle County Cotulla received as much as 1.5 inches of snow during the morning of December 7th before the snow turned back to rain during the afternoon. The city of Laredo also reported light snow at the airport for a few hours on the afternoon of the 7th. By late afternoon, essentially all of South Texas reported rain instead of snow. However, the heaviest snow was yet to come!
Another strong upper level jet streak approached South Texas in the late evening, causing more large scale lift and cooling. The previous upper jet from the morning of the 7th and the approaching upper jet that evening also enhanced the large scale lift by creating an area of diffluence (sometimes called divergence),and enhanced lifting, cooling and frontogenesis over South Texas. As a result, the airmass over South Texas become saturated from the surface to nearly 300mb, with temperatures above freezing only in the lowest 1000 feet of the atmospheric column (see the 12/8/2017 Midnight sounding at Corpus Christi). With the airmass being so saturated between -12 and -20 degrees Celsius, the large scale lift allowed for the production of large, wet snowflakes, especially over the southern and coastal areas of South Texas. By midnight, nearly all areas reporting precipitation were observing either all snow or a mixture of rain and snow (except near the immediate coast).
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Corpus Christi Radar Loop
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Two slow moving bands of precipitation set up over South Texas. One band extended from Victoria County to Webb County and another one ran along the Middle Texas Coastal counties swooping back to Zapata County. Although precipitation was predominantly rain most of the day on December 7th, by 10 pm surface temperatures cooled to just above freezing as the rain/snow transition line pushed southward with rain switching to snow first from Victoria to Cotulla. Within the next hour, the transition line pushed further southward into the Coastal Bend. By 11:30 pm, the band along the coast began to transition to wintry mix. After midnight as temperatures continued to drop to near freezing, all precipitation had switched over to snow and began to accumulate on grassy surfaces, cars, and creating slushy roadways. Snow continued during the overnight hours over much of South Texas, slowly diminishing from northwest to southeast toward morning as the impacts of the upper jet and drier air moving into the region ended the snow (as seen from the Del Rio sounding Friday morning December 8th. The two bands of snow slowly shifted eastward through the early morning. By 5 am, the band along the coast dissipated and the westernmost band of snow moved into the Coastal Bend for a second and final round snow. By 9 AM the snow band had moved offshore, and clouds gradually decreased during the remainder of the day.
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Snowfall Totals - Dec 7-8, 2017 |
In addition to snow, areas around the Southern Coastal Bend experienced a rare phenomenon, THUNDERSNOW! The atmosphere had become convectively unstable, and occasional lightning was reported at Corpus Christi Airport. Thundersnow first began around 1230am and continued off and on through around 6am producing heavier bands of snow, resulting in moderate snowfall and reduced visibilities of nearly 1/2 mile! This heavier snow band moved over the South Side of Corpus Christi (including NAS Corpus Christi), and produced more than 3 inches of snow in some parts of the city.
Most of the Southern Coastal Bend saw at least 1 inch of snow, with the highest amounts occurring in the heavier convective bands of snow over portions of Kleberg, Nueces, and San Patricio counties. Because of these convective bands, some areas received more than 3 inches of snow, with as much as around 7 inches reported on the south side of Corpus Christi due to the convective nature of the snow.
Officially, Corpus Christi received 1.0 inches of snow, tying for the 8th highest daily snowfall accumulation since records were recorded. Victoria Regional Airport received 2.0 inches of snow, tying the 9th highest daily snowfall total. Finally, Laredo's official daily snowfall total of 1.2 inches ranks as the 6th highest daily snowfall total in their history.
Top 10 Daily Snowfall Rankings by City (Click each image to enlarge.) | ||
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Corpus Christi | Victoria | Laredo |
Del Rio TX Radar Loop: 401 AM CST Through 300 PM CST December 7, 2017 |
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KCRP Radar Loop: 904 PM CST December 7 - 901 AM CST December 8, 2017 |
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KCRP Radar Zoom Heavy Snow Band: 223 AM - 400 AM CST December 8, 2017 |
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Satellite IR Loop: 600 PM CST December 7 - 900 AM CST December 8, 2017 |
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NWUS54 KCRP 090126 LSRCRP PRELIMINARY LOCAL STORM REPORT...SUMMARY NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 725 PM CST FRI DEC 08 2017 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0300 AM SNOW CORPUS CHRISTI 27.71N 97.29W 12/08/2017 E1.0 INCH NUECES TX BROADCAST MEDIA BROADCAST MEDIA REPORTS ESTIMATED 1 INCH ACCUMULATION. ALSO UTILITY COMPANY REPORTS 13,000 CUSTOMERS WITHOUT POWER. 0310 AM SNOW 1 SE BEEVILLE 28.40N 97.74W 12/08/2017 U0.0 INCH BEE TX DEPT OF HIGHWAYS HWY 181 CLOSED SOUTHEAST OF BEEVILLE. SLUSHY ROAD CONDITIONS. 0526 AM HEAVY SNOW 3 S CORPUS CHRISTI 27.66N 97.29W 12/08/2017 M2.5 INCH NUECES TX NWS EMPLOYEE 0530 AM SNOW VICTORIA DETAR HOSPITAL 28.85N 97.02W 12/08/2017 M2.0 INCH VICTORIA TX CO-OP OBSERVER 0700 AM HEAVY SNOW 2 ESE CORPUS CHRISTI 27.69N 97.26W 12/08/2017 M5.0 INCH NUECES TX NWS EMPLOYEE 5" OF SNOW MEASURED BY NWS EMPLOYEE. 0700 AM HEAVY SNOW PORTLAND 27.88N 97.33W 12/08/2017 M3.0 INCH SAN PATRICIO TX NWS EMPLOYEE 0700 AM HEAVY SNOW 7 SSE KINGSVILLE 27.42N 97.82W 12/08/2017 M4.5 INCH KLEBERG TX COCORAHS 0700 AM HEAVY SNOW 1 SSE INEZ 28.87N 96.78W 12/08/2017 M2.0 INCH VICTORIA TX COCORAHS 0700 AM HEAVY SNOW 4 NW GOLIAD 28.71N 97.44W 12/08/2017 M1.8 INCH GOLIAD TX COCORAHS 0715 AM HEAVY SNOW 3 S CORPUS CHRISTI 27.66N 97.29W 12/08/2017 M5.0 INCH NUECES TX NWS EMPLOYEE 0800 AM HEAVY SNOW PORTLAND 27.88N 97.33W 12/08/2017 M3.1 INCH SAN PATRICIO TX NWS EMPLOYEE 0853 AM HEAVY SNOW INGLESIDE 27.87N 97.20W 12/08/2017 M4.0 INCH SAN PATRICIO TX SOCIAL MEDIA PICTURE SUBMITTED ON SOCIAL MEDIA OF SNOW IN INGLESIDE. 0857 AM HEAVY SNOW VICTORIA 28.82N 96.98W 12/08/2017 M2.5 INCH VICTORIA TX SOCIAL MEDIA PICTURE SUBMITTED ON SOCIAL MEDIA FROM VICTORIA, TX. 0900 AM SNOW NURSERY 28.92N 97.10W 12/08/2017 M1.5 INCH VICTORIA TX COCORAHS 1.5 INCHES OF SNOW ON THE GROUND 0926 AM HEAVY SNOW Airline/Cimmaron 28.08N 97.24W 12/08/2017 M1.8 INCH REFUGIO TX PUBLIC PICTURES SUBMITTED OF SNOW IN Airline/Cimmaron 0943 AM HEAVY SNOW 2 E KINGS CROSSING GOLF 27.65N 97.36W 12/08/2017 M7.0 INCH NUECES TX NWS EMPLOYEE 7.0" OF SNOW REPORTED BY NWS EMPLOYEE. 0948 AM HEAVY SNOW LAKE CORPUS CHRISTI 28.13N 97.88W 12/08/2017 M3.5 INCH SAN PATRICIO TX EMERGENCY MNGR EMERGENCY MANAGER REPORTS 3.5" OF SNOW. 0958 AM HEAVY SNOW VICTORIA 28.82N 96.98W 12/08/2017 M1.5 INCH VICTORIA TX EMERGENCY MNGR 1000 AM SNOW GEORGE WEST 28.33N 98.12W 12/08/2017 M1.0 INCH LIVE OAK TX EMERGENCY MNGR 1000 AM HEAVY SNOW SINTON 28.03N 97.51W 12/08/2017 M3.5 INCH SAN PATRICIO TX EMERGENCY MNGR 1001 AM HEAVY SNOW ROCKPORT 28.04N 97.05W 12/08/2017 M3.0 INCH ARANSAS TX EMERGENCY MNGR 1009 AM HEAVY SNOW SAN DIEGO 27.76N 98.24W 12/08/2017 M2.0 INCH DUVAL TX EMERGENCY MNGR 1027 AM HEAVY SNOW 3 N LAREDO 27.57N 99.49W 12/08/2017 M1.2 INCH WEBB TX COCORAHS 1034 AM HEAVY SNOW 7 SW PREMONT 27.29N 98.20W 12/08/2017 M4.0 INCH JIM WELLS TX TRAINED SPOTTER 1039 AM HEAVY SNOW 2 SW CORPUS CHRISTI COU 27.68N 97.41W 12/08/2017 M6.2 INCH NUECES TX SOCIAL MEDIA 1047 AM SNOW TILDEN 28.45N 98.54W 12/08/2017 M1.0 INCH MCMULLEN TX LOCAL OFFICIAL 1057 AM SNOW BEEVILLE 28.41N 97.75W 12/08/2017 M0.8 INCH BEE TX EMERGENCY MNGR
Regional Total Snowfall Amounts December 7th through December 8th, 2017 |
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48 Hour Regional Precipitation Amounts Ending 7 AM December 8th, 2017 |
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Daily South Texas and Regional Rainfall Ending 7 AM December 7th, 2017 | |
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COCORAHS PRECIPITATION SUMMARY NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1001 AM CST THU DEC 07 2017 COCORAHS PRECIPITATION REPORTS THESE REPORTS ARE CONSIDERED SUPPLEMENTAL AND UNOFFICIAL VALUES ARE FOR THE PREVIOUS 24 HOURS ENDING AROUND 7 AM LOCAL TIME .B CRP 1207 C DH07/PP/SF/SD/SW : :COCORAHS PRECIPITATION REPORTS IN SOUTH TEXAS : : SNOW SNOW WATER : PCPN FALL DEPTH EQUIV : TXRF05 : AUSTWELL 0.2 ESE * : 0.35 / MM / MM / MM TXRF02 : AUSTWELL 0.3 ESE * : 0.33 / MM / MM / MM TXBEE18 : BEEVILLE 9.0 S * : 0.62 / MM / MM / MM TXGD16 : BEEVILLE 12.6 NNE * : 0.62 / MM / MM / MM TXLO05 : CHOKE CANYON DAM NORTH SI* : 0.70 / MM / MM / MM TXNU52 : CORPUS CHRISTI 4.8 SSE * : 0.35 / MM / MM / MM TXNU38 : CORPUS CHRISTI 4.8 W * : 0.38 / MM / MM / MM TXNU07 : CORPUS CHRISTI 9.0 SSE * : 0.49 / MM / MM / MM TXNU15 : CORPUS CHRISTI 9.1 NW * : 0.35 / MM / MM / MM TXLS05 : COTULLA 1.6 NE * : 0.85 / MM / MM / MM TXLS03 : DILLEY 17.9 ESE * : 0.58 / MM / MM / MM TXWB09 : EL CENIZO 8.8 E * : 0.07 / MM / MM / MM TXLO09 : GEORGE WEST 2.7 NNW * : 0.85 / MM / MM / MM TXLO11 : GEORGE WEST 2.9 E * : 0.76 / MM / MM / MM TXLO12 : GEORGE WEST 8.0 NE * : 0.61 / MM / MM / MM TXLO16 : GEORGE WEST 11.3 S * : 0.60 / 0.0 / MM / MM TXGD06 : GOLIAD 0.4 NW * : 0.83 / MM / MM / MM TXGD03 : GOLIAD 2.4 SE * : 0.66 / MM / MM / MM TXGD08 : GOLIAD 4.1 NW * : 0.81 / MM / MM / MM TXGD27 : GOLIAD 6.5 WNW * : 0.93 / MM / MM / MM TXGD25 : GOLIAD 14.3 NNE * : 0.77 / MM / MM / MM TXGD04 : GOLIAD 14.5 WNW * : 0.89 / MM / MM / MM TXDV01 : HEBBRONVILLE 13.6 E * : 0.39 / MM / MM / MM TXVC37 : INEZ 1.1 SSE * : 0.55 / MM / MM / MM TXKL02 : KINGSVILLE 6.5 SSE * : 0.55 / MM / MM / MM TXWB12 : LAREDO 1.8 N * : 0.01 / MM / MM / MM TXWB47 : LAREDO 2.5 N * : 0.49 / MM / MM / MM TXWB46 : LAREDO 4.5 NNW * : 0.54 / MM / MM / MM TXJW05 : ORANGE GROVE 4.3 SW * : 0.35 / MM / MM / MM TXNU12 : ORANGE GROVE 4.5 SE * : 0.38 / MM / MM / MM TXJW03 : ORANGE GROVE 8.1 WNW * : 0.48 / MM / MM / MM TXJW08 : PALITO BLANCO 1.0 ESE * : 0.70 / MM / MM / MM TXSP18 : PORTLAND 1.3 NW * : 0.35 / MM / MM / MM TXRF08 : REFUGIO 1.0 NNW * : 0.31 / MM / MM / MM TXAR03 : ROCKPORT 2.1 NNW * : 0.43 / MM / MM / MM TXAR06 : ROCKPORT 3.0 NNW * : 0.44 / MM / MM / MM TXCLH15 : SEADRIFT 4.9 ENE * : 0.35 / MM / MM / MM TXCLH01 : SEADRIFT 5.1 E * : 0.22 / MM / MM / MM TXLO13 : THREE RIVERS 8.6 NNE * : 0.62 / MM / MM / MM TXMCM04 : TILDEN 16.0 NNW * : 0.80 / MM / MM / MM TXVC39 : VICTORIA 0.4 SE * : 0.76 / MM / MM / MM TXVC30 : VICTORIA 1.1 S * : 0.75 / MM / MM / MM TXVC10 : VICTORIA 1.6 W * : 0.63 / MM / MM / MM TXVC17 : VICTORIA 2.1 NNW * : 0.83 / MM / MM / MM TXVC41 : VICTORIA 2.2 NW * : 0.78 / MM / MM / MM TXVC26 : VICTORIA 3.8 NW * : 0.90 / MM / MM / MM TXVC29 : VICTORIA 9.5 SW * : 0.72 / MM / MM / MM TXVC25 : VICTORIA 9.5 WSW * : 0.86 / MM / MM / MM TXVC20 : VICTORIA 9.7 ESE * : 0.63 / MM / MM / MM TXVC03 : VICTORIA 11.9 SE * : 0.58 / MM / MM / MM TXVC21 : VICTORIA 14.0 SW * : 0.84 / MM / MM / MM TXGD22 : VICTORIA 15.0 WSW * : 0.90 / MM / MM / MM TXGD15 : WESER 1.9 NW * : 0.82 / MM / MM / MM TXRF03 : WOODSBORO 3.6 S * : 0.27 / MM / MM / MM : .END $$
Daily South Texas and Regional Rainfall Ending 7 AM December 8th, 2017 | |
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COCORAHS PRECIPITATION SUMMARY NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 1001 AM CST FRI DEC 08 2017 COCORAHS PRECIPITATION REPORTS THESE REPORTS ARE CONSIDERED SUPPLEMENTAL AND UNOFFICIAL VALUES ARE FOR THE PREVIOUS 24 HOURS ENDING AROUND 7 AM LOCAL TIME .B CRP 1208 C DH07/PP/SF/SD/SW : :COCORAHS PRECIPITATION REPORTS IN SOUTH TEXAS : : SNOW SNOW WATER : PCPN FALL DEPTH EQUIV : TXLS06 : ARTESIA WELLS 14.0 SE * : 1.68 / MM / MM / MM TXRF05 : AUSTWELL 0.2 ESE * : 0.73 / MM / MM / MM TXRF02 : AUSTWELL 0.3 ESE * : 0.90 / MM / MM / MM TXBEE18 : BEEVILLE 9.0 S * : 0.77 / MM / MM / MM TXLO05 : CHOKE CANYON DAM NORTH SI* : 0.70 / MM / MM / MM TXNU52 : CORPUS CHRISTI 4.8 SSE * : 1.36 / MM / MM / MM TXNU38 : CORPUS CHRISTI 4.8 W * : 0.91 / MM / MM / MM TXNU61 : CORPUS CHRISTI 6.9 SE * : 1.68 / MM / MM / MM TXNU07 : CORPUS CHRISTI 9.0 SSE * : 1.01 / MM / MM / MM TXNU15 : CORPUS CHRISTI 9.1 NW * : 1.19 / MM / MM / MM TXLS03 : DILLEY 17.9 ESE * : 0.63 / MM / MM / MM TXNU10 : FLOUR BLUFF 1.6 SW * : 1.39 / MM / MM / MM TXLO11 : GEORGE WEST 2.9 E * : 0.78 / 1.5 / MM / MM TXLO12 : GEORGE WEST 8.0 NE * : 0.79 / 1.5 / MM / MM TXLO16 : GEORGE WEST 11.3 S * : 0.96 / MM / MM / MM TXGD06 : GOLIAD 0.4 NW * : 0.60 / MM / MM / MM TXGD08 : GOLIAD 4.1 NW * : 0.71 / 1.8 / MM / MM TXGD25 : GOLIAD 14.3 NNE * : 0.51 / 1.4 / MM / MM TXVC37 : INEZ 1.1 SSE * : 0.56 / 2.0 / 2.0 / MM TXKL02 : KINGSVILLE 6.5 SSE * : 1.48 / 4.5 / MM / MM TXWB47 : LAREDO 2.5 N * : 1.00 / 1.2 / 1.2 / MM TXJW05 : ORANGE GROVE 4.3 SW * : 1.20 / MM / MM / MM TXSP18 : PORTLAND 1.3 NW * : MM / 3.0 / 3.0 / MM TXAR03 : ROCKPORT 2.1 NNW * : 0.75 / MM / MM / MM TXAR06 : ROCKPORT 3.0 NNW * : 0.86 / MM / T / MM TXCLH01 : SEADRIFT 5.1 E * : 0.65 / MM / MM / MM TXLO13 : THREE RIVERS 8.6 NNE * : 0.79 / MM / MM / MM TXMCM04 : TILDEN 16.0 NNW * : 0.76 / MM / MM / MM TXVC30 : VICTORIA 1.1 S * : 0.56 / 2.0 / MM / MM TXVC17 : VICTORIA 2.1 NNW * : 0.62 / 2.5 / MM / MM TXVC26 : VICTORIA 3.8 NW * : 0.67 / 3.1 / 3.1 / 0.15 TXVC25 : VICTORIA 9.5 WSW * : 0.75 / 2.0 / MM / MM TXVC20 : VICTORIA 9.7 ESE * : 0.43 / 1.0 / 1.0 / MM TXVC03 : VICTORIA 11.9 SE * : 0.42 / 0.2 / MM / MM TXVC22 : VICTORIA 12.1 W * : 0.20 / 2.0 / MM / MM TXGD15 : WESER 1.9 NW * : 0.54 / MM / MM / MM : .END $$
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925 MB - 00Z 12/07 | 925 MB - 12Z 12/07 |
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850 MB - 00Z 12/08 | 850 MB - 12Z 12/08 |
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925 MB - 00Z 12/08 | 925 MB - 12Z 12/08 |
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Corpus Christi Sounding - 00Z 12/07 | Del Rio TX Sounding - 00Z 12/07 |
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Corpus Christi Sounding - 12Z 12/07 | Del Rio TX Sounding - 12Z 12/07 |
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Corpus Christi Sounding - 00Z 12/08 | Del Rio TX Sounding - 00Z 12/08 |
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Corpus Christi Sounding - 06Z 12/08 | Brownsville Sounding - 06Z 12/08 |
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Corpus Christi Sounding - 12Z 12/08 | Brownsville Sounding - 12Z 12/08 |
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