The December 19th, 2000 Winter Storm
The map below shows snowfall totals reported from the 19 December winter storm for WFO Greenville-Spartanburg's County Warning and Forecast Area (CWA). Amounts of 4" or more meet winter storm criteria, and are lightly shaded. This map represents snowfall amounts as they were reported to the office during the event, and may not represent storm total accumulations, though they should be close.
A winter weather advisory was issued for the entire Greenville-Spartanburg CWA during the 4 AM EST forecast package on the 19th. However, advisory criteria or better were only reached in the northwestern half of the CWA and in a small part of Davie County, NC. Areas further south and east had only rain for most of the event, with only some light snow that evening. The advisory was upgraded to a winter storm warning around 530 AM EST on the 19th for parts of the mountains of northeast Georgia, South Carolina and southern North Carolina after reports of snowfall amounts exceeding 4 inches started coming in from northeast Georgia. In these areas, two narrow bands of heavy snow developed during the early morning hours. As the second band slowly moved east into the Upstate, it rapidly dissipated by 8 AM EST, making it no further east then western Spartanburg County.
The image below is a model sounding valid at noon local time on the 19th for Charlotte, one of the locations in the advisory which received almost no measurable snowfall. The red line is a temperature trace. Notice how the red trace starts right at zero degrees Celsius and stays there up through about the lowest 4000 feet. In actuality, the surface temperature was warmer (see the surface map below) than the sounding indicated.
The map below was valid at 1 pm local time on the 19th. The observation near the center of the screen, with the designator KCLT, is that from Charlotte Douglas International Airport. This is one hour later than the model sounding above (the temperature/dewpoint was the same the previous hour). The temperature at Charlotte verified a little over 2 degrees Celsius warmer than what the model projected. It is interesting to note that the model depicted above, the December 19th 00 UTC run of the Eta, generated .28" of rain at Charlotte during the late morning and early afternoon. In reality, only .10" of rain fell during this time. It is quite possible that the lighter than expected precipitation rates resulted in a warmer than anticipated layer in the lower atmosphere, leading to mostly rain in the North Carolina Piedmont and the eastern part of the Upstate. These model errors apparently were exacerbated further east in the Carolinas. As these locations are outside of our forecast area, they were not investigated.
Page created 12/21/2000