11 Aug 1999 -- GOES-8 water vapor winds animation (Java applet)

26-27 January 2000 -- GOES-8 Satellite Winds
Oklahoma Snow Storm

On 26 January, a widespread area of snow developed across central Oklahoma producing 4-6" of accumulation (~12-23 UTC). The snowfall appeared to be related to isentropic lift associated with warm air advection aloft (850-700 mb). This snow event was not well predicted. It occurred well downstream of an upper level trough/upper low which moved across the region on 27 January. Snow had been forecasted from the trough/upper low (at least a couple of days in advance) to begin after 00 UTC on the 27th. This upper system produced convective precipitation on the 27th. Freezing rain and ice pellets effected north Texas & the heaviest snow fell in parts of eastern Oklahoma with as much as 17" reported in Eufala, OK.

The 2-day period has been divided into 3 hour intervals so that the animations will be managable by most computers. Times appear on the lower bar of the satellite images.

The first column ("Satellite winds") includes overlays of wind barbs, divergence, vorticity, and isotachs at 300 mb from the satellite analysis.

The next 3 columns can be used to compare the divergence, vorticity and isotachs from the satellite analysis with the RUC-2 hourly analyses. (The times of the RUC-2 analyses are labeled in the same color as the corresponding contours. Note that the RUC-2 has not yet been processed by our system for 00-09 UTC period on both days). In general, the RUC-2 wind fields contain more structure than the satellite winds because of the model's high resolution. The RUC-2's upper level divergence field seems to match the location of the snow band on 26 January more consistently than the satellite analysis. The opposite is true for the area of convection on 27 January. A strong divergence/convergence couplet develops with the upper low as it tracks across Oklahoma after 18 UTC on the 27th.

The last 3 columns can be used to compare the divergence, vorticity and isotachs from the satellite analysis with the NOGAPS forecast model (which is used as a first guess in computing the satellite winds). Note the the guess fields are updated every 6 hours. In general, the satellite analysis contains more detailed structure than the model fields.

Time (UTC)	Satellite winds	Div ergence (Sat vs. RUC-2)	Vorticity (Sat vs. RUC-2)	Speed (Sat vs. RUC-2)	Divergence (Sat vs. Guess)	Vorticity (Sat vs. Guess)	Speed (Sat vs. Guess)
00-03 26 Jan 00	X				X	X	X
03-06 26 Jan 00	X				X	X	X
06-09 26 Jan 00	X				X	X	X
09-12 26 Jan 00	X	X	X	X	X	X	X
12-15 26 Jan 00	X	X	X	X	X	X	X
15-18 26 Jan 00	X	X	X	X	X	X	X
18-21 26 Jan 00	X	X	X	X	X	X	X
21-00 26 Jan 00	X	X	X	X	X	X	X
00-03 27 Jan 00	X				X	X	X
03-06 27 Jan 00	X				X	X	X
06-09 27 Jan 00	X				X	X	X
09-12 27 Jan 00	X	X	X	X	X	X	X
12-15 27 Jan 00	X	X	X	X	X	X	X
15-18 27 Jan 00	X	X	X	X	X	X	X
18-21 27 Jan 00	X	X	X	X	X	X	X
21-00 27 Jan 00	X	X	X	X	X	X	X

24 Hour Loops (1 image per hour)

	Divergence	Vorticity	Speed
26 Jan 00	X
27 Jan 00

26-27 January 2000 -- GOES-8 Satellite Winds Oklahoma Snow Storm

26-27 January 2000 -- GOES-8 Satellite Winds
Oklahoma Snow Storm