- Select the desired length of the animation (default is
highlighted in gray).
- Select the interval between images (default is
highlighted).
- Press the "Build Animation" button.
The interval between images partly determines the total number
of images in the animation and hence both the downloading time
and the extent to which the image changes from one image to the
next. For example, an animation length of 2 days with an
interval between images of 12 hours will generate an animation
with 5 images in it, covering a 48-hour period ending with the
latest available image and with 12 hours between images.
Missing images are listed and then automatically skipped.
- To step through animations frame-by-frame, first press the
"Stop" button ("*"), then press the "Next" button ("|>")
repeatedly to advance frames one at a time. Similarly, press the
"Prev" button ("|<") to step backward one frame at a time.
- To restart the animation after stopping it, press the "Resume"
button (">").
- The WWWeb server (virga.sfsu.edu) receives data to construct a
new jet stream analysis every 6 hours, within 2 hours (00Z, 12Z eta
model) or 4 hours (00Z, 06Z, 12Z, and 18Z GFS model) after the map
analysis time. To update an animation to add any newly created map(s)
(which also drops the oldest one from the animation), simply press the
"Build Animation" button again.