Hi, all,
The low-level significant weather prog chart (the one with MVFR/IFR, freezing levels, etc on it)... I have a question about the freezing level lines. There are dashed (green) lines labeled "80" or "120" to indicate where the freezing level is 8000 feet and 12000 feet, and zigzaggy (blue) lines to indicate where the freezing level is to the surface. I've always thought of these as being like contour lines for the freezing level, just very widely spaced.
I'm looking at one today (for 06Z Saturday the 16th),
http://aviationweather.gov/data/products/swl/ll_06_4_cl_new.gif
...which has a "surface" line crossing both a "40" and "80" line in New England. What does that mean?
On the same chart, there is a "80" line horizontally across the northwestern US, with a "120" line across the southwestern US, and a little patch of "surface" between them. Shouldn't there be a "40" in between somewhere?
The "contour line" analogy is breaking down... is there some other way of interpreting these lines?
--kath
The low-level significant weather prog chart (the one with MVFR/IFR, freezing levels, etc on it)... I have a question about the freezing level lines. There are dashed (green) lines labeled "80" or "120" to indicate where the freezing level is 8000 feet and 12000 feet, and zigzaggy (blue) lines to indicate where the freezing level is to the surface. I've always thought of these as being like contour lines for the freezing level, just very widely spaced.
I'm looking at one today (for 06Z Saturday the 16th),
http://aviationweather.gov/data/products/swl/ll_06_4_cl_new.gif
...which has a "surface" line crossing both a "40" and "80" line in New England. What does that mean?
On the same chart, there is a "80" line horizontally across the northwestern US, with a "120" line across the southwestern US, and a little patch of "surface" between them. Shouldn't there be a "40" in between somewhere?
The "contour line" analogy is breaking down... is there some other way of interpreting these lines?
--kath