The potential for heavy snow at higher elevations in the western U.S. will continue for many spots through the weekend. In the meantime, the eastern half of the continental U.S. will transition to above normal temperatures ahead of a pair of cold fronts next week that will bring readings back to closer to normal as we approach Thanksgiving Day. Read More >
(when T1 = H, X, Y, or Z)
(U.S. National Practice definitions included)
Instructions for the proper application of level (elevations above the earth's surface) designator.
1. The designator specified in this table should be used to the greatest extent possible to indicate the level of the data contained within the text of the bulletin.
2. When data at more than one level are contained in the text, the designator for only one of the levels should be used.
3. When the table does not contain a suitable designator for the level, a designator which is not assigned in the table should be used.
The U.S. Practice uses 25 mb increments 1000-100 mb and are included below.
|
|
|
| Entire Atmosphere (e.g. precipitable water) | |
| 1000 hPa | |
| Air properties for the earth's surface | |
| Level of the tropopause | |
| Level of maximum wind | |
| 950 hPa | |
| Level of 0oC isotherm | |
| 975 hPa | |
| 925 hPa | |
| 875 hPa | |
| 900 hPa | |
| Any parameter reduced/sea level (MSLP) | |
| Ground/water properties for the earth's
surface (i.e. snow cover, wave & swell) |
|
| 1000-500 hPa thickness | |
| Boundary Layer | |
| Cloud top level | |
| Hundreds and tens digits of the hectopascal level (e.g. 70 = 700 hPa; 03 = 030 hPa) To include: 81 = 810 hPa = 6000ft FL 82 = 825 hPa 84 = 875 hPa 77 = 775 hPa 73 = 730 hPa = 9000ft FL 72 = 725 hPa 67 = 675 hPa 65 = 650 hPa = 12000ft FL 62 = 625 hPa 50 = 510 hPa = 18000ft FL (U.S. National Practice uses 500 mb level) 11 = First 30 mb average thickness (from surface) 12 = Second 30 mb average thickness 13 = Third 30 mb average thickness 14 = Forth 30 mb average thickness 45 = Fifth 30 mb average thickness 16 = Sixth 30 mb average thickness |
|
| Note: The 810, 730, and 650 hPa levels are not being used as pressure levels, they are being used as geometric heights. | |
