Decoding MAV
Decoding GFS/MAV Numeric Guidance
Decoding MAV, and
NGM, and
NGM Guidance
The AVN-Based MOS MAV guidance is generated from 0000 UTC and 1200 UTC model output from the Aviation (AVN) run of NCEP's Global Spectral Model.
Forecast elements are valid from 6 to 72 hours in advance.
Sample Message
KSLC AVN MOS GUIDANCE 1/25/2001 1200 UTC
DT /JAN 25/JAN 26 /JAN 27 /JAN 28
HR 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12
N/X 18 39 26 38 24
TMP 37 39 39 35 28 24 21 22 28 36 36 35 33 30 30 30 33 35 33 32 27
DPT 21 16 14 19 18 16 14 15 19 25 32 32 29 26 26 22 31 26 27 29 25
CLD SC SC SC CL CL SC SC BK BK OV OV OV OV OV OV OV OV OV OV OV OV
WDR 27 28 27 24 21 18 16 14 14 17 13 18 19 17 14 13 16 19 22 30 28
WSP 16 13 10 04 02 02 04 03 04 06 04 04 06 08 07 05 11 12 06 01 04
P06 1 0 0 12 30 26 30 52 60 34 26
P12 1 33 53 79 43
T06 0/ 0 0/ 0 0/ 0 0/ 0 1/ 0 2/ 0 1/ 1 3/ 0 5/ 1 2/ 0
T12 0/ 0 0/ 0 2/ 0 4/ 1 16/ 1
POZ 1 0 0 0 0 0 0 0 1 0 0 0 0 10 27 11 8 0 0 0 1
POS 56 48 70 85 96100100100 67 26 22 27 30 29 30 53 51 54 50 37 45
TYP S R S S S S S S S R S R R R Z S S S S R R
Q06 0 0 0 0 1 1 1 2 2 1
Q12 0 1 2 3 2
SNW 1 2
CIG 7 7 7 7 7 7 7 7 7 7 7 7 7 6 5 5 3 3 4 4 4
VIS 7 7 7 7 7 7 7 7 7 7 7 7 7 6 6 4 3 4 6 7 7
OBV N N N N N N N N N N N N N BR BR FG FG FG BR N N
|
- HR = Forecast hour, i.e. how many hours from the model run time.
- N/X = daytime maximum/nightime minimum surface temperatures.
- TMP = surface temperature valid at that hour.
- DPT = surface dewpoint valid at that hour.
- CLD = forecast categories of total sky cover valid at that hour.
- WDR = forecasts of the 10-meter wind direction at the hour, given in tens of degrees.
- WSP = forecasts of the 10-meter wind speed at the hour, given in knots.
- P06 = probability of precipitation (PoP) during a 6-h period ending at that time.
- P12 = PoP during a 12-h period ending at that time.
- T06 = probability of thunderstorms/conditional probability of severe thunderstorms during the 6-hr period ending at the indicated time.
- T12 = probability of thunderstorms/conditional probability of severe thunderstorms during the 12-hr period ending at the indicated time.
- POZ = conditional probability of freezing pcp occurring at the hour.
- POS = conditional probability of snow occurring at the hour.
- TYP = conditional precipitation type at the hour.
- Q06 = quantitative precipitation forecast (QPF) category for liquid equivalent precipitation amount during a 6-h period ending at that time.
- Q12 = QPF category for liquid equivalent precipitation amount during a 12-h period ending at the indicated time.
- SNW = snow fall categorical forecasts during a 24-h period ending at the indicated time.
- CIG = ceiling height categorical forecasts at the hour.
- VIS = visibility categorical forecasts at the hour.
- OBV = obstruction to vision categorical forecasts at the hour.
Definitions of Categorical Elements
| MAV Ceiling Height Categories |
| 1 | < 200 feet |
| 2 | 200 - 400 feet |
| 3 | 500 - 900 feet |
| 4 |
1000 - 1900 feet |
| 5 |
2000 - 3000 feet |
| 6 | 3100 - 6500 feet |
| 7 | 6600 - 12,000 feet |
| 8 | > 12,000 feet or unlimited ceiling |
|
| MAV Visibility (VIS) Categories |
| 1 |
1/2 mile or less |
| 2 |
more than 1/2 - or less than 1 mile |
| 3 |
1 mile - less than 2 |
| 4 |
2 - less than 3 miles |
| 5 | 3 - 5 miles |
| 6 | 6 miles |
| 7 |
Vis is > 6 miles |
|
| MAV QPF Categories |
| 0 | no precipitation |
| 1 | 0.01 to 0.09 inches |
| 2 | 0.10 to 0.24 inches |
| 3 | 0.25 to 0.49 inches |
| 4 | 0.50 to 0.99 inches |
| 5 | 1.00 to 1.99 inches |
| 6 | 2.00 inches or greater |
|
| MAV Cloud (CLD) Categories |
| CL | clear |
| SC | scattered > 0 to 4 octas |
| BK | broken > 4 to < 8 octas |
| OV | overcast |
1 octa = 1 eight of the sky.
|
| MAV Obstruction to Vision (OBV) Categories |
| N | none of the following |
| HZ | haze, smoke, dust |
| BR | mist (fog with visibility >= 5/8 mile) |
| FG | fog or ground fog (visibility < 5/8 mile) |
| BL | blowing dust, sand, snow |
|
| MAV Snow Fall Amount Categories |
| 0 | no snow or a trace expected |
| 1 | > a trace to < 2 inches |
| 2 | 2 to < 4 inches |
| 4 | 4 to < 6 inches |
| 6 | 6 to < 8 inches |
| 8 | >= 8 inches |
|
| MAV Precipitation Type (TYP) Categories |
| S | pure snow or snow grains |
| Z |
freezing rain/drizzle, ice pellets, or |
| anything mixed with freezing precip |
| R | pure rain/drizzle or rain mixed with snow |
|
|