About the MAV Text Product

The short-range GFS-Based MOS MAV guidance is generated from 0000, 0600, 1200, and 1800 UTC model output from NCEP's Global Forecast System (GFS). This guidance is valid for stations in the United States, Puerto Rico, and the U.S. Virgin Islands. Station lists and histories can be found at MOS Station Archive Page. Forecast elements are valid from 6 to 72 hours in advance.

Detailed Documentation can be found in the following documents (pdf):

The MAV Message

Sample Message
KDEN   GFS MOS GUIDANCE    3/04/2010  1200 UTC
DT /MAR   4/MAR   5                /MAR   6                /MAR   7
HR   18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 06 12
N/X                    27          53          28          51    24
TMP  48 52 51 40 35 32 30 35 47 50 48 40 38 35 32 36 45 48 45 31 27
DPT  25 25 27 29 29 27 25 25 21 17 18 20 21 21 20 21 21 22 22 23 21
CLD  BK SC SC SC SC OV OV OV BK BK BK SC BK SC SC SC SC SC SC SC SC
WDR  19 14 13 16 20 20 25 25 28 28 28 22 23 23 22 21 12 10 10 17 21
WSP  05 12 11 08 08 07 07 07 08 10 11 08 08 07 07 07 07 10 10 08 07
P06         1     6    14    20    14    25     8     4     2  3  2
P12                    15          27          26           4     3
Q06         0     0     0     0     0     0     0     0     0  0  0
Q12                     0           0           0           0     0
T06      5/11  1/ 2  0/ 1  1/ 2  8/ 3  1/ 1  0/ 0  0/ 0  2/ 8  0/ 0
T12            7/11        1/ 2        8/ 4        0/ 1     2/ 8
POZ   1  1  3  2  2  7  8  3  4  2  3  0  3  3  4  6  3  1  2  0  3
POS  27 16 18 24 28 65 74 72 31 20 37 57 94 87 95 65 41 18 28 50 91
TYP   R  R  R  R  R  S  S  S  R  R  R  S  S  S  S  S  R  R  R  R  S
SNW                     0                       0                 0
CIG   8  8  8  8  8  8  8  7  8  8  7  8  8  8  8  8  8  8  8  8  8
VIS   7  7  7  7  7  7  7  1  7  7  7  7  7  7  7  7  7  7  7  7  7
OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N
  • DT = The day of the month, denoted by the standard three or four letter abbreviation
  • HR = Hour of the day in UTC time. This is the hour at which the forecast is valid, or if the forecast is valid for a period, the end of the forecast period.
  • N/X = nighttime minimum/daytime maximum 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.
  • 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 = snowfall categorical forecasts during a 24-h period ending at the indicated 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.
  • 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 miles
2 1/2 - < 1 miles
3 1 - < 2 miles
4 2 - < 3 miles
5 3 - 5 miles
6 6 miles
7 > 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
FW few > 0 to 2 octas
SC scattered > 2 to 4 octas
BK broken > 4 to < 8 octas
OV overcast


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

Canadian Min/Max Temperature Guidance

In addition to the standard MAV output, additional guidance for Maximum and Minimum Temperatures is also available for select Canadian stations. This is currently only available as an all-stations text product (not included in GRIB and BUFR downloadable data). 

Canadian Min/Max Temperature

Sample Message
GFS-BASED STATISTICAL MAX/MIN GUIDANCE  10/26/15  0000 UTC                     
       MON 26| TUE 27| WED 28                                  
 CWIY      37| 20  43| 20  46                                                   
 CWJI      51| 34  44| 23  43                                                   
 CWJR      49| 41  53| 40  50                                                   
 CWNM      50| 40  53| 42  50                                                   
 CWOE      51| 33  43| 24  49                                                   
 CWPE      46| 28  51| 33  53                                                   
 CWPO      48| 32  46| 31  40                                                   
 CWQP      50| 40  53| 42  59                                                   
 CWRT      47| 30  44| 29  49                                                   
 CWRY      56| 33  42| 23  53                                                   
 CWSS      45| 23  51| 26  50