Ensemble MOS (GEFS MOS) forecasts were discontinued Tuesday, April 16, 2019, after the 0000 UTC model cycle time. This page has been retained for information about legacy data.

About Global Ensemble MOS Message

Ensemble MOS forecasts were based on the 0000 UTC run of the GFS Global model ensemble system. These runs included the operational GFS, a control version of the GFS (run at lower resolution), and 20 bred perturbation runs. Older operational GFS MOS prediction equations** were applied to the output from each of the ensemble runs to produce 21 separate sets of alphanumeric bulletins in the same format as the operational MEX message.

(** The current operational GFS MOS equations were developed with GFS model predictors that are not available in the current Global ensemble output. Therefore we were using operational MOS equations from 2002 to create the ensemble guidance. Ensemble MOS is not available for all stations and elements in the current operational GFS MOS guidance.)

For more information about NCEP's Global Ensemble Prediction System see: http://www.emc.ncep.noaa.gov/index.php?branch=GEFS or http://www.emc.ncep.noaa.gov/gmb/ens/index.html(older site).

For each element and projection, the ensemble MOS summary message contains the operational forecast (OPRN), a mean forecast computed by averaging the separate ensemble MOS forecasts together (MEAN), the standard deviation of the forecasts (STDV), and the most extreme MOS forecasts included in the set (HI,LO). Forecasts of mn/mx, 12-hr PoP and 24-hr PoP valid 12 - 192 hours after 0000 UTC are provided for the same sites as the operational MOS guidance. The ensemble MOS message is updated daily at approximately 1000 UTC.

At this time, the experimental MOS ensemble summary message (described above) is not available.

This product is NOT OPERATIONAL. It is experimental in nature, and has yet to be objectively verified.

The GEFS Ensemble Message

Sample Message

Control
 KIAD   MRF MOS GUIDANCE   10/28/2015  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 WED  28| THU 29| FRI 30| SAT 31| SUN 01| MON 02| TUE 03| WED 04 CLIMO
 X/N  62| 51  70| 42  60| 36  62| 42  66| 46  63| 46  66| 46  66 38 62
 TMP  59| 54  57| 44  50| 39  51| 45  56| 48  55| 48  56| 48  56      
 DPT  57| 50  39| 35  35| 34  38| 42  45| 46  51| 46  48| 46  46      
 CLD  OV| OV  CL| CL  CL| CL  PC| PC  OV| OV  OV| PC  OV| PC  PC      
 P12 100| 85   2|  1   1|  7   4| 15  26| 41  39| 28  14| 27  19 19 19
 P24    |     85|      4|      7|     26|     48|     30|     27    28
 Q12   4|  3   0|  0   0|  0   0|  0   0|  2   2|  0    |             
 Q24    |      0|      0|      0|      0|      3|       |             
 PZP   0|  1   0|  0   2|  0   0|  0   0|  0   0|  0   0|  1   0      
 PSN   0|  0   0|  0   0|  0   0|  0   0|  0   0|  1   0|  0   0      
 PRS   0|  0   0|  1   5|  3   0|  0   0|  0   1|  1   0|  1   0      
 TYP   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R      


                                                                      
Perturbation 1
 KIAD   MRF MOS GUIDANCE   10/28/2015  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 WED  28| THU 29| FRI 30| SAT 31| SUN 01| MON 02| TUE 03| WED 04 CLIMO
 X/N  62| 51  70| 42  59| 34  61| 41  59| 44  70| 46  66| 45  61 38 62
 TMP  59| 54  56| 45  49| 37  50| 44  51| 47  59| 49  55| 47  51      
 DPT  57| 50  38| 34  34| 33  38| 42  43| 43  50| 45  45| 44  39      
 CLD  OV| OV  CL| CL  CL| CL  PC| OV  OV| OV  PC| CL  CL| CL  CL      
 P12 100| 81   1|  0   1|  7   4| 24  49| 44  16| 14  12| 18  17 19 19
 P24    |     81|      5|      7|     64|     44|     17|     21    28
 Q12   4|  3   0|  0   0|  0   0|  0   2|  2   0|  0    |             
 Q24    |      0|      0|      0|      3|      0|       |             
 PZP   0|  1   0|  0   2|  0   0|  0   0|  0   0|  0   0|  0   0      
 PSN   0|  0   0|  0   0|  0   0|  0   0|  0   0|  0   0|  0   0      
 PRS   0|  0   0|  0   5|  4   0|  0   0|  0   1|  1   0|  0   0      
 TYP   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R      

                                                                      
Perturbation 2
 KIAD   MRF MOS GUIDANCE   10/28/2015  0000 UTC                       
 FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192      
 WED  28| THU 29| FRI 30| SAT 31| SUN 01| MON 02| TUE 03| WED 04 CLIMO
 X/N  62| 51  70| 41  59| 36  62| 43  65| 43  65| 42  68| 50  69 38 62
 TMP  59| 54  56| 44  50| 39  51| 46  55| 45  55| 45  58| 51  58      
 DPT  57| 50  39| 35  35| 34  39| 43  45| 42  45| 42  46| 48  47      
 CLD  OV| OV  CL| CL  CL| CL  PC| PC  OV| OV  OV| PC  PC| OV  CL      
 P12 100| 77   3|  1   1|  7   4| 15  37| 32  19| 20  15| 26  21 19 19
 P24    |     77|      3|      7|     37|     32|     23|     39    28
 Q12   4|  2   0|  0   0|  0   0|  0   2|  1   0|  0    |             
 Q24    |      0|      0|      0|      0|      0|       |             
 PZP   0|  1   0|  0   1|  0   0|  0   0|  0   0|  0   0|  0   0      
 PSN   0|  0   0|  0   0|  0   0|  0   0|  0   0|  0   0|  0   0      
 PRS   0|  0   0|  0   3|  4   0|  0   0|  0   1|  1   0|  0   0      
 TYP   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R|  R   R      
                                                                      
 (continued....)

  • FHR = Forecast hour, i.e. how many hours from the model run time
  • X/N = daytime max/nightime min temperatures
  • TMP = temperature valid at that hour
  • DPT = dewpoint valid at that hour
  • CLD = mean total sky cover over the 12-hr period ending at that time
  • WND = maximum sustained surface wind (WND) during a 12-h period
  • P12 = 12-hr probability of precipitation (PoP) ending at that time
  • P24 = 24-hr PoP ending at that time
  • Q12 = 12-hr quantitative precipitation forecast (QPF) ending at that time
  • Q24 = 24-hr QPF ending at that time
  • T12 = 12-hr probability of thunderstorm ending at that time
  • T24 = 24-hr probability of thunderstorm for the 1200-1200 UTC time period ending at that time
  • PZP = conditional probability of freezing pcp occurring for the 12-hr period ending at that time
  • PSN = conditional probability of snow occurring for the 12-hr period ending at that time
  • PRS = conditional probability of rain/snow mix occurring for the 12-hr period ending at that time
  • TYP = conditional precipitation type for the 12-hr period ending at that time
  • SNW = snow fall categorical forecasts during a 24-h period ending at the indicated time.
     
  • CLIMO =  follow the link for Information on climatology

 

Definitions of Categorical Elements

MEX 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


MEX 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
MEX Cloud (CLD) Categories
CL mostly clear                  
PC partly cloudy
OV mostly cloudy


MEX Precipitation Type (TYP) Categories
S pure snow or snow grains
Z freezing rain/drizzle, ice pellets, or
anything mixed with freezing precip
RS rain/drizzle and snow mixed
R pure rain/drizzle