Description of the GFS LAMP Alphanumeric Message

The GFS MOS-Based LAMP guidance is generated using the current station observations for the cycle time, analyses of the observations, simple model output, and the MOS data derived from NCEP's Global Spectral Model. To stay updated about the availability of GFS-LAMP guidance for the different cycle times, please refer to our Changes Document. This guidance is valid for stations in the United States, Puerto Rico, and the U.S. Virgin Islands. Please refer to the following document for the most recent station list. Forecast elements are valid from 1 to 25 hours in advance.

Forecast elements are valid from 1 to 25 hours in advance, except from 1 to 38 hours for CIG, VIS, OBV, P01, CCG, CVS, and PC1.

• With LMP v2.2.0 and beyond, there are 3 types of ASCII text bulletins. They are:

1. The standard bulletin which covers the 1-25 hour period.
2. The extended bulletin which covers the 26-38 hour period.
3. The full bulletin which covers the 1-38 hour period. This bulletin is currently only available via the LAMP website.
4. 15-min Update Bulletins.

    The below example shows the full bulletin, but the key applies to all the bulletins.

 KDCA   GFS LAMP GUIDANCE   8/14/2020  2130 UTC
 DT /AUG  14/AUG  15                                                                /AUG  16
 HR   01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38
 UTC  22 23 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 00 01 02 03 04 05 06 07 08 09 10 11
 TMP  82 81 80 78 77 77 76 75 75 74 74 74 73 73 73 74 74 75 75 76 76 75 74 72 71999999999999999999999999999999999999999
 DPT  71 71 70 70 70 70 70 70 70 69 69 69 68 68 67 67 67 67 66 66 66 66 66 66 66999999999999999999999999999999999999999
 WDR  04 05 05 07 06 05 07 08 08 06 04 04 04 04 05 05 05 06 05 06 07 06 04 03 04 99 99 99 99 99 99 99 99 99 99 99 99 99
 WSP  07 07 07 06 06 06 06 06 05 05 06 06 07 06 06 06 06 06 06 07 08 08 08 07 07 99 99 99 99 99 99 99 99 99 99 99 99 99
 WGS  NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG NG999999999999999999999999999999999999999
 PPO  23 23 23 24 25 22 19 12 12 12 10 10 10 10 11 13 21 23 27 29 33 43 46 55 59999999999999999999999999999999999999999
 PCO   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  Y  Y  Y  Y  Y  X  X  X  X  X  X  X  X  X  X  X  X  X
 P01  64 43 30 16  7  3  3  3  3  5  9 10  8  6  9 11  8  5  6  6  7  8  9 11 10 10 10 11 11  9 10 16 24 26 34 43 45 45
 PC1   Y  Y  Y  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  Y  Y  Y  Y  Y  Y
 P06                          33                19                21                26                48
 LP1   5  9  9  5  3  2  1  0  0  0  0  0  0  0  0  0  0  0  0  1  1  1  1  1  1999999999999999999999999999999999999999
 LC1   L  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  X  X  X  X  X  X  X  X  X  X  X  X  X
 CP1  69 39 35 18 11  8  5  5  3  2  3  4  4  3  6  6  5  5  6  7  5  6  8  8  5999999999999999999999999999999999999999
 CC1   H  M  M  L  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  X  X  X  X  X  X  X  X  X  X  X  X  X
 CLD  OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV OV
 CIG   7  6  7  7  7  7  7  7  7  7  7  7  7  7  7  7  6  6  6  6  5  4  4  4  4  4  3  3  3  4  4  3  3  3  3  3  3  3
 CCG   7  8  7  7  7  6  7  7  7  7  6  7  7  7  6  6  6  6  6  6  5  5  4  4  4  4  4  4  4  4  4  4  4  4  4  4  3  3
 VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  6  5  5  5  6  6  5  5  5  5  5  7  7  7  7  7
 CVS   2  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  6  5  5  5  5  5  6  6  5  5  5  7  5  6  5  6  7  6
 OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N BR BR BR  N  N  N  N  N  N  N

• UTC 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.
• TMP surface temperature valid at that hour.
• DPT surface dewpoint 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.
• WGS forecasts of the 10-meter wind gust at the hour, given in knots.  "NG" means that no gust is forecast.
• PPO probability of precipitation occurring on the hour.  The precipitation need not be measurable.
• PCO categorical forecast of yes (Y) or no (N) indicating if precipitation, not necessarily measurable, will occur on the hour.
• P01 probability of measurable precipitation (PoP) during the 1-h period ending at the indicated time.
• PC1 categorical forecast of yes (Y) or no (N) indicating if measurable precipitation will occur during the 1-h period ending at the indicated time.
• P06 probability of measurable precipitation (PoP) during a 6-h period ending at that time.
• LP1 probability of lightning (at least one total lightning flash) occurring during the 1-hr period ending at the indicated time.
• LC1 categorical forecast of no (N), low (L), medium (M), or high (H) potential for lightning (at least one total lightning flash) occurring during the 1-hr period ending at the indicated time.
• CP1 probability of convection (at least one total lightning flash and/or radar reflectivity of 40dBZ or higher) occurring during the 1-hr period ending at the indicated time.
• CC1 categorical forecast of no (N), low (L), medium (M), or high (H) potential for convection (at least one total lightning flash and/or radar reflectivity of 40dBZ or higher) occurring during the 1-hr period ending at the indicated time.
• POZ* conditional probability of freezing pcp occurring at the hour.  This probability is conditional on precipitation occurring.
• POS* conditional probability of snow occurring at the hour.  This probability is conditional on precipitation occurring.
• TYP* conditional precipitation type at the hour.  This category forecast is conditional on precipitation occurring.
• CLD forecast categories of total sky cover valid at that hour.
• CIG ceiling height categorical forecasts at the hour.
• CCG conditional ceiling height categorical forecasts at the hour.   This category forecast is conditional on precipitation occurring.
• VIS visibility categorical forecasts at the hour.
• CVS conditional visibility categorical forecasts at the hour.   This category forecast is conditional on precipitation occurring.
• OBV obstruction to vision categorical forecasts at the hour.

*In the contiguous United States, these products are available September 1 - May 31.

Definitions of Categorical Elements