NWS/OST/MDL: January 3, 2005
Availability of GFS LAMP guidance
Guidance is currently available from the start times of:
0000, 0100, 0200, 0300, 0400, 0500, 0600, 0700, 0800, 0900, 1000, 1100, 1200,
1300, 1400, 1500, 1600, 1700, 1800, 1900, 2000, 2100, 2200 and 2300 UTC
(LAMP now runs for each hour of the day)
GFSLAMP guidance will be available from all hours in the future.
Projections refer to the number of hours after the cycle time.
Table 1
:
Projections for which the GFS LAMP guidance temperature,
dewpoint, winds, probability of precipitation occurring on
the hour, best category forecasts for precipitation occurring
on the hour, precipitation type, total sky cover, ceiling
height, conditional ceiling height, visibility, conditional
visibility, and obstruction to vision forecasts are issued.
Element

Projection in Hours from Cycle Time

Temperature

Every 1h from 1 to 25 hours

Dewpoint

Every 1h from 1 to 25 hours

Wind Direction

Every 1h from 1 to 25 hours

Wind Speed

Every 1h from 1 to 25 hours

Wind Gusts

Every 1h from 1 to 25 hours

Probability of Precipitation occurring on the hour

Every 1h from 1 to 25 hours

Best Category (yes/no) for precipitation occurring on the hour

Every 1h from 1 to 25 hours

Precipitation Type

Every 1h from 1 to 25 hours

Total Sky Cover

Every 1h from 1 to 25 hours

Ceiling Height

Every 1h from 1 to 25 hours

Conditional Ceiling Height

Every 1h from 1 to 25 hours

Visibility

Every 1h from 1 to 25 hours

Conditional Visibility

Every 1h from 1 to 25 hours

Obstruction to Vision

Every 1h from 1 to 25 hours

Table 2
:
Projections for which the GFS LAMP guidance forecasts of probability
of precipitation in a 6h period are issued. Guidance is provided
for all projections that (1) fall on the valid times of 0000, 0600,
1200, and 1800 UTC, and (2) are at least 6 hours into the forecast
period.
Element

Cycle Time

Projection in Hours from Cycle Time

Probability of
Precipitation in a 6h period

0000 UTC

Every 6h from 6 to 25 hours

0100 UTC

Every 6h from 11 to 25 hours

0200 UTC

Every 6h from 10 to 25 hours

0300 UTC

Every 6h from 9 to 25 hours

0400 UTC

Every 6h from 8 to 25 hours

0500 UTC

Every 6h from 7 to 25 hours

0600 UTC

Every 6h from 6 to 25 hours

0700 UTC

Every 6h from 11 to 25 hours

0800 UTC

Every 6h from 10 to 25 hours

0900 UTC

Every 6h from 9 to 25 hours

1000 UTC

Every 6h from 8 to 25 hours

1100 UTC

Every 6h from 7 to 25 hours

1200 UTC

Every 6h from 6 to 25 hours

1300 UTC

Every 6h from 11 to 25 hours

1400 UTC

Every 6h from 10 to 25 hours

1500 UTC

Every 6h from 9 to 25 hours

1600 UTC

Every 6h from 8 to 25 hours

1700 UTC

Every 6h from 7 to 25 hours

1800 UTC

Every 6h from 6 to 25 hours

1900 UTC

Every 6h from 11 to 25 hours

2000 UTC

Every 6h from 10 to 25 hours

2100 UTC

Every 6h from 9 to 25 hours

2200 UTC

Every 6h from 8 to 25 hours

2300 UTC

Every 6h from 7 to 25 hours

Table 3: Projections for which the GFS LAMP guidance
forecasts of probability of precipitation in a 12h period are issued.
Guidance is provided for all projections that (1) fall on the valid times of
0000, 0600, 1200, and 1800 UTC, and (2) are at least 12 hours into the forecast
period.
Element

Cycle Time

Projection in Hours from Cycle Time

Probability of
Precipitation in a 12h period

0000 UTC

Every 6h from 12 to 25 hours

0100 UTC

Every 6h from 17 to 25 hours

0200 UTC

Every 6h from 16 to 25 hours

0300 UTC

Every 6h from 15 to 25 hours

0400 UTC

Every 6h from 14 to 25 hours

0500 UTC

Every 6h from 13 to 25 hours

0600 UTC

Every 6h from 12 to 25 hours

0700 UTC

Every 6h from 17 to 25 hours

0800 UTC

Every 6h from 16 to 25 hours

0900 UTC

Every 6h from 15 to 25 hours

1000 UTC

Every 6h from 14 to 25 hours

1100 UTC

Every 6h from 13 to 25 hours

1200 UTC

Every 6h from 12 to 25 hours

1300 UTC

Every 6h from 17 to 25 hours

1400 UTC

Every 6h from 16 to 25 hours

1500 UTC

Every 6h from 15 to 25 hours

1600 UTC

Every 6h from 14 to 25 hours

1700 UTC

Every 6h from 13 to 25 hours

1800 UTC

Every 6h from 12 to 25 hours

1900 UTC

Every 6h from 17 to 25 hours

2000 UTC

Every 6h from 16 to 25 hours

2100 UTC

Every 6h from 15 to 25 hours

2200 UTC

Every 6h from 14 to 25 hours

2300 UTC

Every 6h from 13 to 25 hours

Table 4: Projections for which the GFS LAMP guidance
forecasts of probability of thunderstorms in a 2h period and best category
thunderstorm occurrence are issued.
Element

Projection in Hours from Cycle Time

Probability of
Thundstorms in a 2h period

2h periods ending every hour in the first 26
hours after issuance, and ending every even GMT hour thereafter
out to 25 hours.
For example:
Odd start times have 2h guidance valid from 13h,
24h, 35h, 46h, 57h, and then 79h, 911h, 1113h, 1315h, 1517h,
1719h, 1921h, 2123h, and 2325h.
Even start times have 2h guidance valid from 13h, 24h, 35h, 46h, 57h, 68h,
and then 810h, 1012h, 1214h, 1416h, 1618h, 1820h, 2022h, 2224h.

Best Category
(yes/no) for thunderstorms occurring in the 2h period

Same projections as for Probability of Thunderstorms above.

For a schematic depicting the thunderstorm projections, please click
here
(pdf format).