Page 54 - AFMAN 15-111, 12 MAR 2019

54 AFMAN15-111 12 MARCH 2019

Table 10.4. Determining Precipitation Intensity.

Rain / Ice Pellets - Based on Rate-of-Fall (See Notes 1)
Intensity Criteria
Light Rate of up to 0.10” per hr; maximum 0.01 inch in 6 minutes
Rate of 0.11” - 0.30” per hr; more than 0.01 inch to 0.03 inch in 6
Moderate
minutes
Heavy Rate of more than 0.30” per hr; more than 0.03 inch in 6 minutes
Rain - Based on accumulation
Intensity Criteria
Scattered drops that, regardless of duration, do not completely wet an
Light exposed surface up to a condition where individual drops are easily
seen.
Individual drops are not clearly identifiable; spray is observable just
Moderate
above pavements and other hard surfaces
Rain seemingly falls in sheets; individual drops are not identifiable;
Heavy
heavy spray to height of several inches is observed over hard surfaces
Ice Pellets - Based on Accumulation and Visibility
Intensity Criteria
Scattered pellets that do not completely cover an exposed surface
Light
regardless of duration; visibility is not affected
Slow accumulation on ground; visibility reduced by ice pellets to less
Moderate
than 7SM (9999m)
Rapid accumulation on ground; visibility reduced by ice pellets to less
Heavy
than 3SM (4800m)
Snow / Snow Pellets / Drizzle - Based on visibility
Intensity Criteria
Light Visibility > 1/2SM (800m)
Moderate Visibility > 1/4SM (0400m) but ≤ 1/2SM (800m)
Heavy Visibility ≤ 1/4SM (0400m)
Notes:
1. Intensity is determined based on the rate

10.8.3. Hail (GR). When observed on station, regardless of size, hail will be encoded GR as
present weather in column 5. All reports of hail must include the size of the largest hailstone
observed in the Remarks (RMK) section of METAR/SPECI in increments of 1/4 inch. If no
hail size is reported, it will be assumed to be small hail. If the initial observation to report the
beginning or ending of hail is missed (e.g. personnel sheltering for safety), at the first
opportunity, disseminate a full observation including the begin/end times of the hail activity
following the format in Attachment 3. (T-1).