Page 48 - AFMAN 15-111, 12 MAR 2019

48 AFMAN15-111 12 MARCH 2019

10.3.3.2. The descriptors low drifting (DR) and blowing (BL) are only encoded with dust
(DU), sand (SA), and snow (SN) (e.g., BLSN or DRSN). DR will be encoded for DU, SA,
or SN raised by the wind to less than 6 feet above the ground. (T-0). When BLSN is
observed with SN falling from clouds, both phenomena are reported (e.g., SN BLSN).
When, because of BLSN, the weather technician cannot determine whether or not SN is
also falling, then only "BLSN" will be reported. (T-0). BL may also be encoded with spray
(PY).
10.3.3.3. SH is encoded only with one or more of the precipitation types of rain (RA), SN,
PL, GS or GR. The SH descriptor indicates showery-type precipitation. When showery-
type precipitation is encoded with VC (VCSH), the intensity and type of precipitation is
not encoded.

10.3.3.4. The descriptor TS may be encoded by itself, i.e., a TS without associated
precipitation, or it may be encoded with precipitation. If encoding a TS with precipitation,
the following are the authorized types: RA, SN, PL, GS, GR, UP. For example, a TS with
SN and GS would be encoded as "TSSNGS."
10.3.3.5. The descriptor freezing (FZ) is only encoded in combination with FG, drizzle
(DZ) or RA (e.g., FZRA, FZFG, FZDZ). FZ is only reported with FG when the temperature
is less than 0 degrees Celsius.
10.3.4. Precipitation. FBWOSs may have one type of precipitation per observation and
augmented stations may have up to three types of precipitation encoded in a single present
weather group. They are encoded in decreasing predominance based on intensity. Only one
intensity indicator (+ or -) may be encoded and it refers to the intensity of the total precipitation.

10.3.4.1. Precipitation types are DZ, RA, SN, IC, PL, GS, GR and SG. Report the start
and end of all precipitation types.
10.3.4.2. GR is reported regardless of the size of the hail stone. Measure the largest stone
and report the size in ¼ inch increments in the Remarks. If no hail size is reported, it will
be assumed to be small hail. (T-0).
10.3.5. Obscurations. With the exception of VA, DRDU, DRSA, DRSN, MIFG, PRFG, and
BCFG, obscurations are encoded in the body of the report if the surface visibility is less than
7SM (9999 m). Reportable obscurations are FG, BR, FU, VA, DU, SA, HZ, and PY.

10.3.5.1. BR is reported when the obscuration consists of water droplets or ice crystals and
the visibility is at least 5/8 SM (1000 m), but less than 7SM (9999 m).
10.3.5.2. FG is reported when the obscuration consists of water droplets or ice crystals
(FG or FZFG) and the visibility is less than 5/8SM (1000 m). FZ is only reported with FG
when visibility is less than 5/8 SM (1000 m) and temperature is less than 0 degrees Celsius.
10.3.5.3. VA is always reported when present.

10.3.5.4. PY is encoded only when used with the descriptor BL.
10.3.6. Other Weather Phenomena.

10.3.6.1. SQ is reported when a sudden increase in wind speed of at least 16 knots is
observed, and is sustained at 22 knots or more for at least 1 minute.