Section 2. Pilot Weather Report (UA/UUA)
PIREPs are filed at unscheduled times with stations
having sending capability to WMSCR for
dissemination on the Service A domestic aviation
weather system. These reports must be entered into
the operational system as individual reports, not
appended to a surface observation.
9-2-2. PREPARATION FOR
Record PIREP data directly into the operational
system, on FAA Form 7110-2, or on other material
deemed appropriate; for example, 5'' x 8'' plain
FSS specialists must actively solicit PIREPs in
conjunction with preflight and inflight
communications with pilots and assure timely
dissemination of the PIREP information. Each
facility should make special efforts to obtain PIREPs
on departure and arrival weather conditions at
airports within their flight plan area.
9-2-4. PIREP DISPLAY
Maintain a PIREP graphical display to conform to the
particular requirements of your facility. If it is posted
for internal use only, symbology may be used at the
facility's discretion. If it is displayed as a pilot
self-briefing aid, the use of contractions, such as
overcast (OVC), must be applicable.
9-2-5. SOLICITING PIREPs
Solicit PIREPs for the affected area(s) when one
or more of the following weather conditions exist, are
reported, or forecast to occur:
Ceilings at or below 5,000 feet.
Visibility reported on the surface or aloft is
5 miles or less.
Thunderstorms and related phenomenon.
Turbulence of moderate degree or greater.
5. Icing of light degree or greater.
Volcanic eruption, ash clouds, and/or
detection of sulfur dioxide (SO2) in the cabin.
(a) If only SO2 is reported, ask the pilot if
volcanic ash clouds are in the vicinity.
Sulphur dioxide has the odor of a
Pilots may forward PIREPs regarding volcanic activity
using the format described in the Volcanic Activity
Reporting Form (VAR) as depicted in the AIM
b. Also, solicit PIREPs regardless of weather
A NWS or ATC facility indicates a need
because of a specific weather or flight assistance
2. Necessary to determine flying conditions
pertinent to natural hazards (mountain passes, ridges,
peaks) between the weather reporting stations.
The station is designated as responsible for
PIREPs in an offshore coastal area.
Flight watch specialists must solicit sufficient
PIREPs to remain aware of flight conditions.
d. To solicit PIREPs within a specific area,
broadcast a request on NAVAIDs, transcribed
broadcast facilities, or a selected communications
PILOT WEATHER REPORTS ARE REQUESTED
(location/area). CONTACT (name) RADIO/FLIGHT
WATCH ON (frequency) TO REPORT THESE
9-2-6. DATA TO BE INCLUDED IN PIREPs
Include the following reports of flight conditions, as
a. Height and coverage of cloud bases, tops, and
b. Flight visibility.
Restrictions to visibility and weather occurring
Air temperature and changes to temperature
with altitude or range.
e. Direction and speed of wind aloft.
f. Duration and intensity of turbulence.
FAAO JO 7110.10, Para 9-2-7.
Extent, type, and intensity of icing.
FAAO JO 7110.10, Para 9-2-8.
h. Weather conditions and cloud cover through
mountain passes and over ridges and peaks.
i. Location, extent, and movement of
thunderstorms and/or tornadic activity.
j. Excessive winds aloft, LLWS, and other
phenomena bearing on safety and efficiency of flight.
9-2-7. REPORTING TURBULENCE IN
Turbulence reports must include location,
altitude, or range of altitudes, and aircraft type, and
should include whether in clouds or clear air. The
degree of turbulence, intensity, and duration
(occasional, intermittent, and continuous) is
determined by the pilot.
Light. Loose objects in aircraft remain at rest.
2. Moderate. Unsecured objects are dislodged.
Occupants feel definite strains against seat belts and
Severe. Occupants thrown violently against
seat belts. Momentary loss of aircraft control.
Unsecured objects tossed about.
4. Extreme. Aircraft is tossed violently about,
impossible to control. May cause structural damage.
Report Clear Air Turbulence (CAT) or CHOP
if used by the pilot to describe the type of turbulence.
9-2-8. REPORTING ICING CONDITIONS IN
Icing reports must include location, altitude or
range of altitudes, aircraft type, air temperature,
intensity, and type of icing.
b. Icing types.
1. Rime. Rough, milky, opaque ice formed by
the instantaneous freezing of small super-cooled
2. Clear. A glossy, clear or translucent ice
formed by the relatively slow freezing of large
super-cooled water droplets.
3. Mixed. A combination of rime and clear.
c. Icing intensity.
Trace. Ice becomes perceptible. Rate of
accumulation slightly greater than sublimation.
Deicing/anti-icing equipment is not utilized unless
encountered for an extended period of time (over
2. Light. The rate of accumulation may create a
problem if flight is prolonged in this environment
(over 1 hour). Occasional use of deicing/anti-icing
equipment removes/prevents accumulation. It does
not present a problem if deicing/anti-icing is used.
3. Moderate. The rate of accumulation is such
that even short encounters become potentially
hazardous, and use of deicing/anti-icing equipment
or diversion is necessary.
Severe. The rate of accumulation is such that
deicing/anti-icing equipment fails to reduce or
control the hazard. Immediate diversion is necessary.
9-2-9. MEANS USED TO SOLICIT PIREPs
Inform pilots of a need for PIREPs. The following
methods may be used to collect PIREPs:
During preflight weather briefings.
b. On post-flight contacts.
c. During regular air-ground contacts.
Broadcast a request on NAVAID frequencies.
Append a request on HIWAS, TIBS, VOR-
TWEB, or TWEB broadcasts.
Request PIREPs from air carrier and military
operations offices, military pilot-to-forecaster units,
and local aircraft operators.
Solicit from other air traffic facilities.
9-2-10. PIREP CLASSIFICATION
Categorize PIREPs as follows:
a. URGENT. The following weather phenomena
must be classified as an URGENT (UUA) PIREP:
1. Tornadoes, funnel clouds, or waterspouts.
2. Severe or extreme turbulence (including clear
5. Low level wind shear. Classify LLWS
PIREPs as UUA if the pilot reports air speed
fluctuations of 10 knots or more. Classify reports of
LLWS with air speed fluctuations less than 10 knots
as routine. If airspeed fluctuation is not reported,
classify PIREP as UUA.
LLWS defined as windshear within 2,000 feet of the
6. Volcanic eruption, ash clouds, and/or
detection of sulfur dioxide (SO2) in the cabin.
(a) If a pilot only reported the smell of SO2 in
the cabin and confirmed no volcanic ash clouds were
present, classify the report as a ROUTINE PIREP.
(b) Sulphur dioxide has a sulfur-like odor.
7. Any other weather phenomena reported
which are considered by the specialist as being
hazardous, or potentially hazardous, to flight
b. ROUTINE. Classify as ROUTINE (UA) all
PIREPs received except those listed above.
9-2-11. PIREP HANDLING
Upon receipt of a PIREP, accomplish the following:
1. Deliver to the ARTCC Weather Coordinator
as soon as possible.
2. Enter on Service A at the first opportunity.
3. Use in weather briefings, as appropriate.
1. Transmit on Service A as soon as practical.
Broadcast in accordance with established
procedures in Chapter 2.
Use in weather briefings, as appropriate.
9-2-12. OFFSHORE COASTAL ROUTES
When your station has been given responsibility for
collecting offshore coastal route PIREPs:
a. Include the coastal water area when soliciting
PIREPs. At least one PIREP is required hourly
regardless of weather conditions.
The following flight plan sectors are responsible for collecting offshore coastal routes in the
contiguous 48 states, Hawaii, and Puerto Rico: HNL,
SJU, SAN, HHR, OAK, MMV, SEA, BGR,BDR,
MIV, DCA, RDU, MCN, GNV, PIE, MIA, ANB,
GWO, DRI, CXO, and SJT
The Flight Services Safety Operations Supportoffice
assigns PIREP responsibility for an offshore coastal area,
route, or route segment to a specific station. The area
assigned will be within the same ARTCC area as the
station, and the station must have adequate air-ground
communications coverage over its assigned offshore area.
9-2-13. PIREP PREPARATION
To assure proper dissemination of PIREPs to all
system users, the encoding procedures listed below
must be followed:
a. Identify each element by a Text Element
b. Ensure each report includes TEIs for message
type, location, time, altitude/flight level, aircraft
type, and at least one other to describe the reported
c. Precede each TEI, except message type, with a
space and a solidus (/).
d. Follow each TEI, except altitude/flight level,
with a space.
e. Insert zeros in reported values when the number
of digits in the report is less than the number required
by the format.
Use only authorized aircraft designators and
g. In the location TEI, include any three character
alphanumeric identifier to describe locations or
routes. Use only authorized identifiers from FAA
Order JO 7350.8, Location Identifiers.
Omit entries of TEIs, except as listed in subpara
9-2-13b, for which no data was reported.
9-2-14. PIREP FORMAT
Using TEIs as described below, prepare PIREPs for
system entry in the following format:
a. UUA or UA. Message type
- Urgent or Routine
1. Location in reference to a VHF NAVAID or
an airport, using the three or four alphanumeric
identifier. If appropriate, encode the identifier, then
three digits to define a radial and three digits to define
the distance in nautical miles.
/OV KFMG233016/RM RNO 10SW
2. Route segment. Two or more fixes to describe
c. /TM. Time that the reported phenomenon
occurred or was encountered. Report time in four
d. /FL. Altitude/flight level. Enter the altitude in
hundreds of feet (MSL) where the phenomenon was
first encountered. If not known, enter UNKN. If the
aircraft was climbing or descending, enter the
appropriate contraction (DURC or DURD) in the
remarks/RM TEI. If the condition was encountered
within a layer, enter the altitude range within the
appropriate TEI describing the condition.
/FLUNKN /RM DURC
e. /TP. Type aircraft. Enter aircraft type. f not
known, enter UNKN. Icing and turbulence reports
must always include the aircraft type.
/SK. Sky condition. Report height of cloud
bases, tops, and cloud coverage as follows:
Enter the height of the base of a layer of
clouds in hundreds of feet (MSL) using three digits.
Enter the top of a layer in hundreds of feet (MSL)
preceded by the word "-TOP." If reported as clear
above the highest cloud layer, enter a space and
"SKC" following the reported level.
/SK OVC100-TOP110/ SKC
Use authorized contractions for cloud cover.
Cloud cover amount ranges will be entered
with a hyphen and no spaces separating the amounts;
/SK BKN-OVCUNKN-TOP060/BKN120-TOP150/ SKC
4. Unknown heights are indicated by the
5. If a pilot indicates he/she is in the clouds,
enter IMC in the remarks.
/SK OVC065-TOPUNKN /RM IMC
When more than one layer is reported,
separate layers by a solidus (/).
g. /WX. Flight visibility and flight weather.
Report weather conditions encountered by the pilot
Flight visibility, if reported, will be the first
entry in the /WX field. Enter as FV followed by a
two-digit visibility value rounded down, if necessary,
to the nearest whole statute mile and append “SM"
(FV03SM). If visibility is reported as unrestricted,
2. Enter flight weather types using one or more
of the standard surface weather reporting symbols
contained in TBL 9-2-1.
Weather Type and Symbols
Drifting / Blowing Snow
Dust / Blowing Dust
Fog (vis < 5/8SM)
Hail (aprx 1/4" dia or more)
Ice Pellets/ Showers
Mist (vis 5/8SM or more)
Patchy Fog on part of Arpt
Rain / Showers
Sand / Blowing Sand
Sml Hail/Snow Pellet Showers
Sml Hail/Snow Pellets
Snow / Showers
Well developed Dust/Sand Whirls
3. Intensity of precipitation (- for light, no
qualifier for moderate, and + for heavy) must be
indicated with precipitation types, except ice crystals
and hail, including those associated with a
thunderstorm and those of a showery nature.
Intensity of obscurations must be ascribed as
moderate or + heavy for dust and sand storms only.
No intensity for blowing dust, blowing sand, or
/WX FV01SM +DS000-TOP083/ SKC /RM DURC
When more than one form of precipitation is
combined in the report, the dominant type must be
/WX FV00SM +TSRAGR
When FC is entered in /WX, FUNNEL
CLOUD is spelled out on /RM. When +FC is entered
in /WX, TORNADO or WATERSPOUT is spelled
out in the /RM TEI.
/WX FC /RM FUNNEL CLOUD
/WX +FC /RM TORNADO or WATERSPOUT
When the size of hail is stated, enter in 1/4
increments in remarks /RM TEI.
The proximity qualifier VC (Vicinity) is only
used with TS, FG, FC, +FC, SH, PO, BLDU, BLSA,
/WX FV02SM BLDU000-TOP083 VC W
When more than one type of weather is
reported enter in the following order: 1) TORNADO,
WATERSPOUT, OR FUNNEL CLOUD; 2)
Thunderstorm with or without associated
precipitation; 3) Weather phenomena in order of
decreasing predominance. No more than three groups
in a single PIREP.
Weather layers must be entered with the
base and/or top of the layer when reported. Use the
same format as in the /SK TEI.
h. /TA. Air Temperature. Report outside air
temperature using two digits in degrees Celsius.
Prefix negative temperatures with a M; for example,
/TA 08 or /TA M08.
/WV. Wind direction and speed. If reported,
wind direction from which the wind is blowing must
be coded using three figures. Directions less than 100
degrees must be preceded by a "0". For example, a
wind direction of 90 degrees is coded as 090. The
wind speed must be entered as a two or three digit
group immediately following the wind direction. The
speed must be coded in whole knots using the
hundreds digit (if not zero) and the tens and units
digits. The wind group always ends with "KT" to
indicate that winds are reported in knots. Speeds of
less than 10 knots must be coded using a leading zero.
For example, a wind speed of 8 knots must be coded
08KT and a wind speed of 112 knots must be coded
j. /TB. Turbulence. Report intensity, type, and
altitude as follows:
1. Intensity. Enter duration if reported by the
pilot (INTMT, OCNL, CONS) and intensity using
contractions LGT, MOD, SEV, or EXTRM. Separate
a range or variation of intensity with a hyphen; for
example, MOD-SEV. If turbulence was not
encountered, enter NEG.
Type. Enter CAT or CHOP if reported by the
Altitude. Report altitude only if it differs
from value reported in /FL. When a layer of
turbulence is reported, separate height values with a
hyphen. If lower or upper limits are not defined, use
BLO or ABV.
/TB LGT 040
/TB MOD-SEV BLO 080
/TB MOD-SEV CAT 350
/TB NEG 120-180
/TB MOD CHOP 220/NEG 230-280
/TB MOD CAT ABV 290
IC. Icing. Report intensity, type and altitude of
icing as follows:
1. Intensity. Enter intensity first using
contractions TRACE, LGT, MOD, or SEV. Separate
reports of a range or variation of intensity with a
hyphen. If icing was not encountered, enter NEG.
Type. Enter the reported icing type as RIME,
CLR, or MX.
Altitude. Enter the reported icing/altitude
only if different from the value reported in the /FL
TEI. Use a hyphen to separate reported layers of
icing. Use ABV or BLO when a layer is not defined.
/IC LGT-MOD MX 085
/IC LGT RIME
/IC MOD RIME BLO 095
/IC SEV CLR 035-062
4. When icing is reported always report
temperature in the /TA TEI.
l. /RM. Remarks. Use this TEI to report a
phenomenon which is considered important but does
not fit in any of the other TEIs. This includes, but is
not limited to, low level wind shear (LLWS) reports,
thunderstorm lines, coverage and movement, size of
hail (1/4'' increments), lightning, clouds observed
but not encountered, geographical or local
description of where the phenomenon occurred,
International Standard Atmospheric (ISA) reports
and contrails. Report hazardous weather first.
Describe LLWS to the extent possible.
1. Wind Shear. +/- 10 Kts or more fluctuations
in wind speed, within 2,000 Ft of the surface or if
airspeed is not reported, requires an UUA report.
When Low Level Wind Shear is entered in a pilot
report enter LLWS as the first remark in the /RM TEI.
LLWS may be reported as -, +, or +/- depending on
how it effects the aircraft. If the location is different
than the /OV or /FL fields, include the location in the
/RM LLWS +/-15 KT SFC-008 DURC RY22 JFK
FUNNEL, CLOUD, TORNADO, and
WATERSPOUT are entered with the direction of
movement if reported.
/RM TORNADO E MOV E
Thunderstorm. Enter coverage (ISOL, FEW,
SCT, NMRS) and description (LN,BKN LN,SLD
LN) if reported. Follow with "TS," the location and
movement, and the type of lightning if reported.
/RM NMRS TS S MOV E GR1/2
Lightning. Enter frequency (OCNL, FRQ,
CONS), followed by type (LTGIC, LTGCC,
LTGCG, LTGCA, or combinations), if reported.
/RM OCNL LTGICCG
5. Electric Discharge. Enter DISCHARGE
followed by the altitude.
/RM DISCHARGE 120
Clouds. Use remarks when clouds can be seen
but were not encountered and reported in /SK.
/RM CB E MOV N
/RM OVC BLO
7. Plain Language. If specific phraseology is not
adequate, use plain language to describe the
phenomena or local geographic locations. Include
remarks that do not fit in other TEIs like DURC,
DURD, RCA, TOP, TOC, or CONTRAILS.
/RM BUMPY VERY ROUGH RIDE
/UA/OV BIS270030/TM 1445/FL060/TP CVLT/TB
LGT /RM Donner Summit Pass
Volcanic Activity. Volcanic eruption, ash
clouds, and/or sulfur dioxide are Urgent PIREPs.
Reports of volcanic activity must include as much
information as possible; for example, the name of the
mountain, ash clouds observed and their movement,
the height of the top and bottom of the ash clouds, etc.
(a) If a pilot detected the smell of sulfur
dioxide (SO2) in the cabin and reported volcanic ash
clouds, include "VA" in Weather and "SO2" or
"SULPHUR SMELL" in Remarks.
UUA /OV PANC240075 /TM 2010 /FL370/TP DC10 /WX
VA /RM VOLCANIC ERUPTION 2008Z MT AUGUSTINE ASH 40S MOV SSE SO2
(b) If a pilot only detected the smell of sulfur
dioxide (SO2) in the cabin and confirmed there were
no volcanic ash clouds, classify the PIREP as Routine
and include "VA" in Weather and "SO2 NO ASH" or
"SULPHUR SMELL NO ASH" in Remarks.
UA /OV PANC240075 /TM 2010 /FL370/TP DC10 /WX
VA /RM SULPHUR SMELL NO ASH
(c) If a volcanic activity report is received
from other than a pilot, enter Aircraft "UNKN,"
Flight Level "UNKN," and in Remarks
The "SKYSPOTTER" program is a result of
a recommendation from the Safer Skies
FAA/INDUSTRY Joint Safety Analysis and
Implementation Teams. The term "SKYSPOTTER"
indicates that a pilot has received specialized training
in observing and reporting inflight weather
phenomenon, pilot weather reports, or PIREPs.
When a PIREP from a pilot identifying themselves as
a "SKYSPOTTER" aircraft is received, the
additional comment "/AWC" must be added at the
end of the remarks section of the PIREP.
PIREP Text/RM Text/AWC
If ISA is reported.
/RM ISA -10C
9-2-15. PIREP ENCODING
PIREPs must be coded to ensure the PIREP is stored
and subsequently distributed with the surface
observation location nearest the condition being
reported. If more than one METAR location is
appropriate, select the location that provides the
greatest distribution and/or prominence, such as a
major hub airport.