AVIATION ROUTING WEATHER REPORT (METAR)

Present Weather Group w'w'(ww)

Index

Definitions of Present Weather Elements

Present Weather Observing Standards

Present Weather Reporting Standards

Coding Present Weather Groups

Decoding Present Weather Groups

Present Weather includes precipitation, obscurations, other weather phenomena; such as, well-developed dust/sand whirls, squalls, tornadic activity, sandstorms, and duststorms. Present weather may be evaluated instrumentally, manually, or through a combination of instrumental and manual methods. The links in the table below will take you to the definitions and/or standards for the various elements and descriptors.

Table A-10 Notations for Reporting Present Weather¹

QUALIFIER WEATHER PHENOMENA

Intensity
or
Proximity
1 Descriptor

2 Precipitation
3 Obscuration
4 Other
5

- Light
Moderate²
+ Heavy
VC In the
vicinity³
MI Shallow
PR Partial
BC Patches
DR Low Drifting
BL Blowing
SH Shower(s)
TS Thunderstorm
FZ Freezing
DZ Drizzle
RA Rain
SN Snow
SG Snow Grains
IC Ice Crystals
PL Ice Pellets
GR Hail
>5mm in
diameter
GS Small Hail
and/or
Snow Pellets
UP Unknown
Precipitation
BR Mist
FG Fog
FU Smoke
VA Volcanic Ash
DU Widespread
Dust
SA Sand
HZ Haze
PY Spray
PO Well-
developed
Dust/Sand
Whirls
SQ Squalls
FC Funnel
Cloud,
Tornado,
Waterspout⁴
SS Sandstorm
DS Duststorm

The weather groups shall be constructed by considering columns 1 to 5 in the table above in sequence; i.e., intensity, followed by description, followed by weather phenomena, e.g., heavy rain shower(s) is coded as +SHRA.
To denote moderate intensity, no entry or symbol is used.
Used when present weather is within 5 to 10 statute miles of the point(s) of observation.
Tornadoes and waterspouts shall always be coded as +FC.

Definitions of Present Weather Elements

Precipitation

Precipitation is any of the forms of water particles, whether liquid or solid, that fall from the atmosphere and reach the ground. The types of precipitation are:

Drizzle

Fairly uniform precipitation composed exclusively of fine drops with diameters of less than 0.02 inch (0.5 mm) very close together. Drizzle appears to float while following air currents, although unlike fog droplets, it falls to the ground.

Rain

Precipitation, either in the form of drops larger than 0.02 inch (0.5 mm), or smaller drops which, in contrast to drizzle, are widely separated.

Snow

Precipitation of snow crystals, mostly branched in the form of six-pointed stars.

Snow Grains

Precipitation of very small, white, and opaque grains of ice.

Ice Crystals (Diamond Dust)

A fall of unbranched (snow crystals are branched) ice crystals in the form of needles, columns, or plates.

Ice Pellets

Precipitation of transparent or translucent pellets of ice, which are round or irregular, rarely conical, and which have a diameter of 0.2 inch (5 mm), or less. There are two main types:

Hard grains of ice consisting of frozen raindrops, or largely melted and refrozen snowflakes.
Pellets of snow encased in a thin layer of ice which have formed from the freezing, either of droplets intercepted by the pellets, or of water resulting from the partial melting of the pellets.

Hail

Precipitation in the form of small balls or other pieces of ice falling separately or frozen together in irregular lumps.

Small Hail and/or Snow Pellets

Precipitation of white, opaque grains of ice. The grains are round or sometimes conical. Diameters range from about 0.08 to 0.2 inch (2 to 5 mm).

Obscurations

Any phenomenon in the atmosphere, other than precipitation, that reduces the horizontal visibility. These include:

Mist

A visible aggregate of minute water particles suspended in the atmosphere that reduces visibility to less than 7 statute miles but greater than or equal to 5/8 statute mile.

Fog

A visible aggregate of minute water particles (droplets) which are based at the Earth's surface and reduces horizontal visibility to less than 5/8 statute mile and, unlike drizzle, it does not fall to the ground.

Smoke

A suspension in the air of small particles produced by combustion. A transition to haze may occur when smoke particles have traveled great distances (25 to 100 miles or more) and when the larger particles have settled out and the remaining particles have become widely scattered through the atmosphere.

Volcanic Ash

Fine particles of rock powder that originate from a volcano and that may remain suspended in the atmosphere for long periods.

Widespread Dust

Fine particles of earth or other matter raised or suspended in the air by the wind that may have occurred at or far away from the station which may restrict horizontal visibility.

Sand

Sand particles raised by the wind to a height sufficient to reduce visibility.

Haze

A suspension in the air of extremely small, dry particles invisible to the naked eye and sufficiently numerous to give the air an opalescent appearance.

Spray

An ensemble of water droplets torn by the wind from the surface of an extensive body of water, generally from the crests of waves, and carried up a short distance into the air.

Other Weather Phenomena

Well-developed Dust/Sand Whirl

An ensemble of particles of dust or sand, sometimes accompanied by small liter, raised from the ground in the form of a whirling column of varying height with a small diameter and an approximately vertical vertical axis.

Squall

A strong wind characterized by a sudden onset in which the wind speed increases at least 16 knots and is sustained at 22 knots or more for at least one minute.

Funnel Cloud (Tornadic Activity)

These include:

Tornado
A violent, rotating column of air touching the ground.
Funnel Cloud
A violent, rotating column of air which does not touch the surface.
Waterspout
A violent, rotating column of air that forms over a body of water, and touches the water surface.

Sandstorm

Particles of sand carried aloft by a strong wind. The sand particles are mostly confined to the lowest ten feet, and rarely rise more than fifty feet above the ground.

Duststorm

A severe weather condition characterized by strong winds and dust-filled air over an extensive area.

Present Weather Observing Standards

Intensity/Proximity

The intensity qualifiers are: light, moderate, and heavy. The proximity qualifier is vicinity .

Intensity of Precipitation. When more than one form of precipitation is occurring at a time or precipitation is occurring with an obscuration, the intensities determined shall be no greater than that which would be determined if any forms were occurring alone.

The intensity of rain or ice pellets and the intensity of snow or drizzle shall be identified as light, moderate, or heavy in accordance with the following:

Intensity of Rain or Ice Pellets. The intensity of rain and ice pellets shall be based on the criteria given in Table A-6, Table A-7, and Table A-8 below.

Table A-6 Intensity of Rain or Ice Pellets based on Rate-of-Fall

Intensity Criteria

Light Up to 0.10 inch per hour; maximum 0.01 inch in 6 minutes.

Moderate 0.11 inch to 0.30 inch per hour; more than 0.01 inch to 0.03 inch in 6 minutes.

Heavy More than 0.30 inch per hour; more than 0.03 inch in 6 minutes.

Table A-7 Estimating Intensity of Rain

Intensity Criteria

Light From scattered drops that, regardless of duration, do not completely wet an exposed surface up to a condition where individual drops are easily seen.

Moderate Individual drops are not clearly identifiable; spray is observable just above pavements and other hard surfaces.

Heavy Rain seemingly falls in sheets; individual drops are not identifiable; heavy spray to height of several inches is observed over hard surfaces.

Table A-8 Estimating Intensity of Ice Pellets

Intensity Criteria

Light Scattered pellets that do not completely cover an exposed surface regardless of duration. Visibility is not affected.

Moderate Slow accumulation on ground. Visibility reduced by ice pellets to less than 7 statute miles.

Heavy Rapid accumulation on ground. Visibility reduced by ice pellets to less than 3 statute miles.

Intensity of Snow and Drizzle. The intensity of snow and drizzle shall be based on the reported surface visibility in accordance with Table A-9 when occurring alone.

Table A-9 Intensity of Snow or Drizzle Based on Visibility

Intensity Criteria

Light Visibility >1/2 mile.

Moderate Visibility >1/4 mile but < or = 1/2 mile.

Heavy Visibility < or = 1/4 mile.

Proximity Unless otherwise directed elsewhere in this handbook, weather phenomena occurring beyond the point of observation (between 5 and 10 statute miles) shall be reported as (in the) vicinity.

Descriptors

Descriptors are qualifiers which further amplify weather phenomena and are used with certain types of precipitation and obscurations. The descriptor qualifiers are:

Shallow
The descriptor shallow shall only be used to further describe fog that has little vertical extent (less than 6 feet).

Partial and Patches
The descriptor partial and patches shall only be used to further describe fog that has little vertical extent (normally greater than or equal to 6 feet but less than 20 feet), and reduces horizontal visibility, but to a lesser extent vertically. The stars may often be seen by night and the sun by day.

Low Drifting
When dust, sand, or snow is raised by the wind to less than 6 feet, "low drifting" shall be used to further describe the weather phenomenon.

Blowing
When dust, sand, snow, and/or spray is raised by the wind to a height of 6 feet or more, "blowing" shall be used to further describe the weather phenomenon.

Shower(s)
Precipitation characterized by the suddenness with which they start and stop, by the rapid changes of intensity, and usually by rapid changes in the appearance of the sky.

Thunderstorm
A local storm produced by a cumulonimbus cloud that is accompanied by lightning and/or thunder.

Freezing
When fog is occurring and the temperature is below 0^oC, "freezing" shall be used to further describe the phenomenon. When drizzle and/or rain freezes upon impact and forms a glaze on the ground or other exposed objects, "freezing" shall be used to further describe the phenomenon.

Present Weather Reporting Standards

Present weather is reported when it is occurring at, or in the vicinity of, the station and at the time of observation. Unless directed elsewhere, the location of the weather phenomena shall be reported as:

occurring at the station when within 5 statute miles of the point(s) of observation.

in the vicinity of the station when between 5 and 10 statute miles of the points(s) of observation.

distant from the station when beyond 10 statute miles of the point(s) of observation.

Note: Precipitation shall be reported when occurring at the point of observation. Precipitation not occurring at the point of observation but within 10 statute miles shall be reported as in the vicinity.

Obscurations are reported only when the prevailing visibility is less than 7 statute miles or considered operationally significant with the exception of:

Volcanic ash. Volcanic ash shall always be reported when observed.
low drifting dust,
low drifting sand,
low drifting sand,
shallow fog,
partial fog,
and patches (of) fog.

When more than one type of present weather are reported at the same time, present weather shall be reported in the following order:

Tornadic activity - Tornado, Funnel Cloud, or Waterspout.
Thunderstorm(s) with or without associated precipitation.
Present weather in order of decreasing dominance, i.e., the most dominant type is reported first.
Left-to-right in Table A-10 (Columns 1 through 5.)

The reporting notations given in Table A-10 shall be used to report present weather.

Unknown Precipitation. Unknown precipitation shall only be reported by automated stations to indicate precipitation of unknown type when the automated system cannot identify the precipitation with any greater precision.

Other Significant Weather Phenomena. Observers shall be alert to weather phenomena that are visible from the station but not occurring at the station. Examples of such phenomena are fog banks, localized rain, snow blowing over runways, etc. These phenomena shall be reported whenever they are considered to be operationally significant. Volcanic eruptions shall be reported in remarks.

Summary of Weather

Table A-11 contains a summary of the present weather observing and reporting standards according to the type of station.

Table A-11 Summary of Present Weather Observing and Reporting Standards

Present Weather Type of Station

Automated Manual

Funnel Cloud
(Tornadic Activity) Augmented at
designated stations Report FC, or +FC and in remarks TORNADO, FUNNEL CLOUD, WATERSPOUT, time of beginning and time of ending, source, location, and direction of movement.

Thunderstorm Augmented at
designated stations Report TS, time of beginning/ending, location and movement.

Hail Augmented at
designated stations Report GR, time of begining and time of ending, estimated size of largest hailstones in inches preceded by GR.

Small hail and/or
snow pellets Augmented at
designated stations Report GS, time of beginning and time of ending.

Obscurations BR, FG and HZ may
reported Report BR, FG, PRFG, FU, DU, HZ, SA, BLSN, BLSA, BLDU, SS, DS, BLPY, and VA.

N/A Reports non-uniform weather and obscurations.

Precipitation DZ, RA, SN and UP may be
reported Report RA, SHRA, DZ, FZRA, FZDZ, SN, SHSN, SG, GS, IC, GR, PL, and SHPL.

May be reported as FZ Reports descriptor with precipitation.

May report the intensity of precipitation as light, moderate,or heavy. Reports the intensity of precipitation, other than IC, GR, and GS as light, moderate, or heavy.

May report hourly accumulation of liquid precipitation. May report hourly accumulation of liquid precipitation.

May report 3-, 6-, and 24-hour accumulation of precipitation (water equivalent of solid). May report 3-, 6-, and 24-hour accumulation of precipitation (water equivalent of solid).

N/A May report depth and accumulation of solid precipitation.

N/A Reports size of GR.

Squall Report SQ. Report SQ.

Coding and Decoding the Present Weather Group (w'w')

The appropriate notations used in Table A-10 shall be used to code present weather.

The following general rules apply when coding present weather for a METAR or SPECI.

Weather occurring at the point of observation (at the station) or in the vicinity of the station shall be coded in the body of the report; weather observed but not occurring at the point of observation (at the station) or in the vicinity shall be coded in Remarks.
With the exceptions of volcanic ash, low drifting dust, low drifting sand, low drifting snow, shallow fog, partial fog, and patches (of) fog, an obscuration shall be coded in the body of the report if the surface visibility is less than 7 miles or considered operationally significant. Volcanic ash shall always be coded when observed.
Separate groups shall be used for each type of present weather. Each group shall be separated from the other by a space. METAR/SPECI shall contain no more than three present weather groups.
The weather groups shall be constructed by considering columns 1 to 5 in Table A-10 in sequence, i.e., intensity, followed by description, followed by weather phenomena, e.g., heavy rain shower(s) is coded as +SHRA.

Intensity or Proximity Qualifier
1. Intensity shall be coded with precipitation types, except ice crystals and hail, including those associated with a thunderstorm (TS) and those of a showery nature (SH). Tornadoes and waterspouts shall be coded as +FC.
2. No intensity shall be ascribed to the obscurations of blowing dust (BLDU), blowing sand (BLSA), and blowing snow (BLSN). Only moderate or heavy intensity shall be ascribed to sandstorm (SS) and duststorm (DS).
3. The proximity qualifier for vicinity, VC, (weather phenomena observed in the vicinity of but not at the point(s) of observation) shall be coded in combination with thunderstorm (TS), fog (FG), shower(s) (SH), well-developed dust/sand whirls (PO), blowing dust (BLDU), blowing sand (BLSA), blowing snow (BLSN), sandstorm (SS), and duststorm (DS). Intensity qualifiers shall not be coded with VC.
4. VCFG shall be coded to report any type of fog in the vicinity of the point(s) of observation.
5. Precipitation not occurring at the point of observation but within 10 statute miles shall be coded as showers in the vicinity (VCSH).
Descriptor Qualifier
Only one descriptor shall be coded for each weather phenomena group, e.g., -FZDZ. Mist (BR) shall not be coded with any descriptor.
1. The descriptors shallow (MI), partial (PR), and patches (BC) shall only be coded with FG, e.g., MIFG.
2. The descriptors low drifting (DR) and blowing (BL) shall only be coded with dust (DU), sand (SA), and snow (SN), e.g., BLSN or DRSN. DR shall be coded for DU, SA, or SN raised by the wind to less than six feet above the ground.
  When blowing snow is observed with snow falling from clouds, both phenomena are reported, e.g., SN BLSN. If there is blowing snow and the observer cannot determine whether or not snow is also falling, then BLSN shall be reported.
3. PY shall be coded only with blowing (BL).
4. The descriptor shower(s) (SH) shall be coded only with one or more of the precipitation types of rain (RA), snow (SN), ice pellets (PL), small hail (GS), or large hail (GR). The SH descriptor indicates showery-type precipitation. When any type of precipitation is coded with VC, the intensity and type of precipitation shall not be coded.
5. The descriptor thunderstorm (TS) may be coded by itself, i.e., a thunderstorm without associated precipitation, or it may be coded with the precipitation types of rain (RA), snow (SN), ice pellets (PL), small hail and/or snow pellets (GS), or hail (GR). For example, a thunderstorm with snow and small hail and/or snow pellets would be coded as TSSNGS. TS shall not be coded with SH.
6. The descriptor freezing (FZ) shall only be coded in combination with fog (FG), drizzle (DZ), or rain (RA), e.g., FZRA. FZ shall not be coded with SH.
Precipitation. Up to three types of precipitation may be coded in a single present weather group. They shall be coded in order of decreasing dominance based on intensity.
1. Drizzle shall be coded as DZ; rain shall be coded as RA; snow shall be coded as SN; snow grains shall be coded as SG; ice crystals shall be coded as IC; ice pellets shall be coded as PL; hail shall be coded as GR, and small hail and/or snow pellets shall be coded as GS.
2. At automated stations, precipitation of unknown type shall be coded as UP.
Obscuration
1. Mist shall be coded as BR; fog shall be coded as FG; smoke shall be coded as FU; volcanic ash shall be coded as VA; widespread dust shall be coded as DU; sand shall be coded as SA; and haze shall be coded as HZ.
2. Shallow fog (MIFG), patches (of) fog (BCFG), and partial fog (PRFG) may be coded with prevailing visibility of 7 statute miles or greater.
3. Spray shall be coded only as BLPY.
Other Weather Phenomena
1. Well-developed dust/sand whirls shall be coded as PO; squalls shall be coded as SQ; sandstorm shall be coded as SS; and duststorm shall be coded as DS.
2. Tornadoes and waterspouts shall be coded as +FC. Funnel clouds shall be coded as FC.

Decoding the Present Weather Group (w'w')

Find the reported present weather code in the body of the matrix. Follow the row to the left to find the present weather phenomena. Follow the column up to find the qualifier of the present weather phenomena.

Weather Phenomena Matrix

WX PHENOMENA QUALIFIER

Intensity or Proximity Descriptor¹

Light Moderate Heavy Vicinity Shallow Partial Patches Low
Drifting Blowing Shower Thunder-
storm Freezing

Precipitation - + VC² MI PR BC DR³ BL SH TS⁴ FZ

Drizzle DZ -DZ DZ +DZ - - - - - - - - FZDZ

Rain RA -RA RA +RA - - - - - - SHRA TSRA FZRA

Snow SN -SN SN +SN - - - - DRSN BLSN SHSN TSSN -

Snow Grains SG -SG SG +SG - - - - - - - - -

Ice Crystals⁵ IC - IC - - - - - - - - - -

Ice Pellets PL -PL PL +PL - - - - - - SHPL TSPL -

Hail^5,6 GR - GR - - - - - - - SHGR TSGR -

Small Hail^5,7 GS - GS - - - - - - - SHGS TSGS -

Unknown
Precipitation UP Automated Stations Only
- No Intensity - - - - - - - -

Thunderstorms, Showers, Freezing, and their
Proximity Indicator - - - - - - - -

Thunderstorm TS - TS - VCTS⁸ - - - - - - - -

Thunderstorm & Rain TSRA -TSRA TSRA +TSRA - - - - - - - - -

Thunderstorm & Snow TSSN -TSSN TSSN +TSSN - - - - - - - - -

Thunderstorm & Ice Pellets TSPL -TSPL TSPL +TSPL - - - - - - - - -

Thunderstorm & Snow Grains TSGS - TSGS - - - - - - - - - -

Thunderstorm & Hail TSGR - TSGR - - - - - - - - - -

Showers SH - - - VCSH⁹ - - - - - - - -

Rain Showers SHRA -SHRA SHRA +SHRA - - - - - - - - -

Snow Showers SHSN -SHSN SHSN +SHSN - - - - - - - - -

Shower of Ice Pellets SHPL -SHPL SHPL +SHPL - - - - - - - - -

Hail Shower SHGR - SHGR - - - - - - - - - -

Small Hail Shower SHGS - SHGS - - - - - - - - - -

Freezing Drizzle FZDZ -FZDZ FZDZ +FZDZ - - - - - - - - -

Freezing Rain FZRA -FZRA FZRA +FZRA - - - - - - - - -

Freezing Fog¹⁶ FZFG - FZFG¹⁶ - - - - - - - - - -

Obscurations - - - +FZDZ - - - - - - - -

Mist¹⁰ BR - BR¹⁰ - - - - - - - - - -

Fog¹¹ FG - FG¹¹ - VCFG¹² MIFG¹³ PRFG¹⁴ BCFG¹⁵ - - - - FZFG¹⁶

Smoke FU - FU - - - - - - - - - -

Volcanic Ash¹⁷ VA - VA¹⁷ - - - - - - - - - -

Widespread Dust DU - DU - - - - - DRDU BLDU - - -

Sand SA - SA - - - - - DRSA BLSA - - -

Haze HZ - HZ - - - - - - - - - -

Spray py - - - - - - - - BLPY - - -

Blowing
Phenomena - - - - - - - - - - - -

Blowing Snow¹⁸ BLSN - BLSN - VCBLSN - - - - BLSN - - -

Blowing Sand BLSA - BLSA - VCBLSA - - - - BLSA - - -

Blowing Dust BLDU - BLDU - VCBLDU - - - - BLDU - - -

OTHER BLSN - BLSN - VCBLSN - - - - BLSN - -

Sand/Dust Whirls PO - PO - VCPO - - - - - - - -

Squalls¹⁹ SQ - SQ - - - - - - - - - -

Funnel Cloud FC - FC - - - - - - - - - -

Tornado/
Waterspout²⁰ +FC - - +FC - - - - - - - - -

Sandstorm²¹ SS - SS +SS VCSS - - - - - - - -

Duststorm²² DS - DS +DS VCDS - - - - - - - -

Footnotes for Weather Phenomena Matrix

- Only 1 descriptor shall be included for each weather phenomena group; e.g., BCFG. Only 2 exceptions to this rule: VCSH and VCTS.
- Vicinity is defined as >0SM to 10SM of the point of observation for precipitation. Other than precipitation (VCFG, VCBLSN, VCBLSA, BCBLDU, VCPO, VCSS, VCDS), vicinity is 5SM to 10SM.
- Raised by wind to less than 6 feet above the ground.
- TS may be reported by itself if no precipitation is associated with the thunderstorm.
- No intensity is ever given to hail (GR/GS[snow pellets]) or ice crystals(IC).
- Largest hailstone observed has a diamter of 1/4 inch or more.
- Hailstone diameter is less than 1/4 inch. No remark is entered for hailstone size.
- VCTS shall only be used by automated stations. If thunder is heard, TS shall be reported.
- Showers (SH) when associated with the indicator VC, the type and intensity of the showery precipitation shall not be specified; i.e., +VCSHRA is not allowed; only VCSH would be reported. VCSH shall be used to report any type of precipitation not at point of observation, but >0SM to 10SM.
- BR (mist) shall only be used when the visibility is at least 5/8SM, but not more than 6SM.
- For FG (fog) to be reported without the qualifiers VC¹¹, MI¹², PR¹³, or BC¹⁴ the visibility shall be less than 5/8 SM.
- VC is used to report any type of fog observed in the vicinity (5-10 SM) of the station.
- MIFG (shallow fog) to be reported, the visibility at 6 feet above the ground level shall be 5/8 SM or more and the apparent visibility in the fog layer shall be less than 5/8 SM.
- PRFG (partial fog) indicates that a substantial part of the station is covered by fog while the remainder is clear of fog.
- BCFG (patches of fog) indicates that patches of fog randomly cover the station.
- FZFG is any fog consisting predominantly of water droplets at temperatures below 0^oC, whether it is depositing rime or not.
- Volcanic Ash is always reported in the body of the METAR/SPECI when present. Visibility is not a factor.
- SN BLSN indicates snow falling from clouds with blowing snow occurring. If the observer cannot determine whether or not snow is also falling from clouds, then only BLSN shall be reported.
- SQ (squall) is a sudden increase in wind speed of at least 16 knots, the speed rising to 22 knots or more and lasting for at least one minute.
- Tornadoes and Waterspouts shall be reported using the indicator "+", i.e., +FC.
- SS (sandstorm) reported if the visibility is > or = 5/16 SM and < or = 5/8 SM. Report +SS if the visibility is <5/16 SM.
- DS (duststorm) reported if the visibility is > or = 5/16 SM and < or = 5/8 SM. Report +DS if the visibility is < 5/16 SM.

No more than three weather groups shall be used to report weather phenomena at or near the station. If more than one significant weather phenomena is observed, separate weather phenomena groups shall be included in the report. If more than one form of precipitation is observed, the appropriate abbreviations shall be combined in a single group with the predominant type of precipitation being reported first. In such a single group, the intensity shall refer to the total precipitation and be reported with one or no indicator as appropriate; e.g., -RASN FG HZ.

Return to First Page Index

Table A-10 Notations for Reporting Present Weather¹
QUALIFIER		WEATHER PHENOMENA
Intensity or Proximity 1	Descriptor 2	Precipitation 3	Obscuration 4	Other 5
- Light Moderate² + Heavy VC In the vicinity³	MI Shallow PR Partial BC Patches DR Low Drifting BL Blowing SH Shower(s) TS Thunderstorm FZ Freezing	DZ Drizzle RA Rain SN Snow SG Snow Grains IC Ice Crystals PL Ice Pellets GR Hail >5mm in diameter GS Small Hail and/or Snow Pellets UP Unknown Precipitation	BR Mist FG Fog FU Smoke VA Volcanic Ash DU Widespread Dust SA Sand HZ Haze PY Spray	PO Well- developed Dust/Sand Whirls SQ Squalls FC Funnel Cloud, Tornado, Waterspout⁴ SS Sandstorm DS Duststorm
The weather groups shall be constructed by considering columns 1 to 5 in the table above in sequence; i.e., intensity, followed by description, followed by weather phenomena, e.g., heavy rain shower(s) is coded as +SHRA. To denote moderate intensity, no entry or symbol is used. Used when present weather is within 5 to 10 statute miles of the point(s) of observation. Tornadoes and waterspouts shall always be coded as +FC.

Table A-6 Intensity of Rain or Ice Pellets based on Rate-of-Fall
Intensity	Criteria
Light	Up to 0.10 inch per hour; maximum 0.01 inch in 6 minutes.
Moderate	0.11 inch to 0.30 inch per hour; more than 0.01 inch to 0.03 inch in 6 minutes.
Heavy	More than 0.30 inch per hour; more than 0.03 inch in 6 minutes.

Table A-11 Summary of Present Weather Observing and Reporting Standards
Present Weather	Type of Station
Present Weather	Automated	Manual
Funnel Cloud (Tornadic Activity)	Augmented at designated stations	Report FC, or +FC and in remarks TORNADO, FUNNEL CLOUD, WATERSPOUT, time of beginning and time of ending, source, location, and direction of movement.
Thunderstorm	Augmented at designated stations	Report TS, time of beginning/ending, location and movement.
Hail	Augmented at designated stations	Report GR, time of begining and time of ending, estimated size of largest hailstones in inches preceded by GR.
Small hail and/or snow pellets	Augmented at designated stations	Report GS, time of beginning and time of ending.
Obscurations	BR, FG and HZ may reported	Report BR, FG, PRFG, FU, DU, HZ, SA, BLSN, BLSA, BLDU, SS, DS, BLPY, and VA.
Obscurations	N/A	Reports non-uniform weather and obscurations.
Precipitation	DZ, RA, SN and UP may be reported	Report RA, SHRA, DZ, FZRA, FZDZ, SN, SHSN, SG, GS, IC, GR, PL, and SHPL.
	May be reported as FZ	Reports descriptor with precipitation.
	May report the intensity of precipitation as light, moderate,or heavy.	Reports the intensity of precipitation, other than IC, GR, and GS as light, moderate, or heavy.
	May report hourly accumulation of liquid precipitation.	May report hourly accumulation of liquid precipitation.
	May report 3-, 6-, and 24-hour accumulation of precipitation (water equivalent of solid).	May report 3-, 6-, and 24-hour accumulation of precipitation (water equivalent of solid).
	N/A	May report depth and accumulation of solid precipitation.
	N/A	Reports size of GR.
Squall	Report SQ.	Report SQ.