CAP Documentation - NWS Common Alerting Protocol - Virtual Lab

CAP Documentation - NWS Common Alerting Protocol - Virtual Lab
CAP Documentation - NWS Common Alerting Protocol
CAP Documentation
The documentation contained on this site supplements the
OASIS CAP v1.2
standard and
IPAWS CAP profile
by identifying the formats of NWS information contained within our CAP v1.2 IPAWS compliant messages. Thus, users should familiarize themselves with the OASIS CAP standard and IPAWS CAP profile prior to using NWS CAP messages.
The listing on the left side of this page provides documentation of all elements and parameters contained in NWS CAP messages.
Change Log
September 4, 2024
The "Push" section of "How to Get NWS CAP Messages" on the About NWS CAP page was updated to reflect that CAP is available over NWWS as a satellite-based service
and
over the NWWS Internet-based service known as NWWS Open Interface (OI).
August 25, 2022
Users of the previous NWS CAP v1.2 documentation, which was in pdf format, should be aware of the following changes.
 element added to differentiate between the block containing English Wireless Emergency Alert (WEA) text and the block containing Spanish WEA text.
Many parameters added in support of
NWS Impact Based Warning (IBW)
and
Wireless Emergency Alerts (WEA)
AWIPSidentifier
WMOidentifier
NWSheadline
eventMotionDescription (previously stormMotionDescription)
windThreat
maxWindGust
hailThreat
maxHailSize
thunderstormDamageThreat
tornadoDetection
tornadoDamageThreat
flashFloodDetection
flashFloodDamageThreat
snowSquallDetection
snowSquallImpact
waterspoutDetection
BLOCKCHANNEL
WEAHandling
CMAMtext
CMAMlongtext
expiredReferences
info
Last modified date:
Mar 23, 2022
Description
The container for all component parts of the info element.
Format

info elements

area elements


Example

alert elements

info elements

area elements



info elements

area elements



Inclusion
One or more blocks are included in every CAP message that originates from the NWS.
category
Last modified date:
Mar 23, 2022
Description
The code denoting the category of the subject event in the alert message. Multiple instances may occur within an block.
Format

category

Where
category
is one of the following according to the CAP v1.2 standard:
"Geo" - Geophysical (inc. landslide)
"Met" - Meteorological (inc. flood)
"Safety" - General emergency and public safety
"Security" - Law enforcement, military, homeland and local/private security
"Rescue" - Rescue and recovery
"Fire" – Fire suppression and rescue
"Health" - Medical and public health
"Env" - Pollution and other environmental
"Transport" - Public and private transportation
"Infra" - Utility, telecommunication, other non-transport infrastructure
"CBRNE" – Chemical, Biological, Radiological, Nuclear or High-Yield Explosive threat or attack
"Other" – Other events
Example
Met
Health
Inclusion
Included in every block.
event
Last modified date:
Mar 23, 2022
Description
The text denoting the type of the subject event in the alert message.
Format

event

Example
Tornado Warning
Inclusion
Included in every CAP message that originates from the NWS.
severity
Last modified date:
Mar 23, 2022
Description
Severity of the subject event of the alert message
Format

severity

Where
severity
is one of the following values for the given alert type.
“Extreme” - Extraordinary threat to life or property
“Severe” - Significant threat to life or property
“Moderate” - Possible threat to life or property
“Minor” – Minimal to no known threat to life or property
“Unknown” - Severity unknown
Example
Extreme
Inclusion
Included in every block.
certainty
Last modified date:
Mar 23, 2022
Description
Certainty of the subject event of the alert message.
Format

certainty

Where
certainty
is one of the following values for the given alert type.
“Observed” – Determined to have occurred or to be ongoing
“Likely” - Likely (p > ~50%)
“Possible” - Possible but not likely (p <= ~50%)
“Unlikely” - Not expected to occur (p ~ 0)
“Unknown” - Certainty unknown
Example
Expected
Inclusion
Included in every block.
senderName
Last modified date:
Mar 23, 2022
Description
Name of the issuing NWS Office.
Format

senderName

Where
senderName
is the name of the NWS office which issued the alert.
Example
NWS Miami (Southern Florida)
Inclusion
Included in every block.
description
Last modified date:
Mar 23, 2022
Description
The text describing the subject event of the alert message.
Format

description

Example
* WHAT...For the Winter Storm Warning, heavy wet snow. Additional snow  accumulations of 1 to 3 inches this morning. Winds gusting 30 to 40 mph at exposed higher elevation locations. For the Winter Weather Advisory above 4000 feet, snow expected. Total snow accumulations of 2 to 6 inches. Winds gusting as high as 40 mph. For the Winter Storm Watch, heavy snow possible. Total snow accumulations of 15 to 30 inches possible. Winds could gust as high as 45 mph.
* WHERE...This morning slushy roads are possible along Interstate 5. Expect greater travel impacts above 3500 foot elevations such as Highway 89 at Snowmans Summit and on the Mount Shasta Ski Park Road. All other higher elevation roads will be affected early this morning. The main impacts during the advisory time period will be above 4000 feet along portions of Highway 89. The Winter Storm Watch is for all areas.
* WHEN...For the Winter Storm Warning, until 7 AM PST this morning. For the Winter Weather Advisory, from 4 PM this afternoon to 4 AM PST Friday. For the Winter Storm Watch, from Friday morning through Monday morning.
* IMPACTS...Travel could be very difficult to impossible. The hazardous conditions could impact the morning or evening commute.
* View the hazard area in detail at

Inclusion
Included in every block. For alerts which are ended, the may only state that the subject event is no longer expected in the area.
instruction
Last modified date:
Mar 23, 2022
Description
The text describing the recommended action to be taken by recipients of the alert message.
Format

instruction

Example
* Travel is strongly discouraged because of dangerous conditions. * If you must travel, keep tire chains, a flashlight, blankets, food, water, medications, and a fully charged phone with you. * The safest place during a winter storm is indoors. * A Winter Storm Warning means that severe winter weather is occurring and poses a threat to life and property. Take protective action now.
Inclusion
Included in most blocks. For alerts which are ended, an may not be included.
web
Last modified date:
Mar 23, 2022
Description
A hyperlink where additional information about the alert can be found.
Format

URL

Example
http://www.weather.gov
Inclusion
Included in every block.
language
Last modified date:
Mar 23, 2022
Description
The code denoting the language of the info sub-element of the alert message.
Format

language

Where
language
is "en-US" for English or "es-US" for Spanish.
Example
en-US
Inclusion
Included in every NWS CAP block. NWS Spanish language blocks contain Spanish language in the CMAMtext and CMAMlongtext parameters in order to provide Wireless Emergency Alert (WEA) information in Spanish on capable mobile devices. All other information in a Spanish block is in English.
responseType
Last modified date:
Mar 23, 2022
Description
The code denoting the type of action recommended for the target audience. Multiple instances may occur within an block.
Format

responseType

Where
responseType
is one of the following values as defined in the CAP v1.2 standard.
"Shelter" - Take shelter in place or per
"Evacuate" - Relocate as instructed in the
"Prepare" - Make preparations per the
"Execute" - Execute a pre-planned activity identified in
"Avoid" - Avoid the subject event as per the
"Monitor" - Attend to information sources as described in
"Assess" – Evaluate the information in this message. Not used by NWS.
"AllClear" - The subject event no longer poses a threat or concern and any follow on action is described in
"None" - No action recommended
Example
Shelter
Inclusion
Included in every block.
urgency
Last modified date:
Mar 23, 2022
Description
Urgency of the subject event of the alert message.
Format

urgency

Where
urgency
is one of the following values for the given alert type.
“Immediate” - Responsive action SHOULD be taken immediately
“Expected” - Responsive action SHOULD be taken soon (within next hour)
“Future” - Responsive action SHOULD be taken in the near future
“Past” - Responsive action is no longer required
“Unknown” - Urgency not known
Example
Immediate
Inclusion
Included in every block. An value of “Past” is used by NWS to convey that the alert is ended for the area covered by the  block.
effective
Last modified date:
Mar 23, 2022
Description
The effective date and time of the information in the alert message.  In other words, the CAP message itself (i.e., the alert) is effective at the time it is sent.
should not be confused with any use of “effect” and/or “effective” terminology in the plain language text of the alert because they may not have the same meaning.  The date and time may also not be the same as the date and time which reflects the beginning of the subject event in the alert message.
Format

YYYY
MM
DD
hh
mm
ssXzh
zm

Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
T marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros (00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
Example
2011-05-24T16:49:00-07:00
refers to May 24, 2011 at 4:49:00 PM Pacific Daylight Time.
Inclusion
Included in every block.
onset
Last modified date:
Mar 23, 2022
Description
Expected time of the beginning of the subject event in the alert message.  The value for may be the same as that for when the event is already occurring or imminent.
Format

YYYY
MM
DD
hh
mm
ssXzh
zm

Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
T marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros (00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
Example
2011-07-04T17:12:00-05:00
refers to July 4, 2011 at 5:12:00 PM Central Daylight Time.
Inclusion
Included in every block.
expires
Last modified date:
Mar 23, 2022
Description
The expiration date and time of the information in the alert message. This is the time at which the information in the message should be considered stale and no longer used.  The NWS forecaster will update or cancel the alert by the time.   should not be confused with any use of “expire” and/or “expiration” terminology in the plain language text of the alert because they may not have the same meaning.  The date and time may also not be the same as the parameter which reflects the expected end time of the event in the alert message.
Format

YYYY
MM
DD
hh
mm
ssXzh
zm

Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
T marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros (00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
Example
2012-05-30T09:30:00-04:00
refers to May 30, 2012 at 9:30 AM Eastern Daylight Time.
Inclusion
Included in every block.
headline
Last modified date:
Mar 23, 2022
Description
A brief human-readable headline.
Format

headline

Where
headline
is a brief human-readable headline.
Example
Winter Storm Warning issued January 4 at 9:36AM EST until January 6 at 7:00AM EST by NWS Gaylord MI
Inclusion
Included in every CAP message that originates from the NWS.
eventCode
Last modified date:
Mar 23, 2022
Description
A system-specific code identifying the event type of the alert message.
Format


SAME


XXX




NationalWeatherService


PPS


Where:
XXX
is a three character event code from FCC Part 11.31 (
FCC Title 47, Part 11, EAS Rules and Regulations
) or the value “NWS”.
PPS
is the NWS phenomena and significance string for the alert type.  The PPS is a concatenation of the two character Phenomena (PP) and one character Significance (S) code from the NWS Valid Time Event Code (VTEC) string for the alert type.  If the NWS has no VTEC string for the alert type (e.g., Special Weather Statement), then an alternative three-character code will be used (e.g., SPS).  See
for more information about VTEC.
The NWS produces many types of alerts, some of which are not listed in FCC Part 11.31.  A SAME value (
XXX
) of “NWS” means the alert is not for a type listed in FCC Part 11.31.  The NWS has a special agreement with FEMA’s Integrated Public Alert and Warning System (IPAWS) so that alerts with an
XXX
of “NWS” pass through to the IPAWS public alerts feed.  This way, third party redistributors of official alert information have access to all NWS CAP messages through the IPAWS public feed.
Example
For an alert type listed in FCC Part 11.31:

SAME
SVR


NationalWeatherService
SVW

For an alert type NOT listed in FCC Part 11.31:

SAME
NWS


NationalWeatherService
MSY

Inclusion
Included in every block. The following SAME and NationalWeatherService eventCode values may be used in NWS CAP messages.
SAME
eventCode value
NationalWeatherService eventCode value
event
ADR
ADR
Administrative Message
AVA
AVA
Avalanche Watch
AVW
AVW
Avalanche Warning
BLU
BLU
Blue Alert
BZW
BZW
Blizzard Warning
CAE
CAE
Child Abduction Emergency
CDW
CDW
Civil Danger Warning
CEM
CEM
Civil Emergency Message
CFA
CFA
Coastal Flood Watch
CFA
LSA
Lakeshore Flood Watch
CFW
CFW
Coastal Flood Warning
CFW
LSW
Lakeshore Flood Warning
DSW
DSW
Dust Storm Warning
EQW
EQW
Earthquake Warning
EVI
EVI
Evacuation - Immediate
EWW
EWW
Extreme Wind Warning
FFA
FFA
Flash Flood Watch
FFA
FAA
Flood Watch
FFS
FFW
Flash Flood Warning
FFW
FFW
Flash Flood Warning
FLA
FLA
Flood Watch
FLS
FAW
Flood Warning
FLS
FLW
Flood Warning
FLW
FAW
Flood Warning
FLW
FLW
Flood Warning
FRW
FRW
Fire Warning
HLS
HLS
Tropical Cyclone Statement
HLS
TYS
Typhoon Local Statement
HMW
HMW
Hazardous Materials Warning
HUA
HUA
Hurricane Watch
HUA
TYA
Typhoon Watch
HUW
HUW
Hurricane Warning
HUW
TYW
Typhoon Warning
HWA
HWA
High Wind Watch
HWW
HWW
High Wind Warning
LAE
LAE
Local Area Emergency
LEW
LEW
Law Enforcement Warning
NUW
NUW
Nuclear Power Plant Warning
NWS
AQA
Air Quality Alert
NWS
ASY
Air Stagnation Advisory
NWS
AFY
Ashfall Advisory
NWS
MHY
Ashfall Advisory
NWS
MHW
Ashfall Warning
NWS
SAB
Avalanche Advisory
NWS
BHS
Beach Hazards Statement
NWS
DUY
Blowing Dust Advisory
NWS
DUW
Blowing Dust Warning
NWS
BWY
Brisk Wind Advisory
NWS
CFY
Coastal Flood Advisory
NWS
CFS
Coastal Flood Statement
NWS
CWY
Cold Weather Advisory
NWS
FGY
Dense Fog Advisory
NWS
MFY
Dense Fog Advisory
NWS
MSY
Dense Smoke Advisory
NWS
SMY
Dense Smoke Advisory
NWS
DSY
Dust Advisory
NWS
ECA
Extreme Cold Watch
NWS
ECW
Extreme Cold Warning
NWS
RFD
Extreme Fire Danger
NWS
XHA
Extreme Heat Watch
NWS
XHW
Extreme Heat Warning
NWS
FWA
Fire Weather Watch
NWS
FAY
Flood Advisory
NWS
FLY
Flood Advisory
NWS
FZW
Freeze Warning
NWS
FZA
Freeze Watch
NWS
ZFY
Freezing Fog Advisory
NWS
FRY
Frost Advisory
NWS
GLW
Gale Warning
NWS
GLA
Gale Watch
NWS
HZW
Hard Freeze Warning
NWS
HZA
Hard Freeze Watch
NWS
SEW
Hazardous Seas Warning
NWS
SEA
Hazardous Seas Watch
NWS
HTY
Heat Advisory
NWS
UPY
Freezing Spray Advisory
NWS
UPW
Heavy Freezing Spray Warning
NWS
UPA
Heavy Freezing Spray Watch
NWS
SUY
High Surf Advisory
NWS
SUW
High Surf Warning
NWS
HFW
Hurricane Force Wind Warning
NWS
HFA
Hurricane Force Wind Watch
NWS
ESF
Hydrologic Outlook
NWS
LWY
Lake Wind Advisory
NWS
LSY
Lakeshore Flood Advisory
NWS
LSS
Lakeshore Flood Statement
NWS
LOY
Low Water Advisory
NWS
MWS
Marine Weather Statement
NWS
FWW
Red Flag Warning
NWS
RPS
Rip Current Statement
NWS
SCY
Small Craft Advisory
NWS
SWY
Small Craft Advisory for Hazardous Seas
NWS
RBY
Small Craft Advisory for Rough Bar
NWS
SIY
Small Craft Advisory for Winds
NWS
MAW
Special Marine Warning
NWS
SRW
Storm Warning
NWS
SRA
Storm Watch
NWS
HUS
Tropical Cyclone Statement
NWS
TSY
Tsunami Advisory
NWS
WIY
Wind Advisory
NWS
WWY
Winter Weather Advisory
RHW
RHW
Radiological Hazard Warning
SMW
MAW
Special Marine Warning
SPS
SPS
Special Weather Statement
SPW
SPW
Shelter In Place Warning
SSA
SSA
Storm Surge Watch
SSW
SSW
Storm Surge Warning
SVA
SVA
Severe Thunderstorm Watch
SVR
SVW
Severe Thunderstorm Warning
SVS
EWW
Extreme Wind Warning
SVS
SVW
Severe Thunderstorm Warning
SVS
SQW
Snow Squall Warning
SVS
TOW
Tornado Warning
TOA
TOA
Tornado Watch
TOE
TOE
911 Telephone Outage
TOR
TOW
Tornado Warning
TRA
TRA
Tropical Storm Watch
TRW
TRW
Tropical Storm Warning
TSA
TSA
Tsunami Watch
TSW
TSW
Tsunami Warning
VOW
VOW
Volcano Warning
WSA
ECA
Extreme Cold Watch
WSA
WSA
Winter Storm Watch
WSW
ECW
Extreme Cold Warning (Alaska only)
WSW
ISW
Ice Storm Warning
WSW
LEW
Lake Effect Snow Warning
WSW
WSW
Winter Storm Warning
alert
Last modified date:
Mar 23, 2022
Description
The container for all component parts of the alert message.
Format

alert elements

info elements

area elements



Example


Inclusion
Included in every CAP message that originates from the NWS.
scope
Last modified date:
Mar 23, 2022
Description
The code denoting the appropriate handling of the alert message.
Format

scope

Where
scope
is one of the following according to the CAP v1.2 standard:
"Public" - For general dissemination to unrestricted audiences
"Restricted" - For dissemination only to users with a known operational requirement. Not used by the NWS.
"Private" - For dissemination only to specified addresses. Not used by the NWS.
Example
Public
Inclusion
Included in every CAP message that originates from the NWS. NWS does not currently use “Restricted” or “Private”.
sender
Last modified date:
Mar 23, 2022
Description
Email address of the NWS webmaster.
Format

w-nws.webmaster@noaa.gov

Example
w-nws.webmaster@noaa.gov
Inclusion
Included in every CAP message that originates from the NWS.
identifier
Last modified date:
Mar 23, 2022
Description
A string which uniquely identifies the CAP message.
Format

id

Where
id
is a string not to exceed 30 characters.  May contain letters, numbers, and periods (i.e., “.").
Example
urn:oid:2.49.0.1.840.0.3131ccefbad1d7e3316165d8ae3a0f802b688a1e.003.2
Inclusion
Included in every CAP message that originates from the NWS.
msgType
Last modified date:
Mar 23, 2022
Description
The code denoting the nature of the alert message.
Format

msgType

Where
msgType
is one of the following according to the CAP v1.2 standard:
"Alert" - Initial information requiring attention by targeted recipients
"Update" - Updates and supercedes the earlier message(s) identified in
"Cancel" - Cancels the earlier message(s) identified in .
"Ack" - Acknowledges receipt and acceptance of the message(s) identified in . Not currently used by NWS.
"Error" – Indicates rejection of the message(s) identified in ; explanation SHOULD appear in . Not currently used by NWS.
Example
Alert
Inclusion
Included in every CAP message that originates from the NWS.
sent
Last modified date:
Mar 23, 2022
Description
The origination time and date of the alert message.
Format

YYYY-MM-DD
hh:mm:ssXzh:zm

Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros(00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
Example
2011-05-24T16:49:00-07:00
refers to May 24, 2011 at 4:49:00 PM Pacific Daylight Time.
Inclusion
Included in every CAP message that originates from the NWS.
status
Last modified date:
Mar 23, 2022
Description
The code denoting the appropriate handling of the alert message.
Format

status

Where
status
is one of the following:
"Actual" - Actionable by all targeted recipients
"Exercise" - Actionable only by designated exercise participants; exercise identifier SHOULD appear in . Not currently used by NWS.
"System" - For messages that support alert network internal functions. Not currently used by NWS.
"Test" - Technical testing only, all recipients disregard; test identifier SHOULD appear in
"Draft" – A preliminary template or draft, not actionable in its current form. Not currently used by NWS.
Example
Actual
Inclusion
Included in every CAP message that originates from the NWS. Only in rare cases would a value other than “Actual” be used.
code
Last modified date:
Mar 23, 2022
Description
Version of the CAP IPAWS profile as adopted by FEMA to which the subject CAP message conforms.
Format
IPAWSv

Where
is the version of the CAP IPAWS profile as adopted by FEMA.
Example
IPAWSv1.0
Inclusion
Included in every CAP message that originates from the NWS.
note
Last modified date:
Mar 23, 2022
Description
The text describing the purpose or significance of the alert message.
Format

note

Example
This is a only a test.  A national exercise is being conducted.  This is only a test.
Inclusion
Included in NWS CAP messages when the is "Test" or when the alert is for a Non-Weather Emergency Message (NWEM).
references
Last modified date:
Mar 23, 2022
Description
References the most recent message to which the current message refers or replaces.
Format

sender
identifier
sent

Where
sender
identifier
, and
sent
are the , , and elements from the earlier CAP message or messages that this one replaces. When multiple messages are referenced, they are separated by whitespace.
Example
w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.1e85330c03acd93ee99f9e9a40307a7dd4807519.002.1,2021-12-21T22:14:00-05:00 w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.d2de7d9280fc745725ab9b5651f89044c17e6385.002.1,2021-12-22T03:30:00-05:00
Inclusion
Included whenever the NWS updates or cancels an alert for which a CAP message has been produced. NWS references all active messages (ones with at least one active block) impacted by the new message. An “active” block is one that has not yet reached its time. Referencing all alert messages with blocks that still have an time in the future ensures that any messages that may still be playing incorrectly are properly superseded by the most recent Update or Cancel. This resolves issues caused by transmission delays and/or lost messages that may result in message chains being broken. If only a single reference were used, a missed message could result in an alert playing beyond its intended time.
area
Last modified date:
Mar 23, 2022
Description
The container for all sub-elements of the area element.
Format

area elements

Example

Honolulu
21.49,-157.94 21.62,-157.99 21.67,-157.88 21.41,-157.77 21.36,-157.81 21.49,-157.94

UGC
HIC003


SAME
015003


Inclusion
Included in every block.
areaDesc
Last modified date:
Mar 23, 2022
Description
The text describing the affected area of the alert message.
Format

Location[; Location…]

Where
Location
is a county, parish, borough, or independent city.
Example
Mahaska; Poweshiek
Inclusion
Included in every block.
polygon
Last modified date:
Mar 23, 2022
Description
The paired values of points defining a polygon that delineates the affected area of the alert message.
Format

Lat,Lon Lat,Lon Lat,Lon Lat,Lon [; Lat,Lon…]

Where
Lat,Lon
is a latitude and longitude coordinate pair. A minimum of 4 coordinate pairs is present. The first and last pair will always be the same.
Example
41.50,-92.30 41.50,-92.40 41.48,-92.41 41.51,-92.76 41.63,-92.76 41.66,-92.30 41.50,-92.30
Inclusion
Included in NWS blocks with the following .
TOR (Tornado Warning)
SVR (Severe Thunderstorm Warning)
SVS (Severe Weather Statement)
SMW (Special Marine Warning)
MWS (Marine Weather Statement)
FFW (Convective Flash Flood Warning)
FLW (Areal Flood Warning)
FFS (Convective Flash Flood Statement)
FLS (Areal Flood Advisory or Areal Flood Statement)
EWW (Extreme Wind Warning)
geocode
Last modified date:
Mar 23, 2022
Description
The geographic code delineating the affected area of the alert message. Multiple instances MAY occur within an block.
Format

SAME

SAME



UGC

SSFNNN


Where
SAME
is the 6-digit [Specific Area Message Encoding code].
SS
= Two-letter standard Post Office state (or marine area) identifier
or
where
means the
NNN
represents a [3-digit FIPS county], parish, or independent city number.
NNN
may also be
ALL
representing all of the counties in a state, or the numbers
000
representing all, or an unspecified part, of a state.
means the
NNN
represents a 3-digit [NWS zone number].
NNN
may also be
ALL
representing all of the zones in a state, or the numbers
000
representing all, or an unspecified part, of a state.
Many NWS alerts contain the (C) form of the UGC. Alerts using the zone (Z) form of the UGC include non-precipitation watch/warning/advisories and winter storm watch/warning/advisories. There are three listings of NWS zones: public zones, coastal and offshore marine zones, fire weather zones each found on the NWS GIS web page at http://www.nws.noaa.gov/geodata/ under NWSM libraries. Public zones and coastal and offshore marine zones are the zones in primary use in most NWS products and the geographic areas and zone numbering complement one another. Fire weather zones are used only in specialized products and use zone numbering that overlaps public zone numbers (i.e., fire weather and public zone numbers must not be mixed or used together). Fire weather alerts include Red Flag Warnings, Fire Weather Watches,  Rangeland/Grassland Fire Danger and their corresponding NWSevent values  FWW, FWA, and RFD.
Example

SAME
012009


SAME
012095


SAME
012097


SAME
012117


SAME
012127


UGC
FLC009


UGC
FLC095


UGC
FLC097


UGC
FLC117


UGC
FLC127

Inclusion
Included in every CAP message that originates from the NWS.
parameter
Last modified date:
Mar 23, 2022
Description
Denotes additional information associated with the alert message.
Format


valueName


value


Example

VTEC
/O.CON.KDMX.SV.W.0004.000000T0000Z-110321T1845Z/

Inclusion
The NWS often uses parameters in each block to convey additional information.
NWSheadline
Last modified date:
Mar 23, 2022
Description
A general statement that summarizes the alert.
Format

NWSheadline

text


Where
text
is the headline in the traditional NWS alert segment from which the CAP message is derived.  Multiple headlines from the traditional NWS alert segment will generally appear together as one text value often with "... ..." inserted between each headline.  Occasionally when a headline(s) is malformed in the traditional NWS alert segment, the headline (or second or subsequent headlines) will appear at the beginning of the text in the element.
Example

NWSheadline
RED FLAG WARNING IN EFFECT FROM 11 AM THIS MORNING TO 9 PM PDT THIS EVENING FOR FAR SOUTHERN NEVADA BELOW 5000 FEET

Example of Multiple Headlines

NWSheadline
WINTER STORM WARNING REMAINS IN EFFECT FROM 8 PM THIS EVENING TO 11 AM PDT THURSDAY ABOVE 6000 FEET... ...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 8 PM THIS EVENING TO 11 AM PDT THURSDAY BELOW 6000 FEET

Inclusion
Included in many, but not all, NWS alerts.
tornadoDetection
Last modified date:
Mar 23, 2022
Description
Describes whether the tornado is indicated by radar or observed. This is an implied statement of confidence in the evidence that a tornado is occurring.
Format

tornadoDetection

detection


For Tornado Warnings,
detection
is “RADAR INDICATED” or “OBSERVED”
For Severe Thunderstorm Warnings, the only value for
detection
is “POSSIBLE”.
Example

tornadoDetection
RADAR INDICATED

Inclusion
Included with all Tornado Warnings and some Severe Thunderstorm Warnings.
waterspoutDetection
Last modified date:
Mar 23, 2022
Description
Describes whether the waterspout is observed or possible. This is an implied statement of confidence in the evidence that a waterspout is occurring.
Format

waterspoutDetection

detection


Where
detection
is “OBSERVED” or “POSSIBLE”.
Example

waterspoutDetection
POSSIBLE

Inclusion
Included in some Special Marine Warnings and Marine Weather Statements.
tornadoDamageThreat
Last modified date:
Mar 23, 2022
Description
Impact in terms of damage expected from a tornado.
Format

tornadoDamageThreat

damage


Where
damage
is “CONSIDERABLE” or “CATASTROPHIC”.
Example

tornadoDamageThreat
CATASTROPHIC

Inclusion
Only included in Tornado Warnings when there is credible evidence that the tornado is producing considerable or greater damage.
WEAHandling
Last modified date:
Mar 23, 2022
Description
The category of Wireless Emergency Alert (WEA) to be activated.
Format

WEAHandling

Imminent Threat


Where
Imminent Threat
is the category of WEA to be activated.
Example

WEAHandling
Imminent Threat

Inclusion
Included in CAP messages intended to activate WEA.
CMAMtext
Last modified date:
Mar 23, 2022
Description
An emergency message up to 90 characters in length intended for display on mobile devices as a Wireless Emergency Alert (WEA).
Format

CMAMtext

text


Where
text
is an emergency message no longer than 90 characters.
Example

CMAMtext
Tornado Warning in this area til 3:45 AM CST. Take shelter now. Check local media. -NWS

Inclusion
Included in CAP messages which warn of an imminent threat to life and/or property
and
are intended to activate WEA.
CMAMlongtext
Last modified date:
Mar 23, 2022
Description
An emergency message up to 360 characters in length intended for display on mobile devices as a Wireless Emergency Alert (WEA).
Format

CMAMText

text


Where
text
is an emergency message no longer than 360 characters.
Example

CMAMText
National Weather Service: A FLASH FLOOD WARNING is in effect for this area until 5:45 PM MST. This is a dangerous and life-threatening situation. Do not attempt to travel unless you are fleeing an area subject to flooding or under an evacuation order.


Inclusion
Included in CAP messages which warn of an imminent threat to life and/or property
and
are intended to activate WEA.
maxWindGust
Last modified date:
Mar 23, 2022
Description
Anticipated maximum wind gust potential of a storm.
Format

maxWindGust

XXX
MPH

Where
XXX
is the anticipated maximum wind gust potential of the storm.
Example

windGust
80 MPH

Inclusion
Included with Severe Thunderstorm Warnings, some Special Marine Warnings, some Severe Weather Statements, and some Marine Weather Statements.
maxHailSize
Last modified date:
Mar 23, 2022
Description
Maximum hail size expected from the storm.
Format

maxHailSize

X.XX


Where
X.XX
is the expected maximum hail size in inches.
Example

maxHailSize
1.75

Inclusion
Included with Severe Thunderstorm Warnings, Tornado Warnings, Special Marine Warnings, some Severe Weather Statements and some Marine Weather Statements
windThreat
Last modified date:
Mar 23, 2022
Description
Source of information for the wind threat.
Format

windThreat

windThreat


Where
windThreat
is "RADAR INDICATED" or "OBSERVED"
Example

windThreat
RADAR INDICATED

Inclusion
Included with Severe Thunderstorm Warnings, some Special Marine Warnings, some Severe Weather Statements, and some Marine Weather Statements.
hailThreat
Last modified date:
Mar 23, 2022
Description
Source of Information for the hail threat.
Format

hailThreat

hailThreat


Where
hailThreat
is "RADAR INDICATED" or "OBSERVED"
Example

hailThreat
OBSERVED

Inclusion
Included with Severe Thunderstorm Warnings, some Special Marine Warnings, some Severe Weather Statements, and some Marine Weather Statements.
thunderstormDamageThreat
Last modified date:
Mar 23, 2022
Description
Impact in terms of damage expected from a thunderstorm.
Format

thunderstormDamageThreat

damage


Where
damage
is “CONSIDERABLE” or “DESTRUCTIVE”.
Example

thunderstormDamageThreat
CONSIDERABLE

Inclusion
Only included in Severe Thunderstorm Warnings when there is credible evidence that the thunderstorm is producing considerable or greater damage.
AWIPSidentifier
Last modified date:
Mar 23, 2022
Description
Advanced Weather Interactive Processing System (AWIPS) Identifier
Format

AWIPSidentifier

NNNXXX


Where:
NNN
is the AWIPS product category and
XXX
is the AWIPS office identifier.  If the
XXX
is less than 3 characters, the character(s) shall be left justified and filled with blanks to complete the 3-character field. See
for more information.
Example

AWIPSidentifier
FFWPSR

Inclusion
Included in every block.
eventMotionDescription
Last modified date:
Mar 23, 2022
Description
The position and motion of a hazardous event given in local time.
Format

eventMotionDescription

YYYY
MM
DD
hh
mm
ssXzh
zm...event
dirDEG
...
spKT
...
lat,lon [, lat,lon


Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
T marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros (00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
event
= storm
dirDeg
= three-digit direction from which the storm is moving, in degrees from 000 to 359 nonzero direction
sp
= speed of movement of the storm, in knots from 0 to 99 without a leading zero
lat,lon
= coded pair(s) identifying the latitude and longitude of the storm center expressed as a single point (in the case of one pair) or a line (if more than one pair is used) using WGS 84 (see Implementation Notes section of the OASIS CAP Profile document)
Example

eventMotionDescription
2010-08-05T08:46:00-05:00...storm...062DEG...16KT...30.62,-90.82 30.40,-90.91 30.25,-90.79

Means that on August 8, 2010 at 8:46:00 AM Central Daylight Time, the storm was moving from the northeast (to the southwest) at 16 knots. The storm center was located along the line connected by latitude 30.62 longitude -90.82, latitude 30.40 longitude -90.91, and latitude 30.25 longitude -90.79.
Inclusion
Included in NWS CAP messages with the following :
TOR (Tornado Warning)
SVR (Severe Thunderstorm Warning)
SVS (Severe Weather Statement)
SMW (Special Marine Warning)
MWS (Marine Weather Statement)
EWW (Extreme Wind Warning)
WMOidentifier
Last modified date:
Mar 23, 2022
Description
World Meteorological Organization (WMO) identifier
Format

WMOidentifier

T1T2A1A2ii CCCC YYGGgg [BBB]


Where:
T1
is taken from
WMO Manual 386
table A. It is an alpha character that
designates the general code form of the contents of the bulletin (Coded or
plain text).
T2
is taken from
WMO Manual 386
tables B1 through B6 depending on the
designator T1 in table A. It is an alpha character that designates the
data type.
A1
is taken from
WMO Manual 386
tables C1 through C6 depending on
designator T1 in table A (U.S. National practice through C9). It is an
alpha character that designates the geographical area the content of the
bulletin covers.
A2
is taken from
WMO Manual 386
tables C1 through C5 depending on
designator T1 in table A (U.S. National practice through C9). It is an
alpha character that designates the geographical area, or may define the
forecast period.
ii
is taken from the
WMO Manual 386
paragraph 2.3.2.2 definition, or from
table D1 or D2 depending on designator T1 in table A (U.S. National
practice table D3 replaces D2). It is a numeric set of two characters. Go
to the WMO message structure for more details on this group.
CCCC
is the identification of the processing center that generated the
bulletin. Commonly centers use alpha character identification designators
from ICAO's Location Indicators Doc 7910/80, but this is not consistent
throughout the centers.
YYGGgg
is the day, hour, and minute the bulletin was prepared or the
reporting time of the contained reports in it.
BBB
is an optional group of alpha characters
See
for more information.
Example

WMOidentifier
WGUS55 KPSR 242050

Inclusion
Included in every CAP message that originates from the NWS.
EAS-ORG
Last modified date:
Mar 23, 2022
Description
EAS Originator code of the NWS as required by the IPAWS CAP profile.
Format

EAS-ORG

XXX


Where
XXX
is the Special Area Message Encoding (SAME) organization code.  If the alert was originated by the NWS, then
XXX
is assigned a value of "WXR".  If the alert was originated by a civil authority,  then
XXX
is assigned a value of "CIV".
Example

EAS-ORG
WXR

Inclusion
Included in every block.
VTEC
Last modified date:
Mar 23, 2022
Description
Valid Time Event Code (VTEC) of the subject alert message.
Format

VTEC

VTEC


Where
VTEC
is the Valid Time Event Code (VTEC).
See
for more information about VTEC.
Example

VTEC
/O.CON.KDMX.SV.W.0004.000000T0000Z-110321T1845Z/

Inclusion
Included in many, but not all NWS CAP messages.
BLOCKCHANNEL
Last modified date:
Mar 23, 2022
Description
Blocks transmission of the alert across an IPAWS dissemination channel. One or more channels may be blocked.
Format

BLOCKCHANNEL

channel


Where
channel
is one of the following values.
•    “CMAS” – Refers to Wireless Emergency Alerts (WEA)
•    “EAS” – Refers to Emergency Alert System
•    “NWEM” – Refers to Non-Weather Emergency Message
•    “PUBLIC” – Refers to IPAWS public alert dissemination channel
Example

BLOCKCHANNEL
EAS


BLOCKCHANNEL
NWEM


BLOCKCHANNEL
CMAS

Inclusion
NWS often blocks CMAS, since WEA is intended only for the most critical alerts. NWS blocks EAS for alerts which are not intended for EAS via the IPAWS EAS channel. NWS always blocks messages to NWEM, since NWEMs push CAP messages back the NWS which would cause an undesirable dissemination loop. NWS never blocks PUBLIC.
expiredReferences
Last modified date:
Mar 23, 2022
Description
References the most recent message to which the current message refers or replaces.
Format

expiredReferences

sender
identifier
sent


Where
sender
identifier
, and
sent
are the , , and elements from inactive (i.e., time has been exceeded) CAP message(s) that this CAP message replaces. When multiple messages are referenced, they are separated by whitespace.
Example

expiredReferences
w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.ba78bc1780b07d57760cb3f75be064662620ea40.002.1,2021-02-05T05:58:00-05:00 w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.ba78bc1780b07d57760cb3f75be064662620ea40.003.1,2021-02-05T05:58:00-05:00 w-nws.webmaster@noaa.gov,urn:oid:2.49.0.1.840.0.f2d8079fd63d3ebad3bc90e90e1267ab2747da93.003.2,2021-02-05T04:44:00-05:00

Inclusion
Included whenever the NWS updates or cancels an alert for which a CAP message has been produced
and
at least one prior CAP message for the alert is inactive (i.e., time has been exceeded). NWS references all inactive messages impacted by the new message.  Referencing all inactive alert messages ensures any messages that may still be playing incorrectly are properly superseded by the most recent Update or Cancel.  This resolves issues caused by transmission delays and/or lost messages that may result in message chains being broken.
flashFloodDamageThreat
Last modified date:
Mar 23, 2022
Description
Impact in terms of damage expected from a flash flood.
Format

flashFloodDamageThreat

damage


Where
damage
is “CONSIDERABLE” or “CATASTROPHIC”.
Example

flashFloodDamageThreat
CATASTROPHIC

Inclusion
Only included in Flash Flood Warnings when there is credible evidence that the flash flood is producing considerable or greater damage.
snowSquallDetection
Last modified date:
Mar 23, 2022
Description
Describes whether the snow squall is indicated by radar or observed. This is an implied statement of confidence in the evidence that a snow squall is occurring.
Format

snowSquallDetection

detection


Where
detection
is “RADAR INDICATED” or “OBSERVED”.
Example

snowSquallDetection
RADAR INDICATED

Inclusion
Included in most Snow Squall Warnings.
snowSquallImpact
Last modified date:
Mar 23, 2022
Description
Impact of the snow squall.
Format

snowSquallImpact

impact


Where
impact
is “SIGNIFICANT”.
Example

snowSquallImpact
SIGNIFICANT

Inclusion
Only included in Snow Squall Warnings when there is credible evidence that the snow squall is of significant impact.
flashFloodDetection
Last modified date:
Mar 23, 2022
Description
Describes whether the flash flood is indicated by radar or observed. This is an implied statement of confidence in the evidence that a flash flood is occurring.
Format

flashFloodDetection

detection


For Flash Flood Warnings,
detection
is “RADAR INDICATED”, "RADAR AND GAUGE INDICATED", or “OBSERVED”.
Example

flashFloodDetection
RADAR INDICATED

Inclusion
Included with all Flash Flood Warnings.
eventEndingTime
Last modified date:
Mar 23, 2022
Description
The expected end time of the subject event in the alert message. This is the time at which the hazard conditions of the subject event are no longer expected.
Format

eventEndingTime

YYYY
MM
DD
hh
mm
ssXzh
zm


Where:
YYYY
= Year
MM
= Month (01-12)
DD
= Day, 2 digits with leading zeros (01-31)
T marks the start of the time section
hh
= 24-hour format of an hour with leading zeros (00-23)
mm
= Minutes with leading zeros (00-59)
ss
= Seconds, with leading zeros (00-59)
= The symbol "+" if the preceding date and time are in a time zone ahead of UTC, or the symbol "-" if the preceding date and time are in a time zone behind UTC.  If the time is in UTC, the symbol "-" will be used.
zh
= Hours of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
zm
= Minutes of offset from the preceding date and time to UTC, or "00" if the preceding time is in UTC
Example

eventEndingTime
2012-05-30T13:30:00-04:00

Means the hazard conditions of the subject event are no longer expected after 1:30 pm Eastern Daylight Time on May 23, 2012.
Inclusion
Included in most blocks.  The parameter will not be included for very long duration or open-ended alerts (e.g., hurricanes, tsunamis, some long duration floods, etc.) which are in effect until further notice.
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