Chapter 26, Advisories 26-29
Table 26-6. Space Weather Advisory Issuance Criteria
Effect Sub-Effect Parameter Used
Thresholds Impact within
Advisory Area
MOD SEV MOD SEV
GNSS Amplitude
Scintillation S4 (dimensionless) 0.5 0.8
Possible
degraded
service
Possible
unreliable
service
GNSS Phase Scintillation Sigma-phi (radians) 0.4 0.7
GNSS
Vertical Total
Electron Content
(TEC)
TEC units 125 175
RADIATION
Effective dose
(micro-
Sieverts/hour)*
30 80 Possible increased dose rates
above normal levels
HF COM Auroral
Absorption (AA) Kp index 8 9
Possible
degraded
service
Possible
unreliable
service
HF COM Polar Cap
Absorption (PCA)
dB from 30 MHz
riometer data 2 5
HF COM Shortwave Fadeout
(SWF)
Solar X rays
(0.0–0.8 NM)
(W-m-2)
1×10-4
(X1)
1×10-3
(X10)
HF COM Post-Storm
Depression
Maximum Usable
Frequency (MUF) 30% 50%
SATCOM No threshold has been set for this effect
Possible
degraded
service
Possible
unreliable
service
*MOD advisories will only be issued when the MOD threshold is reached between FL250 and FL460.
SEV advisories will be issued when the SEV threshold is reached at any FL above FL250. For context, the
background effective dose rate at FL370 at very high latitudes is approximately 9 micro-Sieverts/hour during solar
minimum and 6 micro -Sieverts/hour during solar maximum. These rates decrease progressively toward the
equatorial regions to values approximately one quarter of what is observed at very high latitudes.
Note: SEV radiation is a rare event with only a few short -lived events occurring during an 11 -year solar
cycle.
26.7.2 Space Weather Advisory Format
The Space Weather Advisory provides an observed or expected location for the impact and 6 -, 12-, 18-,
and 24-hour forecasts. The advisory describes the affected part of the globe in one of three ways:
• Six pre-defined latitude bands of width 30° shown in Table 26-7 (multiple bands may be given in
one advisory), followed by a longitude range in 15-degree increments;*
• The term “DAYLIGHT SIDE,” meaning the extent of the planet that is in daylight; or
• A polygon using latitude and longitude coordinates.
Note: *E18000-W18000 (or E180-W180) is used when the entire band is affected.
Chapter 26, Advisories 26-30
Table 26-7. Latitude Bands Used in Space Weather Advisories
Latitude Bands Used in Space Weather Advisories
High latitudes northern hemisphere (HNH) N90 to N60
Middle latitudes northern hemisphere (MNH) N60 to N30
Equatorial latitudes northern hemisphere (EQN) N30 to equator
Equatorial latitudes southern hemisphere (EQS) Equator to S30
Middle latitudes southern hemisphere (MSH) S30 to S60
High latitudes southern hemisphere (HSH) S60 to S90
By design, the vertical and temporal resolutions of the advisory are very coarse. The use of 30 ° latitude
bands, 15 -degree longitude increments, 1,000-ft vertical increments (for radiation), and six-hour time
intervals will at times result in over -forecasting the affected airspace. In addition, while an entire latitude
band may be forecast to have MOD or SEV space weather, there will often be times that the effect does not
cover the entire width of the band or is intermittent or temporary. Users should refer to the remarks section
of the advisory for additional information. Users can also go to the center’s website, where a graphical
depiction of the space weather event may be provided along with additional information.
Changes to the Space Weather Advisory content and format are possible in the coming years as experience
is gained with the use of this product.
The Space Weather Advisory is not a replacement for the SWPC’s other products or the NOAA Space
Weather Scales, which continue to be provided by the SWPC. Refer to the SWPC’s website for information
on these products and the scales.
Chapter 26, Advisories 26-31
Table 26-8. Format of the Space Weather Advisory
Format Explanation Examples
Communication
header
Product’s coded identification for
the issuing centers. KWNP is the
SWPC, LFPW and YMMC are the
ACFJ, EFKL and EGRR are the
PECASUS, and ZBBB and UUAG
are the CRC.
FNXX01 is for GNSS, FNXX02 is
for HF COM, FNXX03 is for
Radiation, and FNXX04 is for
SATCOM.
FNXX01 KWNP
FNXX01 LFPW
FNXX01 YMMC
FNXX01 EFKL
FNXX02 EGRR
FNXX03 UUAG
FNXX04 ZBBB
SWX ADVISORY Space Weather (SWX) Advisory. SWX ADVISORY
STATUS: Status indicator (optional) for test or
exercise.
TEST
EXER
DTG: Date and time of origin, in
YYYYMMDD/HHMMZ.
20190418/0100Z
SWXC: Name of the Space Weather
Advisory Center (SWXC).
ACFJ
PECASUS
SWPC
CRC
ADVISORY NR: Advisory number (NR). 2019/9
NR RPLC: Advisory number being replaced by
this advisory (optional).
2019/8
SWX EFFECT: Space weather effect. HF COM MOD
HF COM SEV
SATCOM MOD
SATCOM SEV
GNSS MOD
GNSS SEV
RADIATION MOD
RADIATION SEV
OBS (or FCST)
SWX:
Observed (OBS) or expected
(FCST) space weather effect
date/time, location, and altitudes
(altitudes are only used in the
radiation advisory).
18/0100Z EQN W18000-W12000
18/0100Z HNH HSH E180-W180 ABV
FL370
18/0100Z DAYLIGHT SIDE
18/0100Z NO SWX EXP
FCST SWX
+6 HR:
6-hour forecast. Date/time, location,
and altitudes.
Same as above
FCST SWX
+12 HR:
12-hour forecast. Date/time,
location, and altitudes.
Same as above
FCST SWX
+18 HR:
18-hour forecast. Date/time,
location, and altitudes.
Same as above
FCST SWX
+24 HR:
24-hour forecast. Date/time,
location, and altitudes.
Same as above
Chapter 26, Advisories 26-32
Format Explanation Examples
RMK: Remarks (RMK). Additional information
NXT ADVISORY: Date/time when the next (NXT)
scheduled advisory will be issued.
2010418/0700Z
26.7.3 Space Weather Advisory Examples
26.7.3.1 Example Space Weather Advisory—GNSS
Note: “GNSS” is the acronym for Global Navigation Satellite System, which is the term for all the world’s
navigation satellites, which includes the United States’ Global Position Satellites.
FNXX03 KWNP 020100
SWX ADVISORY
DTG: 20190502/0100Z
SWXC: SWPC
ADVISORY NR: 2019/59
NR RPLC: 2019/58
SWX EFFECT: GNSS MOD
OBS SWX: 02/0100Z HNH HSH E18000-W18000
FCST SWX + 6 HR: 02/0700Z HNH HSH E18000-W18000
FCST SWX + 12 HR: 02/1300Z HNH HSH E18000-W18000
FCST SWX + 18 HR: 02/1900Z NO SWX EXP
FCST SWX + 24 HR: 03/0100Z NO SWX EXP
RMK: IONOSPHERIC STORM CONTINUES TO CAUSE LOSS-OF-LOCK
OF GNSS IN AURORA ZONE. THIS ACTIVITY IS
EXPECTED TO SUBSIDE IN THE FORECAST PERIOD
NXT ADVISORY: 20190502/0700Z=
26.7.3.2 Example Space Weather Advisory—RADIATION
FNXX02 EFKL 190300
SWX ADVISORY
DTG: 20190219/0300Z
SWXC: PECASUS
ADVISORY NR: 2019/20
SWX EFFECT: RADIATION MOD
OBS SWX: 19/0300Z HNH HSH E18000-W18000 ABV FL370
FCST SWX + 6 HR: 19/0900Z NO SWX EXP
FCST SWX + 12 HR: 19/1500Z NO SWX EXP
FCST SWX + 18 HR: 19/2100Z NO SWX EXP
FCST SWX + 24 HR: 20/0300Z NO SWX EXP
RMK: RADIATION AT AIRCRAFT ALTITUDES ELEVATED
BY SMALL ENHANCEMENT JUST ABOVE PRESCRIBED
THRESHOLD. DURATION TO BE SHORT-LIVED
NXT ADVISORY: NO FURTHER ADVISORIES=
Chapter 26, Advisories 26-33
26.7.3.3 Example Space Weather Advisory—HF COM
FNXX01 YMMC 020100
SWX ADVISORY
DTG: 20190202/0100Z
SWXC: ACFJ
ADVISORY NR: 2019/10
SWX EFFECT: HF COM MOD
OBS SWX: 02/0100Z DAYLIGHT SIDE
FCST SWX + 6 HR: 02/0700Z DAYLIGHT SIDE
FCST SWX + 12 HR: 02/1300Z DAYLIGHT SIDE
FCST SWX + 18 HR: 02/1900Z NO SWX EXP
FCST SWX + 24 HR: 03/0100Z NO SWX EXP
RMK: LOW END OF BAND HF COM DEGRADED
ON SUNLIT ROUTES. NEXT 12 HOURS
MOST POSSIBLE, DECLINING THEREAFTER.
NXT ADVISORY: 20190202/0700Z=
26.8 Low-Level Wind Shear (LLWS)/Microburst Advisories
When LLWS/microburst is reported by pilots or the integrated terminal weather system (ITWS), or detected
on wind shear detection systems, such as the LLWS Alert System, the weather systems processor (WSP),
or the TDWR, ATC issues the alert to all arriving and departing aircraft. ATC will continue providing the
alert to aircraft until it is broadcast on the ATIS and pilots indicate they have received the appropriate ATIS
code. A statement is included on the ATIS for 20 minutes following the last report or indication of the wind
shear/microburst.
At facilities without the ATIS, ATC broadcasts wind shear/microburst information to all arriving and
departing aircraft for 20 minutes following the last report or indication of the wind shear/microburst.
26.9 Airport Weather Warning (AWW)
The AWW addresses weather phenomena that can adversely impact airport ground operations. Information
contained in this product may be useful to airport managers, fixed -based operators, airline ground
personnel, and others responsible for the safety of grou nd operations. Ground decisions supported by the
AWW information may include fueling delays during thunderstorms, deicing frequency, and other similar
ground operations. AWWs are not intended for use by in-flight operations.
Note: The AWW is not to be confused with the Aviation Watch Notification Message (see
Section 27.17.4.1), which the NWS refers to as “SAW,” but is also known by “AWW” on the websites of
some weather provider services. The Aviation Watch Notification Message was formerly known as the
Alert Severe Weather Watch Bulletin as well as the Severe Weather Forecast Alert.
26.9.1 AWW Issuance
The AWW is issued for select larger airports and is available on NWS WFO s’ websites who have
responsibility for issuing the TAFs for that airport. The AWW is not available on the AWC’s website.
Issuance criteria are established according to local airport requirements. Some examples of criteria are
strong surface winds, freezing rain, heavy snow, and lightning within five miles of the airport.
Chapter 26, Advisories 26-34
26.9.2 AWW Format and Example
The AWW is written in a plain language, free-text format.
WWUS82 KJAX 112212
AWWJAX
FLZ025-112315-
AIRPORT WEATHER WARNING FOR JACKSONVILLE INTERNATIONAL AIRPORT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
612 PM EDT WED MAR 11 2015
...AN AIRPORT WEATHER WARNING HAS BEEN ISSUED FOR JACKSONVILLE
INTERNATIONAL AIRPORT FOR STRONG WINDS AND POSSIBLE WINDSHIFT
VALID UNTIL 700 PM...
A CLUSTER OF THUNDERSTORMS WILL MOVE EASTWARD AT 12 KNOTS AND
AFFECT JACKSONVILLE INTERNATIONAL AIRPORT BY 620 PM. WIND GUSTS
OVER 35 KNOTS ARE LIKELY WITH THESE STORMS...AS WELL AS CLOUD-
TO-GROUND LIGHTNING AND REDUCED VISIBILITIES FROM HEAVY RAIN.
WINDSHIFTS ACCOMPANYING THE THUNDERSTORMS MAY ALTER THE RUNWAY
LANDING PATTERN WITH SOME STRONG WESTERLY WIND GUSTS.
$$