Indices solaires, géomagnétiques et alertes HF

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Cette page présente les indices géomagnétiques et solaires, ainsi que les alertes du Space Weather Prediction Center (NOAA – USA) en vigueur actuellement.
Pour plus d’information sur ces alertes, visitez : http://www.swpc.noaa.gov/noaa-scales-explanation.

Messages émis par le NOAA/Space Weather Prediction Center
Mise à jour : 04/04/2026 11:39:36 UTC
Il y a actuellement 18 message(s) (dont 9 alerte(s) et 18 message(s) encore actif(s) au SWPC)
WARNING : EXTENDED Geomagnetic K-index of 5 expected   03/04/2026 14:51:00 UTC   > Détails
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Space Weather Message Code: WARK05 Serial Number: 2221 Issue Time: 2026 Apr 03 1451 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 2220 Valid From: 2026 Apr 02 0230 UTC Now Valid Until: 2026 Apr 03 2359 UTC Warning Condition: Persistence www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer
WARNING : Geomagnetic Sudden Impulse expected   03/04/2026 15:29:00 UTC   > Détails
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Space Weather Message Code: WARSUD Serial Number: 253 Issue Time: 2026 Apr 03 1529 UTC WARNING: Geomagnetic Sudden Impulse expected Valid From: 2026 Apr 03 1529 UTC Valid To: 2026 Apr 03 1550 UTC IP Shock Passage Observed: 2026 Apr 03 1503 UTC www.swpc.noaa.gov/noaa-scales-explanation Fermer
ALERT : Geomagnetic K-index of 5   03/04/2026 15:42:00 UTC   > Détails
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Space Weather Message Code: ALTK05 Serial Number: 2003 Issue Time: 2026 Apr 03 1542 UTC ALERT: Geomagnetic K-index of 5 Synoptic Period: 1500-1800 UTC Active Warning: Yes NOAA Scale: G1 - Minor www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer
SUMMARY : Geomagnetic Sudden Impulse   03/04/2026 15:45:00 UTC   > Détails
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Space Weather Message Code: SUMSUD Serial Number: 298 Issue Time: 2026 Apr 03 1545 UTC SUMMARY: Geomagnetic Sudden Impulse Observed: 2026 Apr 03 1529 UTC Deviation: 72 nT Station: HAD www.swpc.noaa.gov/noaa-scales-explanation Fermer
WARNING : Geomagnetic K-Index of 6 expected   03/04/2026 15:52:00 UTC   > Détails
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Space Weather Message Code: WARK06 Serial Number: 652 Issue Time: 2026 Apr 03 1552 UTC WARNING: Geomagnetic K-Index of 6 expected Valid From: 2026 Apr 03 1551 UTC Valid To: 2026 Apr 03 2359 UTC Warning Condition: Onset NOAA Scale: G2 - Moderate www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state. Fermer
ALERT : Geomagnetic K-index of 6   03/04/2026 15:55:00 UTC   > Détails
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Space Weather Message Code: ALTK06 Serial Number: 710 Issue Time: 2026 Apr 03 1555 UTC ALERT: Geomagnetic K-index of 6 Synoptic Period: 1500-1800 UTC Active Warning: Yes NOAA Scale: G2 - Moderate www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state. Fermer
WARNING : Geomagnetic K-index of 7 or greater expected   03/04/2026 16:25:00 UTC   > Détails
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Space Weather Message Code: WARK07 Serial Number: 148 Issue Time: 2026 Apr 03 1625 UTC WARNING: Geomagnetic K-index of 7 or greater expected Valid From: 2026 Apr 03 1625 UTC Valid To: 2026 Apr 03 2359 UTC Warning Condition: Onset NOAA Scale: G3 or greater www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude. Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices. Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur. Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur. Radio - HF (high frequency) radio may be intermittent. Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon. Fermer
ALERT : Geomagnetic K-index of 7   03/04/2026 16:47:00 UTC   > Détails
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Space Weather Message Code: ALTK07 Serial Number: 216 Issue Time: 2026 Apr 03 1647 UTC ALERT: Geomagnetic K-index of 7 Synoptic Period: 1500-1800 UTC Active Warning: Yes NOAA Scale: G3 - Strong www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude. Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices. Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur. Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur. Radio - HF (high frequency) radio may be intermittent. Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon. Fermer
ALERT : Geomagnetic K-index of 5   03/04/2026 19:08:00 UTC   > Détails
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Space Weather Message Code: ALTK05 Serial Number: 2004 Issue Time: 2026 Apr 03 1908 UTC ALERT: Geomagnetic K-index of 5 Synoptic Period: 1800-2100 UTC Active Warning: Yes NOAA Scale: G1 - Minor www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer
ALERT : Geomagnetic K-index of 6   03/04/2026 21:01:00 UTC   > Détails
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Space Weather Message Code: ALTK06 Serial Number: 711 Issue Time: 2026 Apr 03 2101 UTC ALERT: Geomagnetic K-index of 6 Synoptic Period: 1800-2100 UTC Active Warning: Yes NOAA Scale: G2 - Moderate www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state. Fermer
WARNING : EXTENDED Geomagnetic K-index of 5 expected   03/04/2026 21:01:00 UTC   > Détails
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Space Weather Message Code: WARK05 Serial Number: 2222 Issue Time: 2026 Apr 03 2101 UTC EXTENDED WARNING: Geomagnetic K-index of 5 expected Extension to Serial Number: 2221 Valid From: 2026 Apr 02 0230 UTC Now Valid Until: 2026 Apr 04 1500 UTC Warning Condition: Persistence www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer
WARNING : EXTENDED Geomagnetic K-index of 4 expected   03/04/2026 21:02:00 UTC   > Détails
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Space Weather Message Code: WARK04 Serial Number: 5310 Issue Time: 2026 Apr 03 2102 UTC EXTENDED WARNING: Geomagnetic K-index of 4 expected Extension to Serial Number: 5309 Valid From: 2026 Apr 02 0047 UTC Now Valid Until: 2026 Apr 04 2359 UTC Warning Condition: Persistence www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Aurora - Aurora may be visible at high latitudes such as Canada and Alaska. Fermer
ALERT : Geomagnetic K-index of 5   03/04/2026 21:41:00 UTC   > Détails
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Space Weather Message Code: ALTK05 Serial Number: 2005 Issue Time: 2026 Apr 03 2141 UTC ALERT: Geomagnetic K-index of 5 Synoptic Period: 2100-2400 UTC Active Warning: Yes NOAA Scale: G1 - Minor www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer
ALERT : Geomagnetic K-index of 6   03/04/2026 23:10:00 UTC   > Détails
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Space Weather Message Code: ALTK06 Serial Number: 712 Issue Time: 2026 Apr 03 2310 UTC ALERT: Geomagnetic K-index of 6 Synoptic Period: 2100-2400 UTC Active Warning: Yes NOAA Scale: G2 - Moderate www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state. Fermer
WARNING : EXTENDED Geomagnetic K-Index of 6 expected   03/04/2026 23:10:00 UTC   > Détails
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Space Weather Message Code: WARK06 Serial Number: 653 Issue Time: 2026 Apr 03 2310 UTC EXTENDED WARNING: Geomagnetic K-Index of 6 expected Extension to Serial Number: 652 Valid From: 2026 Apr 03 1551 UTC Now Valid Until: 2026 Apr 04 0600 UTC Warning Condition: Persistence www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude. Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms. Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible. Radio - HF (high frequency) radio propagation can fade at higher latitudes. Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state. Fermer
ALERT : X-Ray Flux exceeded M5   04/04/2026 01:17:00 UTC   > Détails
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Space Weather Message Code: ALTXMF
Serial Number: 522
Issue Time: 2026 Apr 04 0117 UTC

ALERT: X-Ray Flux exceeded M5
Threshold Reached: 2026 Apr 04 0117 UTC
NOAA Scale: R2 - Moderate
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Area of impact centered on sub-solar point on the sunlit side of Earth. Extent of blackout of HF (high frequency) radio communication dependent upon current X-ray Flux intensity. For real-time information on affected area and expected duration please see http://www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap.

SUMMARY : X-ray Event exceeded M5   04/04/2026 01:46:00 UTC   > Détails
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Space Weather Message Code: SUMXM5 Serial Number: 312 Issue Time: 2026 Apr 04 0146 UTC SUMMARY: X-ray Event exceeded M5 Begin Time: 2026 Apr 04 0107 UTC Maximum Time: 2026 Apr 04 0117 UTC End Time: 2026 Apr 04 0123 UTC X-ray Class: M7.5 Location: N04W04 NOAA Scale: R2 - Moderate www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact centered primarily on sub-solar point on the sunlit side of Earth. Radio - Limited blackout of HF (high frequency) radio communication for tens of minutes. Fermer
ALERT : Geomagnetic K-index of 5   04/04/2026 02:54:00 UTC   > Détails
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Space Weather Message Code: ALTK05 Serial Number: 2006 Issue Time: 2026 Apr 04 0254 UTC ALERT: Geomagnetic K-index of 5 Synoptic Period: 0000-0300 UTC Active Warning: Yes NOAA Scale: G1 - Minor www.swpc.noaa.gov/noaa-scales-explanation Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude. Induced Currents - Weak power grid fluctuations can occur. Spacecraft - Minor impact on satellite operations possible. Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine. Fermer

Conditions HF, indices solaires et géomagnétiques et historique quotidien
La plupart de ces données sont mises à jour en temps réel.

Conditions HF
NOAA Scale Activity
G0
n/a
R0
HF Bands Noise Level
S2-S3
Indices bruts
SFI
133
SSN
118
Ap
46
Kp
3
Kp Lat.
60,4°
X-Ray (HAF)
B5,7 (2,55 MHz)
Protons E>10 MeV
1,43
Electrons >2MeV
772,0
304A (SOHO)
0
304A (SDO/EVE)
376,0
Solar Wind (km/s)
636,7
Proton Density (p/cc)
0,8
Ion Temperature (°K)
146 000,0
IMF Bt (nT)
3,1
IMF Bz (nT)
2,2
Prévisions d'activité géomagnétique polaire (Auroral activity) à 30 minutes
North auroral activity
5 (HPI=10)
Impact as low as
62,5°
Expected in
-137953 min.
Data source
NOAA SWPC
South auroral activity
5 (HPI=10)
Impact as low as
62,5°
Expected in
-137953 min.
Data source
NOAA SWPC
Mise à jour des indices : 04/04/2026 11:38:36 UTC
Historique des indices pour la journée

Cette page réunit de nombreux indices solaires et terrestres. Ces données sont issues des satellites défilants (TIROS n – NOAA), géostationnaires (GOES – NOAA), ainsi que des satellites SOHO (NASA/ESA) et SDO/EVE (NASA). Les données de flux solaire proviennent quant à elles de l’observatoire de Penticton (CA).
Certaines valeurs sont des moyennes calculées sur les 15 dernières minutes (Bt et Bz), le flux solaire est publié à 17:00, 21:00 et 23:00 (UTC). Les autres sont des valeurs en temps réel (ou presque).
Une juxtaposition des données historisées de cette page et de l’historique de réception de FAROS est disponible sur cette page.

Merci à Paul, N0NBH pour son aide et sa patience (son site est très intéressant : www.hamqsl.com)

Plus d’infos sur ces indices :
– NOAA Space Weather Scales – http://www.swpc.noaa.gov/NOAAscales
– NOAA Tips on viewing the Aurora – http://www.swpc.noaa.gov/products/aurora-30-minute-forecast

Références :
– HF Ionospheric Radio Signal Propagation (en) http://www.radio-electronics.com/info/propagation/ionospheric/hf-propagation-basics.php
– Glossaire du SWPC de la NOAA (en) : http://legacy-www.swpc.noaa.gov/info/glossary.html
– What the data means – Scott Bidstrup, W7RI (en) http://www.bidstrup.com/w7ri-hf-radio-propagation.htm
– Understanding HF Radio Propagation Forecasts, N0HR (en) : http://www.n0hr.com/radio_propagation.htm
– Ionosphere Properties and Behaviors – Marcel H. De Canck ON5AU, AntenneX n°110 / Juin 2006 (en) : www.antennex.com (site hors ligne, essayez la « wayback machine »…)
– Ham-Bands propagation properties – Marcel H. De Canck ON5AU, AntenneX n°142 / Février 2009 (en) : www.antennex.com (site hors ligne, essayez la « wayback machine »…)