Space weather

Solar wind speed Solar wind magnetic fields Noon 10.7cm radio flux
Bt Bz

Update

Update

Update
CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-28 05.01 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2622
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 16548 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-27 05.00 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2621
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 13962 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-26 07.40 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 26 0740 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-26 07.29 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 26 0729 UTC
Valid To: 2017 Jul 26 1200 UTC
Warning Condition: Onset

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-26 05.03 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2620
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 18833 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-26 00.38 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 26 0037 UTC
Valid To: 2017 Jul 26 0600 UTC
Warning Condition: Onset

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-25 05.00 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2619
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 14765 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-25 00.01 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 24 2359 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-24 23.00 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 24 2300 UTC
Valid To: 2017 Jul 25 0600 UTC
Warning Condition: Onset

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-24 05.44 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2618
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 5777 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-23 23.24 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 23 2323 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-23 23.12 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 23 2312 UTC
Valid To: 2017 Jul 24 1200 UTC
Warning Condition: Onset

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-23 10.55 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2617
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 3619 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-23 05.51 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3257
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 23 1200 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-22 14.40 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3256
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 23 0600 UTC
Warning Condition: Persistence

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-22 11.42 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 22 1142 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-22 10.29 UTC
Geomagnetic K-index of 5 expected
Valid From: 2017 Jul 22 1028 UTC
Valid To: 2017 Jul 22 1500 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-22 10.05 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2616
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 1273 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-22 05.29 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3255
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 22 1500 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-21 23.54 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3254
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 22 0600 UTC
Warning Condition: Persistence

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-21 14.42 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2615
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 11444 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-21 13.56 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3253
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 21 2359 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-21 05.55 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3252
Valid From: 2017 Jul 21 0212 UTC
Now Valid Until: 2017 Jul 21 1500 UTC
Warning Condition: Persistence

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.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-21 02.33 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 21 0232 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-21 02.14 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 21 0212 UTC
Valid To: 2017 Jul 21 0600 UTC
Warning Condition: Onset

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-20 05.00 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2614
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 13630 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-19 05.01 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2613
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 5472 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-18 05.55 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3250
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 18 1200 UTC
Warning Condition: persistence

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.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-18 05.21 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2612
Begin Time: 2017 Jul 17 0325 UTC
Yesterday Maximum 2MeV Flux: 12226 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-17 22.55 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3249
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 18 0600 UTC
Warning Condition: persistence

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.

ALERT
Geomagnetic K-index of 6
Issued: 2017-07-17 16.42 UTC
Geomagnetic K-index of 6
Threshold Reached: 2017 Jul 17 1642 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

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.

WARNING
Geomagnetic K-Index of 6 expected
Issued: 2017-07-17 16.27 UTC
Geomagnetic K-Index of 6 expected
Valid From: 2017 Jul 17 1626 UTC
Valid To: 2017 Jul 17 2100 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-17 16.07 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 17 1607 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-17 15.37 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3248
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 17 2300 UTC
Warning Condition: persistence

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.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-17 15.37 UTC
Geomagnetic K-index of 5 expected
Valid From: 2017 Jul 17 1536 UTC
Valid To: 2017 Jul 17 2100 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-17 05.55 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3247
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 17 1800 UTC
Warning Condition: persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-17 05.28 UTC
Geomagnetic K-index of 5 expected
Extension to Serial Number: 1366
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 17 1500 UTC
Warning Condition: Persistence

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.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: 2017-07-17 03.42 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2017 Jul 17 0325 UTC
Station: GOES13


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-16 21.55 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 16 2150 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

EXTENDED WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-16 20.23 UTC
Geomagnetic K-index of 5 expected
Extension to Serial Number: 1365
Valid From: 2017 Jul 16 0520 UTC
Now Valid Until: 2017 Jul 17 0600 UTC
Warning Condition: Persistence

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.

ALERT
Geomagnetic K-index of 6
Issued: 2017-07-16 19.58 UTC
Geomagnetic K-index of 6
Threshold Reached: 2017 Jul 16 1957 UTC
Synoptic Period: 1800-2100 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

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.

WARNING
Geomagnetic K-Index of 6 expected
Issued: 2017-07-16 19.50 UTC
Geomagnetic K-Index of 6 expected
Valid From: 2017 Jul 16 1950 UTC
Valid To: 2017 Jul 17 0300 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-16 16.55 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 16 1654 UTC
Synoptic Period: 1500-1800 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

ALERT
Geomagnetic K-index of 6
Issued: 2017-07-16 14.55 UTC
Geomagnetic K-index of 6
Threshold Reached: 2017 Jul 16 1454 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-16 13.09 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 16 1308 UTC
Synoptic Period: 1200-1500 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-16 11.06 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 16 1105 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

WARNING
Geomagnetic K-Index of 6 expected
Issued: 2017-07-16 10.38 UTC
Geomagnetic K-Index of 6 expected
Valid From: 2017 Jul 16 1040 UTC
Valid To: 2017 Jul 16 1800 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

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.

SUMMARY
Geomagnetic Sudden Impulse
Issued: 2017-07-16 06.09 UTC
Geomagnetic Sudden Impulse
Observed: 2017 Jul 16 0601 UTC
Deviation: 40 nT
Station: HAD

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-16 06.07 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 16 0604 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic Sudden Impulse expected
Issued: 2017-07-16 05.24 UTC
Geomagnetic Sudden Impulse expected
Valid From: 2017 Jul 16 0530 UTC
Valid To: 2017 Jul 16 0630 UTC
IP Shock Passage Observed: 2017 Jul 16 0515 UTC

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-16 05.23 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 16 0520 UTC
Valid To: 2017 Jul 17 0600 UTC
Warning Condition: Onset

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.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-16 05.21 UTC
Geomagnetic K-index of 5 expected
Valid From: 2017 Jul 16 0520 UTC
Valid To: 2017 Jul 16 2359 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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.

SUMMARY
Proton Event 10MeV Integral Flux exceeded 10pfu
Issued: 2017-07-15 21.00 UTC
Proton Event 10MeV Integral Flux exceeded 10pfu
Begin Time: 2017 Jul 14 0900 UTC
Maximum Time: 2017 Jul 14 2320 UTC
End Time: 2017 Jul 15 1115 UTC
Maximum 10MeV Flux: 22 pfu
NOAA Scale: S1 - Minor

EXTENDED WARNING
Proton 10MeV Integral Flux above 10pfu expected
Issued: 2017-07-15 11.24 UTC
Proton 10MeV Integral Flux above 10pfu expected
Extension to Serial Number: 460
Valid From: 2017 Jul 14 0530 UTC
Now Valid Until: 2017 Jul 15 2100 UTC
Warning Condition: Persistence
Predicted NOAA Scale: S1 - Minor

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

EXTENDED WARNING
Proton 10MeV Integral Flux above 10pfu expected
Issued: 2017-07-14 17.55 UTC
Proton 10MeV Integral Flux above 10pfu expected
Extension to Serial Number: 459
Valid From: 2017 Jul 14 0530 UTC
Now Valid Until: 2017 Jul 15 1200 UTC
Warning Condition: Persistence
Predicted NOAA Scale: S1 - Minor

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

WATCH
Geomagnetic Storm Category G2 Predicted
Issued: 2017-07-14 10.29 UTC
Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
Jul 15: None (Below G1) Jul 16: G2 (Moderate) Jul 17: G2 (Moderate)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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.

ALERT
Proton Event 10MeV Integral Flux exceeded 10pfu
Issued: 2017-07-14 09.19 UTC
Proton Event 10MeV Integral Flux exceeded 10pfu
Begin Time: 2017 Jul 14 0900 UTC
NOAA Scale: S1 - Minor

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

WARNING
Proton 10MeV Integral Flux above 10pfu expected
Issued: 2017-07-14 05.30 UTC
Proton 10MeV Integral Flux above 10pfu expected
Valid From: 2017 Jul 14 0530 UTC
Valid To: 2017 Jul 14 1800 UTC
Warning Condition: Onset
Predicted NOAA Scale: S1 - Minor

Potential Impacts: Radio - Minor impacts on polar HF (high frequency) radio propagation resulting in fades at lower frequencies.

ALERT
Type IV Radio Emission
Issued: 2017-07-14 02.35 UTC
Type IV Radio Emission
Begin Time: 2017 Jul 14 0202 UTC

Description: Type IV emissions occur in association with major eruptions on the sun and are typically associated with strong coronal mass ejections and solar radiation storms.

SUMMARY
10cm Radio Burst
Issued: 2017-07-14 02.31 UTC
10cm Radio Burst
Begin Time: 2017 Jul 14 0110 UTC
Maximum Time: 2017 Jul 14 0151 UTC
End Time: 2017 Jul 14 0154 UTC
Duration: 44 minutes
Peak Flux: 130 sfu
Latest Penticton Noon Flux: 92 sfu

Description: A 10cm radio burst indicates that the electromagnetic burst associated with a solar flare at the 10cm wavelength was double or greater than the initial 10cm radio background. This can be indicative of significant radio noise in association with a solar flare. This noise is generally short-lived but can cause interference for sensitive receivers including radar, GPS, and satellite communications.

ALERT
Type II Radio Emission
Issued: 2017-07-13 20.49 UTC
Type II Radio Emission
Begin Time: 2017 Jul 13 2006 UTC
Estimated Velocity: 770 km/s

Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-09 23.47 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3245
Valid From: 2017 Jul 09 0023 UTC
Now Valid Until: 2017 Jul 10 0900 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-09 14.56 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3244
Valid From: 2017 Jul 09 0023 UTC
Now Valid Until: 2017 Jul 09 2359 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-09 14.56 UTC
Geomagnetic K-index of 5 expected
Extension to Serial Number: 1363
Valid From: 2017 Jul 09 0220 UTC
Now Valid Until: 2017 Jul 09 2359 UTC
Warning Condition: Persistence

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-09 10.21 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 09 1020 UTC
Synoptic Period: 0900-1200 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-09 02.30 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 09 0230 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-09 02.21 UTC
Geomagnetic K-index of 5 expected
Valid From: 2017 Jul 09 0220 UTC
Valid To: 2017 Jul 09 1500 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-09 02.09 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 09 0206 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-09 00.24 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 09 0023 UTC
Valid To: 2017 Jul 09 1500 UTC
Warning Condition: Onset

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.

WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2017-07-06 20.34 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Jul 07: None (Below G1) Jul 08: None (Below G1) Jul 09: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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.

CANCEL WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2017-07-03 14.11 UTC
Geomagnetic Storm Category G1 Predicted
Cancel Serial Number: 790
Original Issue Time: 2017 Jul 01 1954 UTC

Comment: Solar wind parameters have returned to nominal levels following the passage of the 28 June CME and G1 (Minor) storm conditions are no longer likely.

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-02 14.56 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3242
Valid From: 2017 Jul 01 1640 UTC
Now Valid Until: 2017 Jul 03 1500 UTC
Warning Condition: Persistence

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.

ALERT
Geomagnetic K-index of 5
Issued: 2017-07-02 09.00 UTC
Geomagnetic K-index of 5
Threshold Reached: 2017 Jul 02 0859 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

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.

ALERT
Geomagnetic K-index of 4
Issued: 2017-07-02 06.42 UTC
Geomagnetic K-index of 4
Threshold Reached: 2017 Jul 02 0642 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes

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.

WARNING
Geomagnetic K-index of 5 expected
Issued: 2017-07-02 06.37 UTC
Geomagnetic K-index of 5 expected
Valid From: 2017 Jul 02 0630 UTC
Valid To: 2017 Jul 02 1300 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-02 06.37 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3241
Valid From: 2017 Jul 01 1640 UTC
Now Valid Until: 2017 Jul 02 1500 UTC
Warning Condition: Persistence

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.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-01 23.59 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3240
Valid From: 2017 Jul 01 1640 UTC
Now Valid Until: 2017 Jul 02 1200 UTC
Warning Condition: Persistence

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.

WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2017-07-01 19.54 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Jul 02: G1 (Minor) Jul 03: G1 (Minor) Jul 04: None (Below G1)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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.

SUMMARY
Geomagnetic Sudden Impulse
Issued: 2017-07-01 17.35 UTC
Geomagnetic Sudden Impulse
Observed: 2017 Jul 01 1712 UTC
Deviation: 20 nT
Station: CMO

WARNING
Geomagnetic Sudden Impulse expected
Issued: 2017-07-01 16.51 UTC
Geomagnetic Sudden Impulse expected
Valid From: 2017 Jul 01 1715 UTC
Valid To: 2017 Jul 01 1745 UTC
IP Shock Passage Observed: 2017 Jul 01 1625 UTC

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-01 16.41 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 01 1640 UTC
Valid To: 2017 Jul 01 2359 UTC
Warning Condition: Onset

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.

WARNING
Geomagnetic K-index of 4 expected
Issued: 2017-07-01 05.33 UTC
Geomagnetic K-index of 4 expected
Valid From: 2017 Jul 01 0532 UTC
Valid To: 2017 Jul 01 1200 UTC
Warning Condition: Onset

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.

WATCH
Geomagnetic Storm Category G1 Predicted
Issued: 2017-06-30 15.18 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
Jul 01: None (Below G1) Jul 02: None (Below G1) Jul 03: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

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.

Table

Date Radio flux 10.7 cm SESC Sunspot number Sunspot area 10E-6 New regions GOES15 X-ray Bkgd flux Flares
X-ray Optical
C M X S 1 2 3
2017-06-28 72 13 60 0 A5.2 0 0 0 0 0 0 0
2017-06-29 72 12 50 0 A4.3 0 0 0 0 0 0 0
2017-06-30 72 11 50 0 A3.7 0 0 0 0 0 0 0
2017-07-01 71 11 20 0 A3.4 0 0 0 0 0 0 0
2017-07-02 71 11 20 0 A3.5 0 0 0 0 0 0 0
2017-07-03 72 0 0 0 A6.5 0 1 0 4 0 0 0
2017-07-04 72 0 0 0 A9.3 1 0 0 0 0 0 0
2017-07-05 73 11 70 1 A9.0 0 0 0 2 0 0 0
2017-07-06 76 16 140 0 A8.4 0 0 0 3 0 0 0
2017-07-07 80 25 310 0 B1.4 1 0 0 19 1 0 0
2017-07-08 87 24 480 0 B1.7 1 0 0 23 0 2 0
2017-07-09 91 31 710 0 B2.1 4 1 0 16 1 1 0
2017-07-10 95 32 690 0 B1.3 1 0 0 2 0 0 0
2017-07-11 91 27 620 0 B1.3 1 0 0 5 0 0 0
2017-07-12 90 43 590 1 B1.6 0 0 0 0 0 0 0
2017-07-13 92 55 470 0 B1.4 4 0 0 4 0 0 0
2017-07-14 94 58 490 1 B5.6 2 1 0 11 2 0 0
2017-07-15 92 34 390 0 B1.9 5 0 0 6 0 0 0
2017-07-16 87 26 350 0 B2.1 5 0 0 3 0 0 0
2017-07-17 86 13 450 0 B2.0 2 0 0 0 0 0 0
2017-07-18 78 0 0 0 B2.4 6 0 0 0 0 0 0
2017-07-19 73 0 0 0 B1.5 1 0 0 0 0 0 0
2017-07-20 70 0 0 0 A8.8 0 0 0 0 0 0 0
2017-07-21 69 0 0 0 A4.8 0 0 0 0 0 0 0
2017-07-22 70 0 0 0 A4.2 0 0 0 0 0 0 0
2017-07-23 71 0 0 0 A5.0 0 0 0 0 0 0 0
2017-07-24 70 0 0 0 A4.8 0 0 0 0 0 0 0
2017-07-25 70 12 10 1 A4.5 0 0 0 0 0 0 0
2017-07-26 69 0 0 0 A3.8 0 0 0 1 0 0 0
2017-07-27 68 0 0 0 A3.9 0 0 0 0 0 0 0
Average/Total 78 16 199 4 34 3 0 99 4 3 0

Summary graph

Flares

Solar wind

Solar Wind

The solar wind is a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons, protons and alpha particles with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature, and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy, from the high temperature of the corona and magnetic, electrical and electromagnetic phenomena in it.

The solar wind is divided into two components, respectively termed the slow solar wind and the fast solar wind. The slow solar wind has a velocity of about 400 km/s, a temperature of 1.4–1.6×10e6 K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s, a temperature of 8×10e5 K and it nearly matches the composition of the Sun's photosphere. The slow solar wind is twice as dense and more variable in intensity than the fast solar wind. The slow wind also has a more complex structure, with turbulent regions and large-scale structures.

Solar radio flux at 10.7 cm

Solar radio flux at 10.7 cm

The solar radio flux at 10.7 cm (2800 MHz) is an excellent indicator of solar activity. Often called the F10.7 index, it is one of the longest running records of solar activity. The F10.7 radio emissions originates high in the chromosphere and low in the corona of the solar atmosphere. The F10.7 correlates well with the sunspot number as well as a number of UltraViolet (UV) and visible solar irradiance records. Reported in “solar flux units”, (s.f.u.), the F10.7 can vary from below 50 s.f.u., to above 300 s.f.u., over the course of a solar cycle.

Flares

Flares

A solar flare is a sudden flash of brightness observed over the Sun's surface or the solar limb, which is interpreted as a large energy release of up to 6 × 10e25 joules of energy. They are often, but not always, followed by a colossal coronal mass ejection. The flare ejects clouds of electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two after the event.

Solar flares affect all layers of the solar atmosphere (photosphere, chromosphere, and corona), when the plasma medium is heated to tens of millions of kelvin, while the electrons, protons, and heavier ions are accelerated to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy is spread over frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. The same energy releases may produce coronal mass ejections (CME), although the relation between CMEs and flares is still not well established.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one every week when the Sun is "quiet", following the 11-year cycle (the solar cycle). Large flares are less frequent than smaller ones.

Classification

Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square metre, W/m2) of 100 to 800 picometre X-rays near Earth, as measured on the GOES spacecraft.

Classification Peak Flux Range at 100-800 picometer
W/m2
A < 10e-7
B 10e-7 to 10e-6
C 10e-6 to 10e-5
M 10e-5 to 10e-4
X 10e-4 to 10e-3
Z > 10e-3

An earlier flare classification is based on Hα spectral observations. The scheme uses both the intensity and emitting surface. The classification in intensity is qualitative, referring to the flares as: (f)aint, (n)ormal or (b)rilliant. The emitting surface is measured in terms of millionths of the hemisphere and is described below. (The total hemisphere area AH = 6.2 × 1012 km2.)

Classification Corrected area
(millionths of hemisphere)
S < 100
1 100 - 250
2 250 - 600
3 600 - 1200
4 > 1200

Sunspot number

Sunspots

Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They correspond to concentrations of magnetic field that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere. Sunspots usually appear in pairs, with pair members of opposite magnetic polarity. The number of sunspots varies according to the approximately 11-year solar cycle.

Sunspot populations quickly rise and more slowly fall on an irregular cycle of 11 years, although significant variations in the number of sunspots attending the 11-year period are known over longer spans of time. For example, from 1900 to the 1960s, the solar maxima trend of sunspot count has been upward; from the 1960s to the present, it has diminished somewhat. Over the last decades the Sun has had a markedly high average level of sunspot activity; it was last similarly active over 8,000 years ago.

The number of sunspots correlates with the intensity of solar radiation over the period since 1979, when satellite measurements of absolute radiative flux became available. Since sunspots are darker than the surrounding photosphere it might be expected that more sunspots would lead to less solar radiation and a decreased solar constant. However, the surrounding margins of sunspots are brighter than the average, and so are hotter; overall, more sunspots increase the Sun's solar constant or brightness. The variation caused by the sunspot cycle to solar output is relatively small, on the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W/m2 compared to 1366 W/m2 for the average solar constant).

K-indices



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Data


Estimated Planetary

Estimated Planetary

Date A K-indices (UTC)
0h 3h 6h 9h 12h 15h 18h 21h
2017-06-29 5 1 2 2 2 1 1 1 1
2017-06-30 4 0 1 1 1 2 1 1 2
2017-07-01 11 2 3 3 2 3 3 3 2
2017-07-02 18 3 2 5 4 3 2 3 4
2017-07-03 5 2 2 1 2 1 1 1 1
2017-07-04 4 1 1 1 1 1 1 1 2
2017-07-05 3 1 1 1 1 1 0 0 1
2017-07-06 7 1 1 2 2 2 2 2 3
2017-07-07 5 2 2 1 1 1 1 1 2
2017-07-08 3 1 1 1 1 1 0 1 1
2017-07-09 28 5 4 2 5 2 3 4 4
2017-07-10 9 3 4 2 1 1 2 1 2
2017-07-11 8 2 3 3 2 1 2 1 2
2017-07-12 4 1 1 1 1 1 1 0 1
2017-07-13 4 1 1 1 1 1 1 1 2
2017-07-14 4 1 1 1 1 1 1 0 1
2017-07-15 4 1 1 1 1 1 1 1 1
2017-07-16 41 2 1 4 5 6 5 6 5
2017-07-17 27 3 4 4 4 4 6 2 2
2017-07-18 7 3 3 2 1 2 1 0 1
2017-07-19 4 1 1 0 1 1 1 1 1
2017-07-20 7 1 2 1 1 1 2 3 3
2017-07-21 14 4 3 3 1 2 3 1 3
2017-07-22 16 3 2 4 5 2 2 2 3
2017-07-23 14 3 3 3 3 3 2 2 4
2017-07-24 12 3 3 3 2 2 2 2 4
2017-07-25 9 2 2 2 2 3 2 2 3
2017-07-26 11 3 2 4 2 2 2 1 1
2017-07-27 6 1 1 2 1 2 2 1 3
2017-07-28 6 2 1 1 2

Middle Latitude

Date A K-indices
2017-06-29 6 1 2 2 3 2 2 1 0
2017-06-30 4 0 0 1 1 2 2 2 2
2017-07-01 14 2 4 3 2 3 3 3 2
2017-07-02 20 3 3 4 4 3 3 3 4
2017-07-03 7 2 3 2 2 2 1 1 1
2017-07-04 5 1 1 1 2 2 1 2 2
2017-07-05 2 1 1 0 1 1 0 1 1
2017-07-06 8 0 1 2 2 2 3 2 3
2017-07-07 5 2 2 1 1 2 1 1 2
2017-07-08 3 1 0 1 1 2 1 1 1
2017-07-09 26 5 3 3 5 3 3 4 4
2017-07-10 11 3 4 1 1 2 2 3 2
2017-07-11 9 2 3 3 2 2 2 1 2
2017-07-12 5 1 1 1 2 2 2 1 1
2017-07-13 5 1 1 1 1 2 2 2 2
2017-07-14 3 1 1 0 1 2 1 1 1
2017-07-15 4 1 1 1 1 2 1 1 1
2017-07-16 29 2 1 4 5 4 4 5 5
2017-07-17 23 3 4 4 4 4 5 2 2
2017-07-18 7 3 3 1 1 2 1 1 1
2017-07-19 5 1 1 1 2 2 2 1 1
2017-07-20 6 0 2 1 1 2 2 2 3
2017-07-21 13 3 4 2 1 3 3 1 3
2017-07-22 18 3 2 4 5 2 2 3 3
2017-07-23 16 3 3 4 3 3 2 2 4
2017-07-24 13 3 3 4 3 2 1 2 3
2017-07-25 9 3 2 2 2 2 2 2 3
2017-07-26 15 4 3 5 2 2 2 1 1
2017-07-27 8 1 2 2 1 3 2 1 3
2017-07-28 2 1 1 2

High Latitude

Date A K-indices
2017-06-29 7 1 2 3 4 0 0 0 1
2017-06-30 2 0 0 1 1 2 0 0 1
2017-07-01 15 2 4 3 1 4 4 2 1
2017-07-02 22 2 3 6 4 4 1 2 2
2017-07-03 6 1 3 1 3 1 1 1 0
2017-07-04 2 1 2 1 0 0 0 0 1
2017-07-05 0 0 0 0 0 0 0 0 0
2017-07-06 3 0 1 1 0 1 2 1 2
2017-07-07 3 2 2 0 0 1 0 1 1
2017-07-08 0 0 1 0 0 0 0 0 0
2017-07-09 28 4 4 3 6 3 4 3 3
2017-07-10 12 4 4 2 2 1 2 2 2
2017-07-11 13 2 4 4 2 3 2 2 1
2017-07-12 4 1 2 1 1 2 2 1 0
2017-07-13 4 1 1 0 1 3 1 1 0
2017-07-14 3 1 1 0 0 0 0 3 0
2017-07-15 1 0 1 1 0 0 0 0 0
2017-07-16 91 1 1 5 7 9 6 4 4
2017-07-17 54 3 4 6 6 6 7 1 2
2017-07-18 13 3 4 3 1 2 1 4 1
2017-07-19 2 1 1 0 2 0 0 0 1
2017-07-20 6 1 2 1 1 1 1 3 2
2017-07-21 19 3 4 3 2 4 5 2 2
2017-07-22 31 3 3 6 6 3 3 3 3
2017-07-23 35 2 3 6 6 6 2 2 2
2017-07-24 21 2 3 5 4 5 3 1 2
2017-07-25 18 3 2 4 4 5 2 2 2
2017-07-26 19 3 2 5 5 4 2 1 0
2017-07-27 12 0 1 1 1 2 4 1 5
2017-07-28 2 2 0 3

About

The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label K comes from the German word Kennziffer meaning “characteristic digit”. The K-index was introduced by Julius Bartels in 1938.

The Estimated 3-hour Planetary Kp-index is derived at the NOAA Space Weather Prediction Center using data from the following ground-based magnetometers:

  • Sitka, Alaska
  • Meanook, Canada
  • Ottawa, Canada
  • Fredericksburg, Virginia
  • Hartland, UK
  • Wingst, Germany
  • Niemegk, Germany
  • Canberra, Australia

These data are made available thanks to the cooperative efforts between SWPC and data providers around the world, which currently includes the U.S. Geological Survey, Natural Resources Canada (NRCAN), the British Geological Survey, the German Research Centre for Geosciences (GFZ), and Geoscience Australia. Important magnetometer observations are also contributed by the Institut de Physique du Globe de Paris and the Korean Space Weather Center K-index Watches are issued when the highest predicted NOAA estimated Kp-indices for a day are K = 5, 6, 7, or >= 8 and is reported in terms of the NOAA G scale. K-index Warnings are issued when NOAA estimated Kp-indices of 4, 5, 6, and 7 or greater are expected. K-index Alerts are issued when the NOAA estimated Kp-indices reach 4, 5, 6, 7, 8, or 9.


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