Alerts Issued in May 2017


Space Weather Message Code: ALTK04
Serial Number: 1980
Issue Time: 2017 May 29 1352 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 29 1348 UTC
Synoptic Period: 1200-1500 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3226
Issue Time: 2017 May 29 1321 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 29 1322 UTC
Valid To: 2017 May 29 2100 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WARK05
Serial Number: 1356
Issue Time: 2017 May 28 1443 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 1355
Valid From: 2017 May 27 2204 UTC
Now Valid Until: 2017 May 28 2100 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.


Space Weather Message Code: ALTK05
Serial Number: 1115
Issue Time: 2017 May 28 1026 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 May 28 1020 UTC
Synoptic Period: 0900-1200 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.


Space Weather Message Code: ALTK06
Serial Number: 435
Issue Time: 2017 May 28 0824 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2017 May 28 0823 UTC
Synoptic Period: 0600-0900 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.


Space Weather Message Code: ALTK05
Serial Number: 1114
Issue Time: 2017 May 28 0719 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 May 28 0718 UTC
Synoptic Period: 0600-0900 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.


Space Weather Message Code: WARK04
Serial Number: 3225
Issue Time: 2017 May 28 0430 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 3224
Valid From: 2017 May 27 1530 UTC
Now Valid Until: 2017 May 29 0000 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.


Space Weather Message Code: ALTK07
Serial Number: 105
Issue Time: 2017 May 28 0420 UTC

ALERT: Geomagnetic K-index of 7
Threshold Reached: 2017 May 28 0419 UTC
Synoptic Period: 0300-0600 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.


Space Weather Message Code: WARK07
Serial Number: 69
Issue Time: 2017 May 28 0410 UTC

WARNING: Geomagnetic K-index of 7 or greater expected
Valid From: 2017 May 28 0409 UTC
Valid To: 2017 May 28 0900 UTC
Warning Condition: Onset
NOAA Scale: G3 or greater - Strong to Extreme
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.


Space Weather Message Code: WARK06
Serial Number: 387
Issue Time: 2017 May 28 0410 UTC

EXTENDED WARNING: Geomagnetic K-Index of 6 expected
Extension to Serial Number: 386
Valid From: 2017 May 27 2320 UTC
Now Valid Until: 2017 May 28 0900 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WARK05
Serial Number: 1355
Issue Time: 2017 May 28 0410 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 1354
Valid From: 2017 May 27 2204 UTC
Now Valid Until: 2017 May 28 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.


Space Weather Message Code: ALTK06
Serial Number: 434
Issue Time: 2017 May 28 0350 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2017 May 28 0349 UTC
Synoptic Period: 0300-0600 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.


Space Weather Message Code: ALTK05
Serial Number: 1113
Issue Time: 2017 May 28 0330 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 May 28 0329 UTC
Synoptic Period: 0300-0600 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.


Space Weather Message Code: ALTK06
Serial Number: 433
Issue Time: 2017 May 28 0225 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2017 May 28 0224 UTC
Synoptic Period: 0000-0300 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.


Space Weather Message Code: ALTK05
Serial Number: 1112
Issue Time: 2017 May 28 0106 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 May 28 0105 UTC
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.


Space Weather Message Code: ALTK06
Serial Number: 432
Issue Time: 2017 May 27 2323 UTC

ALERT: Geomagnetic K-index of 6
Threshold Reached: 2017 May 27 2322 UTC
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.


Space Weather Message Code: WARK06
Serial Number: 386
Issue Time: 2017 May 27 2320 UTC

WARNING: Geomagnetic K-Index of 6 expected
Valid From: 2017 May 27 2320 UTC
Valid To: 2017 May 28 0600 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.


Space Weather Message Code: ALTK05
Serial Number: 1111
Issue Time: 2017 May 27 2255 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 May 27 2255 UTC
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.


Space Weather Message Code: WARK05
Serial Number: 1354
Issue Time: 2017 May 27 2204 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2017 May 27 2204 UTC
Valid To: 2017 May 28 0600 UTC
Warning Condition: Onset
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.


Space Weather Message Code: ALTK04
Serial Number: 1979
Issue Time: 2017 May 27 2202 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 27 2202 UTC
Synoptic Period: 2100-2400 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3224
Issue Time: 2017 May 27 2045 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 3223
Valid From: 2017 May 27 1530 UTC
Now Valid Until: 2017 May 28 0900 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.


Space Weather Message Code: SUMSUD
Serial Number: 220
Issue Time: 2017 May 27 1546 UTC

SUMMARY: Geomagnetic Sudden Impulse
Observed: 2017 May 27 1536 UTC
Deviation: 19 nT
Station: BOU
www.swpc.noaa.gov/noaa-scales-explanation


Space Weather Message Code: WARK04
Serial Number: 3223
Issue Time: 2017 May 27 1523 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 27 1530 UTC
Valid To: 2017 May 27 2100 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WARSUD
Serial Number: 174
Issue Time: 2017 May 27 1505 UTC

WARNING: Geomagnetic Sudden Impulse expected
Valid From: 2017 May 27 1545 UTC
Valid To: 2017 May 27 1630 UTC
IP Shock Passage Observed: 2017 May 27 1446 UTC
www.swpc.noaa.gov/noaa-scales-explanation


Space Weather Message Code: ALTEF3
Serial Number: 2608
Issue Time: 2017 May 27 0501 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2607
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 13745 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2607
Issue Time: 2017 May 26 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2606
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 17618 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2606
Issue Time: 2017 May 25 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2605
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 13965 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2605
Issue Time: 2017 May 24 0501 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2604
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 9338 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: WARK04
Serial Number: 3222
Issue Time: 2017 May 23 0545 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 23 0544 UTC
Valid To: 2017 May 23 1200 UTC
Warning Condition: Onset
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.


Space Weather Message Code: ALTEF3
Serial Number: 2604
Issue Time: 2017 May 23 0536 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2603
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 26098 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2603
Issue Time: 2017 May 22 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2602
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 13009 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: WARK04
Serial Number: 3221
Issue Time: 2017 May 21 1755 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 3220
Valid From: 2017 May 19 1614 UTC
Now Valid Until: 2017 May 22 0300 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.


Space Weather Message Code: ALTEF3
Serial Number: 2602
Issue Time: 2017 May 21 0639 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2601
Begin Time: 2017 May 20 1705 UTC
Yesterday Maximum 2MeV Flux: 1718 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2601
Issue Time: 2017 May 20 1720 UTC

ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2017 May 20 1705 UTC
Station: GOES13
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: WARK05
Serial Number: 1353
Issue Time: 2017 May 20 1450 UTC

EXTENDED WARNING: Geomagnetic K-index of 5 expected
Extension to Serial Number: 1352
Valid From: 2017 May 20 0729 UTC
Now Valid Until: 2017 May 20 2100 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.


Space Weather Message Code: WARK05
Serial Number: 1352
Issue Time: 2017 May 20 0730 UTC

WARNING: Geomagnetic K-index of 5 expected
Valid From: 2017 May 20 0729 UTC
Valid To: 2017 May 20 1500 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WARK04
Serial Number: 3220
Issue Time: 2017 May 20 0241 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 3219
Valid From: 2017 May 19 1614 UTC
Now Valid Until: 2017 May 21 1800 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.


Space Weather Message Code: ALTK04
Serial Number: 1978
Issue Time: 2017 May 20 0240 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 20 0235 UTC
Synoptic Period: 0000-0300 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3219
Issue Time: 2017 May 19 1614 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 19 1614 UTC
Valid To: 2017 May 20 0600 UTC
Warning Condition: Onset
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.


Space Weather Message Code: ALTK04
Serial Number: 1977
Issue Time: 2017 May 18 0139 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 18 0139 UTC
Synoptic Period: 0000-0300 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3218
Issue Time: 2017 May 18 0119 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 18 0115 UTC
Valid To: 2017 May 18 0900 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WATA30
Serial Number: 160
Issue Time: 2017 May 17 1752 UTC

WATCH: Geomagnetic Storm Category G2 Predicted
Highest Storm Level Predicted by Day:
May 18: G1 (Minor) May 19: G2 (Moderate) May 20: G1 (Minor)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
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.


Space Weather Message Code: WATA30
Serial Number: 159
Issue Time: 2017 May 17 1748 UTC

CANCEL WATCH: Geomagnetic Storm Category G2 Predicted
Cancel Serial Number: 158
Original Issue Time: 2017 May 16 2126 UTC

Comment: The G2 (Moderate) Geomagnetic Storm Watch for 17 May 2017 has been canceled. A new Watch product will be issued shortly to update conditions expected 18-20 May 2017
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.


Space Weather Message Code: WATA30
Serial Number: 158
Issue Time: 2017 May 16 2126 UTC

WATCH: Geomagnetic Storm Category G2 Predicted
Highest Storm Level Predicted by Day:
May 17: G2 (Moderate) May 18: G2 (Moderate) May 19: G2 (Moderate)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
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.


Space Weather Message Code: WARK04
Serial Number: 3217
Issue Time: 2017 May 15 2208 UTC

EXTENDED WARNING: Geomagnetic K-index of 4 expected
Extension to Serial Number: 3216
Valid From: 2017 May 15 0957 UTC
Now Valid Until: 2017 May 16 2100 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.


Space Weather Message Code: WATA30
Serial Number: 157
Issue Time: 2017 May 15 2106 UTC

WATCH: Geomagnetic Storm Category G2 Predicted
Highest Storm Level Predicted by Day:
May 16: G1 (Minor) May 17: G2 (Moderate) May 18: G2 (Moderate)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
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.


Space Weather Message Code: ALTK04
Serial Number: 1976
Issue Time: 2017 May 15 1152 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 15 1150 UTC
Synoptic Period: 0900-1200 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3216
Issue Time: 2017 May 15 0958 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 15 0957 UTC
Valid To: 2017 May 15 2359 UTC
Warning Condition: Onset
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.


Space Weather Message Code: WATA30
Serial Number: 156
Issue Time: 2017 May 14 2027 UTC

WATCH: Geomagnetic Storm Category G2 Predicted
Highest Storm Level Predicted by Day:
May 15: None (Below G1) May 16: G1 (Minor) May 17: G2 (Moderate)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
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.


Space Weather Message Code: WATA20
Serial Number: 785
Issue Time: 2017 May 13 1929 UTC

WATCH: Geomagnetic Storm Category G1 Predicted
Highest Storm Level Predicted by Day:
May 14: None (Below G1) May 15: None (Below G1) May 16: G1 (Minor)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
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.


Space Weather Message Code: ALTEF3
Serial Number: 2600
Issue Time: 2017 May 07 1630 UTC

ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2017 May 07 1615 UTC
Station: GOES-13
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTK04
Serial Number: 1975
Issue Time: 2017 May 04 2222 UTC

ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 May 04 2222 UTC
Synoptic Period: 2100-2400 UTC
Active Warning: Yes
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.


Space Weather Message Code: WARK04
Serial Number: 3215
Issue Time: 2017 May 04 2135 UTC

WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 May 04 2135 UTC
Valid To: 2017 May 05 0600 UTC
Warning Condition: Onset
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.


Space Weather Message Code: ALTEF3
Serial Number: 2599
Issue Time: 2017 May 04 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2598
Begin Time: 2017 Apr 21 1425 UTC
Yesterday Maximum 2MeV Flux: 7832 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2598
Issue Time: 2017 May 03 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2597
Begin Time: 2017 Apr 21 1425 UTC
Yesterday Maximum 2MeV Flux: 8389 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2597
Issue Time: 2017 May 02 0500 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2596
Begin Time: 2017 Apr 21 1425 UTC
Yesterday Maximum 2MeV Flux: 5370 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.


Space Weather Message Code: ALTEF3
Serial Number: 2596
Issue Time: 2017 May 01 0501 UTC

CONTINUED ALERT: Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2595
Begin Time: 2017 Apr 21 1425 UTC
Yesterday Maximum 2MeV Flux: 8939 pfu
www.swpc.noaa.gov/noaa-scales-explanation
Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.