Di Enzo Ragusa
L’influenza del buco coronale, con polarità negativa sta arrivando sul nostro pianeta. Prevista nei prossimi giorni una tempesta geomagnetica di potenza moderata G2. La tempesta continuerà ancora per i prossimi due giorni, 28 e 29 marzo.
Un flusso di vento solare ad alta velocità prodotto da un ricorrente buco coronale, con polarità negativa, è oggi diventato geoeffettivo. La previsione è per una tempesta moderata di classe G2, che si prolungherà anche per il 28 e 29 marzo.
Geomagnetic K-index 5 (G1 – tempesta geomagnetica debole) è stata raggiunta alle ore 05:59 UTC di oggi 27 marzo.
“I parametri del vento solare dovrebbero migliorare nel corso dei prossimi tre giorni (27-29 marzo) a causa della comparsa di un CIR [regione co-rotante di interazione tra flussi lenti e veloci] seguito dall’influenza di una ricorrente CH HSS a polarità negativa,” ha riferito SWPC, aggiungendo che i dati di STEREO-A prevedono una velocità del vento solare arrivare fino a 650-700 km/s durante il passaggio del vento solare. “Questa caratteristica del buco coronale probabilmente produrrà condizioni di tempesta moderata G2 durante la sua ultima rotazione prevedendo l’impatto sulla magnetosfera terrestre il 28/29 marzo”, ha riferito il centro.
Nel frattempo, l’attività solare resta molto bassa, ma nell’ultima giornata è affiorata una interessante regione classificata beta nell’emisfero nord – AR2644 – che sta producendo brillamenti solari multipli di classe B e uno di classe C.
L’attività solare è destinata a continuare a livelli molto bassi, con solo delle piccole probabilità di brillamenti di classe C nel corso dei prossimi tre giorni.
Updates
10:24 UTC
G2 geomagnetic storm
Geomagnetic K-index of 6 threshold (G2 – Moderate geomagnetic storm) was reached at 10:24 UTC.
Area of impact is primarily poleward of 55 degrees Geomagnetic Latitude.
Under G2 conditions, power grid fluctuations can occur, high-latitude power systems may experience voltage alarms. Satellite orientation irregularities may occur and increased drag on low Earth-orbit satellites is possible. HF (high frequency) radio propagation can fade at higher latitudes. Aurora may be seen as low as New York to Wisconsin to Washington state.
SWPC Alerts, Watches and Warnings
Space Weather Message Code: ALTK06
Serial Number: 425
Issue Time: 2017 Mar 27 1024 UTC
ALERT: Geomagnetic K-index of 6
Threshold Reached: 2017 Mar 27 1024 UTC
Synoptic Period: 0900-1200 UTC
Active Warning: Yes
NOAA Scale: G2 – Moderate
NOAA Space Weather Scale descriptions can be found at
www.swpc.noaa.gov/noaa-scales-
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: 1078
Issue Time: 2017 Mar 27 0740 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 Mar 27 0735 UTC
Synoptic Period: 0600-0900 UTC
Active Warning: Yes
NOAA Scale: G1 – Minor
NOAA Space Weather Scale descriptions can be found at
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: 1077
Issue Time: 2017 Mar 27 0559 UTC
ALERT: Geomagnetic K-index of 5
Threshold Reached: 2017 Mar 27 0559 UTC
Synoptic Period: 0300-0600 UTC
Active Warning: Yes
NOAA Scale: G1 – Minor
NOAA Space Weather Scale descriptions can be found at
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: 1327
Issue Time: 2017 Mar 27 0520 UTC
WARNING: Geomagnetic K-index of 5 expected
Valid From: 2017 Mar 27 0520 UTC
Valid To: 2017 Mar 27 1500 UTC
Warning Condition: Onset
NOAA Scale: G1 – Minor
NOAA Space Weather Scale descriptions can be found at
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: 1966
Issue Time: 2017 Mar 27 0500 UTC
ALERT: Geomagnetic K-index of 4
Threshold Reached: 2017 Mar 27 0459 UTC
Synoptic Period: 0300-0600 UTC
Active Warning: Yes
NOAA Space Weather Scale descriptions can be found at
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: 3177
Issue Time: 2017 Mar 27 0351 UTC
WARNING: Geomagnetic K-index of 4 expected
Valid From: 2017 Mar 27 0350 UTC
Valid To: 2017 Mar 27 2359 UTC
Warning Condition: Onset
NOAA Space Weather Scale descriptions can be found at
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: 151
Issue Time: 2017 Mar 26 1902 UTC
WATCH: Geomagnetic Storm Category G2 Predicted
Highest Storm Level Predicted by Day:
Mar 27: G1 (Minor) Mar 28: G2 (Moderate) Mar 29: G2 (Moderate)
THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT
NOAA Space Weather Scale descriptions can be found at
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.
Featured image: Coronal hole on March 25, 2017. Credit: NASA SDO/AIA, LMSAL
Fonte: The Watchers
