Coronal hole causes G1 - Minor geomagnetic storm

Coronal hole causes G1 - Minor geomagnetic storm

A geomagnetic storm reaching G1 - Minor levels is currently in progress due to the arrival of the co-rotating interaction region (CIR) associated with coronal hole 55. The proton flux might reach S1 - Minor levels in the period between February 16 and 18 due to the magnetic complexity and location of the Region 2497.

After four M-class solar flares produced by Region 2497 over the last couple of days, solar activity decreased on February 16, 2016, and only C-class activity was observed. Additionlly, partial-halo Coronal Mass Ejection associated with long-duration C8.9 flare from February 11 seems to have passed our planet unnoticed. From February 16 to 18, solar activity is expected to remain at low levels, however, the Region 2497 could still produce Minor to Moderate M-class flares.

Image credit: NOAA/SWPC

Over the last 24 hours, the greater than 2 MeV electron flux was at normal to moderate levels and is expected to remain such in the period between February 16 and 17. 

The greater than 10 MeV proton flux remained at background levels at the same time. On February 18, the anticipated arrival of a polar-connected, negative polarity, CH HSS, should redistribute the electrons. 

Sunspots on February 16, 2016. Image credit: NASA SDO/HMI

The proton flux might reach S1 (Minor) levels in the period between February 16 and 18 due to the magnetic complexity and location of the Region 2497.

The solar wind environment, as observed by the ACE satellite, was indicative of enhanced conditions influenced by the onset of a co-rotating interaction region ahead of a negative polarity CH HSS, over the last 24 hours. The wind speed increased steadily from 420 km/s (261 mps) to the peak values near 550 km/s (341.7 mps) before settling to a period ending values near 500 km/s (311 mps).

The total field (Bt) gradually increased from near 5 nT to 16 nT while Bz was variable but reached its highest deflections later in the period. The maximum southward deflection was -16 nT and the phi angle was predominantly in a negative (towards the Sun) orientation.

Enhanced solar wind conditions are expected to continue throughout February 16 to 18 due to the anticipated CIR ahead of the CH HSS.

The geomagnetic field was quiet to active with an isolated period of G1-Minor storm conditions between 09:00 and 12:00 UTC on February 16 synoptic period due to the arrival of the CIR associated with coronal hole 55.

In the period between February 16 and 17, the geomagnetic field will mostly remain active with G1 - Minor storm conditions due to the onset of a CIR and subsequent negative polarity CH HSS. Persistent CH HSS effects in which active conditions are likely, is expected on February 18.

SWPC Alerts

Space Weather Message Code: ALTK05
Serial Number: 924
Issue Time: 2016 Feb 16 1418 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2016 Feb 16 1417 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.

***

Space Weather Message Code: ALTK05
Serial Number: 923
Issue Time: 2016 Feb 16 1201 UTC

ALERT: Geomagnetic K-index of 5
Threshold Reached: 2016 Feb 16 1159 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.

Featured image: NASA SDO AIA/193 February 16, 2016.

Tags: g1 storm

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