SOHO/LASCO Halo CME 20251015

Halo Alert: halo-message.20251015

UCMEO 93001 51016 1838/
51015 61500 81948 1300/ 299// 133// 40349
51015 61401 81441 42250 14246 1112/
99999

PLAIN

SOHO/LASCO HALO CME October 15, 2025

C2 Start Time: 15:00 UT

C3 Start Time: 16:42 - 20:30 UT

Type of CME:
Partial HALO CME — FRONTSIDE
pa1: 300    pa2: 299      Total Width: 359 degrees

Velocity Measurements:

C2:   10 points    353.1 km/sec @ PA 300
C3:   4 points 417.8 km/sec @ PA 299
Average through both(C2/C3) fields: 349.5 km/sec Acceleration: 37.18 m/sec^2

COMMENT: LASCO C2/C3 shows a partial halo that surrounds the NW quadrant that is likely associated with solar flare. NOAA reports a M1.1 solar flare from AR 14246 in location [N22,W50]. GOES-19 SUVI Composite 195 Angstroms shows opening field lines @ 14:01 UT along with coronal dimming.

Preliminary UCMEO velocity and position measurements are delivered first.
Images, movies, and time/height information for this event will be available at:

https://umbra.nascom.nasa.gov/lasco/observations/halo/2025/251015

Best Regards,

--Taylor Lanier

BT
[Images from original message are omitted here]

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SOHO/LASCO C2 Diff
SOHO/LASCO C2
STEREO/COR2 BEHIND

SOHO/LASCO C3 Diff SOHO/LASCO C3 GOES-19 SUVI 195 Angstroms

STEREO/COR2 AHEAD Diff