SOHO/LASCO Halo CME 20251105a

Halo Alert: halo-message.20251105a

UCMEO 93001 51106 2300/
51105 61100 81248 0511/ 051// 323// 40919
51105 61036 81119 12348 14274 1112/
99999

PLAIN

SOHO/LASCO HALO CME November 05, 2025

C2 Start Time: 11:00 UT

C3 Start Time: 11:18 – 14:06 UT

Type of CME:
Asymmetric HALO CME — FRONTSIDE
pa1: 51      pa2: 51       Total Width: 360 degrees

Velocity Measurements:

C2 4 points 978.6 km/sec @ PA 51
C3 5 points 877.3 km/sec @ PA 51
Average through both fields: 919.8 km/sec Acceleration: -56.99 m/sec^2.

COMMENT: A frontside, full HALO event can be seen in LASCO C2/C3 in the
Northeast quadrant @ 11:00 UT and in the Eastern hemisphere in COR2 A
starting @ 10:53 UT. As reported by NOAA, the CME is associated with a long
duration M7.4 eruptive solar flare in AR 14274 [N23,E48]. Opening lines of the
CME can be viewed in SDO/AIA 193 starting @ 10:36 UT with a peak @ 11:19 UT.

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/2025/251105a/

Best Regards,

--Taylor Lanier

BT

[Images from original message are omitted here]

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SOHO/LASCO C2 Diff	SOHO/LASCO C3 Diff	AR 14274

STEREO/COR2 AHEAD	SDO/AIA 193 Diff	STEREO/COR2 AHEAD Diff

SOHO/LASCO C2	SOHO/LASCO C3	GOES-19 SUVI 131 Angstroms