SOHO/LASCO Halo CME 20251201b

Halo Alert: halo-message.20251201b

UCMEO 93001 51202 2030/
51201 60324 80424 0351/ 035// 323// 41446
51201 60406 80630 11767 ///// 3122/
99999

PLAIN

SOHO/LASCO HALO CME December 01, 2025

C2 Start Time: 03:24 UT

C3 Start Time: 04:06 – 06:30 UT

Type of CME:
Partial HALO CME — FRONTSIDE
pa1: 35      pa2: 35       Total Width: 360 degrees

Velocity Measurements:

C2 4 points 1335.3 km/sec @ PA 35
C3 6 points 1533.6 km/sec @ PA 35
Average through both fields: 1446.7 km/sec Acceleration: 45.58 m/sec^2.

COMMENT: A partial HALO event can be seen in LASCO C2/C3 in the far Northeast
quadrant @ 03:24. According to NOAA, the CME is associated with a prominence
eruption located in [N17,E67]. Opening lines associated with the CME can be viewed
in SDO/AIA 193 starting @ 03:24 UT in the Northeast limb.

STEREO BEACON Data
COR2 A shows a bright, asymmetric partial HALO CME in the Northeast quadrant
03:38 - 06:53 UT. Preliminary time/height measure shows 4 points - 1281.1 km/sec @ 55 deg.

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/2025/251201b/

Best Regards,

--Taylor Lanier

BT

[Images from original message are omitted here]

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SOHO/LASCO C2	SOHO/LASCO C3	SDO / AIA 193A

GOES-19 CCOR-1	SDO / AIA 193A DIff	STEREO / COR2 AHEAD Diff

SOHO/LASCO C2 DIFF	SOHO/LASCO C3 DIFF	GOES-19 SUVI 131A