SOHO/LASCO Halo CME 20251029

Halo Alert: halo-message.20251029

UCMEO 93001 51029 2355/
51029 60012 80224 0252/ 025// 333// 40963
51029 62342 80015 ///// ///// /////
99999

PLAIN

SOHO/LASCO HALO CME October 29, 2025

C2 Start Time: 00:12 UT

C3 Start Time: 00:30 - 03:30 UT

Type of CME:
Partial HALO CME — BACKSIDE
pa1: 25    pa2: 25      Total Width: 360 degrees

Velocity Measurements:

C2:   4 points    1004.8 km/sec @ PA 25
C3:   7 points 990.9 km/sec @ PA 25
Average through both(C2/C3) fields: 963.7 km/sec Acceleration: -4.29 m/sec^2

COMMENT: LASCO C2/C3 shows a partial halo found in the NE quadrant starting @ 00:12 UT.
COR2 A displays the partial halo spread across the Northern hemisphere starting at
00:38 UT. SDO AIA 193A shows an emission of solar plasma starting @ 23:42 UT along
with CME-associated opening lines along the NE limb. Additionally, opening lines
appear in GOES-19 SUVI Composite 195 Angstroms starting @ 23:48, and plasma emission
can be seen in GOES-19 SUVI Composite 171 Angstroms @ 00:13 UT found near the NE limb.

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/2025/251029

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

GOES-19 SUVI 171 Angstrom	STEREO/COR2 AHEAD Diff	SDO/AIA 193 Diff