SOHO/LASCO Halo CME 20260401

Halo Alert: halo-message.20260401

UCMEO 93001 60401 2130/
60401 62324 80148 3291/ 329// 333// 41009
60401 62308 82328 41622 14403 1212/
99999

PLAIN

SOHO/LASCO HALO CME April 1, 2026

C2 Start Time: 23:24 UT

C3 Start Time: 23:30 – 03:30 UT

Type of CME:
Asymmetric Full HALO CME — FRONTSIDE
pa1: 329      pa2: 329       Total Width: 360 degrees

Velocity Measurements:

C2 5 points 926.5 km/sec @ PA 329
C3 7 points 1005.3 km/sec @ PA 329
Average through both fields: 1009.6 km/sec Acceleration: -1.77 m/sec^2.

COMMENT: A full, asymmetrical HALO event can be seen in LASCO C2/C3
in the Northwest quadrant starting @ 23:24. NOAA reports a CME that is
associated with an eruptive C6.1 class solar flare located in AR 14403. A solar
flare associated with the event can be seen in SDO/AIA 193 beginning @ 22:18
UT in the Northwest quadrant along with a post-eruptive arcade and dimming to
the North.

STEREO BEACON Data
Due to data gaps from 11:53 - 04:23 UT, preliminary time/height measurements
could not be performed at this time.

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/2026/260401/

Best Regards,

--Taylor Lanier

BT

[Images from the original alert message are omitted here]

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SOHO/LASCO C2 Diff	SOHO/LASCO C3 Diff	SDO AIA 193 Angstrom

GOES-19 CCOR1	SDO/AIA 193 Angstroms Diff	STEREO/COR2 AHEAD

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