SOHO/LASCO Halo CME 20260316

Halo Alert: halo-message.20260316

UCMEO 93001 60317 2115/
60316 61212 81624 3451/ 345// 113// 30235
60316 61200 81215 21519 14392 1112/
99999

PLAIN

SOHO/LASCO HALO CME March 16, 2026

C2 Start Time: 12:12 UT

C3 Start Time: 13:54 – 17:54 UT

Type of CME:
Partial HALO CME — FRONTSIDE
pa1: 345      pa2: 345       Total Width: 360 degrees

Velocity Measurements:

C2 4 points 200.1 km/sec @ PA 345
C3 3 points 344.5 km/sec @ PA 345
Average through both fields: 235.2 km/sec Acceleration: 23.41 m/sec^2.

COMMENT: A partial HALO event can be seen in LASCO C2/C3 in the Southeast
                      quadrant starting @ 12:12. NOAA reports a CME that is associated with
                      an eruptive M2.7 class solar flare located in AR 14392. SDO/AIA 193 shows
                     the solar flare associated with the event starting @ 12:00 UT in the Southeast
                      quadrant along with an EUV wave and a post-eruptive arcades.

STEREO BEACON Data
                  COR2 A shows a partial HALO CME in the Eastern hemisphere 12:38 - 14:53.
                  Preliminary time/height measure shows 4 points - 551.2 km/sec @ 108 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/2026/260316/

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 171 Angstrom

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

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