SOHO/LASCO Halo CME 20260318

Halo Alert: halo-message.20260318

UCMEO 93001 60318 2015/
60318 60924 81136 2741/ 274// 113// 30378
60318 60827 80842 31504 14392 1112/
99999

PLAIN

SOHO/LASCO HALO CME March 18, 2026

C2 Start Time: 09:24 UT

C3 Start Time: 11:06 - 12:30 UT

Type of CME:
Partial HALO CME - FRONTSIDE
pa1: 274      pa2: 274       Total Width: 360 degrees

Velocity Measurements:

C2 4 points 377.7 km/sec @ PA 274
C3 4 points 357.0 km/sec @ PA 274
Average through both fields: 378.5 km/sec Acceleration: -3.21 m/sec^2.

COMMENT: A partial HALO event can be seen in LASCO C2/C3 in the Southwest
         quadrant starting @ 09:24. Additionally, NOAA reports a CME that is
         correlated with an eruptive M2.7 class solar flare located in AR 14392.
         The solar flare that is associated with the event is best seen in SDO/AIA 193
         starting @ 08:27 UT in the Southwest quadrant showing an EUV wave, post-eruptive
         arcades, and dimming along the Southwest quadrant.

STEREO BEACON Data
        COR2 A shows a partial HALO CME in the Eastern hemisphere 09:23 - 12:23 UT.
        Preliminary time/height measure shows 4 points - 391.5 km/sec @ 118 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/2026/260318/

Best Regards,

--Taylor Lanier

BT

[Images from the original alert message are omitted here]

________________________________________________
Soho-halo-alert mailing list
soho-halo-alert@lists.nasa.gov

SOHO/LASCO C2 Diff	SOHO/LASCO C3 Diff	SDO AIA 171 Angstrom

GOES - CCOR-1	SDO/AIA 193 Angstrom Diff	STEREO/COR2 AHEAD Diff

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