SOHO/LASCO Halo CME 20251111

Halo Alert: halo-message.20251111

UCMEO 93001 51111 1915/
51111 71024 81442 3341/ 333// 333// 41671
51111 60951 81021 42423 14274 1112/
99999

PLAIN

SOHO/LASCO   HALO CME NOVEMBER 11, 2025

C2 Start Time:      10:24 UT

C3 Start Time:      10:30 - 14:42 UT

Type of CME:
FULL HALO CME — FRONTSIDE
pa1: 334      pa2: 333       Total Width: 360 degrees

Velocity Measurements:

C2    1 points     Could not measure C2
C3    6 points     1671.4 km/sec @ PA 324
          Only C3 FOV:      1671.4 km/sec Acceleration: 209.76 m/sec^2.

COMMENT: SDO AIA 193 shows a flare from AR 14274 09:51 - 10:21 UT at location
             [N23, W24]. The flare produces an amazing global EUV wave
                        and a dimming that spans ~80% of the Northern Hemisphere
            along with a post loop arcade.

        Increased proton particles seen in the LASCO C2 and C3 fields of view.

        A Solar energetic particle (SEP) event detected by GOES.
         Flux of > 100MeV proton exceeds 1 pfu beginning 2025-11-11 10:20 UT

            STEREO Beacon Data
            COR2 A, 10:23 - 11:38 UT; shows an asymetric HALO CME over the Northeast.
            Preliminary time/height measure gives 1852.0 km/sec @ 060 degrees.


NOAA/GOES reports a X5.1 class X-ray flare from AR 14274 09:49/10:04/10:17 UT

Preliminary UCMEO velocity and position measurements are delivered first.
Images, movies, and time/height information for this event will soon be available at:

https://umbra.nascom.nasa.gov/lasco/observations/halo/2025/251111a/

Best Regards,

--Kevin Schenk

BT

[Images from the original alert message are omitted here]

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SOHO/LASCO C2 Diff	SOHO/LASCO C3 Diff	SDO AIA 195 angstrom

GOES-19 CCOR1	SDO AIA 195 angstrom Diff	STEREO/COR2 AHEAD Diff

SOHO/LASCO C2	SOHO/LASCO C3	GOES-19 SUVI 195A