SOHO/LASCO Halo CME 20211102

Halo Alert: halo-message.20211102

UCMEO 93001 11102 1922/
11102 60248 80654 0181/ 017// 333// 41629
11102 60136 80339 10114 12891 1112/
99999

PLAIN

SOHO/LASCO HALO CME November 02, 2021

C2 Start Time:     02:48 UT

C3 Start Time:        03:06 - 06:54 UT

Type of CME:
Asymmetric HALO CME — FRONTSIDE
pa1: 018      pa2: 017       Total Width: 360 degrees

Velocity Measurements:

C2    3 points    1074.8 km/sec @ PA 018
C3    9 points    1548.6 km/sec @ PA 018
Average through both fields:     1629.4 km/sec Acceleration: -38.43 m/sec^2.

COMMENT:       AIA 193 shows a flare of AR 12891 at location [N14, E01] 02:45-03:39 UT.
                                            This event produces a dimming across the disk with an EUV wave
                                         followed by a bright post loop arcade.
                             AIA 304 shows a cooler loop elevated at approximately 00:39 UT and ribbon
           flaring of the filament adjacent and East of AR 12891 beginning
                                             01:36 UT. This emission is part of the CME seen in LASCO.


            STEREO Beacon Data - Data Gap: 00:38 - 03:38 UT
            COR2 A, shows a CME in progress over the West.
            Preliminary time/height measure gives 0521.7 km/sec @ 318 degrees.

NOAA/GOES reports a M1.7 class X-ray flare of AR12891 01:20/03:01/03:50 UT.

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/2021/211102/

Best Regards,

--Kevin Schenk

BT

[Images from the original alert message are omitted here]