OK, OK, a G3 Strong Geomagnetic Storm was caused by a CME that nobody saw coming. WTF?

According to NOAA the CH windstream hasn't arrived yet, so they roll out the old 'co-rotating interaction region' and 'transient' excuses because they don't know what happened either, LOL.

By 'transient' I believe they're referring to the hobos who hang around in Boulder this time of year'. Seriously tho', it means 'a CME we didn't see coming'

NOAA says-
Geospace

.24 hr Summary...
Geomagnetic field activity ranged from unsettled to severe storm levels.
The increase in activity is likely attributed to a slow moving transient
combined with the effects from a corotating interaction region ahead of
the expected recurrent CH HSS.

.Forecast...
Geomagnetic field activity is expected to be at major storm levels to
begin the current forecast period, but decrease to unsettled to active
levels by the end of day 1 (29 Jun). Activity should remain at unsettled
levels with minor storm conditions expected on day 2 (30 Jun) due to
effects associated with a 5-degree filament that erupted during 28/0129
- 0250 UTC time-frame. This activity should be short lived and
conditions should begin a steady decline back to quiet to unsettled
levels by midday on day three (1 Jul).

24-hour Magnetopause Simulation:

[link to iswa.gsfc.nasa.gov:8080]

GOES Magnetometer:

[link to www.swpc.noaa.gov]