Routine Space Environment Product (Daily)
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FXXX12 KWNP 231231

:Product: Forecast Discussion
:Issued: 2017 May 23 1230 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
#             Forecast Discussion
Solar Activity

.24 hr Summary...
Solar activity was very low. Regions 2656 (N11W21, Axx/alpha) and Region
2659 (N14E05, Hrx/alpha) were stable and and remained inactive
throughout the period. Regions 2658 (S08W24, Axx/alpha) and Region 2660
(S11W21, Bxo/beta) exhibited slight decay and were inactive.

A partial HALO CME is visible off the West limb during a data gap in
coronagraph imagery. As it currently stands, the images stop at 23/0236
UTC, then resume at 23/0824 UTC with a CME well underway. An area of
dimming is visible in AIA/193 imagery starting near 23/0326 UTC. Further
analysis will need to be conducted once the coronagraph imagery updates
to determine if the two events are connected, and also to determine if
the ejecta has an Earth-directed component.

Solar activity is expected to be very low, with a slight chance for
C-class flares, throughout the forecast period (23-25 May).

Energetic Particles

.24 hr Summary...
The greater than 2 MeV electron flux was at high levels with a peak flux
of 26,098 pfu observed at 22/1650 UTC. The greater than 10 MeV
proton flux remained at background values.

The greater than 2 MeV electron flux is expected to reach high levels,
with a chance for very high levels, on all three days of the forecast
period (23-25 May) in response to elevated wind speeds from CH HSS
influence. The greater than 10 MeV proton flux is expected to continue
at background levels.

Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of persistent, but waning CH HSS
influence. Solar wind speeds began the period near 525 km/s, increased
to 575 km/s, then decreased to near 500 km/s by the end of the period.
Total field (Bt) was steady near 5 nT, while the Bz component mainly
fluctuated between +/-3 nT, seeing a maximum southward deflection to -5
nT. The phi angle remained in a negative sector during the period.

Solar wind parameters are expected to remain slightly enhanced, yet
continue to slowly diminish, during the forecast period (23-25 May) as
CH HSS influences continue.


.24 hr Summary...
The geomagnetic field was at quiet to unsettled levels.

The geomagnetic field is expected to be at quiet to unsettled levels on
days one and two (23-24 May) as CH HSS effects persist. A decrease to
mostly quiet levels is expected by day three (25 May) as the negative
polarity CH HSS moves out of a geoeffective position. is the U.S. government's official web portal to all federal, state and local government web resources and services.