393
FXXX12 KWNP 120031
DAYDIS

:Product: Forecast Discussion
:Issued: 2024 May 12 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
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#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity was high. Region 3664 (S18W63, Fkc/beta-gamma-delta)
reigned as the largest and most productive region on the disk, but was
largely unchanged from the previous reporting period. The region
produced an X5.8/2b flare (R3/Strong) at 11/0123 UTC, with accompanying
Type II and IV sweeps, a Castelli-U burst signature, and an 800 sfu
Tenflare observed. An associated fast, halo CME is expected to merge
with the preceding in-transit CMEs and arrive at Earth by midday on 12
May. In addition to the X5.8 flare, Region 3664 produced an X1.5/2b
flare at 11/1144 UTC and multiple M-class flares throughout the period.
New Region 3675 (S12W38, Cro/beta) was numbered but was otherwise
unremarkable. The remaining regions were either stable or in decay.

.Forecast...
Solar activity is expected to persist at high to very high levels over
12-14 May, with M-class (R1-R2/Minor-Moderate) and X-class flares
(R3/Strong) expected, due primarily to the flare potential of Region
3664.

Energetic Particle

.24 hr Summary...
The greater than 10 MeV proton flux reached S1 (Minor) levels at 10/1335
UTC and S2 (Moderate) levels at 10/1745 UTC; a peak flux of 207 pfu was
observed at 10/1745 UTC. The greater than 100 MeV proton flux reached
the 1 pfu alert threshold at 11/0210 UTC and reached a peak flux of 7
pfu at 11/0210 UTC. The greater than 2 MeV electron flux was at normal
to moderate levels throughout the day.

.Forecast...
The greater than 10 MeV proton flux is expected to persist at S1-S2
(Minor-Moderate) storm levels through 12 May. Additional proton
enhancements are likely on 13-14 May due to the flare potential and
location of Region 3664. The greater than 2 MeV electron flux is
expected to be at normal to moderate levels over 12-13 May, and is
likely to increase to high levels on 14 May following a prolonged period
of elevated geomagnetic activity and enhanced solar wind conditions.

Solar Wind

.24 hr Summary...
The solar wind environment was strongly enhanced this period due to
continued CME activity. Solar wind speeds increased from a low of around
680 km/s at 11/1000 UTC to a peak of around 920 km/s. Total field
reached a peak of 56 nT and Bz was sustained southward, by as much as
-50 nT, through much of the period.

.Forecast...
A strongly enhanced solar wind environment and continued CME influences
are expected to continue on 12-13 May, and begin to wane by 14 May as
CME influences subside. Some CH HSS influences are expected over 13-14
May, though CME influences are expected to be the primary driver of
geomagnetic activity.

Geospace

.24 hr Summary...
The geomagnetic field reached G5 (Extreme) geomagnetic storm periods in
response to CME activity.

.Forecast...
Periods of G4-G5 (Severe-Extreme) geomagnetic storms are likely on 12
May due to continued CME activity and the anticipated arrival of another
series of CMEs associated with eruptive activity from Region 3664 over
09-11 May. Periods of G2-G3 (Moderate-Strong) storming are likely on 13
Apr due to continued CME activity and positive polarity CH HSS
influences. Periods of G1 (Minor) storms are likely on 14 May due to
waning CME influences and CH HSS influences.