National Weather Service Text Product Display

Routine Space Environment Product (Daily)
Issued by NWS
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13
000
FXXX12 KWNP 230031
DAYDIS

:Product: Forecast Discussion
:Issued: 2013 May 23 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
#
#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity increased to high levels. Region 1745 (N13W80, Cao/beta)
produced a long-duration M5/3n flare at 22/1332 UTC (R2, Moderate)
associated with Types II and IV radio sweeps (estimated Type II speed
1237 km/s), and a 370 sfu Tenflare. A fast moving, partial-halo coronal
mass ejection (estimated speed 1488 km/s) was also associated with the
M5 flare with the bulk of the ejecta directed westward, though there
appeared to be a small Earthward component. Region 1756 (S20E41,
Dai/beta-gamma) produced occasional C-class flares during the period as
it grew at a moderate pace and developed a beta-gamma magnetic
configuration. Region 1755 (N10E52, Dsi/beta-gamma) showed gradual spot
and penumbral growth in its trailer portion and developed a beta-gamma
magnetic configuration.

.Forecast...
Solar activity is expected to be low during the period (23 - 25 May)
with a chance for an M-class flare and a slight chance for an X-class
flare.

Energetic Particle

.24 hr Summary...
The greater than 10 MeV and greater than 100 MeV proton flux at
geosynchronous orbit reached event levels in the wake of the M5/3n
flare. The greater than 10 MeV proton event reached the S1 (Minor) event
threshold at 22/1420 UTC and reached the S2 (Moderate) threshold at
22/1730 UTC. The greater than 100 MeV proton flux reached event
threshold (1 pfu) at 22/1455 UTC. Thus far, the peak greater than 100
MeV flux has been 3 pfu at 22/1830 UTC. The greater than 2 MeV electron
flux at geosynchronous orbit was at normal to moderate levels.

.Forecast...
The greater than 10 MeV proton flux at geosynchronous orbit is expected
to remain at event levels during 23 - 24 May and is likely to reach
event levels on 25 May. The greater than 2 MeV electron flux at
geosynchronous orbit is expected to be at normal to moderate levels on
23 May, then increase to moderate to high levels on 24 - 25 May in
response to a recurrent coronal hole high-speed stream (CH HSS).

Solar Wind

.24 hr Summary...
ACE data indicated possible CH HSS effects. Wind speed was elevated in
the 410 to 500 km/s range. Phi data indicated a Toward (-) solar sector
orientation during most of the period. IMF Bt was variable in the 1 to 7
nT range with a gradual upward trend after approximately 22/1830 UTC.
IMF Bz ranged from +/- 4 nT and was mostly southward after 22/1200 UTC.
Just after 22/2045 UTC, ACE/SWEPAM data became suspect due to likely
proton contamination from the earlier CME.

.Forecast...
Wind speed is expected to remain elevated through the period (23 - 25
May) as the CH HSS persists. A minor increase in wind speed and IMF Bt
is expected midday on 24 May to early on 25 May with the arrival of a
glancing blow from todays partial-halo coronal mass ejection (CME).

Geospace

.24 hr Summary...
The geomagnetic field was at quiet to (briefly) active levels.

.Forecast...
Geomagnetic field activity is expected to be at unsettled to active
levels on 23 May, with a slight chance for minor storm levels, due to CH
HSS effects. Activity is expected to decrease to quiet to unsettled
levels for the first part of 24 May, with a slight chance for active
levels, as CH HSS effects diminish. Activity is expected to return to
unsettled to active levels midday on 24 May through 25 May, with a
slight chance for minor storm levels, due to an expected glancing blow
from todays partial halo CME.
National Weather Service Weather Forecast Office
