National Weather Service Text Product Display

Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 251230
DAYDIS

:Product: Forecast Discussion
:Issued: 2013 May 25 1230 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 was at low levels.  Region 1755 (N11E18, Dai/beta-gamma)
produced the largest event of the period, a C2 flare, at 25/1049 UTC.
Region 1756 (S20E07, Ehi/beta-gamma) was steady while Region 1755 showed
a slight decay trend it its trailer spot area.  No Earth-directed
coronal mass ejections (CMEs) were observed.

.Forecast...
Solar activity is expected to be low with a chance for M-class flares
for the next three days (25 - 27 May).

Energetic Particle

.24 hr Summary...
The greater than 10 MeV proton flux decreased below the NOAA Scale S1
(Minor) threshold at 25/0845 UTC, and continues to steadily decrease.
The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels, reaching a maximum value of 2060 pfu at 24/1935 UTC.

.Forecast...
The greater than 10 MeV proton flux is expected to continue decreasing
for the next three days (25 - 27 May), as it recovers from the 22 May
proton event.  The greater than 2 MeV electron flux is expected to be at
normal to moderate levels for the remainder of day one (25 May).
Electron flux is expected to increase to moderate to high levels for
days two and three (26 - 27 May) due to the enhanced solar wind features
caused by the CME arrival.

Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of a CME arrival, observed around
25/1730 UTC.  Solar wind speed was initially steady at approximately 450
km/s, and suddenly increased to approximately 550 km/s after 25/1730
UTC.  Wind speed slowly decreased from 550 km/s to 475 km/s since the
initial CME impact, but another wind speed enhancement to around 600
km/s was observed after 25/0930 UTC from what appears to be a
combination of CME and coronal hole high speed stream (CH HSS) effects.
The total field values ranged from 1 nT to 15 nT while the Bz component
ranged from +12 nT to -15 nT, both field values peaked in conjunction
with the CME arrival.  The phi angle was configured in a predominately
negative (toward) sector, but showed some variability after 25/0000 UTC.

.Forecast...
Solar wind speed is expected to remain elevated for the next three days
(25 - 27 May) due to CME effects and CH HSS influence.

Geospace

.24 hr Summary...
The geomagnetic field was at predominately unsettled to active levels
with two isolated periods of NOAA Scale G1 (Minor) Geomagnetic Storm
conditions due to a CME.

.Forecast...
The geomagnetic field is expected to be at predominately unsettled to
active levels with a chance for an isolated period of NOAA Scale G1
(Minor) Geomagnetic Storm conditions on day one (25 May) as CME
influence continues.  The field is expected to return to predominately
quiet to unsettled conditions for day two and three (26 - 27 May) as CME
effects subside.
National Weather Service Weather Forecast Office
