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Prediction Detail

Prediction for CME (2018-08-20T21:24:00-CME-001)

CME Observed Time: 2018-08-20T21:24Z
CME Note: The CME is associated with a filament eruption occurring around 2018-08-20T18:00Z at N40W05 in SDO 193.
CME Shock Arrival Time: 2018-08-25T06:00Z
Observed Geomagnetic Storm Parameters due to CME:
Max Kp: 7.0
Dst min. in nT: -169
Dst min. time: 2018-08-26T07:00Z

Predicted Arrival Time: 2018-08-24T14:00Z
Predicted geomagnetic storm max Kp range due to CME: 4.0 - 4.0
Prediction Method: WSA-ENLIL + Cone (NOAA/SWPC)
Prediction Method Note:
Product: 3-Day Forecast
Issued: 2018 Aug 24 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction

A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Aug 24-Aug 26 2018 is 4 (below NOAA
Scale levels).

NOAA Kp index breakdown Aug 24-Aug 26 2018

            Aug 24     Aug 25     Aug 26
00-03UT        2          4          3     
03-06UT        2          4          2     
06-09UT        2          3          2     
09-12UT        1          2          2     
12-15UT        1          3          2     
15-18UT        1          2          2     
18-21UT        2          1          2     
21-00UT        4          2          2     

Rationale: No G1 (Minor) or greater geomagnetic storms are expected.
Active levels are expected late on day one through early on day two
(24-25 Aug) due to the anticipated arrival of the 20 Aug CME with
possible combined effects from a weak CH HSS.

Product: Forecast Discussion
Issued: 2018 Aug 22 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction

Solar Activity

.24 hr Summary...
Solar activity was very low. Region 2719 (S12E09) decayed into a plage
region and was inactive.

At approximately 20/22 UTC a faint and slow-moving CME was seen in LASCO
coronagraph imagery. The source region for this CME is unclear, and the
bulk of the ejecta appears to be directed southwest of the Sun-Earth
line. Further analysis of this event determined that a glancing blow
from the CME is possible. However, due to it's lack of density and slow
nature, impact is expected to be negligible.

Solar activity is expected to be very low for the next three days (22-24

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux reached high levels this period
with a peak flux of 9,290 pfu observed at 21/2025 UTC. The greater than
10 MeV proton flux was steady at background levels.

The greater than 2 MeV electron flux is expected to reach high levels
for the next three days (22-24 Aug) due to enhanced solar wind
conditions. The greater than 10 MeV proton flux is expected to continue
at background levels throughout the forecast period.

Solar Wind

.24 hr Summary...
Solar wind parameters reflected a negative polarity CH HSS. Solar wind
speeds steadily declined from around 600 km/s to around 450 km/s. Total
field strength was steady near 5 nT. There were no significant
deviations in the Bz component. The phi angle remained negative.

Solar wind parameters are expected to remain enhanced for the next three
days (22-24 Aug) due to the continued, but waning, influence of a
negative polarity CH HSS.


.24 hr Summary...
The geomagnetic field was at quiet to unsettled levels due to the
continued influence of the negative polarity CH HSS.

Mostly unsettled levels are expected over the next three days
(22-24 Aug) due to the continued influence of a negative polarity CH

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Lead Time: 78.58 hour(s)
Difference: 16.00 hour(s)
Prediction submitted by Leila Mays (GSFC) on 2018-08-21T23:25Z
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Important Disclaimer Notice

If you are looking for the official U.S. Government forecast for space weather, please go to NOAA's Space Weather Prediction Center ( This "Experimental Research Information" consists of preliminary NASA research products and should be interpreted and used accordingly.

NASA Official: Dr. Maria Kuznetsova
Curator: Chiu Wiegand