Routine Space Environment Product (Daily)
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FXXX12 KWNP 200035

:Product: Forecast Discussion
:Issued: 2014 Aug 20 0035 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 low. The largest flare of the period was a C1/Sf at
19/2331 UTC from Region 2146 (N08E35, Hsx/alpha). No new active regions
were numbered. All other regions were stable, inactive, and
unremarkable. No Earth-directed coronal mass ejections (CMEs) were
observed in coronagraph imagery.

Solar activity is likely to be low, with a slight chance for M-class
(R1-Minor) activity, for the next three days (20-22 Aug).

Energetic Particles

.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit briefly
reached moderate levels again while the greater than 10 MeV proton flux
at geosynchronous orbit remained at background levels.

The greater than 2 MeV electron flux at geosynchronous orbit is expected
to be at normal to moderate levels for days one through three (20-22
Aug). The greater than 10 MeV proton flux at geosynchronous orbit is
expected to remain at background levels (below S1-Minor) throughout the
forecast period.

Solar Wind

.24 hr Summary...
An interplanetary shock passage was observed by the ACE spacecraft at
approximately 19/0558 UTC - the arrival of the anticipated 15 August
CME. Bt displayed a weak, but sudden increase, from 6 nT to 10 nT at
approximately 19/0558 UTC. Values varied slightly between 3 nT and 13 nT
for the next several hours, until approximately 19/1725 UTC when it
began a steady increase to peak at 19 nT at approximately 19/2212 UTC.
Bz varied between -11 nT and 13 nT following the CMEs passage, seeing a
maximum southward deviation to -16 nT at 19/1936 UTC. Phi was at a
predominately positive (away) orientation through 19/2130 UTC when it
rotated to a negative (towards) position to end the period.

The solar wind environment is expected to reflect CME characteristics
for the majority of day 1 (20 Aug), with a return to mostly nominal
conditions expected by days end. Day 2 and day 3 (21-22 Aug) may see
the combination of waning CME effects, along with a weak CH HSS from a
negative polarity CH, number 83. Speeds are not forecast in excess of
500 km/s.


.24 hr Summary...
The geomagnetic field was at quiet to G2 moderate storm levels. A 12 nT
geomagnetic sudden impulse (SI) was recorded at the Boulder magnetometer
at 19/0700 UTC, the result of the anticipated 15 August CME. An agitated
field persisted after the SI through the end of the period, then
combined with nighttime sub-storming to push conditions to the G2
moderate levels at 19/2301 UTC.

G1 minor to G2 moderate storm levels are expected through the first few
periods of day 1 (20 August) as the CME influence persists. Conditions
are expected to return to quiet to unsettled levels by the end of day 1,
into days two and three (21-22 Aug) as CME conditions wane and possible
CH HSS effects occur. is the U.S. government's official web portal to all federal, state and local government web resources and services.