Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 280031
DAYDIS

:Product: Forecast Discussion
:Issued: 2015 Jul 28 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 was at very low levels. Region 2390 (S17W13,
Dai/beta-gamma) underwent decay as it lost penumbra in its intermediate
spots. The region appeared to become more magnetically simple early in
the period, but regained opposite polarity umbra amongst the trailer
spots as the period progressed - indicative of continued minor magnetic
instability. The region remained predominantly stable as only a few
weak, B-class and optical subflares were observed during the period.
Region 2389 (S12E23, Cro/beta) decayed further as it lost penumbral
coverage and decreased in total area. The region was in a simple bipolar
configuration, but retained some weak, E-W aligned magnetic shear.
Region 2391 (N05E71, Hsx/alpha) was quiet and unchanged as it rotated
further onto the visible disc.

A prominence located along the NE limb at about N18E90, was active and
lost some density, but remained in place as material was reabsorbed. No
Earth-directed coronal mass ejections (CMEs) were observed in available
coronagraph imagery.

.Forecast...
Solar activity is expected to be very low with a chance for C-class
activity for the next three days (28-30 Jul) primarily due to the flare
potential of Region 2390.


Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to moderate levels
with a peak flux of 248 pfu observed at 27/0005 UTC. The greater than 10
MeV proton flux remained at background levels throughout the period.

.Forecast...
The greater than 2 MeV electron flux at geosynchronous orbit is expected
to be at normal to moderate levels for the forecast period (28-30 Jul)
while the greater than 10 MeV proton flux is expected to remain at
background levels (below S1-Minor).


Solar Wind

.24 hr Summary...
Solar wind and interplanetary magnetic field (IMF) parameters indicated
a slightly disturbed environment. Solar wind velocity was variable and
ranged from around 425-525 km/s with a slow, steady uptick in speed from
the start of the period until about 27/0800 UTC, when velocity seemed to
peak and wind speed decreased back down to about 450-475 km/s. The IMF
strength ranged from 3-7 nT. The Bz component was variable, but did have
a sustained period of mainly southward deflection between 27/0400-1200
UTC. The phi angle was predominantly positive (away) but did vary
between sectors from about 27/0500-1100 UTC as Earth was aligned along
an edge of the heliospheric sheet current. Analysis of solar wind
parameters and IMF conditions suggested a weak co-rotating interaction
region (CIR) ahead of the positive polarity coronal hole (CH HSS) may
have crossed the ACE satellite early on 27 Jul.

.Forecast...
The solar wind environment is likely to remain nominal to slightly
disturbed on day one (28 Jul) as IMF conditions are expected to remain
slightly disturbed due to continued influences from the CIR. Day two (29
Jul) is expected to see an increase in solar wind velocity as the
positive polarity coronal hole high speed stream (CH HSS) becomes most
geoeffective. Day three (30 Jul) is expected to see some waning of solar
wind velocity and a return to more ambient IMF conditions as the CH HSS
rotates further west.


Geospace

.24 hr Summary...
The geomagnetic field was at quiet to active levels. The brief active
period from 27/0900-1200 UTC was likely due to the extended period of
southward Bz, coupled with slightly higher total magnetic field strength
and slightly elevated solar wind velocities.

.Forecast...
Quiet to unsettled conditions are expected on day one (28 Jul) as the
solar wind environment remains little changed from present conditions.
Day two (29 Jul) is expected to see quiet to active conditions due to
the positive polarity CH HSS. Quiet to unsettled conditions are expected
for day three (30 Jul) as the CH HSS rotates further west and out of a
favorable Earth-connected position.


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