Routine Space Environment Product (Daily)
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000
FXXX12 KWNP 191230
DAYDIS

:Product: Forecast Discussion
:Issued: 2015 Apr 19 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 low. The largest event of the period was a C5/1n
flare at 18/1419 UTC associated with a filament eruption near Region
2321 (N11W22, Eai/beta-gamma). The 7 degree long filament, centered near
N05W16, resulted in an asymmetric, faint full-halo coronal mass ejection
(CME), first visible in SOHO/LASCO C2 imagery at 18/1524 UTC.  WSA-Enlil
model output and forecaster analysis suggests this CME will arrive at
Earth late on 21 Apr/early 22 Apr.

Region 2321 continued a moderate decay trend throughout the period while
Regions 2324 (N19E01, Cki/beta) and 2325 (N05E10, Cai/beta) underwent
only minor decay.  The remaining four active regions on the visible disk
were relatively stable throughout the period.

.Forecast...
Solar activity is likely to be low with a slight chance for M-class
(R1-Minor) flares on days one and two (19-20 Apr).  Solar activity is
likely to be very low with a chance for C-class flares on day three (21
Apr).

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at moderate to high levels,
reaching a peak flux value of 3,740 pfu at 18/1640 UTC.  The greater
than 10 MeV proton flux was at background levels throughout the period.

.Forecast...
The greater than 2 MeV electron flux is expected to persist at moderate
to high levels over the next three days (19-21 Apr).  The greater than
10 MeV proton flux is expected to remain at background levels for the
next three days (19-21 Apr).

Solar Wind

.24 hr Summary...
Solar wind parameters continued to return to near-background levels this
period.  Solar wind speeds steadily decreased from initial values near
550 km/s to end-of-period values near 425 km/s.  IMF total field values
were steady between 1-5 nT and Bz reached a maximum southward component
of -5 nT early in the period.  The phi angle was variable early in the
period but settled into a negative (towards the Sun) solar sector
orientation after 18/2015 UTC, where it remained for the rest of the
period.

.Forecast...
Solar wind parameters are expected to persist at near-background levels
on day one (19 Apr) under a nominal solar wind regime.  An enhanced
solar wind environment is expected on days two and three (20-21 Apr) due
to the influence of a positive polarity coronal hole high speed stream
(CH HSS) as well as the anticipated arrival of the 18 Apr CME late on
day three (21 Apr).

Geospace

.24 hr Summary...
The geomagnetic field was at quiet to unsettled levels under a nominal
solar wind regime.

.Forecast...
Geomagnetic field activity is expected to be at quiet to unsettled
levels on day one (19 Apr) due to a continued nominal solar wind
environment.  Quiet to active geomagnetic field conditions are expected
on days two and three (20-21 Apr) due to a combination of the influence
of a positive polarity CH HSS and the arrival of the 18 CME late on day
three (21 Apr).


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