National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXXX12 KWNP 181231
DAYDIS

:Product: Forecast Discussion
:Issued: 2024 Apr 18 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 reached moderate levels. Region 3643 (S12E27,
Fki/beta-gamma) produced three R1 (Minor) events, the largest of which
was an M2.2/Sf flare at 18/0248 UTC. Regions 3643 and 3645 (S09E17,
Dai/beta-gamma) exhibited moderate development this period with marked
increases in total size and spot count. The remaining regions were
either stable or in decay.

Multiple CMEs were observed off the SE following a series of eruptions
from the vicinity of Region 3638 (S18E14, Cri/beta) after 17/1730 UTC.
Analysis suggests these CMEs are near misses directed to the East of the
Sun-Earth line. No Earth-directed CMEs were detected in available
satellite imagery.

.Forecast...
Solar activity is expected to reach moderate levels over 18-20 Apr with
M-class flares (R1-R2/Minor-Moderate) likely, and a slight chance for
X-class (R3/Strong) flares.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to moderate levels
and the greater than 10 MeV proton flux was at background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to be at normal to
moderate levels over 18-20 Apr. There is a slight chance for the greater
than 10 MeV proton flux to reach S1 (Minor) levels over 18-20 Apr.

Solar Wind

.24 hr Summary...
A weakly enhanced solar wind environment prevailed throughout the
period. Total field strength ranged 1-10 nT and Bz varied +9/-8 nT.
Solar wind speeds increased from 350 km/s to a peak of 415 km/s, before
gradually returning to around 350 km/s by the end of the period.

.Forecast...
Enhanced solar wind conditions are likely on 18 Apr due to the
anticipated arrival of a CME from 15 Apr. Weakly enhanced conditions are
likely on 19 Apr as CME influences wane, and again on 20 Apr due to the
onset of negative polarity CH HSS influences.

Geospace

.24 hr Summary...
The geomagnetic field was quiet.

.Forecast...
Active conditions and periods of G1 (Minor) storming are likely on 18
Apr due the anticipated arrival of a CME from 15 Apr. Quiet to unsettled
conditions are expected on 19 Apr following CME passage. Quiet to
unsettled levels are expected again on 20 Apr due to the onset of
negative polarity CH HSS influences.