Message:22678 In: SPACWX.USA
From: N4SDDate: Wed, 20 May 26 12:32:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather Forecast Discussion
Message-ID: <13721_N4SD>
Path: N2MH4|WB4WPF|KA3VSP|N4SD
R:260520/2127Z 31435@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260520/1411Z 12463@WB4WPF.#SFL.FL.USA.NOAM LinBPQ6.0.25
R:260520/1405Z 2299@KA3VSP.DE.USA.NOAM BPQ6.0.25
R:260520/1232Z 13721@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX12 KWNP 201231
DAYDIS
:Product: Forecast Discussion
:Issued: 2026 May 20 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 continued at low levels during the reporting period. The
largest events were a C2.1/Sf flare at 19/1920 UTC and a C1.4 flare at
19/2203 UTC, both from Region 4436 (N18W71, Cso/beta). This region was
responsible for the majority of the periods activity, which otherwise
consisted of occasional low-level B-class flaring.
There are currently five numbered regions on the visible disk. Most
regions continued to show gradual decay, with a few exhibiting localized
development. Region 4436 transitioned into a well-defined bipolar group
following a phase of stability, characterized by new flux emergence and
consolidation within its trailing spots of opposite polarity. Region
4439 (N06E23, Cao/beta) remained mostly stable, though slight divergence
was observed in its trailing spots. Region 4440 remained a stable
unipolar group. Region 4441 (N07W22, Dao/beta) showed mild overall
growth after new flux emerged between the leading and trailing spots,
immediately consolidating with the like-polarity poles. Region 4443
(S16E30, Axx/alpha) experienced continued decay to a single unipolar
spot.
A CME associated with the B8.2 flare from Region 4440 was observed off
the northeast limb, first appearing in LASCO C2 imagery at 19/1101 UTC.
Analysis indicates this ejecta is not Earth-directed. No other
Earth-directed CMEs were observed in available coronagraph imagery.
.Forecast...
Solar activity is expected to remain at low levels through 21 May, with
a slight chance for isolated M-class flares (R1-R2/Minor-Moderate)
primarily due to the complexity of Region 4441 and the recent flaring
history of Region 4436. An increase in activity is anticipated starting
22 May as multiple active regions, tracked via far-side satellite and
helioseismology imagery, rotate into view.
Energetic Particle
.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit remained at
high levels, reaching a peak flux of 2,860 pfu observed at 19/1650 UTC.
The greater than 10 MeV proton flux at geosynchronous orbit remained at
background levels.
.Forecast...
The greater than 2 MeV electron flux is expected to return to normal to
moderate levels through 21 May as current conditions wane. A return to
high levels is anticipated on 22 May following the geoeffective onset of
a new coronal hole high-speed stream. The greater than 10 MeV proton
flux is expected to remain at background levels through 22 May.
Solar Wind
.24 hr Summary...
Solar wind parameters trended toward background conditions with wind
speeds around 475 km/s, Total field strength decreased to 4 nT, and Bz
becoming mostly northward. Phi has continued in a negative orientation.
.Forecast...
Solar wind parameters are expected to continue trending toward nominal
conditions through early on 21 May. Mild enhancements are likely on 21
May from a solar sector boundary crossing, with more pronounced
high-speed stream conditions expected on 22 May due to the onset of a
positive polarity coronal hole high-speed stream (+CH HSS).
Geospace
.24 hr Summary...
The geomagnetic field was initially at active levels before becoming
quiet to unsettled as parameters waned.
.Forecast...
Geomagnetic field activity is expected to be at mostly quiet to
unsettled levels over 20–21 May as enhancements wane. Isolated active
periods are likely expected on 22 May following the onset of the
approaching +CH HSS.
------
73 de Sperry N4SD
N4SD@N4SD.#TIDE.VA.USA.NOAM
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