Message:22800 In: SPACWX.USA
From: N4SDDate: Thu, 21 May 26 00:31:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather Forecast Discussion
Message-ID: <13776_N4SD>
Path: N2MH4|N3MEL|KA3VSP|N4SD
R:260521/0228Z 31504@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260521/0228Z 17576@N3MEL.#EPA.PA.USA.NOAM LinBPQ6.0.25
R:260521/0208Z 2320@KA3VSP.DE.USA.NOAM BPQ6.0.25
R:260521/0031Z 13776@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX12 KWNP 210031
DAYDIS
:Product: Forecast Discussion
:Issued: 2026 May 21 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 continued at low levels during the past 24 hours, with
four active regions on the visible disk. The largest events were a C1.0
at 20/0443 UTC from the NE limb and a C1.0/Sf at 20/1017 UTC from
Region 4439 (N06E15, Hrx/alpha), that was accompanied by Type-III radio
sweeps. This region was responsible for the majority of the periods
activity, which otherwise included a B8.7 flare at 20/0332 UTC from
Region 4436 (N18W78, Csi/beta). Region 4441 (N07W30, Eai/beta) showed
some development during the period while 4443 (S16E23, Axx/alpha)
remained stable.
Coronal activity was observed in CCOR-1 imagery after 20/1700, but
additional data is needed for further analysis.
.Forecast...
Solar activity is expected to remain at low levels through 23 May, with
a slight chance for isolated M-class flares (R1-R2/Minor-Moderate) on 21
May, primarily due to the complexity of Region 4441 and the recent
flaring history of Region 4436. An increased in activity is anticipated
22-23 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 level of 1716 pfu at 20/1615 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 on 21 May as current conditions wane. A return to
high levels is anticipated on 22-23 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 23 May.
Solar Wind
.24 hr Summary...
Solar wind parameters trended toward background conditions with speeds
reaching a peak of 542 km/s at 20/0222Z and then decreasing steadily
throughout the reporting period, ending at ~450 km/s. Total IMF reached
6 nT at 20/0158Z. The maximum southward component of Bz reached -5 nT at
20/0010Z, and the phi angle remained on the negative sector.
.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 22-23 May due to the influences
of a positive polarity coronal hole high-speed stream (+CH HSS).
Geospace
.24 hr Summary...
The geomagnetic field has been at quiet to unsettled levels for the past
24 hours.
.Forecast...
Isolated active periods are likely on 21 May following an anticipated
sector boundary crossing and the onset of the approaching +CH HSS. Quiet
to unsettled levels are anticipated 22-23 May due to persisting +CH HSS
influences.
------
73 de Sperry N4SD
N4SD@N4SD.#TIDE.VA.USA.NOAM
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