Message:23130 In: SPACWX.USA
From: N4SDDate: Wed, 27 May 26 00:32:00 Z
Newsgroups: SPACWX.USA
Subject: Space Weather Forecast Discussion
Message-ID: <14341_N4SD>
Path: N2MH4|N3MEL|KA3VSP|N4SD
R:260527/0346Z 31695@N2MH4.#SENC.NC.USA.NOAM LinBPQ6.0.24
R:260527/0312Z 17879@N3MEL.#EPA.PA.USA.NOAM LinBPQ6.0.25
R:260527/0232Z 2572@KA3VSP.DE.USA.NOAM BPQ6.0.25
R:260527/0032Z 14341@N4SD.#TIDE.VA.USA.NOAM BPQ6.0.24
FXXX12 KWNP 270031
DAYDIS
:Product: Forecast Discussion
:Issued: 2026 May 27 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 remained at low levels. The largest event of the period
was a C9.7 flare at 26/1238 UTC from Region 4446 (S16E43,
Fho/beta-gamma). This region was responsible for the majority of the
flare activity, though Region 4448 (S08E42, Dso/beta) produced a C2.4/Sf
flare at 26/0717 UTC and several occulted flares were observed from
beyond the northeast limb.
There are nine numbered regions on the visible disk. As the sunspot
complex in the southeast rotated further away from limb foreshortening
effects, it was determined that Regions 4451 (S16, L=122) and 4446 were
part of the same large, complex sunspot group and were consolidated
under Region 4446 with its complex gamma configuration. Region 4447
(S16W02, Dsi/beta) remained stable in physical extent with some minor
consolidation noted in its trailing spots. Region 4448 (S08E42,
Dao/beta) was stable in size, though new flux emergence was observed.
Region 4452 (N09W07, Cro/beta) was newly numbered this period following
rapid growth into a bipolar group. The remaining regions on the visible
disk were relatively simple and were stable or in gradual decay.
A relatively slow CME was observed off the southeast limb, first visible
in LASCO C2 imagery at 26/0436 UTC. STEREO-A COR2 imagery at 26/0438 UTC
confirmed this to be a front-sided eruption but the source is uncertain.
Analysis indicates it possesses no Earth-directed component.
Additionally, a Type II radio emission beginning at 26/1244 UTC is
believed to be associated with the C9.7 flare that peaked at 26/1238
UTC, with an estimated shock velocity of 650 km/s. However, any
associated CME was too faint or narrow to be seen. No other
Earth-directed CMEs were observed in available coronagraph imagery.
.Forecast...
Solar activity is expected to be at low to moderate levels through 29
May. There is an increasing chance for isolated M-class flares
(R1-R2/Minor-Moderate) due to the eruptive potential of the various
sunspot groups in the southeast and the anticipated rotation of one or
several active regions onto the visible disk.
Energetic Particle
.24 hr Summary...
The greater than 2 MeV electron flux at geosynchronous orbit was at low
to moderate levels, with a peak flux of 455 pfu observed at 26/1715 UTC.
The greater than 10 MeV proton flux at geosynchronous orbit remained
elevated, driven by a large far-sided partial halo CME first seen in
GOES-19 CCOR-1 imagery at 25/2200 UTC. The greater than 10 MeV flux
crossed the S1 (Minor) solar radiation storm threshold at 26/0010 UTC,
reaching a peak flux of 238 pfu at 26/0110 UTC before entering a slow,
gradual decline to end the period near 1 pfu.
.Forecast...
The greater than 2 MeV electron flux is expected to remain at low to
moderate levels through 29 May, as approaching high-speed stream
enhancements are not anticipated to be sufficient to raise flux levels.
The greater than 10 MeV proton flux is expected to continue its gradual
decline toward background levels. There remains a chance for proton flux
to return to S1 (Minor) or greater levels, primarily due to potential
further eruptive events from beyond the limb with enhancements from
current visible regions not expected given their complexity and
locations on the disk.
Solar Wind
.24 hr Summary...
Solar wind parameters were slightly above ambient background levels,
likely reflecting weak negative polarity coronal hole high-speed stream
(-CH HSS) influences. Total magnetic field (Bt) was variable with a a
peak of 10 nT but was around 6 nT for most of the period. The
north-south (Bz) component was mostly northward but deviated south late
in the period reaching a maximum deflection of -7 nT. Solar wind speeds
were steady around 400 km/s for most of the period before an enhancement
at approximately 26/1800 UTC, where a slight deflection in the phi angle
and a sharp drop in Bz to its lowest values of the period were
accompanied by a minor increase in solar wind speed up to 450 km/s.
.Forecast...
Solar wind parameters are anticipated to become enhanced on 27 May ahead
with the arrival of a relatively weak -CH HSS. High-speed stream
influences are likely to persist through 28 May before trending back
toward background conditions on 29 May.
Geospace
.24 hr Summary...
The geomagnetic field remained at quiet levels, with an isolated active
period late due to slightly enhanced parameters and some periods of
southward Bz.
.Forecast...
The geomagnetic field is anticipated to increase to unsettled to active
levels 27–28 May due to the anticipated onset and influence of the -CH
HSS. A return to quiet to unsettled levels is expected on 29 May as
stream influences subside.
------
73 de Sperry N4SD
N4SD@N4SD.#TIDE.VA.USA.NOAM
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