強いフレアが起きればオーロラが見えますか？
必ずしも見えません。フレアと地球方向への質量放出は別です。太陽風、磁場の向き、観測地、暗さや天候も関係します。
宇宙天気
今日の太陽は活発？太陽フレア、磁気嵐、太陽風の最新観測を確認し、観測地のオーロラ予報と合わせて見てみましょう。
G0
観測 · NOAA磁気嵐
基準未満S0
観測 · NOAA太陽放射線嵐
基準未満R0
観測 · NOAA電波障害
基準未満太陽風速度
400.40 km/s観測陽子密度
4.24 p/cm³観測Bt:
8.49 nT観測Bz:
0.99 nT観測地磁気活動 · Kp
3.00 Kp観測Dst 指数
-34.00 nT観測太陽風速度
400.4 km/s
星間磁場
8.49 nT
BtBz
Bt は磁場の全体の強さです。Bz が負の状態が続くと南向きの磁場となり、太陽風のエネルギーが入りやすくなりますが、オーロラを保証しません。
フレア発生確率
予報・警報 →C25%
M1%
X1%
予報・警報
NOAA SWPC ↗3日予報
1.67
Kp予報
Kp は 0～9 で、5 から磁気嵐の基準に達します。地球全体の指標であり、各都市でオーロラが見える確率ではありません。
3日予報公式公報・英語原文
:Product: 3-Day Forecast
:Issued: 2026 Oct 31 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
A. NOAA Geomagnetic Activity Observation and Forecast
The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Oct 31-Nov 02 2026 is 5.00 (NOAA Scale
G1).
NOAA Kp index breakdown Oct 31-Nov 02 2026
Oct 31 Nov 01 Nov 02
00-03UT 5.00 (G1) 3.67 2.67
03-06UT 4.67 (G1) 4.67 (G1) 2.33
06-09UT 4.33 3.33 2.33
09-12UT 4.00 2.67 2.33
12-15UT 3.00 2.33 2.33
15-18UT 3.00 3.33 2.00
18-21UT 3.67 3.67 2.33
21-00UT 4.00 3.33 2.67
Rationale: The geomagnetic field is likely to reach G1 (Minor)
geomagnetic storm levels on 31 Oct - 01 Nov due to influence from a
positive polarity CH HSS. Unsettled conditions are likely on 02 Nov as
CH HSS influence wanes.
B. NOAA Solar Radiation Activity Observation and Forecast
Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
below S-scale storm level thresholds.
Solar Radiation Storm Forecast for Oct 31-Nov 02 2026
Oct 31 Nov 01 Nov 02
S1 or greater 1% 1% 1%
Rationale: No S1 (Minor) or greater solar radiation storms are expected.
No significant active region activity favorable for radiation storm
production is forecast.
C. NOAA Radio Blackout Activity and Forecast
No radio blackouts were observed over the past 24 hours.
Radio Blackout Forecast for Oct 31-Nov 02 2026
Oct 31 Nov 01 Nov 02
R1-R2 1% 1% 1%
R3 or greater 1% 1% 1%
Rationale: No R1 (Minor) or greater radio blackouts are expected. No
significant active region flare activity is forecast.
予報・警報公式公報・英語原文
:Product: Forecast Discussion
:Issued: 2026 Oct 31 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity
.24 hr Summary...
Solar activity continued at very low levels. Newly numbered Region 4564
(N12E75, Hsx/alpha) rotated around the E limb with no apparent trailer
spot. It was mostly quiet and stable.
No Earth-directed CMEs were observed at the available coronagraph
imagery.
.Forecast...
Solar activity is expected to be at very low levels with a slight chance
for isolated C-class flares through 02 Nov.
Energetic Particle
.24 hr Summary...
The greater than 2 MeV electron flux reached high levels, with a peak
flux of 4,488 pfu observed at 30/1430 UTC. The greater than 10 MeV
proton flux remained steady at background levels.
.Forecast...
The greater than 2 MeV electron flux is expected to decrease to normal
to moderate levels on 31 Oct Oct and remain there through 02 Nov. The
greater than 10 MeV proton flux is anticipated to persist at background
levels through 02 Nov.
Solar Wind
.24 hr Summary...
Solar wind parameters suggested mild influence from a solar sector
boundary crossing. Total magnetic field strength reached a peak of 9 nT
and the Bz component reached as far south as -8 nT. Solar wind speeds
remained low, with values observed between 307-354 km/s. Phi angle
transitioned from mostly negative to positive after 30/0513 UTC.
.Forecast...
Solar wind disturbances are likely to be observed on 31 Oct and slow
wane through 02 Nov, due to the anticipated arrival of a recurrent,
equatorial, positive polarity CH HSS.
Geospace
.24 hr Summary...
The geomagnetic field was at quiet to active levels during the period.
.Forecast...
The geomagnetic field is expected to reach G1 (Minor) geomagnetic storm
levels on 31 Oct - 01 Nov due to influence from a positive polarity CH
HSS. Unsettled conditions are likely on 02 Nov as CH HSS influence
wanes.
27日先までの見通し公式公報・英語原文
:Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2026 Oct 26 0118 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# https://www.swpc.noaa.gov/content/subscription-services
#
# 27-day Space Weather Outlook Table
# Issued 2026-10-26
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2026 Oct 26 88 5 2
2026 Oct 27 84 5 2
2026 Oct 28 84 5 2
2026 Oct 29 84 5 2
2026 Oct 30 84 5 2
2026 Oct 31 84 30 5
2026 Nov 01 84 20 4
2026 Nov 02 82 10 3
2026 Nov 03 82 5 2
2026 Nov 04 82 5 2
2026 Nov 05 82 10 3
2026 Nov 06 82 10 3
2026 Nov 07 82 10 3
2026 Nov 08 84 5 2
2026 Nov 09 84 15 4
2026 Nov 10 82 10 3
2026 Nov 11 82 10 3
2026 Nov 12 80 10 3
2026 Nov 13 80 5 2
2026 Nov 14 80 5 2
2026 Nov 15 80 5 2
2026 Nov 16 80 10 3
2026 Nov 17 80 20 4
2026 Nov 18 80 20 4
2026 Nov 19 80 10 3
2026 Nov 20 80 5 2
2026 Nov 21 80 5 2
黒点活動領域公式公報・英語原文
:Product: Summary of Space Weather Observations dayobs.txt
:Issued: 2026 Oct 31 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# https://www.swpc.noaa.gov/content/subscription-services
#
# Summary of Space Weather Observations
#
:Solar_Region_Summary: 2026 Oct 30
# Region Location Sunspot Characteristics
# Helio Spot Spot Mag.
# Num Lat.,CMD Long. Area Extent class count class
4563 S19W94 353 10 1 AXX 1 A
4564 N04E56 203 30 5 CRO 4 B
4565 N12E75 184 60 2 HSX 1 A
宇宙天気は何を観測しますか？
太陽活動と地球周辺の宇宙環境の変化です。太陽フレア、高エネルギー粒子、磁気嵐はそれぞれ異なる現象です。
公開観測や予報には遅延や修正があります。オーロラの可視性や運用の安全性を保証するものではありません。重要な判断には公式情報をご確認ください。