 roduct: 3-Day Forecast
:Issued: 2025 May 15 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 May 15-May 17 2025 is 3.67 (below NOAA
Scale levels).
NOAA Kp index breakdown May 15-May 17 2025
May 15 May 16 May 17
00-03UT 2.33 2.33 3.33
03-06UT 2.33 2.33 2.00
06-09UT 2.67 2.33 2.00
09-12UT 2.67 1.67 3.00
12-15UT 2.00 2.33 3.00
15-18UT 2.67 2.33 3.67
18-21UT 3.67 2.00 3.33
21-00UT 3.00 2.33 3.33
Rationale: No G1 (Minor) or greater geomagnetic storms are expected. No
significant transient or recurrent solar wind features are forecast.
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 May 15-May 17 2025
May 15 May 16 May 17
S1 or greater 10% 5% 5%
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
Radio blackouts reaching the R3 levels were observed over the past 24
hours. The largest was at May 14 2025 0825 UTC.
Radio Blackout Forecast for May 15-May 17 2025
May 15 May 16 May 17
R1-R2 75% 75% 75%
R3 or greater 30% 30% 30%
Rationale: Given the magnetic complexity of Region 4087, theres a 75%
chance that M-Class (R1-R2, Minor-Moderate) level flare activity will
occur through 17 May with a 30% chance for X-Class (R3-Strong) levels
during the same time.
--- MBSE BBS v1.1.1 (Linux-x86_64)
* Origin: Outpost BBS * Johnson City, TN (618:618/1)
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