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FXXX10 KWNP 170031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Aug 17 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
#
#             3-Day Forecast
#
A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Aug 17-Aug 19 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Aug 17-Aug 19 2025

             Aug 17       Aug 18       Aug 19
00-03UT       1.67         2.00         3.67
03-06UT       1.67         2.00         5.00 (G1)
06-09UT       1.33         1.00         5.00 (G1)
09-12UT       1.33         1.00         3.67
12-15UT       1.33         1.00         4.33
15-18UT       1.33         3.33         4.00
18-21UT       1.33         4.00         3.67
21-00UT       1.67         4.00         3.00

Rationale: Periods of G1 (Minor) geomagnetic storms are likely on 19 Aug
due to negative polarity CH HSS influence.

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 Aug 17-Aug 19 2025

              Aug 17  Aug 18  Aug 19
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 Aug 17-Aug 19 2025

              Aug 17        Aug 18        Aug 19
R1-R2           20%           15%           15%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts over 17-19 Aug.