932
FXXX10 KWNP 200031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Aug 20 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 5 (NOAA Scale
G1).
The greatest expected 3 hr Kp for Aug 20-Aug 22 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Aug 20-Aug 22 2025

             Aug 20       Aug 21       Aug 22
00-03UT       3.67         3.67         2.00
03-06UT       3.00         3.67         3.00
06-09UT       3.00         3.33         2.33
09-12UT       2.67         2.67         1.67
12-15UT       3.67         2.33         1.67
15-18UT       5.00 (G1)    2.33         2.33
18-21UT       4.67 (G1)    2.33         2.00
21-00UT       4.00         3.00         2.00

Rationale: Isolated periods of G1 (Minor) geomagnetic storming are
likely on 20 August, due to negative polarity CH HSS effects, followed
by a possible glancing blow from a CME that left the Sun on 17
August.

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 20-Aug 22 2025

              Aug 20  Aug 21  Aug 22
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

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Aug 19 2025 0439 UTC.

Radio Blackout Forecast for Aug 20-Aug 22 2025

              Aug 20        Aug 21        Aug 22
R1-R2           10%           10%           10%
R3 or greater    1%            1%            1%

Rationale: Solar activity will likely be at very low to low levels, with
a slight chance for for M-class flares due to the anticipated return of
old active regions.