688
FXXX10 KWNP 180031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Oct 18 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 3 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Oct 18-Oct 20 2025 is 4.33 (below NOAA
Scale levels).

NOAA Kp index breakdown Oct 18-Oct 20 2025

             Oct 18       Oct 19       Oct 20
00-03UT       3.00         4.00         2.67
03-06UT       2.33         3.00         2.67
06-09UT       2.00         2.67         2.67
09-12UT       2.00         2.33         2.67
12-15UT       2.00         2.00         3.00
15-18UT       4.00         2.00         3.00
18-21UT       4.00         2.00         3.67
21-00UT       4.33         2.33         2.67

Rationale: There is a chance for G1 (Minor) activity on 18 Oct due to
CME effects.

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 18-Oct 20 2025

              Oct 18  Oct 19  Oct 20
S1 or greater   10%      5%      5%

Rationale: There is a slight chance for a greater than 10 MeV proton
event above the S1 (Minor) levels through 18 Oct.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Oct 17 2025 0128 UTC.

Radio Blackout Forecast for Oct 18-Oct 20 2025

              Oct 18        Oct 19        Oct 20
R1-R2           60%           40%           40%
R3 or greater   15%            5%            5%

Rationale: Minor to moderate (R1-R2) radio blackouts are likely through
18 Oct, with a slight chance for an isolated R3 (Strong) event, due to
the flare potential of Regions 4246 and 4248. Probabilities decrease
slightly on 19-20 Oct as AR 4246 rotates beyond the western limb.