173
FXXX10 KWNP 261231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Jun 26 1230 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 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Jun 26-Jun 28 2025 is 4.67 (NOAA Scale
G1).

NOAA Kp index breakdown Jun 26-Jun 28 2025

             Jun 26       Jun 27       Jun 28
00-03UT       4.00         4.00         3.67
03-06UT       3.33         4.67 (G1)    3.33
06-09UT       3.67         4.00         3.00
09-12UT       2.67         3.33         2.67
12-15UT       3.00         2.33         2.33
15-18UT       3.00         2.33         2.33
18-21UT       4.00         2.67         2.67
21-00UT       4.67 (G1)    3.00         2.67

Rationale: G1 (Minor) geomagnetic storming is likely, with a chance for
an insolated G2 (Moderate) storming period, on 26-27 June due to
negative polarity CH HSS 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 Jun 26-Jun 28 2025

              Jun 26  Jun 27  Jun 28
S1 or greater    5%      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

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Jun 26-Jun 28 2025

              Jun 26        Jun 27        Jun 28
R1-R2           30%           35%           35%
R3 or greater    5%            5%            5%

Rationale: A chance for R1-R2 (Minor-Moderate) radio blackouts, with a
slight chance for X-class flares (R3-Strong), will persist through 28
June.