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.

