674
FXXX10 KWNP 271231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 May 27 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 May 27-May 29 2026 is 3.67 (below NOAA
Scale levels).

NOAA Kp index breakdown May 27-May 29 2026

             May 27       May 28       May 29
00-03UT       2.33         3.00         1.67
03-06UT       2.33         3.67         2.00
06-09UT       3.00         3.00         1.67
09-12UT       2.33         2.33         1.33
12-15UT       2.33         2.00         1.33
15-18UT       2.33         1.67         1.67
18-21UT       2.67         2.67         2.00
21-00UT       3.00         1.67         2.33

Rationale: No G1 (Minor) or greater geomagnetic storms are expected.

B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-19 over the past 24 hours, was
below S-scale storm level thresholds.

Solar Radiation Storm Forecast for May 27-May 29 2026

              May 27  May 28  May 29
S1 or greater   10%      5%      5%

Rationale: There is a slight chance for a return to S1 (Minor) solar
radiation storm levels on 27 May due to the currently elevated
background proton flux.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for May 27-May 29 2026

              May 27        May 28        May 29
R1-R2           40%           40%           40%
R3 or greater    5%            5%            5%

Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts
through 29 May due to the flaring potential of the visible disk and
regions rotating onto the eastern limb.