664
FXXX10 KWNP 311231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Jul 31 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 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Jul 31-Aug 02 2026 is 5.67 (NOAA Scale
G2).

NOAA Kp index breakdown Jul 31-Aug 02 2026

             Jul 31       Aug 01       Aug 02
00-03UT       1.33         3.00         1.33
03-06UT       1.00         2.33         4.00
06-09UT       1.33         2.00         5.67 (G2)
09-12UT       1.67         1.33         4.33
12-15UT       1.67         4.00         5.00 (G1)
15-18UT       2.33         3.67         3.00
18-21UT       2.67         3.00         2.00
21-00UT       3.67         2.67         3.00

Rationale: G1-G2 (Minor-Moderate) geomagnetic storms are likely on 02
Aug due to the anticipated arrival of a CME that left the Sun on 30 Jul.

B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
above S-scale storm level thresholds.

Solar Radiation Storm Forecast for Jul 31-Aug 02 2026

              Jul 31  Aug 01  Aug 02
S1 or greater   40%      5%      5%

Rationale: There remains a chance for S1 (Minor) or greater solar
radiation storms over 31 Jul.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Jul 30 2026 1700 UTC.

Radio Blackout Forecast for Jul 31-Aug 02 2026

              Jul 31        Aug 01        Aug 02
R1-R2           30%           30%           30%
R3 or greater    1%            1%            1%

Rationale: A chance exists for R1-R2 (Minor-Moderate) radio blackouts
over 31 Jul - 02 Aug due to eruptive potential of multiple regions on
the Suns visible disk.