FXXX10 KWNP 201231

DAYTDF



:Product: 3-Day Forecast

:Issued: 2026 Mar 20 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 Mar 20-Mar 22 2026 is 6.33 (NOAA Scale

G2).



NOAA Kp index breakdown Mar 20-Mar 22 2026



             Mar 20       Mar 21       Mar 22

00-03UT       2.00         4.67 (G1)    4.67 (G1)

03-06UT       2.67         6.33 (G2)    5.00 (G1)

06-09UT       3.67         5.67 (G2)    4.33     

09-12UT       3.67         5.33 (G1)    4.00     

12-15UT       4.67 (G1)    4.33         2.67     

15-18UT       4.67 (G1)    4.67 (G1)    3.33     

18-21UT       6.00 (G2)    4.67 (G1)    4.33     

21-00UT       6.33 (G2)    4.33         4.33     



Rationale: The geomagnetic field is expected to be at active to G2

(Moderate) storm levels on 20 Mar as CMEs from 16-17 Mar are anticipated

to arrive. Additional G2 (Moderate) storm conditions are likely, with G3

(Strong) conditions possible, on 21 Mar as the CME from 18 Mar is

expected to arrive in conjunction with the onset of a negative polarity

CH HSS. Unsettled to G1 (Minor) levels are expected on 22 Mar as CME/CH

HSS effects persist.



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 Mar 20-Mar 22 2026



              Mar 20  Mar 21  Mar 22

S1 or greater    1%      1%      1%



Rationale: No S1 (Minor) or greater solar radiation storms are expected.





C. NOAA Radio Blackout Activity and Forecast



No radio blackouts were observed over the past 24 hours.



Radio Blackout Forecast for Mar 20-Mar 22 2026



              Mar 20        Mar 21        Mar 22

R1-R2           15%           15%           15%

R3 or greater    1%            1%            1%



Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio

blackouts on 20-22 Mar.