Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 20 May 2025 23:32 UT)

Date T index 20 May 87 Observed Australian Regional MUFs Cocos Island Region: Near predicted monthly values during local day. Depressed by 15% during local night. Niue Island Region: Near predicted monthly values during local day. Depressed by 25% during local night. Northern Australian Region: Near predicted monthly values during local day. Depressed by 20% during local night. Southern Australian Region: Near predicted monthly values during local day. Depressed by 25% during local night. Antarctic Region (Casey/Davis/Mawson): Depressed by 15% over the UT day. Monthly T index: Month T index Apr 123 May 113 Jun 111

Ionospheric Forecast

(last updated 20 May 2025 23:32 UT)

Date T index MUFs 21 May 90 Depressed 15%/near predicted monthly values 22 May 90 Depressed 15%/near predicted monthly values 23 May 90 Depressed 15%/near predicted monthly values COMMENT: Maximum usable frequencies (MUFs) in the Australian region on UT day 20-May were near predicted monthly values during local day and 20-25% depressed during local night. Spread F was observed at Hobart during local night hours. MUFs are expected to be near predicted monthly values to 15% depressed over 21-23 May. Shortwave fadeouts are possible.