Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 12 Sep 2025 23:30 UT)

Date T index 12 Sep 86 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Near predicted monthly values. Northern Australian Region: Mostly near predicted monthly values. Southern Australian Region: Mostly near predicted monthly values. Antarctic Region (Casey/Davis/Mawson): Depressed by 15% over the UT day. Monthly T index: Month T index Aug 96 Sep 92 Oct 90

Ionospheric Forecast

(last updated 12 Sep 2025 23:30 UT)

Date T index MUFs 13 Sep 90 Near predicted monthly values 14 Sep 90 Near predicted monthly values 15 Sep 80 Near predicted monthly values to 10-20% depressed COMMENT: ASWFC Preliminary HF Communications Warning 83 was issued on 12 September and is current for 15-16 Sep. Maximum usable frequencies (MUFs) in the Australian region on UT day 12-Sep were near predicted values. MUFs are expected to be near predicted values over 13-14 Sep but may begin to depress by 15-Sep due to anticipated geomagnetic activity from a coronal hole.