Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 27 Apr 2026 23:30 UT)

Date T index 27 Apr 85 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Enhanced by 15% during local day. Near predicted monthly values during local night. Northern Australian Region: Near predicted monthly values. Southern Australian Region: Near predicted monthly values. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Mar 92 Apr 83 May 81

Ionospheric Forecast

(last updated 27 Apr 2026 23:30 UT)

Date T index MUFs 28 Apr 80 Near predicted monthly values 29 Apr 80 Near predicted monthly values 30 Apr 80 Near predicted monthly values COMMENT: ASWFC SWF HF Communications Warning 43 was issued on 27 April and is current for 27-29 Apr. Maximum Usable Frequencies (MUFs) in the Australian and Antarctic regions were near predicted monthly values across UT day 27-Apr. Spread-F was observed at sites in the Southern Australian region. MUFs are expected to remain near predicted values over 28-29 Apr, with some small depressions possible on 30-Apr due to forecast geomagnetic activity. Shortwave fadeouts are probable.