Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 18 Jan 2026 23:34 UT)

Date T index 18 Jan 96 Observed Australian Regional MUFs Cocos Island Region: Enhanced by 15% during local day. Near predicted monthly values during local night. Niue Island Region: Enhanced by 25% during local day. Near predicted monthly values during local night. Northern Australian Region: Enhanced by 20% during local day. Near predicted monthly values during local night. Depressed by 25% after local dawn. 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 Dec 110 Jan 89 Feb 88

Ionospheric Forecast

(last updated 18 Jan 2026 23:34 UT)

Date T index MUFs 19 Jan 70 Depressed 10 to 15%/near predicted monthly values 20 Jan 45 Depressed 25 to 35%/near predicted monthly values 21 Jan 45 Depressed 25 to 35%/near predicted monthly values COMMENT: ASWFC SWF HF Communications Warning 10 was issued on 18 January and is current for 18-20 Jan. Maximum Usable Frequencies (MUFs) on UT day 17-Jan were mostly near predicted monthly values, with some enhancements observed in Northern Australia, the Cocos Islands, and Niue Island regions during local daytime hours. Some depressions up to 25% were observed in the Australian region after local dawn. Strong spread-F and sporadic-E were observed in the Southern Australian region. MUFs in the Australian region are expected to be depressed by 10-15% on 19-Jan due to coronal hole high-speed wind stream effects. Depressions of 25-35% are likely on 20-21 Jan due to a potential CME impact forecast for this day. Shortwave fadeouts are probable, and sporadic-E may be observed during local night hours.