Summary and Forecast

The Local Geomagnetic overview and 1 hour forecast is based on the the method developed by Watermann and Gleisner described in DMI Technical Report 06-18 (Geomagnetic Activity Forecast Service (GAFS) Final Project Report Vol. 1).

The method uses time shifted solar wind data (IMF and velocity) from DISCOVR satellite at L1 as input. A linear prediction filter with 5 coefficients is applied to, based on the solar wind data, predict geomagnetic variations at a set of selected ground magnetometer stations; Ny-Ålesund, Tromsø and Dombås as indicated on the map.

Note: The prediction fails or looses accuracy for disturbances not directly driven by the solar wind, such as substorms.

Disturbance levels are based on the measured deviation in the Horizontal North (X) component -Rx:

Ny-Ålesund

Colour	Description	Physical Measure	Threshold
	Quiet	K<3	Rx < 95 nT
	Disturbed	K ⁓ 3-4	95 nT ≤ Rx < 160 nT
	Minor storm	K=5	160 nT ≤ Rx < 270 nT
	Moderate storm	K=6	270 nT ≤ Rx < 415 nT
	Strong storm	K=7	415 nT ≤ Rx < 595 nT
	Severe storm	K=8	595 nT ≤ Rx < 945 nT
	Extreme storm	K=9	Rx ≥ 945 nT

Tromsø

Colour	Description	Physical Measure	Threshold
	Quiet	K<3	Rx < 125 nT
	Disturbed	K ⁓ 3-4	125 nT ≤ Rx < 230 nT
	Minor storm	K=5	230 nT ≤ Rx < 375 nT
	Moderate storm	K=6	375 nT ≤ Rx < 545 nT
	Strong storm	K=7	545 nT ≤ Rx < 750 nT
	Severe storm	K=8	750 nT ≤ Rx < 1155 nT
	Extreme storm	K=9	Rx ≥ 1155 nT

Dombås

Colour	Description	Physical Measure	Threshold
	Quiet	K<4	Rx < 25 nT
	Disturbed	K ⁓ 4	25 nT ≤ Rx < 50 nT
	Minor storm	K=5	50 nT ≤ Rx < 115 nT
	Moderate storm	K=6	115 nT ≤ Rx < 250 nT
	Strong storm	K=7	250 nT ≤ Rx < 450 nT
	Severe storm	K=8	450 nT ≤ Rx < 845 nT
	Extreme storm	K=9	Rx ≥ 845 nT

The corresponding provisional K-indices in last seven days