Space Weather Advisory Bulletin #06- 5
NOAA ^ | 14 December 2006



**** GEOMAGNETIC STORM IN PROGRESS ****


A geomagnetic storm began on December 14 at 1416 UTC (9:16 A.M. EST).



The Mauna Loa Solar Observatory (MLSO), operated by the High Altitude Observatory
in Boulder Colorado, is allowing SEC to use their latest H-alpha and Helium-I images
while the SEC GOES SXI images are unavailable.



A solar flare on 13 December at 0240 UTC (12 December, 9:40 P.M. EST) from NOAA Region 930 produced strong radio blackouts (R3) ...
R 3 Strong

HF Radio: Wide area blackout of HF radio communication, loss of radio contact for about an hour on sunlit side of Earth.

Navigation: Low-frequency navigation signals degraded for about an hour.


. . . and an associated moderate (S2) solar radiation storm.
S 2 Moderate

Biological: passengers and crew in high-flying aircraft at high latitudes may be exposed to elevated radiation risk.***

Satellite operations: infrequent single-event upsets possible.

Other systems: small effects on HF propagation through the polar regions and navigation at polar cap locations possibly affected.

A large Earth-directed coronal mass ejection was also observed with this event, producing today's geomagnetic storming.

Strong to severe (G3 and G4) geomagnetic storming is expected to last through 15 December.
G 4 Severe

Power systems: possible widespread voltage control problems and some protective systems will mistakenly trip out key assets from the grid.

Spacecraft operations: may experience surface charging and tracking problems, corrections may be needed for orientation problems.

Other systems: induced pipeline currents affect preventive measures, HF radio propagation sporadic, satellite navigation degraded for hours, low-frequency radio navigation disrupted, and aurora has been seen as low as Alabama and northern California (typically 45° geomagnetic lat.)**.

G 3 Strong

Power systems: voltage corrections may be required, false alarms triggered on some protection devices.

Spacecraft operations: surface charging may occur on satellite components, drag may increase on low-Earth-orbit satellites, and corrections may be needed for orientation problems.

Other systems: intermittent satellite navigation and low-frequency radio navigation problems may occur, HF radio may be intermittent, and aurora has been seen as low as Illinois and Oregon (typically 50° geomagnetic lat.)**.



Region 930 is a large sunspot group which is still rotating across the visible disk.

Because of the current position of Region 930, additional activity has greater potential to quickly impact Earth.

Agencies impacted by space weather storms should continue to closely monitor space weather conditions during the next four days.