Detailed hourly weather forecast in Cerna v Posumavi

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 latitude.).

Protection from UV radiation from the Sun is not necessary. A UV index reading of 0 to 2 means low danger from the sun's UV rays for the average person. Wear sunglasses on bright days. If you burn easily, cover up and use broad spectrum SPF 30+ sunscreen. Bright surfaces, such as sand, water, and snow, will increase UV exposure.

Protection from UV radiation from the Sun is necessary. A UV index reading of 3 to 5 means moderate risk of harm from unprotected sun exposure. Stay in shade near midday when the sun is strongest. If outdoors, wear sun protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating. Bright surfaces, such as sand, water, and snow, will increase UV exposure.

Protection from UV radiation from the Sun is necessary. A UV index reading of 6 to 7 means high risk of harm from unprotected sun exposure. Protection against skin and eye damage is needed. Reduce time in the sun between 10 a.m. and 4 p.m. If outdoors, seek shade and wear sun protective clothing, a wide-brimmed hat, and UV-blocking sunglasses. Generously apply broad spectrum SPF 30+ sunscreen every 2 hours, even on cloudy days, and after swimming or sweating. Bright surfaces, such as sand, water, and snow, will increase UV exposure.

Power systems: High-latitude power systems may experience voltage alarms, long-duration storms may cause transformer damage.

Spacecraft operations: Corrective actions to orientation may be required by ground control; possible changes in drag affect orbit predictions.

Other systems: HF radio propagation can fade at higher latitudes, and aurora has been seen as low as New York and Idaho (typically 55° geomagnetic latitude.).