Space Weather

Each scale is NOAA's own current reading, not a derived recommendation. R can affect sunlit HF, S can affect polar HF and satellites, and G can affect high-latitude HF, aurora, and navigation.

Solar radio flux (F10.7) is broad solar-activity context relevant to upper-HF support; it runs roughly 65 sfu at solar minimum to 250+ sfu at solar maximum. The planetary K index (Kp) is a global geomagnetic-activity measure over a three-hour period, running 0–9; NOAA's G scale storms begin at Kp 5. Neither measures your path or proves a band is open.

X-ray flux is the GOES measurement NOAA's R scale is derived from, shown as the class amateurs quote (A, B, C, M, X, each 10x the last). Solar wind speed, total field (Bt), and Bz (GSM) are current readings from NOAA's real-time solar-wind monitors; a disturbed reading can precede a geomagnetic storm, but one reading is not that forecast. None of these measure your path or prove a band is open.

Four broad readings of the environment above, derived only from evidence that is currently fresh -- never a claim that a path, band, or contact is open. Unknown means the evidence needed to say is incomplete, which is a different statement from Nominal.

The same four states, grouped by the band ranges NOAA's scales and F10.7 speak to instead of by effect. This does not predict whether any specific band or path is open; check current activity and reported spots before relying on it.

Kp intervals NOAA forecasts three hours at a time, out to about four days. Underway means the interval has started; Ahead means it has not yet, decided by the clock rather than by NOAA's own status field, which can mark a row hours out the same way it marks the current one.

• Sep 15, 21:00 UTCUnderwayKp 4.67G1
• Sep 16, 00:00 UTCAheadKp 3.67Below G1
• Sep 16, 03:00 UTCAheadKp 3.33Below G1
• Sep 16, 06:00 UTCAheadKp 3.00Below G1
• Sep 16, 09:00 UTCAheadKp 2.67Below G1
• Sep 16, 12:00 UTCAheadKp 3.00Below G1
• Sep 16, 15:00 UTCAheadKp 3.33Below G1
• Sep 16, 18:00 UTCAheadKp 3.67Below G1
• Sep 16, 21:00 UTCAheadKp 4.67G1
• Sep 17, 00:00 UTCAheadKp 4.00Below G1

NOAA's own chance of radio-blackout and solar-radiation-storm activity over the next three days, and the highest geomagnetic scale expected each day. The percentages are NOAA's, not a dalMap estimate.

The first week of NOAA's 27-day space-weather outlook: predicted solar radio flux, the planetary A index, and the largest Kp expected each day. NOAA issues this weekly; a stale issue is shown as stale and emptied rather than presented as a week partly already past.

Recent NOAA bulletins that bear on radio operating: alerts, watches, warnings, and summaries for radio blackouts, solar radiation storms, geomagnetic storms, and aurora. A canceled bulletin withdraws its own earlier issue rather than standing beside it.

• WarningG1 - Minor

  Geomagnetic K-index of 5 expected

  High-latitude HF, aurora, navigation, or satellite operations may be affected.

  Issued Sep 15, 18:56 UTC

• Warning

  Geomagnetic K-index of 4 expected

  High-latitude HF, aurora, navigation, or satellite operations may be affected.

  Issued Sep 15, 18:50 UTC

• WatchG1

  Geomagnetic Storm Category G1 Predicted

  High-latitude HF, aurora, navigation, or satellite operations may be affected.

  Issued Sep 15, 17:37 UTC

• Alert

  Geomagnetic K-index of 4

  High-latitude HF, aurora, navigation, or satellite operations may be affected.

  Issued Sep 14, 18:02 UTC

NOAA's Solar Region Summary: each numbered sunspot region's location, area, McIntosh class, and magnetic type. Beta-Gamma-Delta regions carry the greatest flare risk; this lists what NOAA observed, not a flare forecast or a claim that any region will produce one.