This is a sample eAlert
(see this page for (un)subscribing
SFI:271 A:147 K:5 frm 7 (78 nT) 1200 31 Oct
Frcst: SWX next 24h:severe: G4 S3 R3
Obs: SWX last 24h:extreme: G5 S3 R1
Flare: 6h hi:M1(1525Z Oct30) 24h hi:M1(0205Z Oct30)
SSN: 293 (30 Oct 2003)
S Wind: 1001 km/s @ 8.5 protons/cm3
Bz: 7.2 nT at 2003 Oct 31 1203Z
Global HF Propagation Conditions
for 1100Z on 31 Oct, 2003
Low Latitude: Poor
Mid Latitude: Poor
Hi Latitude: Poor(PCA)
Warning (12): Geomagnetic K-index of 7 or greater expected
From: 2003 Oct 30 1700 UTC To: 2003 Oct 31 1600 UTC
Alert (133): Geomagnetic K-index of 6
Period: 1500-1800 UTC
Threshold Reached on 2003 Oct 30 1705 UTC
In these eAlerts, you see the following abbreviations:
SFI = The 10.7-cm Solar Flux Index.
A = The Ap Index (Planetary) from the Ak Index, a daily index of geomagnetic activity for a specific station or network of stations (represented generically here by k) derived as the average of the eight 3-hourly ak indexes in a Universal Time day.
K = The Kp index. A 3-hourly planetary index of geomagnetic activity calculated by the Institut fur Geophysik der Gottingen Universitat, F.R. Germany, from the K indexes observed at 13 stations primarily in the Northern Hemisphere. The Kp indexes, which date from 1932, are used to determine the ap indexes.
nT = NanoTeslas.
The line, "SFI:271 A:147 K:5 frm 7 (78 nT) 1200 31 Oct" is to be read as:
10.7-cm Solar Flux Index is 271.
Planetary A Index is 147
Planetary K Index is 5, down from 7
The nT reading is 78.
These readings are as of 1200 GMT, on the 31st of October (UTC).
Next, you see the forecast (Frcst).
SWX = Solar Weather. The forecast is for the next 24 hours, from the time/date of the SFI line. First, you get the overall rating of the expected solar weather conditions. In this example, it is expected to be "severe" in activity.
Then, you get specific conditions expected.
G4, S3, and R3 are levels, as defined by The NOAA Space Weather Scales tables. See http://www.sec.noaa.gov/NOAAscales/
The G scale refers to Geomagnetic Activity. The scale is:
G5 = Extreme - Kp = 9
G4 = Severe - Kp = 8
G3 = Strong - Kp = 7
G2 = Moderate - Kp = 6
G1 = Minor - Kp = 5
The S scale refers to Solar Activity. This scale is:
S5 = Extreme - Flux level of > 10 Mev = 10^5
S4 = Severe - Flux level of > 10 Mev = 10^4
S3 = Strong - Flux level of > 10 Mev = 10^3
S2 = Moderate - Flux level of > 10 Mev = 10^2
S1 = Minor - Flux level of > 10 Mev = 10
The R scale refers to Radio Blackouts. The scale is:
(NOTE: the ^-5 is -5 superscripted, and so on)
R5 = Extreme - X20 Class Flare, Flux = 2x10^-3
R4 = Severe - X10 Class Flare, Flux = 10^-3
R3 = Strong - X1 Class Flare, Flux = 10^-4
R2 = Moderate - M5 Class Flare, Flux = 5x10^-5
R1 = Minor - M1 Class Flare, Flux = 10^-5
Next, you will see the Observed Space Weather (SWX). The format is the same as for that of the Forecast, and is for the last 24 hours as of the SFI reading date and time.
Next is the Solar Flare summary. It shows the classification of the highest flare during the last 6 hours, and the last 24 hours. What is a Flare, and how are they classified?
This is then followed by the estimated SSN - Smoothed Sunspot Number - and the date of the reporting.
The Aurora Index follows, then the Solar Wind reading.
Next is the "Bz" reading - the orientation being south if this is negative, or north if this is positive. If negative, it typically means that geomagnetic activity is being increased.
After the Bz reading is the general HF conditions, shown for three latitude regions. A PCA is a "Polar Cap Absorption" event. This means that the polar regions will not typically propagation any HF radio signal.
Any further Warnings or Alerts are then listed.
Some notes of interest:
1) eAlerts are sent out any time the Kp (planetary K) index is at
or above 5, and also whenever the solar flux changes. eAlerts
are not sent out during times when the Kp index is below 5, even
if there are a lot of changes. This keeps the eAlerts from
becoming excessive. However, during days of very high geomagnetic
activity, when the Kp index may stay at or rise above 5, you may
receive eAlerts every three hours during the course of the storm.
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Thank you! -- Tomas, NW7US.
copyright, 1998 - 2004, Tomas Hood (NW7US), all rights reserved.