Report of Solar-Geophysical Activity

Issued: 2006 Apr 14 2200 UTC

Prepared jointly by the U.S. Dept. of Commerce, NOAA, # Space Environment Center and the U.S. Air Force.

 

Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 104 Issued at 2200Z on 14 Apr 2006 IA. Analysis of Solar Active Regions and Activity from 13/2100Z to 14/2100Z: Solar activity remained very low. No significant flares occurred during the past 24 hours.

IB. Solar Activity Forecast: Solar activity is expected to be at very low to low levels.

IIA. Geophysical Activity Summary 13/2100Z to 14/2100Z:

The geomagnetic field ranged from quiet to major storm levels. An interval of major to severe storm conditions was observed at the Boulder magnetometer between 14/0600Z and 1200Z. The interplanetary magnetic field strengthened, and the Z-component rotated smoothly from 13/1500Z through 14/1200Z from 17 nT through a maximum negative value of -15 nT. Solar wind speeds ranged from approximately 480 km/s to 570 km/s. The unusual solar wind conditions appear to be consistent with a corotating interaction region that may have been complicated by the presence of transient flow. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels today.

IIB. Geophysical Activity Forecast: The geomagnetic field is expected to be unsettled to active. Isolated periods of minor to major storm conditions are possible on 15-16 April due to a coronal hole high speed stream. Predominantly unsettled conditions will return on 17 April.

III. Event Probabilities 15 Apr-17 Apr

Class M 05/05/05

Class X 01/01/01

Proton 01/01/01

PCAF green

IV. Penticton 10.7 cm Flux

Observed 14 Apr 079

Predicted 15 Apr-17 Apr 080/080/080

90 Day Mean 14 Apr 080

V. Geomagnetic A Indices

Observed Afr/Ap 13 Apr 009/013

Estimated Afr/Ap 14 Apr 032/040

Predicted Afr/Ap 15 Apr-17 Apr 025/030-020/025-015/015 VI. Geomagnetic Activity Probabilities 15 Apr-17 Apr A. Middle Latitudes

Active 35/30/25

Minor storm 25/20/15

Major-severe storm 10/10/05

B. High Latitudes

Active 40/35/30

Minor storm 25/25/20

Major-severe storm 15/10/10