Joint USAF/NOAA Report of Solar and Geophysical Activity 26 Aug 2002

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 238 Issued at 2200Z on 26 Aug 2002

IA.  Analysis of Solar Active Regions and Activity from  25/2100Z

to 26/2100Z:  Solar activity was moderate. Region 83 (S19W56)

produced two small M-class flares, an M1/Sf at 25/2346 UTC and an

M1/Sf at 26/0103 UTC. In addition, several C-class subflares

occurred in Region 85 (S09W19). The largest was a C4/Sf at 26/0945

UTC. New Region 90 (S03E48) was numbered.
IB.  Solar Activity Forecast:  Solar activity is expected to be low

to moderate.
IIA.  Geophysical Activity Summary 25/2100Z to 26/2100Z:

The geomagnetic field ranged from quiet to major storm levels. A

shock in the solar wind was observed by the NASA ACE spacecraft at

26/1048 UTC. The most active 3-hour geomagnetic period was 26/1500

to 1800 UTC. This activity is believed to be related to the M5

flare/CME event which occurred on 22 August. The greater than 10 MeV

proton event ended at 26/1335 UTC (start at 24/0140 UTC and 317 pfu

peak at 24/0835 UTC).
IIB.  Geophysical Activity Forecast:  The geomagnetic field is

expected to be unsettled to active becoming quiet to unsettled over

the next 24 hours.
III.  Event Probabilities 27 Aug-29 Aug

Class M    40/30/30

Class X    01/01/01

Proton     01/01/01

PCAF       green
IV.  Penticton 10.7 cm Flux

Observed           26 Aug 169

Predicted   27 Aug-29 Aug  160/155/150

90 Day Mean        26 Aug 170
V.  Geomagnetic A Indices

Observed Afr/Ap 25 Aug  004/009

Estimated Afr/Ap 26 Aug  016/018

Predicted Afr/Ap 27 Aug-29 Aug  012/015-008/010-008/008
VI.  Geomagnetic Activity Probabilities 27 Aug-29 Aug

A.  Middle Latitudes

Active                30/30/30

Minor storm           15/15/15

Major-severe storm    05/05/05

B.  High Latitudes

Active                30/30/30

Minor storm           15/15/15

Major-severe storm    05/05/05