Joint USAF/NOAA Report of Solar and Geophysical Activity SDF Number 078 Issued at 2200Z on 18 Mar 2012 IA. Analysis of Solar Active Regions and Activity from 17/2100Z to 18/2100Z: Solar activity was low. Region 1434 (S20W40) produced a single C1/Sn flare at 17/0237Z and ended the period as a Dso type group with beta magnetic characteristics. Region 1435 (S25W50) grew larger and more magnetically complex, ending as a Dao type group with beta-gamma magnetic characteristics. A non-Earth-directed CME was observed in SOHO/LASCO C2 imagery at 18/0024Z and believed to originate from old Region 1429 (N19, L=295). IB. Solar Activity Forecast: Solar activity is expected to be low with a slight chance for an M-class flare from Regions 1434 or 1435. IIA. Geophysical Activity Summary 17/2100Z to 18/2100Z: The geomagnetic field ranged from quiet to active levels. The coronal hole high speed stream abated over the course of the day. Solar wind speed at the ACE spacecraft began declining from 650 km/s at 17/2300Z to end the period near 500 km/s. Bt decreased and Bz was neutral to slightly negative. With the departure of the high speed stream, the geomagnetic field activity decreased from active to quiet levels. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period. IIB. Geophysical Activity Forecast: The geomagnetic field is expected to range from quiet to active levels as a CME from 15 March arrives early in the period on Day 1 (19 March). There is a slight chance for minor storm levels. Activity levels are expected to decline to unsettled on Day 2 (20 March) and quiet by Day 3 (21 March) as the effects from the CME subside. III. Event Probabilities 19 Mar-21 Mar Class M 15/15/15 Class X 05/05/05 Proton 05/05/05 PCAF green