Joint USAF/NOAA Report of Solar and Geophysical Activity 17 March 2012
Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 077 Issued at 2200Z on 17 Mar 2012
IA. Analysis of Solar Active Regions and Activity from 16/2100Z to 17/2100Z: Solar activity was moderate. Region 1435 (S26W37) grew rapidly overnight ending the period as a Dro type group with beta magnetic characteristics. Nearby Region 1434 (S22W27) produced an impulsive M1/Sf flare at 17/2039Z. This flare was accompanied by a Type II radio sweep (1140 km/s). A northward directed wave was visible in SDO/AIA 193 imagery. Region 1432 (N14W39), currently a Cro type group with beta magnetic characteristics, produced a C1 flare at 17/0312, but was generally quiet overnight. New Region 1437 (S34E15) was numbered today. It and the remaining regions were small, magnetically simple, and stable.
IB. Solar Activity Forecast: Solar activity is expected to be low with a chance for an isolated M-class flare all three days (18-20 March), particularly from the vicinity of Regions 1434 and 1435.
IIA. Geophysical Activity Summary 16/2100Z to 17/2100Z: Geomagnetic field activity ranged from quiet to active levels with isolated minor to major storm levels observed at high latitudes. This activity was in response to the continued presence of a high speed solar wind stream. Solar wind speed, measured at the ACE spacecraft, remained around 650 km/s while Bz ranged between +5 and -5 nT. The greater than 2 MeV electron flux at geosynchronous orbit reached high levels during the period.
IIB. Geophysical Activity Forecast: Geomagnetic field activity is expected to begin at unsettled levels and increase to active to isolated minor storm levels on Day 1 (18 March) as a CME from 15 March arrives. Activity levels are expected to be predominantly active on Day 2 (19 March), declining to unsettled levels on Day 3 (20 March) as effects from the CME subside. Analysis of the M1/Sf flare is ongoing to determine if it was associated with an Earth-directed CME.
III. Event Probabilities 18 Mar-20 Mar
Class M 30/30/30
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 17 Mar 102
Predicted 18 Mar-20 Mar 100/100/105
90 Day Mean 17 Mar 124
V. Geomagnetic A Indices
Observed Afr/Ap 16 Mar 017/021
Estimated Afr/Ap 17 Mar 013/016
Predicted Afr/Ap 18 Mar-20 Mar 018/025-015/020-008/010
VI. Geomagnetic Activity Probabilities 18 Mar-20 Mar
A. Middle Latitudes
Active 40/30/05
Minor storm 20/15/01
Major-severe storm 05/01/01
B. High Latitudes
Active 15/15/15
Minor storm 25/20/10
Major-severe storm 35/25/05
