Joint USAF/NOAA Report of Solar and Geophysical Activity 18 March 2012

:Product: Report of Solar-Geophysical Activity
:Issued: 2012 Mar 18 2200 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
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
IV. Penticton 10.7 cm Flux
Observed 18 Mar 102
Predicted 19 Mar-21 Mar 100/105/105
90 Day Mean 18 Mar 124
V. Geomagnetic A Indices
Observed Afr/Ap 17 Mar 015/022
Estimated Afr/Ap 18 Mar 011/013
Predicted Afr/Ap 19 Mar-21 Mar 015/020-008/010-005/005
VI. Geomagnetic Activity Probabilities 19 Mar-21 Mar
A. Middle Latitudes
Active 30/05/05
Minor storm 15/01/01
Major-severe storm 01/01/01
B. High Latitudes
Active 15/15/15
Minor storm 20/10/15
Major-severe storm 15/05/05