Joint USAF/NOAA Report of Solar and Geophysical Activity 29 March 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Mar 29 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 088 Issued at 2200Z on 29 Mar 2011
IA. Analysis of Solar Active Regions and Activity from 28/2100Z
to 29/2100Z: Solar activity remained at low levels. Region 1183
(N15E39) produced a single C1 flare at 29/0515Z, along with several
optical subflares early in the period. Region 1183 showed gradual
spot and penumbral growth through the summary period and was
classified as an Eac group with a beta magnetic configuration.
Region 1176 (S16W24) showed no significant changes during the period
and produced an isolated B-class flare. No new regions were
numbered.
IB. Solar Activity Forecast: Solar activity is expected to be low
during the period (30 March – 01 April) with a chance for an M-class
flare from Region 1183. Old Region 1169 (N17, L=078) is expected to
return to the visible disk late on day 1 (30 March) and may also
provide a chance for an M-class flare.
IIA. Geophysical Activity Summary 28/2100Z to 29/2100Z:
Geomagnetic activity was at quiet levels. A weak geomagnetic sudden
impulse (SI) occurred at 29/1604Z (8 nT, as measured by the Boulder
USGS magnetometer). The SI likely represented the passage of the
halo-CME observed on 24 March. ACE solar wind data showed increased
velocities (313 to 384 km/s), as well as increases in density (2 to
27 p/cc) and IMF Bt (5 to 9 nT) following the CME passage. IMF Bz
was mostly northward following the passage.
IIB. Geophysical Activity Forecast: Geomagnetic activity is
expected to be at quiet to unsettled levels during the period (30
March – 01 April) with a chance for brief active levels due to
recurrent coronal hole high-speed stream effects.
III. Event Probabilities 30 Mar-01 Apr
Class M 40/40/40
Class X 05/05/05
Proton 01/01/01
PCAF green
IV. Penticton 10.7 cm Flux
Observed 29 Mar 116
Predicted 30 Mar-01 Apr 120/125/130
90 Day Mean 29 Mar 097
V. Geomagnetic A Indices
Observed Afr/Ap 28 Mar 002/003
Estimated Afr/Ap 29 Mar 003/005
Predicted Afr/Ap 30 Mar-01 Apr 010/010-010/010-008/008
VI. Geomagnetic Activity Probabilities 30 Mar-01 Apr
A. Middle Latitudes
Active 20/20/15
Minor storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 25/25/20
Minor storm 10/10/05
Major-severe storm 01/01/01