Joint USAF/NOAA Report of Solar and Geophysical Activity 30 March 2011

:Product: Report of Solar-Geophysical Activity
:Issued: 2011 Mar 30 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 089 Issued at 2200Z on 30 Mar 2011
IA. Analysis of Solar Active Regions and Activity from 29/2100Z
to 30/2100Z: Solar activity remained at low levels. Isolated B- and
C-class flares were observed from Region 1176 (S17W37) and Region
1183 (N15E27). Region 1176 showed magnetic simplification and was
classified as an Fso group with a beta magnetic structure. Region
1183 showed a minor increase in spot count and area and was
classified as an Eai group with a beta magnetic structure. Two
filaments disappeared during the period. The first was 9 degrees in
extent, centered near N48E16, and disappeared early in the period.
The second was 7 degrees in extent, centered near S27E21, and
disappeared around mid-period. There was no significant CME activity
associated with either disappearance. A back-sided partial-halo CME
was observed early in the period, first visible in SOHO/LASCO C2
images at 29/2024Z, with an estimated plane-of-sky velocity of 1075
km/sec. The source of the CME was an active region about a day
beyond the northeast limb. No new regions were numbered.
IB. Solar Activity Forecast: Solar activity is expected to be low
during the period (31 March – 02 April) with a chance for moderate
activity (isolated M-class).
IIA. Geophysical Activity Summary 29/2100Z to 30/2100Z:
Geomagnetic activity was at quiet to active levels. An active period
was observed during 30/0000 – 0300Z, followed by quiet levels for
the rest of the period. A geomagnetic sudden impulse (SI) was
observed at 30/0018Z (12 nT, as measured by the Boulder USGS
magnetometer). ACE solar wind data indicated the increased activity
was associated with a period of southward IMF Bz (maximum deflection
-8 nT at 29/2306Z) combined with increased IMF Bt (peak 15 nT at
29/2359Z).
IIB. Geophysical Activity Forecast: Geomagnetic activity is
expected to be at quiet to unsettled levels during days 1 – 2 (31
March – 01 April) with a chance for brief active levels due to
recurrent coronal hole high-speed stream effects. Activity is
expected to decrease to quiet levels on day 3 (02 April) as coronal
hole effects subside.
III. Event Probabilities 31 Mar-02 Apr
Class M 40/40/40
Class X 05/05/05
Proton 05/05/05
PCAF green
IV. Penticton 10.7 cm Flux
Observed 30 Mar 118
Predicted 31 Mar-02 Apr 125/130/135
90 Day Mean 30 Mar 098
V. Geomagnetic A Indices
Observed Afr/Ap 29 Mar 002/004
Estimated Afr/Ap 30 Mar 007/008
Predicted Afr/Ap 31 Mar-02 Apr 010/010-008/008-005/005
VI. Geomagnetic Activity Probabilities 31 Mar-02 Apr
A. Middle Latitudes
Active 20/15/10
Minor storm 05/05/01
Major-severe storm 01/01/01
B. High Latitudes
Active 25/20/15
Minor storm 10/05/01
Major-severe storm 01/01/01