Status Report

Joint USAF/NOAA Report of Solar and Geophysical Activity 28 April 2012

By SpaceRef Editor
April 28, 2012
Filed under , ,

Prepared jointly by the U.S. Dept. of Commerce, NOAA,
Space Weather Prediction Center and the U.S. Air Force.
Updated 2012 Apr 28 2200 UTC

Joint USAF/NOAA Report of Solar and Geophysical Activity
SDF Number 119 Issued at 2200Z on 28 Apr 2012

IA. Analysis of Solar Active Regions and Activity from 27/2100Z
to 28/2100Z: Solar activity was at low levels due to single,
low-level C-class events from Regions 1461 (N10W89), 1466 (N12W51),
1467 (N12E18), 1469 (S19E14) and new Region 1470 (S17E61). New
Region 1471 (S23E70) was also numbered during the period. A 16
degree filament eruption was observed in SDO/AIA 304 imagery at
28/1045Z. During the period of the eruption, the SE to NW oriented
filament was centered near S32W33. LASCO/C2 imagery observed an
associated slow-moving, non-Earth directed CME lifting off the SW
limb at 28/1224Z.

IB. Solar Activity Forecast: Solar activity is expected to be low
with a slight chance for M-class activity for the next three days
(29 April – 01 May).

IIA. Geophysical Activity Summary 27/2100Z to 28/2100Z:
The geomagnetic field was at quiet to unsettled levels with an
isolated high latitude active period between 28/0900 – 1200Z.
Through the period, ACE solar wind velocities steadily decreased
from about 490 km/s to near 420km/s while the Bz component of the
interplanetary magnetic field was variable between +/-4 nT. The
greater than 2 MeV electron flux at geosynchronous orbit was at high
levels throughout the period.

IIB. Geophysical Activity Forecast: The geomagnetic field is
expected to be at predominately quiet levels for days one and two
(29 – 30 April). By day three (01 May), quiet to unsettled levels,
with isolated active periods, are expected as a coronal hole high
speed stream moves into a geoeffective position.

III. Event Probabilities 29 Apr-01 May
Class M 20/20/20
Class X 01/01/01
Proton 01/01/01
PCAF green

IV. Penticton 10.7 cm Flux
Observed 28 Apr 121
Predicted 29 Apr-01 May 125/120/120
90 Day Mean 28 Apr 112

V. Geomagnetic A Indices
Observed Afr/Ap 27 Apr 007/008
Estimated Afr/Ap 28 Apr 005/005
Predicted Afr/Ap 29 Apr-01 May 004/005-004/005-007/008

VI. Geomagnetic Activity Probabilities 29 Apr-01 May
A. Middle Latitudes
Active 10/10/15
Minor storm 01/01/05
Major-severe storm 01/01/01
B. High Latitudes
Active 10/10/20
Minor storm 01/01/05
Major-severe storm 01/01/01

SpaceRef staff editor.