NOAA SEC Report of Solar-Geophysical Activity 28 Apr 2002

:Product: Report of Solar-Geophysical Activity

:Issued: 2002 Apr 28 2210 UTC

# Prepared jointly by the U.S. Dept. of Commerce, NOAA,

#Space Environment Center and the U.S. Air Force.

#

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 118 Issued at 2200Z on 28 Apr 2002

IA.  Analysis of Solar Active Regions and Activity from  27/2100Z

to 28/2100Z:  Solar activity was low. The only C-class flare of the

period was a C1/Sf from Region 9924 (S15W64) at 28/1823Z. No

significant activity or changes were noted in any of the active

regions.

IB.  Solar Activity Forecast:  Solar activity is expected to continue

at low levels. Regions 9914 (N05W51), 9915 (N12W40) and 9919

(N14E01) have the best potential for isolated C-class flares.

IIA.  Geophysical Activity Summary 27/2100Z to 28/2100Z:

The geomagnetic field was quiet to active. The recurrent high speed

coronal hole stream developed late last period and produced mostly

active conditions during local nighttime hours.

IIB.  Geophysical Activity Forecast:  The geomagnetic field is

expected to continue at quiet to active levels. The active periods

will occur predominantly during local nighttime hours.

III.  Event Probabilities 29 Apr-01 May

Class M    15/15/20

Class X    01/01/05

Proton     01/01/01

PCAF       green

IV.  Penticton 10.7 cm Flux

Observed           28 Apr 147

Predicted   29 Apr-01 May  145/145/150

90 Day Mean        28 Apr 194

V.  Geomagnetic A Indices

Observed Afr/Ap 27 Apr  010/008

Estimated Afr/Ap 28 Apr  015/018

Predicted Afr/Ap 29 Apr-01 May  012/012-010/008-005/008

VI.  Geomagnetic Activity Probabilities 29 Apr-01 May

A.  Middle Latitudes

Active                35/30/25

Minor storm           15/10/05

Major-severe storm    05/05/01

B.  High Latitudes

Active                50/40/30

Minor storm           25/15/05

Major-severe storm    05/05/01