Solar activity report

Viewing archive of Tuesday, 28 April 1998

Any mentioned solar flare in this report has a scaling factor applied by the Space Weather Prediction Center (SWPC). Because of the SWPC scaling factor, solar flares are reported as 42% smaller than for the science quality data. The scaling factor has been removed from our archived solar flare data to reflect the true physical units.

Report of Solar-Geophysical Activity 1998 Apr 28 2200 UTC
Prepared by the NOAA © SWPC and processed by SpaceWeatherLive.com

Joint USAF/NOAA Report of Solar and Geophysical Activity

SDF Number 118 Issued at 2200Z on 28 APR 1998

IA. Analysis of Solar Active Regions and Activity from 27-2100Z to 28-2100Z

SOLAR ACTIVITY DROPPED PRECIPITOUSLY TO A VERY LOW LEVEL. ONLY B-CLASS ENHANCEMENTS WERE OBSERVED. REGION 8210 (S17E31) RETAINED ITS DELTA CONFIGURATION, DEVELOPED ADDITIONAL MIXED POLARITIES, AND EXHIBITED MINOR GROWTH. H-ALPHA FIBRIL AND VECTOR MAGNETOGRAPH DATA INDICATE STRONG SHEAR IN THIS REGION WHERE THE DELTA IS LOCATED. A FILAMENT IN THIS REGION FADED RAPIDLY BETWEEN 28/1851-1914Z. TWO SMALL REGIONS EMERGED ON THE DISK NEAR S30W64 AND S25E55 AND WERE NUMBERED AS REGIONS 8212 AND 8213 RESPECTIVELY.

IB. Solar Activity Forecast

SOLAR ACTIVITY SHOULD BECOME LOW TO MODERATE DURING THE NEXT THREE DAYS. REGION 8210 RETAINS THE CAPABILITY OF PRODUCING ANOTHER SMALL X-CLASS EVENT. OLD REGION 8194 WILL BE RETURNING TO THE EAST LIMB NEAR S18 AROUND 01 MAY. THIS REGION PRODUCED A LONG DURATION M1 FLARE ON 20 APR FROM SEVERAL DAYS BEYOND THE WEST LIMB THAT RESULTED IN A LARGE SOLAR PROTON EVENT AT EARTH. ACTIVITY LEVELS MAY INCREASE UPON THE RETURN OF THIS REGION.

IIA. Geophysical Activity Summary 27-2100Z to 28-2100Z

THE GEOMAGNETIC FIELD WAS QUIET TO UNSETTLED. SOLAR WIND VELOCITIES DECREASED DURING THE PERIOD TO BELOW 400 KM/S INDICATING AN END OF THE CORONAL HOLE RELATED DISTURBANCE OF THE LAST SEVERAL DAYS. ENERGETIC ELECTRON FLUXES AT GEOSYNCHRONOUS ORBIT WERE PREDOMINANTLY HIGH.

IIB. Geophysical Activity Forecast

THE GEOMAGNETIC FIELD SHOULD BE QUIET TO UNSETTLED UNTIL NEAR MIDDAY ON 29 APR WHEN A HALO CME RELATED DISTURBANCE IS EXPECTED TO BEGIN. UNSETTLED TO MINOR STORM CONDITIONS SHOULD BE EXPERIENCED FROM THAT TIME AND THROUGH 30 APR. ISOLATED PERIODS OF MAJOR STORMING ARE POSSIBLE. PREDOMINANTLY UNSETTLED TO ACTIVE CONDITIONS ARE EXPECTED ON 01 MAY AS THE DISTURBANCE PASSES THE EARTH.

III. Event Probabilities 29 APR to 01 MAY

Class M	20%	20%	25%
Class X	15%	15%	15%
Proton	15%	15%	15%
PCAF	GREEN

IV. Penticton 10.7 cm Flux

  Observed       28 APR 098
  Predicted   29 APR-01 MAY  099/100/103
  90 Day Mean        28 APR 104

V. Geomagnetic A Indices

OBSERVED AFR/AP 27 APR  012/014
ESTIMATED AFR/AP 28 APR  010/015
PREDICTED AFR/AP 29 APR-01 MAY  020/020-020/020-015/015

VI. Geomagnetic Activity Probabilities 29 APR to 01 MAY

A. Middle Latitudes
Active	30%	30%	25%
Minor storm	30%	30%	15%
Major-severe storm	10%	10%	05%

B. High Latitudes
Active	30%	30%	25%
Minor storm	35%	40%	15%
Major-severe storm	15%	15%	05%

All times in UTC

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