NOAA/UDAF Report of Solar-Geophysical Activity 26 Mar 2000

:Product: Report of Solar-Geophysical Activity

:Issued: 2000 Mar 26 2200 UT

# 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 086 ISSUED AT 2200Z ON 26 MAR 2000

IA.  ANALYSIS OF SOLAR ACTIVE REGIONS AND ACTIVITY FROM  25/2100Z

TO 26/2100Z:  SOLAR ACTIVITY WAS MODERATE DUE TO A SINGLE M-CLASS

EVENT; AN M2/SF FROM REGION 8926 (S12W55) AT 26/1734UT. THIS EVENT

ALSO PRODUCED A 3 DEGREE LONG, DISAPPEARING SOLAR FILAMENT (DSF)

NEAR THE REGION CENTER AT S11W55. THIS REGION ALSO PRODUCED A C2/SF

AT 25/2205UT. REGION 8921 (S14W02) PRODUCED A C7/1F AT 25/2243UT.

THIS EVENT WAS ACCOMPANIED BY TYPE II AND IV RADIO SWEEPS. OTHER

ACTIVE REGIONS INCLUDED: 8916 (N08W30), 8920 (N23W07), 8924

(N10E39), AND 8925 (S18E38), ALL OF WHICH PRODUCED ISOLATED OPTICAL

SUBFLARES. REGIONS 8924 AND 8925 SHOWED AN INCREASE IN SIZE DURING

THE PERIOD AND ALSO DEVELOPED INTO MORE COMPLEX BETA-GAMMA MAGNETIC

CLASSIFICATIONS.

IB.  SOLAR ACTIVITY FORECAST:  SOLAR ACTIVITY IS EXPECTED TO BE

MOSTLY LOW WITH THE POSSIBILITY OF ISOLATED M-CLASS EVENTS.

IIA.  GEOPHYSICAL ACTIVITY SUMMARY FROM 25/2100Z TO 26/2100Z:

THE GEOMAGNETIC FIELD WAS MOSTLY QUIET TO UNSETTLED WITH ONE ISOLATED

ACTIVE PERIOD AT 26/15-1800UT.

IIB.  GEOPHYSICAL ACTIVITY FORECAST:  THE GEOMAGNETIC FIELD IS

EXPECTED TO BE QUIET TO UNSETTLED ON THE FIRST DAY OF THE PERIOD AND

QUIET TO ACTIVE ON THE SECOND AND THIRD DAYS. ACTIVE CONDITIONS ARE

POSSIBLE DUE TO FAVORABLE INDICATIONS, THAT THE C7/1F EVENT

DESCRIBED ABOVE, COULD HAVE ALSO PRODUCED AN EARTH-DIRECTED CORONAL

MASS EJECTION (CME). THESE INDICATORS AND THE REGION’S CENTRAL

POSITION AT THE TIME OF THE EVENT COMBINE TO PRODUCE POSSIBLE

GEOEFFECTIVE CONDITIONS. IMAGES FROM THE SOHO/LASCO SPACECRAFT WERE

NOT AVAILABLE AT THE TIME OF THE EVENT, MAKING IT DIFFICULT TO

VERIFY THE PRESENCE OF AN EARTH-DIRECTED CME.

III.  EVENT PROBABILITIES 27 MAR-29 MAR

CLASS M    60/60/60

CLASS X    10/10/10

PROTON     05/05/05

PCAF       GREEN

IV.  PENTICTON 10.7 CM FLUX

OBSERVED           26 MAR 211

PREDICTED   27 MAR-29 MAR  205/200/200

90 DAY MEAN        26 MAR 177

V.  GEOMAGNETIC A INDICES

OBSERVED AFR/AP 25 MAR  005/008

ESTIMATED AFR/AP 26 MAR  008/008

PREDICTED AFR/AP 27 MAR-29 MAR  008/008-020/025-020/020

VI.  GEOMAGNETIC ACTIVITY PROBABILITIES 27 MAR-29 MAR

A.  MIDDLE LATITUDES

ACTIVE                30/60/60

MINOR STORM           05/10/10

MAJOR-SEVERE STORM    01/01/01

B.  HIGH LATITUDES

ACTIVE                40/70/70

MINOR STORM           10/25/20

MAJOR-SEVERE STORM    01/01/01