SOLAR ACTIVITY HAS BEEN MODERATE. REGION 9090 (N15W83) PRODUCED TODAY'S ONLY M-CLASS FLARE, AN M1/SF AT 27/2342Z. THE REGION WAS QUIET FOR THE REMAINDER OF THE DAY AS IT ROTATED AROUND THE WEST LIMB. REGION 9103 (N10E03) SHOWED GROWTH DURING THE PAST 24 HOURS BUT COULD ONLY PRODUCE A SUBFLARE. REGION 9097 (N09W55), CURRENTLY THE LARGEST REGION ON THE DISK, CONTINUED TO DECAY QUIETLY. CLOSER ANALYSIS OF YESTERDAY'S HALO CME USING AVAILABLE EIT AND H-ALPHA DATA INDICATE THAT THE TRANSIENT ORIGINATED FROM THE BACKSIDE OF THE SUN.

SOLAR ACTIVITY IS EXPECTED TO BE LOW FOR THE NEXT THREE DAYS, BUT THERE IS A CHANCE FOR AN ISOLATED M-CLASS EVENT, WITH REGIONS 9097 AND 9103 AS THE MOST LIKELY SOURCES. IIA. GEOPHYSICAL ACTIVITY SUMMARY 27/2100Z TO 28/2100Z: THE GEOMAGNETIC FIELD HAS RANGED FROM QUIET TO MINOR STORM LEVELS DURING THE PAST 24 HOURS. AN INITIALLY QUIET TO UNSETTLED FIELD BECAME DISTURBED WITH THE ARRIVAL OF THE TRANSIENT MATERIAL FROM THE CME OF 25 JULY. THE FIRST INDICATION OF THE TRANSIENT WAS A SHOCK AT ACE AT 0543Z, SHORTLY FOLLOWED BY A SUDDEN IMPULSE AT 0635Z (MEASURING 41 NT ON THE BOULDER MAGNETOMETER). THE SHOCK WAS FOLLOWED BY STRONG TO MODERATELY SOUTHWARD BZ FIELDS (-5 TO -15 NT) UNTIL 1318Z WHEN BZ INTENSIFIED TO STRONGLY NEGATIVE VALUES FOR ABOUT 3 HOURS (-15 TO -20 NT). MINOR STORM LEVELS (ESTIMATED KP'S OF 5) WERE SUSTAINED FOR 12 HOURS FROM 0600-1800Z. A GREATER THAN 10 PFU PROTON EVENT AT GREATER THAN 10 MEV WAS OBSERVED: PARTICLE FLUXES BEGAN TO RISE SLOWLY AFTER 0200Z AND ATTAINED THRESHOLD AT 1050Z. THE PEAK OF THE EVENT WAS 18 PFU AT 1130Z AND THE EVENT FELL BELOW THRESHOLD AT 1310Z.

THE GEOMAGNETIC FIELD IS EXPECTED TO BE ACTIVE FOR THE NEXT 24 HOURS, WITH A POSSIBILITY FOR SOME ISOLATED MINOR STORM PERIODS. NIGHTTIME SECTORS IN PARTICULAR MAY EXPERIENCE EFFECTS OF LOCAL SUBSTORM ACTIVITY AS THE CURRENT DISTURBANCE SUBSIDES. PREDOMINANTLY UNSETTLED CONDITIONS ARE EXPECTED FOR THE SECOND AND THIRD DAYS.

  Спостережуваний       28 JUL 158
  Прогнозований   29 JUL-31 JUL  155/155/150
  Середнє значення за останні 90 днів        28 JUL 189

OBSERVED AFR/AP 27 JUL  006/009
ESTIMATED AFR/AP 28 JUL  030/030
PREDICTED AFR/AP 29 JUL-31 JUL  020/020-010/015-010/012