(3) AN AREA OF CONVECTION (INVEST 98W) HAS PERSISTED NEAR
17.8N 153.1E, APPROXIMATELY 551 NM EAST-NORTHEAST OF GUAM. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY AND A 312036Z SSMIS 91GHZ MICROWAVE
PASS SHOW A BROAD AREA OF CONVECTION BEGINNING TO CONSOLIDATE AROUND
A LOW LEVEL CIRCULATION (LLC) WITH STRONG SURFACE CONVERGENCE BEING
INTRODUCED FROM CONSISTENT SOUTHWESTERLY FLOW. A PARTIAL 312300Z
ASCAT-B PASS REVEALS AN ELONGATED LLC WITH 15-20 KNOT WINDS IN THE
EASTERN SEMICIRCLE WITH ISOLATED AREAS OF 25 KNOT WINDS, LIKELY
ASSOCIATED WITH THUNDERSTORM ACTIVITY, AND LOWER WINDS IN THE
WESTERN SEMICIRCLE. RECENT WATER VAPOR ANALYSIS INDICATES INVEST 98W
IS LOCATED DIRECTLY SOUTH OF A TUTT CELL WHICH IS HINDERING
DEVELOPMENT AT THIS TIME. HOWEVER, THE TUTT CELL IS FORECAST TO
SHIFT WEST OVER THE NEXT 24 HOURS, THUS INCREASING UPPER LEVEL
OUTFLOW AND POTENTIALLY DEEPENING INVEST 98W. INVEST 98W IS IN A
MARGINAL ENVIRONMENT WITH ROBUST EQUATORWARD OUTFLOW ALOFT AND WARM
(29-30 C) SEA SURFACE TEMPERATURES, OFFSET BY MODERATE (15-20 KTS)
VERTICAL WIND SHEAR AND UPPER LEVEL CONVERGENCE ASSOCIATED WITH THE
AFOREMENTIONED TUTT CELL. GLOBAL MODELS AGREE INVEST 98W WILL
CONSOLIDATE AS IT TRACKS NORTHWARD OVER THE NEXT 24-36 HOURS.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1006 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS MEDIUM.
WTPN22 PGTW 011430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 98W)//
REF/A/JOINT TYPHOON WRNCEN PEARL HARBOR HI/010521Z AUG 21//
AMPN/REF IS TROPICAL CYCLONE FORMATION ALERT (WTPN21 PGTW 010530)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
150 NM EITHER SIDE OF A LINE FROM 19.7N 154.3E TO 25.4N 152.6E
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 18 TO 23 KNOTS. METSAT
IMAGERY AT 011200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 20.0N 154.2E. THE SYSTEM IS MOVING NORTHWARD AT 12 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 98W) PREVIOUSLY LOCATED
NEAR 17.5N 153.0E IS NOW LOCATED NEAR 20.0N 154.2E, APPROXIMATELY
766 NM EAST-SOUTHEAST OF IWO-TO. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING CONVECTION
OBSCURING AN ILL-DEFINED LOW LEVEL CIRCULATION (LLC). A 010749Z
SSMIS 91GHZ MICROWAVE IMAGE REVEALS DEEP CONVECTION CONCENTRATED IN
THE SOUTHERN PERIPHERY. RECENT WATER VAPOR ANALYSIS INDICATES INVEST
98W IS LOCATED DIRECTLY SOUTH OF A TUTT CELL WHICH IS HINDERING
DEVELOPMENT AT THIS TIME. HOWEVER, THE TUTT CELL IS FORECAST TO
SHIFT WEST, THUS INCREASING UPPER LEVEL OUTFLOW AND POTENTIALLY
DEEPENING INVEST 98W. INVEST 98W IS IN A MARGINAL ENVIRONMENT WITH
ROBUST EQUATORWARD OUTFLOW ALOFT AND WARM (29-30 C) SEA SURFACE
TEMPERATURES, OFFSET BY MODERATE TO HIGH (15-25 KTS) VERTICAL WIND
SHEAR AND UPPER LEVEL CONVERGENCE ASSOCIATED WITH THE AFOREMENTIONED
TUTT CELL. GLOBAL MODELS AGREE INVEST 98W WILL UNDERGO MARGINAL
CONSOLIDATION AS IT TRACKS NORTH-NORTHEASTWARD OVER THE NEXT 24-36
HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 18 TO 23
KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1005 MB.
THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE
WITHIN THE NEXT 24 HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
021430Z.
4. SEE REF A FOR DETAILS ON A TROPICAL CYCLONE FORMATION ALERT
LOCATED NEAR 26.8N 143.4E.//
NNNN
WWJP27 RJTD 020000
WARNING AND SUMMARY 020000.
WARNING VALID 030000.
WARNING IS UPDATED EVERY 6 HOURS. WARNING.
TROPICAL DEPRESSION 1006 HPA
AT 21.4N 154.9E SEA AROUND OF MINAMITORISIMA MOVING NORTH 10 KNOTS.
POSITION FAIR.
MAX WINDS 30 KNOTS.
WARNING.
DENSE FOG OBSERVED LOCALLY OVER SEA OF OKHOTSK NORTHERN PART OF SEA
OF JAPAN MIDDLE OF SEA OF JAPAN YELLOW SEA EAST CHINA SEA.
WARNING.
DENSE FOG OBSERVED LOCALLY OVER WATERS BOUNDED BY 37N 141E 40N 142E
42N 141E 47N 152E 55N 162E 60N 163E 60N 180E 40N 180E 37N 160E 37N
141E.
SUMMARY.
LOW 1004 HPA AT 42N 137E NNW SLOWLY.
LOW 1006 HPA AT 57N 162E SSE 15 KT.
LOW 996 HPA AT 47N 177E ENE 15 KT.
TROPICAL DEPRESSION 998 HPA AT 26N 125E ALMOST STATIONARY.
TROPICAL DEPRESSION 1004 HPA AT 30N 140E NW 15 KT.
HIGH 1016 HPA AT 50N 148E ESE 10 KT.
HIGH 1018 HPA AT 31N 168E ALMOST STATIONARY.
STATIONARY FRONT FROM 42N 145E TO 43N 153E 42N 161E 42N 168E 44N 173E
47N 177E 49N 180E.