WTPN21 PGTW 171430
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 92W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 100 NM
OF EITHER SIDE OF A LINE FROM 21.5N 127.1E TO 25.3N 127.3E 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 081712Z INDICATES THAT
A CIRCULATION CENTER IS LOCATEDNEAR 21.6N 127.1E. THE SYSTEM IS MOVING
NORTH-NORTHEASTWARD AT 03 KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED NEAR
21.2N 127.7E IS NOW LOCATED NEAR 21.5N 127.1E, APPROXIMATELY 283 NM
SOUTH OF KADENA AFB. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY
DEPICTS A QUICKLY CONSOLIDATING AND A PARTIALLY EXPOSED LOW LEVEL
CIRCULATION CENTER (LLCC), EMBEDDED WITHIN A REVERSE ORIENTED MONSOON
TROF. FLARING CONVECTION ALONG THE EASTERN PERIPHERY OF THE CIRCULATION
HAS BEGUN TO CONSOLIDATE INTO FORMATIVE BANDING. A 171235Z ASCAT-B PASS
SHOWED A FORMATIVE LLCC TO THE WEST OF AN EXTENSIVE REGION OF 20-25 KNOT
WINDS EXTENDING ALONG THE ENTIRE EASTERN HALF OF THE CIRCULATION, WITH
SOME EMBEDDED WINDS OF 30 KNOTS ISOLATED IN THE NORTHEASTERN QUADRANT.
ANIMATED WATER VAPOR IMAGERY INDICATES A TUTT-CELL POSITIONED
APPROXIMATELY 200NM NORTH OF 92W, WHICH HAS BEGUN TO ENHANCE THE
POLEWARD OUTFLOW, AND SUPPORTING CONVECTIVE DEVELOPMENT IN AND AROUND
THE LLCC. ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES FAVORABLE
CONDITIONS FOR DEVELOPMENT WITH LOW VERTICAL WIND SHEAR (5-10 KTS), WARM
SEA SURFACE TEMPERATURES (30 C) AND GOOD POLEWARD OUTFLOW ALOFT ONLY
OFFSET BY DRY MID-LEVEL AIR TO THE NORTH DUE TO THE AFOREMENTIONED TUTT
CELL. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 92W WILL TRACK NORTHWARD
AND SLOWLY INTENSIFY OVER THE NEXT 24 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
181430Z.
//
NNNN
(1) THE AREA OF CONVECTION (INVEST 92W) PREVIOUSLY LOCATED NEAR
20.3N 126.5E IS NOW LOCATED NEAR 21.2N 127.7E, APPROXIMATELY 306 NM
SOUTH OF KADENA AFB. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
AS WELL AS A 170419Z ATMS 88.2 GHZ IMAGE DEPICTS A SLOWLY
CONSOLIDATING AND HIGHLY ELONGATED LOW LEVEL CIRCULATION (LLC),
EMBEDDED WITHIN A REVERSE ORIENTED MONSOON TROF. FLARING CONVECTION
IS FORMING ALONG THE SOUTHEASTERN FLANK OF THE LLC IN THE CONVERGENT
FLOW SOUTH OF THE TROF AXIS. ANIMATED WATER VAPOR IMAGERY INDICATES A
TUTT-CELL POSITIONED APPROXIMATELY 200NM NORTHEAST OF 92W, WHICH IS
IMPARTING NORTHERLY SHEAR OVER 92W AND DRAWING IN DRY MID-LEVEL
ACROSS THE REGION TO THE NORTH OF THE LLC. ENVIRONMENTAL ANALYSIS FOR
THE AREA INDICATES MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT
WITH MODERATE NORTHERLY VERTICAL WIND SHEAR (20 KTS) AND DRY MID-
LEVEL AIR TO THE NORTH, OFFSET BY WARM SEA SURFACE TEMPERATURES (30
C) AND MODERATE EQUATORWARD OUTFLOW ALOFT. GLOBAL MODELS ARE IN GOOD
AGREEMENT THAT 92W WILL TRACK NORTHWARD OVER THE NEXT 24 TO 48 HOURS.
GLOBAL MODELS ARE ALSO IN AGREEMENT THAT 92W WILL VERY SLOWLY
CONSOLIDATE AND ONLY MINIMALLY INTENSIFY OVER THE NEXT COUPLE OF
DAYS, HINDERED BY PERSISTENT DRY AIR AND MODERATE SHEAR MAXIMUM
SUSTAINED SURFACE WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS UPGRADED TO MEDIUM.
(1) AN AREA OF CONVECTION (INVEST 92W) HAS PERSISTED NEAR 19.8N
125.1E, APPROXIMATELY 320 NM SOUTH OF KADENA. ANIMATED MULTISPECTRAL
SATELLITE IMAGERY (MSI) DEPICTS THE DISORGANIZED LOW LEVEL CIRCULATION
(LLC) WITH FLARING CONVECTION FROM THE SOUTHEAST. 92W IS STARTING TO
FORM WITHIN THE TROUGHING THAT CURRENTLY EXTENDS INTO THE LUZON STRAIT.
ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES MARGINALLY FAVORABLE
CONDITIONS FOR DEVELOPMENT WITH MODERATE VERTICAL WIND SHEAR (20 KTS)
OFFSET BY WARM SEA SURFACE TEMPERATURES (30 C) AND MODERATE EQUATORWARD
OUTFLOW ALOFT. GLOBAL MODELS ARE IN GOOD AGREEMENT THAT 92W WILL TRACK
NORTHWARD OVER THE NEXT 24 TO 48 HOURS. HOWEVER, MODELS ARE MIXED
REGARDING THE RATE OF INTENSIFICATION FOR 92W. ECENS AND GEFS ENSEMBLE
GUIDANCE SHOW A FAIR AGREEMENT THAT 92W WILL DEVELOP, BUT WITH THE ECENS
MODEL BEING MORE AGGRESSIVE THAN THE GEFS. MAXIMUM SUSTAINED SURFACE
WINDS ARE ESTIMATED AT 13 TO 18 KNOTS. MINIMUM SEA LEVEL PRESSURE IS
ESTIMATED TO BE NEAR 1008 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS LOW.
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