WPAC: INVEST 99W

[Hayabusa]

99W.INVEST

99W.INVEST.15kts.0mb.4.3N.134.2E

[Hayabusa]

ABPW10 PGTW 141730
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/SIGNIFICANT TROPICAL WEATHER ADVISORY FOR THE WESTERN AND SOUTH
PACIFIC OCEANS REISSUED/141730Z-150600ZFEB2023//
RMKS/
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 99W) HAS PERSISTED NEAR 5.2N
133.9E, APPROXIMATELY 134 NM SOUTH-SOUTHWEST OF PALAU. ANIMATED
ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS A BROAD CIRCULATION
WITH RAGGED ILL-DEFINED CONVECTIVE BANDING. A 141259Z ASCAT METOP-B
BULLSEYE SHOWS 15-20 KNOT WIND FIELDS ON THE NORTHERN AND SOUTHERN
EDGES OF 99W WITH SPOTTY AREAS OF 25KTS MAINLY ON THE SOUTHERN EDGE.
ENVIRONMENTAL ANALYSIS REVEALS THE AREA TO BE UNFAVORABLE FOR 99W TO
DEVELOP DUE TO THE HIGH (30-50KT) VWS AND NO UPPER LEVEL EXHAUST
SYSTEM ESTABLISHED, BUT THERE IS STILL HOPE HELD WITHIN THE WARM (28-
29C) SSTS AND STRONG VORTICITY SIGNATURES ON THE 850MB CHART. GLOBAL
MODELS ARE IN AGREEMENT THAT 99W WILL CONTINUE ON A NORTH-
NORTHWESTERLY TRACK OVER THE NEXT FEW DAYS TOWARDS THE PHILIPPINES AND
STRUGGLE TO DEVELOP INTO A MEANINGFUL SYSTEM. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 17 TO 23 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 1007 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS
IS LOW.

[Hayabusa]

[cycloneye]

THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR
7.7N 131.8E IS NOW LOCATED NEAR 7.2N 129.3E, APPROXIMATELY 220 NM EAST
OF DAVAO, PHILIPPINES. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
AND A 172212Z GMI 89GHZ MICROWAVE PASS REVEAL AN AREA OF BROAD AND
DISORGANIZED CONVECTION, GRADUALLY CONSOLIDATING INTO A LOW-LEVEL
CIRCULATION (LLC) ALONG AN ELONGATED TROUGH AXIS. A 180033Z ASCAT-B
BULLSEYE SCATTEROMETRY PASS DEPICTS A LOCALIZED REGION OF 25-30KT WINDS
CONCENTRATED WITHIN THE SOUTHEASTERN EDGE OF AN ELONGATED TROUGH.
ENVIRONMENTAL ANALYSIS SHOWS THAT 99W IS IN A FAVORABLE AREA FOR
DEVELOPMENT AS SUPPORTED BY GOOD POLEWARD OUTFLOW CHANNELS, LOW (05-10KT)
VWS, AND WARM (28-29C) SSTS. DETERMINISTIC MODELS AND A MAJORITY OF
ENSEMBLE MEMBERS ARE IN AGREEMENT THAT THIS CIRCULATION WILL CONTINUE
ALONG A NORTH-NORTHWESTERN TRAJECTORY ALONG THE EAST COAST OF THE
PHILIPPINES AND WILL CONSOLIDATE TO A MORE ORGANIZED CIRCULATION OVER THE
NEXT 48-72 HOURS. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 15 TO
20 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. THE
POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE
NEXT 24 HOURS IS UPGRADED TO MEDIUM.

[cycloneye]

THE AREA OF CONVECTION (INVEST 99W) PREVIOUSLY LOCATED NEAR
16.0N 123.6E IS NOW LOCATED NEAR 17.2N 124.3E, APPROXIMATELY 246 NM
NORTHEAST OF MANILA, PHILIPPINES. ANIMATED ENHANCED INFRARED IMAGERY
(EIR) AND A 200854Z SSMIS 91GHZ MICROWAVE PASS SHOWS AN AREA OF DEEP
CONVECTION DISPLACED TO THE NORTHEAST OF A LOW LEVEL CIRCULATION CENTER
(LLCC). ENVIRONMENTAL ANALYSIS REVEALS THAT 99W IS IN A MARGINALLY
FAVORABLE REGION FOR DEVELOPMENT AS A RESULT OF MODERATE TO HIGH (15-20KT)
VWS, OFFSET BY GOOD POLEWARD OUTFLOW AND WARM (26-27C) SSTS. THE VWS IS
EXPECTED TO INCREASE SIGNIFICANTLY TO 30-40 KNOTS BETWEEN NOW AND TAU 24,
THEN OVER 40 KNOTS BY TAU 36. IN ADDITION, THE MID-LEVEL MOISTURE IS
EXPECTED TO GRADUALLY DECREASE OVER THE NEXT 48 HOURS AS DRY AIR FORM THE
NORTHEAST COLD SURGE WILL INFRINGE INTO THE CIRCULATION. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 15 TO 20 KNOTS. MINIMUM SEA LEVEL PRESSURE
IS ESTIMATED TO BE NEAR 1004 MB. THE POTENTIAL FOR THE DEVELOPMENT OF A
SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS DOWNGRADED TO
LOW.