Discussing the latest on In-Fa as it nears the Okinawan islands. The storm’s track has wavered a bit south of Okinawa Honto but is still close enough to bring tropical storm conditions by Tuesday Night in to Wednesday. Meanwhile, northern Taiwan needs to watch the storm too. Plus Inflow from In-fa is combining with inflow from a TD near Hong Kong creating additional monsoonal moisture for the Philippines. That TD has a lot of questions with it but right now it does show signs of strengthening.
A broad area of convection is spinning up east of Luzon today. Guidance continues to suggest development from this area with a possible impact for SW Japan and a monsoonal surge across Luzon in to next week.
This has been labeled Invest 98W by JTWC.
1. WESTERN NORTH PACIFIC AREA (180 TO MALAY PENINSULA):
A. TROPICAL CYCLONE SUMMARY: NONE.
B. TROPICAL DISTURBANCE SUMMARY:
(1) AN AREA OF CONVECTION (INVEST 98W) HAS PERSISTED NEAR
17.5N 137.5E, APPROXIMATELY 484 NM WEST-NORTHWEST OF GUAM. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY AND A PARTIAL 140343Z AMSR2 89GHZ
MICROWAVE IMAGE DEPICT WEAK FORMATIVE BANDING WITH ASSOCIATED AREAS
OF DEEP CONVECTION IN THE SOUTHEAST QUADRANT OF A LOW LEVEL
CIRCULATION. ENVIRONMENTAL ANALYSIS INDICATES MARGINAL CONDITIONS
FOR DEVELOPMENT WITH GOOD EQUATORWARD OUTFLOW ALOFT AND WARM (30-
31C) SEA SURFACE TEMPERATURES, OFFSET BY MODERATE (15-20 KTS)
VERTICAL WIND SHEAR (VWS). GFS AND NAVGEM HAVE BEEN CONSISTENT WITH
FORMATION OF A TROPICAL CYCLONE NEAR THIS LOCATION FOR THE PAST FOUR
MODEL RUNS. NUMERICAL MODELS ARE IN GENERAL AGREEMENT THAT INVEST
98W WILL TRACK POLEWARD AS IT QUICKLY CONSOLIDATES AND INTENSIFIES
OVER THE NEXT 24-48 HOURS. IN THE UPPER LEVELS, OUTFLOW IS EXPECTED
TO GRADUALLY IMPROVE WITH DECREASING VWS OVER THE NEXT 1 TO 2 DAYS
DUE TO A FAVORABLE CONFIGURATION OF AN UPPER LOW OVER WESTERN JAPAN
AND THE TUTT TO THE NORTHEAST. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 13 TO 18 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.
Let’s take a look across the tropics, today we have a few areas to watch but nothing that screams “ALERT ALERT”.
A tropical wave is popping some thunderstorms south of Guam. This also has a low chance of development and little model support but still is worth watching.
In the extended forecast though the CPC two week hazards map does show something possible from the 14th on. This likely is somewhat due to the wave south of Guam as well.
July 18, 2021 
WesternPacificWeather.com 
