WPAC: NARI - Post-Tropical

[Hayabusa]

93W INVEST 250710 0000 20.8N 141.2E

[cycloneye]

AN AREA OF CONVECTION (INVEST 93W) HAS PERSISTED NEAR 20.6N
142.2E, APPROXIMATELY 169 NM SOUTH OF IWO TO. MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A POORLY ORGANIZED LOW LEVEL CIRCULATION CENTER
(LLCC) OBSCURED BY FLARING CONVECTION THAT IS SHEARED FROM THE EAST. A
092329Z ASCAT PASS REVEALS AN ELONGATED CIRCULATION WITH ITS STRONGEST
WINDS ISOLATED TO THE SOUTH. ENVIRONMENTAL ANALYSIS FOR THE AREA
INDICATES MARGINALLY FAVORABLE CONDITIONS FOR DEVELOPMENT WITH LOW TO
MODERATE VERTICAL WIND SHEAR (10-15 KTS), WARM SEA SURFACE
TEMPERATURES (30-31 C) AND MODERATE EQUATORWARD OUTFLOW ALOFT. GLOBAL
DETERMINISTIC MODELS ARE IN FAIR AGREEMENT THAT THE AREA OF CONVECTION
93W WILL CONTINUE NORTH AS IT GRADUALLY INTENSIFIES OVER THE NEXT 72
HOURS. ENSEMBLE GUIDANCE AGREES ON A NORTHEASTWARD TRACK WITH ECENS
BEING MORE AGGRESSIVE ON DEVELOPMENT THAN THE GEFS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 18 TO 23 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 LOW.

[cycloneye]

Up to medium.

THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR
20.6N 142.2E IS NOW LOCATED NEAR 23.2N 141.8E, APPROXIMATELY 99 NM
SOUTH-SOUTHEAST OF IWO TO. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) DEPICTS A COMPACT, CONSOLIDATING LOW LEVEL CIRCULATION
CENTER (LLCC) OBSCURED BY FLARING CONVECTION DIRECTLY OVER THE CENTER.
A 101131Z METOP-B ASCAT PASS REVEALS AN ILL-DEFINED CIRCULATION WITH
ELEVATED (25-30KT) SOUTHERLY WINDS ALONG THE EASTERN PERIPHERY
BEGINNING TO WRAP INTO THE SYSTEM. ENVIRONMENTAL ANALYSIS FOR THE AREA
INDICATES A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH LOW TO MODERATE
(15-20 KTS) VERTICAL WIND SHEAR FROM THE NORTHWEST, WARM SEA SURFACE
TEMPERATURES (29-30 C) AND MODERATE EQUATORWARD OUTFLOW ALOFT. GLOBAL
DETERMINISTIC AND ENSEMBLE MODELS ARE IN GOOD AGREEMENT ON A NORTHWARD
TRACK WITH MARGINAL INTENSIFICATION OVER THE NEXT 24 HOURS, WITH ECENS
BEING THE MOST AGGRESSIVE OVERALL. MAXIMUM SUSTAINED SURFACE WINDS ARE
ESTIMATED AT 20 TO 25 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 UPGRADED TO MEDIUM.

[StormWeather]

Invest 93W is now high chance.

[b]WTPN21 PGTW 102030
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 93W)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
120 NM EITHER SIDE OF A LINE FROM 24.1N 141.1E TO 27.1N 141.4E
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 23 TO 28 KNOTS. METSAT
IMAGERY AT 101800Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 24.4N 141.1E. THE SYSTEM IS MOVING NORTH-NORTHWESTWARD AT 14
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 93W) PREVIOUSLY LOCATED NEAR
23.2N 141.8E IS NOW LOCATED NEAR 24.4N 141.1E, APPROXIMATELY 26 NM
SOUTH-SOUTHWEST OF IWO TO. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY (EIR) DEPICTS A COMPACT, WELL DEFINED LOW LEVEL CIRCULATION
CENTER (LLCC) OBSCURED BY PERSISTENT CONVECTION BUILDING OVER THE
CENTER. A SURFACE OBSERVATION TAKEN FROM IWO TO AT 101800Z SHOWS EAST-
SOUTHEASTERLY WINDS OF 20 KNOTS GUSTING AT 31 KNOTS. A 101637Z AMSR2 GW1
89GHZ IMAGE REVEALS CONVECTIVE BANDING WRAPPING ALONG THE SOUTHERN
PERIPHERY OF THE SYSTEM. ENVIRONMENTAL ANALYSIS FOR THE AREA INDICATES A
FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH LOW TO MODERATE (15-20 KTS)
VERTICAL WIND SHEAR FROM THE NORTHWEST, WARM SEA SURFACE TEMPERATURES
(29-30 C) AND MODERATE EASTWARD OUTFLOW. A TROPICAL UPPER TROPOSPHERIC
TROUGH (TUTT) FURTHER EAST OF THE SYSTEM IS ENHANCING THE EASTWARD
OUTFLOW CHANNEL OF THE SYSTEM. GLOBAL DETERMINISTIC AND ENSEMBLE MODELS
ARE IN GOOD AGREEMENT ON A NORTHWARD TRACK WITH MARGINAL INTENSIFICATION
OVER THE NEXT 24 HOURS, WITH ECENS BEING THE MOST AGGRESSIVE OVERALL.
MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 23 TO 28 KNOTS.
MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1001 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
112030Z.
//NNNN

https://www.metoc.navy.mil/jtwc/products/wp9325web.txt

[cycloneye]

And just like that JTWC upgrades to TD 06W.

06W SIX 250711 0000 25.0N 140.4E WPAC 30 1004

[Hayabusa]

JMA TD 00Z but still no TC warning

WWJP27 RJTD 110000
WARNING AND SUMMARY 110000.
WARNING VALID 120000.
WARNING IS UPDATED EVERY 6 HOURS.
WARNING.
TROPICAL DEPRESSION 1004 HPA
AT 24.9N 140.4E OGASAWARA SHOTO MOVING NW 11 KNOTS.
POSITION FAIR.
MAX WINDS 30 KNOTS NEAR CENTER.

[Hayabusa]

[cycloneye]

FORECAST DISCUSSION: TS 06W WILL REMAIN IN A WEAK STEERING
ENVIRONMENT FOR THE FIRST 24 HOURS OF THE FORECAST PERIOD. DURING
THIS TIME, TS 06W WILL REMAIN SLOW AND QUASI-STATIONARY,
POTENTIALLY RESULTING IN IRREGULAR MOTION. THE SUBTROPICAL RIDGE TO
THE NORTHEAST WILL BUILD OVER THE FIRST 36 HOURS OF THE FORECAST,
ALLOWING FOR FASTER MOVEMENT NORTH-NORTHEASTWARD. BETWEEN TAU
36-48, THE TRACK MOTION WILL BE STEERED NEARLY NORTHWARD FOR THE
REMAINDER OF THE FORECAST PERIOD. THE SYSTEM WILL REMAIN TROPICAL
UNTIL TAU 48, WHEN TS 06W BEGINS EXTRATROPICAL TRANSITION. A
LONGWAVE TROUGH WILL CAUSE THE SYSTEM TO BECOME BAROCLINIC, AND THE
SYSTEM WILL LOSE THE FAVORABLE HEAT SOURCE OF WARM SEA SURFACE
TEMPERATURES (SST) BETWEEN TAU 48-72. EXTRATROPICAL TRANSITION IS
ANTICIPATED TO BE COMPLETED BY TAU 72. TS 06W WILL STRUGGLE TO
INTENSIFY OVER THE FIRST 36 HOURS OF THE FORECAST WHILE IN A
HIGH-SHEAR ENVIRONMENT. ONCE SHEAR DECREASES, THE SYSTEM WILL
GRADUALLY INTENSIFY TO A PEAK OF 55KTS BY TAU 48. SLIGHT WEAKENING
TO 45KTS IS ANTICIPATED AS THE SYSTEM BECOMES EXTRATROPICAL.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE HAS A LARGE SPREAD
AT THE END OF THE FORECAST PERIOD, WITH GALWEM LYING SIGNIFICANTLY
FAR TO THE WEST OF THE MAIN BULK OF THE JTWC MULTI-MODEL CONSENSUS
MEMBERS. THE COMPLETE TRACK SPREAD BY TAU 72 IS 560NM. THE
INTENSITY GUIDANCE REPRESENTS SLOW INTENSIFICATION IN THE EARLY
TERM FORECAST, BUT BEGINS TO SPREAD AFTER TAU 36. THE PEAK
INTENSITY SPREAD IS 20KTS BETWEEN 45-65KTS AT TAU 48.

[Sciencerocks]

 https://x.com/VortixWx/status/1943798764898333102

[Hayabusa]

JMA finally upgrades

T2505(Nari)
Issued at 2025/07/12 19:00 UTC
Analysis at 07/12 18 UTC
Grade TS
Scale -
Intensity -
Center position N25°25′ (25.4°)
E141°40′ (141.7°)
Direction and speed of movement N Slow
Central pressure 998 hPa
Maximum sustained wind speed near center 18 m/s (35 kt)
Maximum wind gust speed 25 m/s (50 kt)
Radius of 30-kt wind area SE280 km (150 NM)
NW110 km (60 NM)

[cycloneye]

 https://x.com/mscuyugan/status/1944207878119993842

[cycloneye]

[cycloneye]

REMARKS:
142100Z POSITION NEAR 43.6N 144.6E.
14JUL25. TROPICAL STORM 06W (NARI), LOCATED APPROXIMATELY 166 NM
NORTHEAST OF MISAWA, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 29
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR)
SATELLITE IMAGERY DEPICTS 06W WITH AN EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) THAT IS PASSING OVER THE EASTERN EXTENT OF HOKKAIDO.
THE STRONGEST WINDS REMAIN WITHIN THE SOUTHEASTERN QUADRANT, WHICH
IS EXPECTED TO REMAIN THE CASE OVER THE NEXT 24 HOURS. 06W IS
FORECAST TO BEGIN TRACKING MORE EAST-NORTHEASTWARD AS INTERACTION
WITH THE JET TO THE NORTH INCREASES. EXTRATROPICAL TRANSITION IS
FORECAST TO COMPLETE AT TAU 12 AS WESTERLY SHEAR RAPIDLY INCREASES
AND SEA SURFACE TEMPERATURES DRASTICALLY DROP (BELOW 18 C).
THESE ENVIRONMENTAL FACTORS WILL ALSO AID IN THE WEAKENING OF THE
VORTEX OVER THE NEXT 24 HOURS AS THE SYSTEM BECOMES ABSORBED BY
THE STRONG UPPER-LEVEL WESTERLY FLOW. NUMERICAL MODEL TRACK GUIDANCE
IS IN GOOD AGREEMENT WITH MINIMAL CROSS-TRACK AND ALONG-TRACK
SPREAD. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT WITH ALL MODELS
DEPICTING STEADY WEAKENING THROUGHOUT THE FORECAST PERIOD.
THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON
WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR
SIGNS OF REGENERATION.