Tropical Storm Nongfa

Map key

Saffir–Simpson scale

  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown

Storm type

Tropical cyclone

Subtropical cyclone

Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression

On August 23, 2025, the PAGASA began tracking a weather system that originated from an area of low pressure just east of Surigao del Sur on Mindanao. ^{[1] [2] [3]} On August 27, the JMA began monitoring the same system, identifying it as a tropical depression located approximately 106 nautical miles (196 km) off the northwestern coast of Luzon. However, six hours later, the JMA downgraded the system back to a low-pressure area. This decision was later reversed in their next weather advisory bulletin, where the system was once again classified as a tropical depression.^{[ citation needed ]} On August 28, PAGASA also upgraded the disturbance to a tropical depression, assigning it the local name Jacinto, the replacement name for Jolina. JTWC subsequently issued a TCFA and initially classified the system as a monsoon depression. A few hours later, the JTWC reclassified it as a tropical depression and designated it as 20W as it moved westwards. ^[4] 20W then moved into the South China Sea under a marginally favourable environment, characterised by northerly to northeasterly upper-level flow that slightly hindered development. ^[5] Satellite imagery also depicted a partially exposed low-level circulation centre (LLCC), with disorganised convection flaring over the southern quadrant. ^[5] On August 30, 20W was upgraded to a tropical storm and assigned the name Nongfa by the JMA, accompanied by vigorous convection with deep, cold cloud tops and tightening rainbands, indicating a mature structure. ^[6] Shortly after, Nongfa made landfall between Quảng Trị and Hà Tĩnh at 15:30 ICT (08:30 UTC). ^[7] The storm later interacted with land, moving westward through mountainous terrains in Vietnam and Laos. Both agencies issued their final advisories on August 31 as the system weakened into a remnant trough. The remnants of Nongfa later crossed into the Bay of Bengal but did not redevelop, as it remained over the basin only briefly before making landfall in India. On 6 September, the remnants of Nongfa entered North Indian Basin and developed into a new system that consolidated into a depression over southwestern Rajasthan state in India. The following day, the resulting system strengthened into a deep depression, becoming Deep Depression LAND 04.^{[ where? ][ citation needed ]}

Preparations and impact

Philippines

The PAGASA issued warnings for heavy rainfall due to the combined effects of the low-pressure area and the southwest monsoon. ^{[8] [9]}

Hong Kong and Macau

On August 28, the HKO issued the Standby Signal No. 1 at 19:10 HKT (11:10 UTC) ^[10] and Macau’s SMG issued the same signal at 19:00 MST (11:00 UTC). ^{[11] [12]} All signals were later cancelled and was replaced with the Strong Monsoon Signal for respective territories at 18:10 HKT (10:10 UTC) ^[13] and 16:30 MST (08:30 UTC) on August 29. ^{[14] [15]}

Vietnam

Nongfa unleashed downpours in Vietnam, cutting off roads and dozens of mountain villages during its landfall between the Quảng Trị and the Hà Tĩnh provinces. In the Hà Tĩnh province, roads in the Hương Khê District submerged, forcing road closures in National Highway 15  [ fr; vi ]. In the Phúc Trạch commune, 46 households of the Chứt ethnic minority were isolated. Hương Khê also experienced some cars and motorbikes flooded on Trần Phú Street, while incomplete drainages worsened the flooding. In Nghệ An, officials banned all sea activities by 30 August and returned all fishing boats to shore. According to Trần Phong, the chairman of Quảng Trị, provincial authorities conducted emergency meetings on 29 August to coordinate evacuation and storm responses. ^[16]

Thailand

On 3 September, Prasert Jantararuangtong, Thailand’s Deputy Prime Minister and Minister of the Digital Economy and Society, expressed concern over flooding across several regions affected by Nongfa and the prevailing monsoon trough. He noted that the storm had brought heavy rainfall to the Pa Sak, Yom, and Nan river basins. ^[17]

Nongfa also triggered flash floods in Phetchabun Province, particularly affecting residential and agricultural areas in the districts of Lom Kao, Nam Nao, Lom Sak, Mueang Phetchabun, and Nong Phai. Authorities evacuated vulnerable residents and moved belongings to higher ground as water levels began to recede, eventually flowing into the Pa Sak Jolasid Dam. Heavy rainfall near the Sirikit Dam led to a rapid rise in the Nan River, especially in Phitsanulok, prompting dam operators to reduce water discharge to mitigate downstream flooding. Meanwhile, overflow at the Mae Mok Dam, which exceeded its storage capacity—was released through the spillway, causing increased water levels in the Yom River basin.

In response, Prasert instructed the Office of the National Water Resources (ONWR) to establish temporary water management centers around the affected basins to ensure effective flood response and water flow control. Emergency assistance was also mobilized for affected communities. He emphasized that all flood response centers must continuously monitor the situation and coordinate closely to address flood-related issues. ^[17]

See also

• Tropical cyclones portal

• Weather of 2025
• Tropical cyclones in 2025

References

1. "Pagasa: LPA within PAR now has 'high' chance of becoming cyclone". Philippine Daily Inquirer . August 23, 2025. Retrieved August 28, 2025.
2. "LPA east of Surigao del Sur may intensify, will be called Jacinto —PAGASA". GMA News . August 24, 2025. Retrieved August 28, 2025.
3. "LPA east of Mindanao has 'high potential' to become tropical cyclone -- PAGASA". August 24, 2025. Retrieved August 28, 2025.
4. "Tropical Cyclone Formation Alert (Invest 93W)". Joint Typhoon Warning Center . August 28, 2025. Retrieved August 28, 2025.
5. "Prognostic Reasoning for Tropical Depression 20W (Twenty) No. 6". Joint Typhoon Warning Center . August 29, 2025. Retrieved August 29, 2025.
6. "Prognostic Reasoning for Tropical Depression 20W (Twenty) No. 8". Joint Typhoon Warning Center . August 30, 2025. Retrieved August 30, 2025.
7. "Storm Nongfa weakens after hitting Vietnam's Ha Tinh-Quang Tri". Tuoi Tre News. August 30, 2025. Retrieved August 30, 2025.
8. "Rainy week expected with potential 'Jacinto,' habagat". ABS-CBN . August 25, 2025. Retrieved August 25, 2025.
9. "PAGASA warns of heavy rains from LPA, Southwest Monsoon". GMA News . August 25, 2025. Retrieved August 28, 2025.
10. "Hong Kong weather: T1 warning to remain in effect until Friday morning". South China Morning Post . August 28, 2025. Retrieved August 29, 2025.
11. "Sinal 1 de tufão içado".
12. "Tropical cyclone signal no. 1 issued at 7 p.m." Teledifusão de Macau . August 28, 2025. Retrieved August 29, 2025.
13. "Hong Kong cancels T1 typhoon alert, issues strong monsoon signal". The SCMP.
14. "Direcção dos Serviços Meteorológicos e Geofísicos". August 29, 2025. Retrieved August 31, 2025.
15. "所有熱帶氣旋警告16:30取消". Teledifusão de Macau. August 29, 2025. Retrieved August 31, 2025.
16. "Storm Nongfa lashes Vietnam's central coast, villages cut of by floods". VN Express International. August 30, 2025. Retrieved August 30, 2025.
17. "Storm Nongfa causes widespread flooding in Thailand's major river basins". The Nation. September 3, 2025. Retrieved September 3, 2025.

Tropical Storm Nongfa (Jacinto)

Nongfa over Vietnam on August 30

v t e Tropical cyclones of the 2025 Pacific typhoon season
	TD TD STS Wutip TD Auring TS Sepat TD 03W TS Mun TY Danas STS Nari TD 07W TS 08W STS Wipha TS Francisco TY Co-may TY Krosa TS Bailu TD TD TD Iona TD 14W TD 15W TY Podul TD Fabian TD 17W TS Lingling TY Kajiki TS Nongfa TS Peipah TY Tapah TS Mitag VITY Ragasa VITY Neoguri TY Bualoi TY Matmo VSTY Halong TY Nakri TD TD
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