“Siony” Maintains Strength While Moving Westward Toward Luzon Strait

According to PAGASA’s 11:00 AM weather forecast today, November 5, 2020, Severe Tropical Strom “Siony” has maintained its strength while moving westward toward Luzon Strait.

Location of the Eye of Siony

In PAGASA’s forecast, as of 10:00 AM today, the eye of Severe Tropical Storm “Siony” was estimated based on all available data at 475 km East of Basco, Batanes (20.0 °N, 126.5 °E ).

Movement and Strenght of Siony

Severe Tropical Storm Siony is moving Westward at 25 km/h with a strength of maximum sustained winds of 95 km/h near the center and gustiness of up to 115 km/h.

Forecast Position of Siony

Here is the forecast position of Siony:

November 6, 2020 (24 Hour-Tomorrow morning): in the vicinity of Basco, Batanes(20.5 °N, 121.9 °E)

November 7, 2020 (48 Hour-Saturday morning): 405 km West Northwest of Basco, Batanes (OUTSIDE PAR)( 21.7 °N, 118.3 °E)

November 8, 2020 (72 Hour-Sunday morning):  790 km West of Laoag City, Ilocos Norte (OUTSIDE PAR)( 18.4 °N, 113.1 °E)

Wind Signal

Tropical Cyclone Wind Signal No. 2

Two areas in Luzon are under Tropical Cyclone Wind Signal No. 2:

• Batanes
• Babuyan Islands

Tropical Cyclone Wind Signal No. 1

These areas in Luzon are under Tropical Cyclone Wind Signal No. 1:

• The northern portion of mainland Cagayan (Santa Ana, Gonzaga, Lal-Lo, Allacapan, Santa Teresita, Buguey, Camalaniugan, Aparri, Ballesteros, Abulug, Pamplona, Sanchez-Mira, Claveria, Santa Praxedes)
• The northern portion of Apayao (Santa Marcela, Luna, Calanasan)
• The northern portion of Ilocos Norte (Adams, Pagudpud, Bangui, Dumalneg, Burgos, Vintar, Pasuquin, Bacarra)

Track and Intensity Outlook

Track of Siony

• Severe Tropical Storm Siony will accelerate westward or west-northwestward in the next 48 hours.
• On the forecast track, tomorrow morning the center of Siony will likely pass over (landfall) or near (close approach) the vicinity of:
  • Batanes or Babuyan Islands
• After leaving the Philippine Area of Responsibility (PAR) on Friday afternoon or evening, this tropical cyclone is forecast to turn towards the southwest on Saturday morning and accelerate over the West Philippine Sea towards the general direction of central or southern Vietnam.

Intensity of Siony

• Severe Tropical Storm Siony is forecast to reach typhoon category with a peak intensity of 120 km/h by tomorrow morning as it passes near or over the Batanes-Babuyan Islands area.
• After exiting the PAR, Siony will gradually weaken due to increasingly unfavorable conditions over the West Philippine Sea associated with a northeasterly surge.

Hazards Affecting Land Areas

Strong winds

• A strong breeze to near gale conditions due to the prevailing northeasterlies will continue over:
  • Batanes,
  • Babuyan Islands
  • The northern portion of Ilocos Norte
  • The northern and eastern coastal areas of mainland Cagayan until the arrival of tropical cyclone winds.
• Based on all available meteorological data, the earliest onset of strong breeze to near gale conditions associated with Siony over the areas currently under Tropical Cyclone Wind Signal (TCWS) #2 and #1 will be between tonight and tomorrow early morning.
• Damaging gale- to storm-force winds will begin to affect areas under TCWS #2 tomorrow morning.
• Based on the intensity outlook for Siony, TCWS #3 remains to be the highest wind signal to be hoisted during the passage.

Heavy Rains

• In the next 24 hours, the trough of “SIONY” will bring scattered light to moderate with at times heavy rain showers over:
  • Pangasinan
  • Most parts of:
    • Central Luzon
    • Metro Manila
    • CALABARZON
    • MIMAROPA
    • Bicol Region
    • Visayas
    • Mindanao.
• Early morning tomorrow, moderate to heavy rains due to Siony will begin affecting:
  • Batanes
  • Babuyan Islands

Flooding

• Flooding (including flash floods) and rain-induced landslides may occur during heavy or prolonged rainfall especially in areas identified in geohazard maps as highly or very highly susceptible to these hazards.
• PAGASA Regional Services Divisions may issue local thunderstorm/rainfall advisories and heavy rainfall warnings while the Hydrometeorology Division and River Basin Flood Forecasting and Warning Centers may issue General Flood Advisories and Basin Flood Bulletins as appropriate.

Hazards Affecting Coastal Waters

• In the next 24 hours, the coastal waters of areas under:
  • TCWS #2 and #1: will have rough to high seas (3.0 to 7.0 m)
  • Under gale warning: will be experiencing rough to very rough seas (2.5 to 5.5 m).

Furthermore, the complete list of seaboards where Gale Warnings are in effect is detailed in Gale Warning #45 issued at 5:00 AM today. And, sea travel is risky over these waters for all types of seacrafts in areas under TCWS and small seacrafts in areas under a gale warning.

• Moderate to rough seas (1.5 to 2.5 m) will be experienced over:
  • The western seaboards of Central and Southern Luzon
  • The eastern seaboards of Visayas and Mindanao.

Mariners of small seacrafts are advised to take precautionary measures when venturing out to sea. Inexperienced mariners should avoid navigating in these conditions.

Also, as of 10:00 AM today, here are the other tropical systems that are being monitored:

• The center of Tropical Storm “GONI” (formerly “ROLLY”) was estimated at 1,075 km West of Southern Luzon (14.4°N,111.1°E) (OUTSIDE PAR). It has maximum sustained winds of 75 km/h near the center and gustiness of up to 90 km/h. It is moving west-northwestward slowly towards the southern portion of Vietnam.
• The LPA was estimated 1,920 km East of Visayas (10.9°N,143.3°E) (OUTSIDE PAR). It is forecast to move generally west-northwestward and may enter the PAR tomorrow or Saturday. This LPA is less likely to develop into a tropical depression in the next 24 hours

Furthermore, PAGASA’s next Severe Weather Bulletin will be issued today at 2:00 PM.

Source: PAGASA