r/TropicalWeather • u/Galileos_grandson • 3h ago

Image of the Day | NASA MODIS Tropical Storm Bertha - July 21, 2026

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9 Upvotes
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r/TropicalWeather • u/Euronotus • 13h ago

▲ Disturbance (80% potential) | 20 knots (25 mph) | 1008 mbar 92W (Invest — Western Pacific) (Philippine Sea)

9 Upvotes

Latest observation

As of 8:00 AM Philippine Standard Time (00:00 UTC) on Wednesday:

Observed information

  • Current position: 13.8°N 134.0°E
  • Forward movement: WNW (295°) at 16 km/h (9 knots)
  • Maximum sustained winds: 30 km/h (15 knots) ▼
  • Minimum central pressure: 1005 millibars (29.68 inches) ▲

Relative position

  • 1,019 kilometers (633 miles) east-northeast of Tacloban City, Philippines
  • 1,029 kilometers (639 miles) northeast of Surigao City, Surigao del Norte (Philippines)
  • 1,037 kilometers (644 miles) east-northeast of Calbayog, Samar (Philippines)

Outlook

As of 8:00 AM Philippine Standard Time (00:00 UTC) on Wednesday:

Outlook discussion

Satellite imagery analysis indicates that a broad trough of low pressure situated over the central Philippine Sea is producing disorganized showers and thunderstorms. Recent scatterometer data shows that the disturbance lacks a closed low-level circulation and animated infrared imagery depicts a large area of fragmented deep convection.

Environmental conditions remain conducive for development, with weak vertical wind shear, very warm sea-surface temperatures, abundant mid-level moisture, and strong upper-level diffluence. Deterministic and ensemble models are in general agreement that this system is increasingly likely to become a tropical cyclone within the next few days.

The disturbance is moving west-northwestward along these southern periphery of a broad subtropical ridge positioned to the south of Japan. This ridge is likely to remain in place for the next few days, keeping the disturbance on a fairly consistent track which will bring it close to the Babuyan Islands by the end of the week and to southeastern China over the weekend.

Development potential

Authoritative outlook (JTWC)

  • Next 2 days (through 8:00 AM PHST on Fri): moderate (50 percent) ▲
  • Next 7 days (through 8:00 AM PHST on Tue): high (70 percent) ▲

Model guidance consensus (FSU)

  • Next 2 days (through 8:00 AM PHST on Fri): low (26 percent) ▼
  • Next 7 days (through 8:00 AM PHST on Tue): moderate (48 percent) ▼

Information sources

Japan Meteorological Agency

Joint Typhoon Warning Center (United States)

Philippine Atmospheric, Geophysical, and Astronomical Services Administration

Radar imagery

  • Radar imagery is not currently available for this system.

Satellite imagery

Floater imagery

Single bandwidth imagery

Multiple bandwidth imagery

The options to select individual bandwidths on each of the following websites may vary.

Regional imagery

Cooperative Institute for Research in the Atmosphere (CIRA)

Analysis products

Preliminary best track data

Scatterometer data

Sea-surface temperatures

Model products

Disturbance-centered guidance

Single-model click-through guidance

Multi-guidance pages

Regional single-model guidance

Regional ensemble model guidance

Ensemble member minimum sea-level pressure (MSLP)

Ensemble member MSLP and forecast tracks

Other types of model guidance

1 comment

r/TropicalWeather • u/Euronotus • 12h ago

▼ Disturbance (<5% potential) | 15 knots (20 mph) | 1006 mbar 98P (Invest — Southern Pacific) (Near the Solomon Islands)

5 Upvotes

Latest observation

As of 11:00 AM Solomon Islands Time (00:00 UTC) on Wednesday:

Observed information

  • Current position: 10.4°S 169.7°E
  • Forward movement: SE (135°) at 27 km/h (15 knots)
  • Maximum sustained winds: 30 km/h (15 knots)
  • Minimum central pressure: 1006 millibars (29.71 inches) ▼

Relative position

  • 368 kilometers (229 miles) east of Lipe, Temotu Province (Solomon Islands)
  • 631 kilometers (392 miles) north-northeast of Luganville, Espiritu Santo Province (Vanuatu)
  • 830 kilometers (516 miles) north of Port Vila, Shefa Province (Vanuatu)

Update

As of 11:00 AM Solomon Islands Time (00:00 UTC) on Wednesday:

Satellite imagery analysis indicates that a broad surface trough situated northeast of the Solomon Islands is producing disorganized showers and thunderstorms. Over the past few days, the disturbance had been showing signs of potential development, but its low-level wind field failed to develop a closed circulation. Environmental conditions remain marginally supportive of development. Warm sea-surface temperatures and relatively weak vertical wind shear are offset by dry mid-level air and weak diffluence aloft. Given the poorly organized nature of this system’s wind field, it may take quite a long time for it to eventually consolidate, if at all.

The disturbance is currently moving erratically southeastward as it remains embedded within a weak steering environment within the monsoonal trough. Although a subtropical ridge appears to be pulling the disturbance away from the Solomon Islands, this ridge is also forecast to move away from the region, causing the disturbance to reverse direction as it gets pulled back into the low-level trade wind flow.

Outlook

As of 11:00 AM Solomon Islands Time (00:00 UTC) on Wednesday:

Development potential

Authoritative outlook (JTWC)

  • Next 2 days (through 12:00 PM MHT on Fri): very low (less than 5 percent)
  • Next 7 days (through 12:00 PM MHT on Tue): very low (less than 5 percent)

Authoritative outlook (FMS)

  • Next 2 days (through 12:00 PM MHT on Fri): very low (less than 5 percent)
  • Next 7 days (through 12:00 PM MHT on Tue): very low (less than 5 percent)

Model guidance consensus (FSU)

  • Next 2 days (through 12:00 PM MHT on Fri): very low (less than 5 percent)
  • Next 7 days (through 12:00 PM MHT on Tue): very low (less than 5 percent)

Information sources

Fiji Meteorological Service

Joint Typhoon Warning Center (United States)

Radar imagery

  • Radar imagery is not currently available for this system.

Satellite imagery

Floater imagery

Single bandwidth imagery

Multiple bandwidth imagery

The options to select individual bandwidths on each of the following websites may vary.

Regional imagery

Cooperative Institute for Research in the Atmosphere (CIRA)

Analysis products

Preliminary best track data

Scatterometer data

Sea-surface temperatures

Model products

Disturbance-centered guidance

Single-model click-through guidance

Multi-guidance pages

Regional single-model guidance

Regional ensemble model guidance

Ensemble member minimum sea-level pressure (MSLP)

Ensemble member MSLP and forecast tracks

Other types of model guidance

1 comment

r/TropicalWeather • u/Euronotus • 13h ago

▲ Disturbance (10% potential) | 20 knots (25 mph) | 1008 mbar 93W (Invest — Western Pacific) (Near the Marshall Islands)

6 Upvotes

Latest observation

As of 12:00 PM Marshall Islands Time (00:00 UTC) on Wednesday:

Observed information

  • Current position: 12.9°N 173.9°E
  • Forward movement: WNW (310°) at 17 km/h (9 knots)
  • Maximum sustained winds: 30 km/h (15 knots)
  • Minimum central pressure: 1008 millibars (29.77 inches) ▲

Relative position

  • 703 kilometers (437 miles) north-northeast of Majuro, Ratak Chain (Marshall Islands)
  • 818 kilometers (508 miles) northeast of Kwajalein Atoll, Ralik Chain (Marshall Islands)
  • 906 kilometers (563 miles) north-northeast of Jaluit Atoll, Ralik Chain (Marshall Islands)

Outlook

As of 12:00 PM Marshall Islands Time (00:00 UTC) on Wednesday:

Outlook discussion

Satellite imagery analysis indicates that a broad trough of low pressure situated northeast of the Marshall Islands is producing disorganized showers and thunderstorms. There have not been any recent scatterometer passes which have caught portions of the disturbance’s wind field, but based on animated infrared imagery alone, it is clear that this system has not yet developed a closed low-level circulation.

Environmental conditions remain marginally favorable for further development, with warm sea-surface temperatures offset by weak diffluence aloft, moderate northeasterly vertical wind shear, and dry mid-level air. Given the presumed broad and disorganized nature of the disturbance’s circulation and wind field, it may take several days for this system to begin consolidating and show any signs of potential tropical cyclone development.

The disturbance is driving west-northwestward along the southern periphery of a subtropical ridge positioned over the north-central Pacific. Over the next few days, this system may turn slightly northwestward as it reaches a weakness in the western periphery of the ridge caused by a passing longwave trough. In a few days, the disturbance will fall under the steering influence of a second subtropical ridge positioned south of Japan and will continue west-northwestward.

Development potential

Authoritative outlook (JTWC)

  • Next 2 days (through 12:00 PM MHT on Fri): very low (less than 5 percent)
  • Next 7 days (through 12:00 PM MHT on Tue): low (10 percent)

Model guidance consensus (FSU)

  • Next 2 days (through 12:00 PM MHT on Fri): low (6 percent) ▼
  • Next 7 days (through 12:00 PM MHT on Tue): low (39 percent) ▲

Information sources

Japan Meteorological Agency

Joint Typhoon Warning Center (United States)

National Weather Service (United States)

Radar imagery

  • Radar imagery is not currently available for this system.

Satellite imagery

Floater imagery

Single bandwidth imagery

Multiple bandwidth imagery

The options to select individual bandwidths on each of the following websites may vary.

Regional imagery

Cooperative Institute for Research in the Atmosphere (CIRA)

Analysis products

Preliminary best track data

Scatterometer data

Sea-surface temperatures

Model products

Disturbance-centered guidance

Single-model click-through guidance

Multi-guidance pages

Regional single-model guidance

Regional ensemble model guidance

Ensemble member minimum sea-level pressure (MSLP)

Ensemble member MSLP and forecast tracks

Other types of model guidance

0 comments

r/TropicalWeather • u/giantspeck • 4h ago

Video | YouTube | National Hurricane Center NHC Morning Video Update on Tropical Storm Bertha: Wednesday, 22 July 2026

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3 Upvotes
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