{ "number": 737, "headline": "September 17, 2025 Wednesday Hurricane Season", "standfirst": "Tropical Storm Gabrielle will struggle for several days", "desk": "tropics", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2025-09-18", "published": "2025-09-18T00:48:05.744000Z", "updated": null, "access": "free", "body_html": "
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Good Evening!

Rain showers spreading through Southern California this evening from the remnants of Tropical Storm Mario.

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Temperature Analysis

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Still rather hot across the Mississippi River Valley this evening with some places still in the 90s past 7:30 PM ET.

HRRR Simulated Radar Next 18-hours

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Showers continue across SoCal and in the Central Plains around a weak mid-level trough. Scattered showers also through Florida from a stationary frontal boundary connected to the lingering coastal storm finally departing the Mid-Atlantic.

North America Precipitable Water | Next 6-days

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  1. Next tropical storm in the Eastern Pacific \u2014> Narda \u2014 will push moisture into Southern California again by this weekend

  2. Tropical Storm Gabrielle passes east of Bermuda but uncertainty about intensity: TS to major hurricane

  3. Atmospheric rivers plow into Western Canada and then Pacific Northwest U.S. into next week \u2014 autumn like pattern

NOAA WPC Precipitation + Anomaly

Little if any rain from the Northeast through Mid-Atlantic into North Florida = brown & red = much below normal through next 7-days.

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Atlantic Basin Outlook | 8 PM ET Update

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2 more areas on the Atlantic Outlook but low chances \u2026 from tropical waves

2025 Hurricane Season [Day 109]. My FORECAST for this year is (still) 14 named storms, 7 hurricanes, and 3 major hurricanes (near average)

2025 Season to Date: 6 named storms, 1 hurricanes, and 1 majors | ACE = 40 ACE of Erin: 32.2 (140-knots maximum wind)

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Gabrielle should become a hurricane in 4-days by Sunday, but there is uncertainty as the center reformed/jumped northward to almost 20\u00b0N \u2026 I think previous forecasts of Category 4+ were contingent on a much further south center (15\u00b0N)

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Tropical Storm Gabrielle (07L) ATCF Spaghetti

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HCCA is faster and to the right \u2014 out to sea along with Google\u2019s Deep Mind (GDMI) and GraphCast models (GDMI). GFS is drifting off to the west along with HAFS with weaker intensity.

ECMWF Ensembles 12z | Gabrielle

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Some variety in the maximum intensity but near majority show Category 3 pressure < 960s mb

ECMWF 12-Days Integrated Vapor Transport | 12z cycle

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We need to watch the tropical waves that do NOT gain latitude so quickly \u2026 as ECMWF Control shows a scenario of a major hurricane developing east of Florida. This is over the \u201cforecast skill horizon\u201d \u2014 and it doesn\u2019t affect land. There\u2019s some folks on social media that don\u2019t want to show these \u201cextended range\u201d solutions, but I think they\u2019re useful to keep an eye upon for monitoring trends and extreme events.

Way out there at Day 14 \u2014 this major hurricane misses East Coast \u2026 but nothing imminent \u2014 just showing the pattern favors development into late Sept / early October.

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Atlantic Basin | ECMWF 18z | Precipitable Water Next 6-days

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ECMWF 18z model not excited about Gabrielle with only tropical storm intensity through 5-days \u2026 weaker end of the spectrum.

ECMWF 18z | +5 Days MSLP | UV850 | PWAT

HAFS A and HAFS B mesoscale models (18z) with disorganized, minimum TS intensity at Day 5.

The uncertainty with intensity is not unusual with a system in its formative stages \u2026 and we have plenty of time to watch Gabrielle

Atlantic Satellite Imagery | Infrared

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Mid-Level Water Vapor

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Tropical Upper Tropospheric Trough (TUTT) undercutting Gabrielle

Water Vapor | Mid-level

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This is not a hospitable environment for a tropical system \u2014 what a mess.

SST and SST Anomaly | ECMWF 12:00 UTC Forecast

Warm pool 28\u00b0 to 29\u00b0C plenty sufficient for any category of hurricane along the entire track of Gabrielle (07L)

NOAA Tropical Surface Analysis | 18z

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Atlantic Tropical Waves = 3

Eastern Atlantic and Africa Visible Satellite

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Massive blowup of convection for a tropical wave just coming off Africa tonight. Another one marked as 10% by NHC already faded \u2014 with minimal convection.

ECMWF EPS 12z Ensemble | All Cyclone Tracks Through 10-days

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ECMWF EPS 12z Ensemble | All Cyclone Tracks Through 13.5-days

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Low chance of random TS/H in the western portions of the Atlantic basin

AIFS-ENS Comparison at 12z | Active Tracks at Day 10

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AIFS-ENS Comparison at 12z | Active Tracks at Day 15

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A.I. trained ensembles showing strong signal of TS/H closer to the mainland U.S. into early October. Fits the overall pattern \u2026 but nothing imminent.

AIFS-ENS 12z | 15-day Loop of Active Cyclones

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Busy Atlantic during the next 2-weeks with potential for 1-3 named tropical systems

Eastern Pacific Tropical Update | Invest 96E

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Next system will be named Narda.

Western Pacific Typhoon Season Update | 90W and 91W

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Both Invest 90W and 91W could become Super Typhoons

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Very warm SSTs > 28\u00b0C across entire Western Pacific basin

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ECMWF 18z | 5-days Snapshot | UV850 | PWAT | MSLP

A big Super Typhoon + a little Super Typhoon = 2

Monster from HAFS-A with Invest 90W in only 102-hours to 192 knot winds at 850-hPa and pressure 912 mb \u2026 yikes!

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Integrated Vapor Transport | Next 8-days

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Due westward track for 90W between Philippines and Taiwan into China in 7-days \u2014 Hong Kong will need to keep close watch

850 hPa Wind Speed next 12-days | Interesting looping track possible for 91W in the subtropics at high intensity

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No doubt about potential for extreme intensity \u2026

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Rain showers spreading through Southern California this evening from the remnants of Tropical Storm Mario.

Still rather hot across the Mississippi River Valley this evening with some places still in the 90s past 7:30 PM ET.

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