{ "number": 730, "headline": "September 10, 2025 Wednesday Evening Update", "standfirst": "NHC spawned a 20% chance yellow hatchling for MDR into next week", "desk": "notebook", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2025-09-11", "published": "2025-09-11T00:48:25.182000Z", "updated": null, "access": "free", "body_html": "
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Good Evening! Update to move the maps and models forward.

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Lower 48 Precipitation Forecast | Next 6-days

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Tropical Storm Marco \u2014> Hurricane

Only scattered showers in the mountain west + easterly flow across Florida peninsula for next several days. The rest of the Lower 48 is under control of more Canadian dry air \u2014 but pretty hot after the September sunshine moderated the air mass.

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Weather | Fronts this Evening

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RTMA Temperatures and Anomaly | 7:30 PM ET

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Lower 48 is above normal +1.7\u00b0F

Low Temperatures Thursday Morning

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High Temperatures Thursday

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Rainfall Next 36-hours | NWS NDFD

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7-Day Precipitation from NOAA WPC

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North America Upper Level Height Anomaly | AIFS 18z | Next 10-days

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The Canadian blocking ridge is strongly in charge through 10-days \u2014 a very persistent pattern for mid-September. On either side, wave breaking events will spawn mid-level or cut-off troughs that will provide unsettled weather for the western u>S> and the Southeast \u2014 and a bit cooler as a result.

ECMWF EPS 12z | 7-day Temperature Anomaly | Week 1 (Sept 10-16)

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ECMWF EPS 12z | 7-day Temperature Anomaly | Week 2 (Sept 17-23)

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Atlantic Hurricane Season

2025 Hurricane Season [Day 102]. 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)

ECMWF 12-Days Integrated Vapor Transport | 12z cycle

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Bit of a traffic jam in the MDR from the ECMWF 12z flagship model with 3 candidate tropical waves all squished together by Day 12. Just one scenario of 51 members, but suggests an uptick in TS/H activity next week!

ECMWF 18z | Precipitable Water Next 6-days

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A tropical wave by this weekend coming off Africa is next shot at a tropical system but may not develop into a TD for 7-8 days.

ECMWF 18z | Vorticity 6-day Forecast

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By Tuesday, a circulation makes it to 45\u00b0W and will likely develop in a day or two after that \u2026 20% chance from NHC, but we won\u2019t count our chickens before they hatch!

Atlantic Basin Outlook | 8 PM ET Update

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20% chance of development for a tropical wave that will emerge off Africa on Fri-Sat, and head westward over warm waters.

Atlantic Satellite Imagery | Infrared

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Water Vapor | Mid-level

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SST and SST Anomaly | ECMWF 12z analysis

NOAA Tropical Surface Analysis | 18z

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Atlantic Tropical Waves = 2 but not candidates for development

Eastern Atlantic and Africa Infrared Satellite

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NASA Dust 5-day Forecast | 12z

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ECMWF EPS 12z Ensemble | Active Cyclone Tracks Through 7-days

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Weaker signal at 12z than previous 00z cycle \u2026 corresponds with NHC 20% chance.

ECMWF EPS 12z Ensemble | Active Cyclone Tracks Through 12-days

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Majority of members feature a hurricane. Another wave on its heels develops right off the coast of Africa.

ECMWF EPS 12z Ensemble | Active Cyclone Tracks Through 15-days

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Many major hurricane possibilities \u2014 over the central Atlantic (September 25th)

AIFS-ENS Comparison at 12Z | Active Tracks at Day 9

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AIFS ENS is very excited about this tropical wave \u2014 high chance > 90%

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

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A more active Atlantic basin for sure, but thankfully everything looks to be recurving or staying away off the U.S. mainland.

Eastern Pacific Tropical Update

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Tropical Storm Marco still scheduled in the next 48-hours, or so.

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Tracks are over warm water \u2026 and should become a hurricane, and potentially a major hurricane.

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5-day charts from ECMWF 18z | 974 mb = Category 2

Maps sourced from weathermodels.com designed and innovated by yours truly! Please subscribe there for real-time access to the newest maps, charts from all of the weather models including ECMWF.

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Tropical Storm Marco \u2014> Hurricane

Only scattered showers in the mountain west + easterly flow across Florida peninsula for next several days. The rest of the Lower 48 is under control of more Canadian dry air \u2014 but pretty hot after the September sunshine moderated the air mass.

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