{ "number": 711, "headline": "August 21, 2025 Thursday Evening Weather Update", "standfirst": "Taste of fall: cooler weather on the way 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": "2025-08-22", "published": "2025-08-22T01:16:24.782000Z", "updated": null, "access": "free", "body_html": "
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2025 Atlantic Hurricane Season [Day 82]. My FORECAST for this year is 14 named storms, 7 hurricanes, and 3 major hurricanes.

2025 Season to Date: 5 named storms, 1 hurricanes, and 1 majors | ACE = 34

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Thursday Evening Tropical Update

  1. Hurricane Erin is pulling away from the East Coast of the U.S. but maintaining strong Category 2 winds + massive gale and TS force wind field.

  2. Tropical wave moving west at lower latitude in MDR (Invest 99L) still showing sustained convection (40% chance of development) \u2014 and a low-level circulation will trigger advisories on Fernand perhaps this evening yet.

  3. Tropical wave (80%) northeast of the Leeward Island will likely become a tropical depression by this weekend

  4. Next week \u2014 ensemble suites continue to show the Atlantic going DEAD quiet into first week of September.

Good Evening!

A taste of fall will arrive as a trough and Canadian cold front clear out much of the eastern Lower 48 with dry + cool air into next week. Gone will be the highs in the 80s and 90s replaced with 60s and 70s. More like football weather!

Behind Erin is Invest 90L \u2014 which will probably get Gabrielle \u2014 but playing the tropical storm name game is tricky with Invest 99L on the precipice of being Fernand.

A system in the Eastern Pacific off Mexico will likely develop this weekend. It\u2019s been two weeks since Ivo (09E) \u2014 next name is Juliette.

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Hurricane Erin is still generating deep-convection within inner-core and has sprawling \u2014 galaxy

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Current Temperatures | 7:30 PM ET | RTMA

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Temperature Anomaly | 7:30 PM ET | RTMA

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Lower 48 temperature anomaly is +1.6\u00b0F above normal

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

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  1. Invest 90L (80% chance) becomes a storm and heads north before combining with the frontal boundary behind Erin \u2014 could briefly become a 80-knot hurricane

  2. Small but vigorous Invest 99L (50% chance) could briefly become a storm on a westward track into the Caribbean graveyard. No further intensification after 1-2 days.

ECMWF AIFS 18z | 500 mb Height Anomaly Next 10-days

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Into weekend: Strong Canadian trough plunges through the Great Lakes and Northeast bringing much cooler air into the Lower 48 behind it \u2026 taste of fall.

Next week: continued northerly flow out of Canada as the \u201cpolar vortex\u201d intensifies over the Arctic.

Week 1 Temperature Anomaly | ECMWF EPS 12z

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Well below normal temperatures across the central U.S. into final week of August.

Week 2 Temperature Anomaly | ECMWF EPS 12z | Aug 28 - Sep 03

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Heat dome in western Canada vs. cooler trough across the Midwest and Northeast U.S. into early September.

Forecast High Temperatures Next 8-days | Blend of Models

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Refreshing 60s and 70s replace 80s and 90s into next week.

Low Temperatures Friday Morning

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High Temperatures on Friday

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Very hot across the Southwest and California. 90s in Texas and Florida \u2026 115 million at least 90\u00b0F

Back to Tropics \u2014> Atlantic Basin

ECMWF 18z | Next 6-days of Vorticity

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Invest 90L heads east of Bermuda \u2014 bet it becomes a hurricane.

Invest 99L opens up soon \u2014 so if it is named, needs to be in the next 12-24 hours.

ECMWF 10-Days Integrated Vapor Transport | 12z cycle

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Massive Erin undergoes \u201cextratropical transition\u201d in the central north Atlantic early next week and may affect U.K. or western Europe with some wind/rain as a \u201cpost tropical\u201d cyclone. The post-tropical version of Erin may be \u201cmajor hurricane force\u201d with central pressure in the 948 - 952 mb range \u2014 very intense for late August in the North Atlantic extratropics.

Thereafter, next week looks DEAD quiet across the Atlantic basin \u2026 but every African easterly wave needs to be watched into the peak of the season.

Lower 48 Precipitation for next 8-days |

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Precipitation total next 48-hours

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NOAA WPC Precipitation Next 7-days

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Atlantic Basin Outlook | 8 PM ET Update

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Hurricane Erin | Category 2 100 mph Winds| MSLP: 952 mb

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90th Percentile in size \u2014 tropical storm force winds > 500 n miles across

NHC:  A pair of ASCAT passes from a few hours ago confirmed Erin's large size with its associated tropical-storm-force winds extending nearly 500 n mi across. In  fact, comparing Erin with other systems around the same intensity and in similar locations over the past couple of decades indicates that it is around the 90th percentile in size.

ATCF Spaghetti | 18z Interpolated Models

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Massive Wind Field of Erin

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Invest 90L and Invest 99L

Atlantic Satellite Imagery | Infrared

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Water Vapor

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Wind shear from mid-level troughs stops tropical storm formation \u2014 tips over / tilts the vortex \u2014 prevents surface circulation (fire/spark) from connecting to the chimney

NASA GEOS-5 12z | 5-day Dust

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ECMWF SST and Anomaly

Note the cold anomaly from the wake of Erin \u2014> upwelling from the slower movement east of the Bahamas.

NOAA Tropical Surface Analysis | 18z

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Atlantic Tropical Waves = 3 including 90L, 99L and Hurricane Erin

Satellite Image of African Easterly Waves

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ECMWF AIFS-Ensemble | A.I. Trained 12Z | All Tracks at 15 days

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Also much quieter Atlantic into September 5th. Fine with me!

Eastern Pacific Tropical Update

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Next storm will be named Juliette \u2014 10E \u2014 this weekend!

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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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Hurricane Erin is pulling away from the East Coast of the U.S. but maintaining strong Category 2 winds + massive gale and TS force wind field.

Tropical wave moving west at lower latitude in MDR (Invest 99L) still showing sustained convection (40% chance of development) \u2014 and a low-level circulation will trigger advisories on Fernand perhaps this evening yet.

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