{ "number": 944, "headline": "May 27, 2026 Wednesday Tropical Update", "standfirst": "GFS model with a known model bias spinning up bogus-canes", "desk": "tropics", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2026-05-28", "published": "2026-05-28T02:33:45.834000Z", "updated": null, "access": "free", "body_html": "
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This is post number 944: Good Evening! Day 148 of 2026. 4 more days until start of Atlantic Hurricane Season. Thank you to paid subscribers for renewing (some for Year 3) \u2026 and all new folks for 2026. Coupon (Annual 33% off)

Author: Dr. Ryan Maue (X @RyanWeather X @weathertrader)

The NOAA GFS version 16 \u2014 flagship global model \u2014 has had a serious flaw for several years that causes tropical cyclones to spin up when strong Caribbean \u2014> Gulf of Mexico flow patterns persist. The initial vorticity is shed from the mountains of Colombia and Venezuela (yes \u2014 that\u2019s weird) and continues across/near Central America while gaining latitude. The cyclonic vorticity develops into an intense hurricane off the Yucatan and threatens Florida. This was the 12z cycle from earlier Wednesday afternoon.

This is ephemeral or bogus-canes \u2014 and will be a false alarm at this intensity. However, that does not discount the otherwise very moist tropical moisture plume.

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You may see these forecast cycles with \u201cmonster hurricane\u201d shared on social media (X, Facebook, TikTok) but don\u2019t be fooled about GFS. It\u2019s been doing this for years. We hope the next version 17 coming soon (later in 2026) solves this major problem.

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Here is the updated 18z forecast cycle from GFS \u2014 similar large scale pattern, of course, but a different & less ambitious outcome through 10-12 days. All that being said, we should monitor the Gulf of Mexico and western Caribbean for weak tropical depression / storm systems into early June \u2014 that\u2019s the \u201chot spot\u201d for Atlantic storms in the early part of the season.

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Just to set your mind at ease, the ECMWF 12z full-physics ensembles had a blank slate for the Gulf and Caribbean through Day 10.

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And, AIFSv2 Ensembles at 18z showed 1 member with potential TS = 2% through 10-days.

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My Atlantic Hurricane Season Forecast (2026)

From April 7, 2026: Atlantic Seasonal Hurricane Forecast: (11/5/2)

9-13 Named Storms (11 most likely)
4-7 Hurricanes (5 or 6 most likely)
1-3 Major Hurricanes (2 most likely)
Accumulated Cyclone Energy: 75-85 (well below normal)

NOAA 2026 Atlantic Hurricane Season Forecast

More details in Thursday, May 21, 2026 Tropical Update

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Atlantic Basin Satellite Channels

Saharan dust has crossed into Caribbean \u2026 milky haze tracks back to the African coast.

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GeoColor satellite shows the visible \u201ctrue color\u201d just as you\u2019d see from space \u2014 in geostationary orbit (locked in place to look down) \u2026 aside from the puffy clouds and some storms, you can see the milky brown haze = African dust or Saharan Air Layers (SAL) that come off Western Africa into the Atlantic Ocean. SAL is bad for the hurricane business = stable/warm layer that limits instability and convection (storms)

Infrared (Channel 13) colorized \u2014> showers and thunderstorms

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Very limited convection over the tropical basin

Water Vapor (Mid-Level Ch. 9) - troughs + areas of descending/dry air

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Massive upper-level trough from Florida extending through Bahamas along 25\u00b0N latitude to eastern Atlantic = VERY hostile environment in late May.

ECMWF 18z | Precipitation Type + MSLP | Next 6-days

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The Intertropical Convergence Zone (ITCZ) in the tropics along 5\u00b0N to 10\u00b0N is where moist air can ascend and form thunderstorms or like a convective pot boiling over = convection. In the coming weeks, especially into late June, we\u2019ll look for areas of disturbed weather \u2014 which means persistent convection \u2014 and potential formation of low pressure swirls along the ITCZ with tropical waves, in the Caribbean and Gulf of Mexico (America) with decaying frontal boundaries, and other pathways like tropical transition or subtropical cut-off lows. Lots of options/ways to form a tropical storm in the Atlantic in any given season.

The Bermuda High \u2014> Azores High in the subtropics usually keeps things quiet in the latitude around 30\u00b0N and suppresses the ITCZ to the south in late May into June. On the periphery of the Bermuda High, moisture plumes out of the Caribbean into the Gulf and then Texas + Southeast.

NASA GEOS5 (12z) \u2014> African dust plume forecast next 5-days

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NASA runs a version of GFS internally that is configured to ingest / test various satellite based instruments. Their dust algorithm with GEOS-5 is very good, and I really like to show the evolution of African dust (Saharan Air Layers) over the Atlantic.

Right on schedule into early June, we have multiple plumes coming off the continent that will sweep into the Caribbean on a 5-7 day frequency.

North Atlantic Tropics | Quiet Next 7-days

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3 Tropical Waves \u2014 none developing. The eastern most is embedded with the SAL and is heavily suppressed convectively.

Global Ocean Temperatures \u2014> Sea Surface Temperature (SST)

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Tropical storms need at least 26\u00b0C SST to form and intensify \u2026 and hurricanes most often become major with 28\u00b0C SST (at least) \u2026 the Atlantic has plenty of real estate that could support a TS or H, but nothing percolating as the basin is very hostile or unfavorable to formation. Note, it is the \u201cactual\u201d ocean temperatures that fuel hurricanes, not anomalies or deviations from climatology.

There are still rather cool (relative) areas in the Western Pacific and North Atlantic compared to the growing warmth along the Equator and off the western coast of Mexico with the oncoming El Ni\u00f1o. The recent 20-year climatology highlights much better than an older 1991-2020 baseline.

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The Atlantic remains cooler than past 2-decades across the Main Development Region [MDR] from the Lesser Antilles (Caribbean) to the Azores and coast of Africa. This is NOT a positive signal you\u2019d expect for an active season, but Atlantic SST varies on short-time scales (1-2 weeks) and a change in position of the Bermuda/Azores subtropical ridges can adjust trade winds to quickly warm up the Atlantic MDR.

The SAL + strong trade winds should keep the MDR cooler than normal into early June.

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My favorite parameter \u2014> Precipitable Water (PWAT) next 6-days

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Tropical storms and hurricanes are bundles of high moisture air > 2\u201d in the column (or more) so we look for areas of concentrated high PWAT air in the tropics \u2014> and we also can view frontal boundaries or dry air input from the middle-latitudes into the subtropics or tropics + Saharan Air Layers (dry)

Boatloads of tropical moisture from the Caribbean and Gulf of Mexico surging into Texas to Florida. Heavy rain continues to add up \u2014 very welcome, too.

Integrated Vapor Transport \u2014> IVT next 6-days

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The transport of rivers of moist air \u2014> IVT is great metric to show tropical storm development. The impressive plume of tropical moisture is easily tracked through the Caribbean into the Gulf of Mexico \u2014 with the subtropical ridge pushed well east to the Azores as the massive upper-level trough dominates the Western subtropical Atlantic.

Western Pacific Basin \u2014 Typhoon Season is Underway | Jangmi (06W)

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Tropical Depression 06W \u2014> Jangmi was named earlier Wednesday (30 knots)

Jangmi does not have an inner-core \u2014 but will eventually build one in the next few days.

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Track of Jangmi is well east of Taiwan \u2014 with southern islands of Japan under most threat at storm expands in size and undergoes extratropical transition.

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Ocean Temperatures (SST) very warm > 28\u00b0F over the \u201cwarm pool\u201d plenty sufficient for any category of Typhoon, assuming one can form, but actually slightly cooler than normal along the northern side of the warm pool, with a sharp gradient north of the Kuroshio Current wall. Jangmi has 3-4 days over the warmest water before hitting the much cooler waters.

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HAFS-A mesoscale model \u2014 much more ambitious with Jangmi \u2014> Category 4 with minimum pressure in the mid-940s mb \u2026 I\u2019m skeptical based upon the current disorganized state of the system, but who knows, maybe it can rapidly intensify.

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This is very rapid intensification through 72-hours from HAFS-A. We\u2019ll see!

ECMWF Full Physics Ensemble Tracks \u2014 50 members next 10-days

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I\u2019ll note a difference between ECMWF full-physics and the Google Deep Mind \u2026 there\u2019s almost no cross-track spread with the Google ensemble forecasts. We want more spread \u2014 to capture outliers especially at the outset of any storm development. Something to watch in the coming weeks/months of hurricane season.

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ECMWF IVT shows the circulation and intensification of Jangmi (06W)

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IVT is under-utilized for tropical storm formation and intensity forecasting

WPAC Precipitation + MSLP Next 6-days \u2026 ECMWF 18z in low 970s mb

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ECMWF AIFS-Single v2 (Data Driven Forecast System)

ECMWF flagship A.I. weather modeling system \u2014 develops a 960 mb typhoon (Cat 3)

And, the ensembles from AIFS-ENS v2 (different than AIFS-Single) \u2014 similar track + intensity (18z update)

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Eastern Pacific Tropics | Quiet next 7-days | Ghost Town

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Thank you for reaching the end of this post! Hopefully you enjoyed the tour of the global tropics and what\u2019s coming in the weeks/months ahead in the tropics here on Weather Trader on Substack.

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 and AIFS, and NOAA GFS/GEFS, HRRR/RRFS and Blend of Models (NBM). NOAA WPC and SPC for fronts/convective outlooks.

For 2026 Hurricane Season: Every 6 or 12 hours, we get an update including these model output

", "body_key": null, "teaser_html": "

The NOAA GFS version 16 \u2014 flagship global model \u2014 has had a serious flaw for several years that causes tropical cyclones to spin up when strong Caribbean \u2014> Gulf of Mexico flow patterns persist. The initial vorticity is shed from the mountains of Colombia and Venezuela (yes \u2014 that\u2019s weird) and continues across/near Central America while gaining latitude. The cyclonic vorticity develops into an intense hurricane off the Yucatan and threatens Florida. This was the 12z cycle from earlier Wednesday afternoon.

This is ephemeral or bogus-canes \u2014 and will be a false alarm at this intensity. However, that does not discount the otherwise very moist tropical moisture plume.

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