{ "number": 939, "headline": "May 19, 2026 Tuesday Tropical Update", "standfirst": "Atlantic hurricane season starts June 1st and we have many new forecasting tools", "desk": "tropics", "dateline": { "place": "Weather Trader", "state": null, "lat": null, "lon": null, "site_key": null, "site_name": null, "site_url": null, "accent": null }, "edition": "2026-05-20", "published": "2026-05-20T00:10:06.156000Z", "updated": null, "access": "free", "body_html": "
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This is post number 939: Good Evening! Day 139 of 2026. 11 more days until start of Atlantic Hurricane Season. Thank you to paying subscribers for renewing (some for Year 3) \u2026 and all new folks for 2026.

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

A Super El Ni\u00f1o is on the way for Summer/Fall 2026!

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Getting ready for the start of Atlantic Hurricane Season June 1st, and since U.S. weather is rather quiet, I\u2019m going to fill up a post with global tropics related maps, charts, and analysis. I admit I REALLY missed the tropics.

In 2026, we now have mature data-driven weather prediction ensembles (AIFS-Ensemble v2) in addition to full-physics ensemble systems like ECMWF EPS.

Let\u2019s talk about an embarrassment of riches thanks to rapid advancement in A.I. tools and techniques for weather modeling:

Every 6 or 12 hours, we get an update including these model output:

This requires a lot of data processing, and many individual companies do it for a modest subscription of $15/$30 month, but there are free options. I believe there is a market void for an \u201cad revenue\u201d supported weather maps site that is of much higher quality e.g. 4K TV style mapping, especially for videos. We\u2019ll see if that\u2019s viable!

GOES East Geostationary Satellite: Full Disk earlier Tuesday \u2014 GeoColor

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Eastern Pacific + Central Pacific

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Northwest Pacific \u2014 not the tropics \u2014 but a view probably few see daily

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Weather Trader is entirely reader-supported publication (no ads). To receive all new posts and support our work, consider becoming a free or paid subscriber. ALL CONTENT is original (human \u2014 Ryan) and not A.I.

With the expected Super El Ni\u00f1o into the summer/fall, the Atlantic hurricane season will likely be quieter / less active that recent years. We can simply take the climatology over the past 30-years and sort the seasons, and look below the median for typical outcomes. We now have three full decades of observed storms in the Atlantic since the positive (warm) phase of Atlantic Multidecadal Variability onset in 1995. My forecast last year (2025) was pretty good \u2014 largely based upon a simple model I developed in grad school using the Multivariate ENSO Index (MEI), so we\u2019ll give 2026 a whirl. This was from post on April 7 \u2014>

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

Atlantic Basin Satellite Channels

GeoColor show 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)

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

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Water Vapor (Mid-Level Channel 9) \u2014> troughs and areas of descending/dry air
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ECMWF 12z | Precipitation Type + MSLP | Next 8-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 \u2014> African dust plume forecast next 10-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 late May, we have a major plume coming off the continent.

North Atlantic Tropics | Quiet Next 7-days

National Hurricane Center (NHC) is issuing Tropical Weather Outlooks (TWO)

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Tropical Wave in northern South America \u2026 and another moving through Central America into the Eastern Pacific \u2026 neither expected to develop

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Ocean Temperatures \u2014> Sea Surface Temperature (SST)

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.

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However, we do look at SST anomaly to see where excessive warmth may be located e.g. \"marine heat waves\u201d that could fuel stronger hurricanes than otherwise expected.

Here, I use the ECMWF HRES SST anomaly vs. the 20-year model climatology (1996-2025) to show recent trends. The Atlantic is actually cooler than past 2-decades across the Main Development Region 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.

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My favorite parameter \u2014> Precipitable Water (PWAT) next 8-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)

Integrated Vapor Transport \u2014> IVT next 10-days

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The transport of rivers of moist air \u2014> IVT is great metric to show tropical storm development. Here, we see the Bermuda High / subtropical ridge in charge \u2014 extending to the Azores across the Atlantic.

Simulated Water Vapor | ECMWF 12z next 10-days

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High Resolution global models can \u201csimulate\u201d water vapor as you\u2019d see from geostationary satellites. This is also a fantastic way to quickly visualize the various weather systems e.g. troughs, convection, and other storms.

Western Pacific Basin \u2014 Typhoon Season is Underway

Watching area of possible development in 5-7 days near Mariana Islands, but nothing suspect in the next 48-hours from JTWC.

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Ocean Temperatures (SST) very warm > 28\u00b0F over the \u201cwarm pool\u201d plenty sufficient for any category of Super Typhoon, assuming one can form

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ECMWF Full Physics Ensemble Tracks \u2014 50 members

Tropical Storm formation possible in 5-days, and then development into a strong Typhoon

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IVT shows the circulation and intensification into Day 10 (May 29th)

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WPAC Precipitable Water (PWAT) next 8-days

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The Western Pacific is quite hostile with subtropical and mid-latitude upper-level troughs constantly mixing into the Main Development Region (sub-20\u00b0N) over the warm pool waters. Simulated Water Vapor Satellite next 10-days from ECMWF 12z

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ECMWF AIFS-Single v2 (Data Driven Forecast System)

A.I. weather modeling system next 15-days

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And, the ensembles from AIFS-ENS v2 (different than AIFS-Single) \u2014 quite ambitious with the storm formation and intensification!

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Eastern Pacific Tropics | Quiet next 7-days

Ocean temperatures are very warm across the basin with the cooler water roughly WNW of 15\u00b0N and 110\u00b0W

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The ITCZ / monsoon trough in the Eastern Pacific has boatloads of moisture \u2026 just waiting for a spin or tropical wave or vorticity source to create a tropical storm.

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Thanks for reading Weather Trader! This post is public so feel free to share it, and increase this newsletter\u2019s reach.

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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.

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Getting ready for the start of Atlantic Hurricane Season June 1st, and since U.S. weather is rather quiet, I\u2019m going to fill up a post with global tropics related maps, charts, and analysis. I admit I REALLY missed the tropics.

In 2026, we now have mature data-driven weather prediction ensembles (AIFS-Ensemble v2) in addition to full-physics ensemble systems like ECMWF EPS.

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