June 1, 2026 Monday Tropical Update
Atlantic Hurricane Season gets underway + Eastern Pacific tropical activity
June 2026 was the 18th-warmest June in the 132-year national record (1895–2026), at 70.6°F against a 1991–2020 normal of 69.5°F (+1.2°F).
June 2026 was the 32nd-wettest June in the 132-year national record (1895–2026), at 3.3in against a 1991–2020 normal of 3.1in (+0.2in).
NOAA/NCEI Climate at a Glance, contiguous United States. This is the observed record for the month, not a score of anything said in this piece — the forecast ledger begins 2026-08-17 and cannot reach earlier posts.
While most folks in the business expect a quiet season overall, I think it will be front-loaded with plenty of activity, and then a complete fall off a cliff later on as the Super El Niño cranks up & really couples the atmospheric circulation with the ocean warmth in the Equatorial Pacific.
Headlines for Monday
Western Pacific: Tropical Storm Jangmi (06W) undergoing post-tropical transition along the coast of Japan — could see gusty/damaging winds from the large circulation
Eastern Pacific hurricane season underway with Invest 90E (90% chance) expected to become a tropical depression or week tropical storm in the coming days.
Atlantic: More favorable sub-seasonal environment heading into mid-June with ECMWF ensembles picking up on potential Caribbean / Gulf development in extended range (12-dasy)
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)
Atlantic Basin Satellite Channels
The Saharan Air Layer and dust has mostly been mixed out of the lower-atmosphere across the tropical Atlantic, but more plumes await emergence off the African continent.
GeoColor satellite shows the visible “true color” just as you’d see from space — in geostationary orbit (locked in place to look down) … aside from the puffy clouds and some storms, you may 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 inhibits convection (storms)
Infrared (Channel 13) colorized —> showers and thunderstorms
Remarkable empty / clear Caribbean with only scattered showers to the coast of Africa. The only deep convection is along the Yucatan in the Gulf and with a trough in the Bahamas.
Water Vapor (Mid-Level Ch. 9) - troughs + areas of descending/dry air
Plenty of yellow = dry air from Panama through the Caribbean in across the Leeward Islands all the way to the Canary Islands.
ECMWF 18z | Precipitation Type + MSLP | Next 10-days
Not seeing anything organized across the Atlantic including the Gulf and Caribbean. However, into mid-June, surge of moisture and more favorable background conditions with MJO passing through could help spin up something close to home.
NASA GEOS5 (00z) —> African dust plume forecast next 10-days
Saharan Air Layer and African dust activity will decrease after this plume pushes through the Caribbean into the Gulf — while mixing/raining out.
Then, rather quiet for early June across the Eastern Atlantic / African coast for dust.
North Atlantic Tropics | Quiet Next 7-days
2 Tropical Waves — not developing in the Atlantic.
Atlantic Ocean Surface Temperatures (SST)
The Atlantic remains cooler than past 2-decades across the Main Development Region [MDR] from the Lesser Antilles (Caribbean) to the Canary Islands and coast of Africa. The North Atlantic off the East Coast and into the mid-latitudes is also quite cool.
My favorite parameter —> Precipitable Water (PWAT) next 10-days
The tropical wave in the central MDR Atlantic perks up a little bit, departs the ITCZ slightly, and could develop a little circulation and vorticity, but unlikely to get classified. Your eyeball can track that feature into the Caribbean and then near the Yucatan in 10-days — perhaps being one of the seedlings for storm formation.
Tropical storms and hurricanes are bundles of high moisture air > 2” in the column (or more) so we look for areas of concentrated high PWAT air in the tropics —> 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 —> IVT next 12-days
Eastern Pacific is busy with 2 or perhaps 3 systems. A moisture plume surges through the Caribbean into the Gulf and then northward through eastern U.S. by mid-June.
ECMWF Ensemble Spaghetti Next 15-days
50-ensembles or realizations of the next 15-day forecast of sea level pressure (L’s) tracked … and then plotted on top of each other.
Notable: handful (~10/50) members in the Gulf of Mexico by Days 12-15 = 20% chance of a TS/Hurricane, which is better odds than climatology for early/mid June.
AIFS-Ensembles (Machine Learning version of ECMWF model at 12z) through 15-days: not as excited about the Gulf, but not zero chance.
Eastern Pacific Tropics | 2026 Season To Get Underway
Amanda, Boris, Cristina, Douglas, Elida
90% Chance of Tropical Depression development with Invest 90E, another system along coast of Mexico into weekend/next week —> 30%
Some deep convection with Invest 90E … and a cyclonic look to the visible cloud field.
Coast of Mexico is clear this evening into Central America
ECMWF Precipitable Water Next 10-days
AIFS-Ensemble Next 12-days for Eastern Pacific
Not expecting too much out of Invest 90E, but next system(s) along coast of Mexico in the 8-10 day range could be the season’s first hurricane. Ocean temperatures are VERY warm > 30°C over large pool off coast of Mexico.
Western Pacific Basin — Typhoon Season is Underway | Jangmi (06W)
Threat of gusty winds with the extratropical transition of Jangmi (06W)
ECMWF IVT shows a monsoon trough setting up out of the Bay of Bengal through the South China Sea and then up off the eastern side of Japan. May see another tropical system behind Jangmi, briefly.
Global Ocean Temperatures —> Sea Surface Temperature (SST)
Tropical storms need at least 26°C SST to form and intensify … and hurricanes most often become major with 28°C SST (at least) … 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 “actual” 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 Niño. The recent 20-year climatology highlights much better than an older 1991-2020 baseline.
Thank you for reaching the end of this post! Hopefully you enjoyed the tour of the global tropics and what’s coming in the weeks/months ahead in the tropics here on Weather Trader on Substack.
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For 2026 Hurricane Season: Every 6 or 12 hours, we get an update including these model output
ECMWF EPS full-physics ensembles … 50 perturbed members + control/HRES
ECMWF AIFS-Ensemble (data driven) … another 50 members + control
ECMWF AIFS-Single … a special deterministic system that has exceptional skill
NOAA GEFSv12 Ensembles … 30 perturbed members + control
NOAA GFSv16 … 13-km high resolution global deterministic
UK Met Office MOGREPS lagged ensembles … global 14-km 72-members per day
Environment Canada ensembles + Germany ICON + Australia BOM Unified Model
New Google WeatherNext 1000-member ensemble system (!) more on that in future post
NOAA 2026 Atlantic Hurricane Season Forecast
More details in Thursday, May 21, 2026 Tropical Update
The Intertropical Convergence Zone (ITCZ) in the tropics along 5°N to 10°N 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’ll look for areas of disturbed weather — which means persistent convection — 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 —> Azores High in the subtropics usually keeps things quiet in the latitude around 30°N 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.
- Milepost
- 948 · laid 2026-06-01T23:03:17.286000Z
- Source
- https://weather.substack.com/p/june-1-2026-monday-tropical-update
- Digest
- 08a9fabeb0d364763cab02eaa17495083aa2977c17d3106fccf07e6e74b2b0f0
- Machine
- JSON