Tuesday Headline

The Tropical Disturbance over South Texas now expected to emerge over the very warm waters of the Gulf of America —> and qualify as a tropical depression or tropical storm —> first name is Arthur. NHC has issued a “Potential Tropical Cyclone” advisory for 01L (no name yet)

Regardless of any “named storm” development the deep tropical moisture will inundate the coast and deliver “boatloads” — upwards of 4”-6”+ from Texas into the Mississippi River Valley over next 7-days. This is separate from a powerful Great Lakes storm system with severe weather and also heavy — and not needed — rain (update on that later this evening).

Timeline:

• Wednesday morning —> named storm formation off coast of Corpus Christi, Texas

• Landfall later into early Thursday along TX/LA state line

• Continued track through the Deep South — continuing to focus heavy rainfall with Gulf tropical moisture

• A predecessor rainfall event (PRE) is setting up downstream of PTC 01L (Arthur)

Next 48-hours Simulated Radar

Very soggy pattern! 7-day Rainfall Totals from Blend of Models —> astounding.

All of this red is at least 2” with many areas of 4” to 6” embedded within … and we should expect these tropical downpours to deliver a LOT of rain in short order —> gullywashers!

Integrated Vapor Transport — Next 6-days

The Tropical System is embedded within a “deep layer tropical moisture plume” with origin in Caribbean and into the Gulf of America.

There is also a strong upper-level trough to the north associated with Canadian origin air mass — and the influence of the mid-latitude weather system (strong trough for mid-June) will provide upper-level jet stream energy to provide a “baroclinic kick” to the tropical disturbance —> assisting its intensification to Arthur.

This unusual situation can occur when a surface low encounters the jet stream quadrant (right rear) and phases to increase convergence and ascent —> intensification of the surface circulation.

ECMWF 06z | Precipitable Water | My Favorite Parameter

The red PWAT > 2” and even some 3” areas embedded within the tropical low. Note how the system retains much of its circulation / coherence while within the frontal boundary draped along the Deep South / Gulf coast.

This is a recipe for HUGE rainfall totals with daytime heating + tropical moisture.

Great Lakes Powerful Storm System into Thursday

More on this later today — unusually strong land cyclone aided by a Canadian trough —> severe weather and heavy rain

Zooming Out on Atlantic

Flagship model: ECMWF AIFS 06z —> Integrated Vapor Transport next 10-days

Saharan Air — African Dust Next 10-days

A moderate Dust Layer (with Saharan Air) moving across the Main Development Region — and will reach the Caribbean in 2-3 days before decaying/wringing out with gravity and some convection/storms. Another SAL emerges in 5-6 days to repeat the pattern — typical for mid-to-late June.

Sea Surface Temperature Anomaly | Atlantic

Change in Actual SST | 2026 minus 2025

Huge cooling across much of the North Atlantic basin compared to last year!

Global SST Anomaly

El Niño underway! Very warm SST anomaly along the equatorial Pacific

But we don’t usually show the actual SST near the Galapagos Islands

The famous tortoises live on islands usually within cool Equatorial waters … but we see 27°C actual SST surrounding their home. Galapagos Giant Tortoise

Atlantic basin outside of the Gulf of America is rather quiet — typical for mid-June.

Tropical Wave Analysis: n = 4 in Atlantic + 1 in Eastern Pacific = none developing.

Some convection along the ITCZ displaced well south

HUGE Rainfall Totals for mid-June

Blend of Models —> Precipitation Next 8-days

ECMWF 06z | Precipitation + MSLP | Next 6-days

Surface low ~1004 mb does develop right along the Texas coast —> Arthur

Weather Pattern: 500 mb Height Anomaly | AIFS-Single Next 10-days

Very strong mid-level trough maintains its grip on the Midwest and Great Lakes for the next 7-days. The flow out of the Northwest is straight from the Arctic = cool and dry … very intense trough for mid-June. This trough will fuel a powerful storm system (Low 985 mb)

A Pacific origin trough swoops into the replace the Canadian vortex into next weekend.

Eastern Pacific — One area of interest Invest 93E (10% chance)

Western Pacific Typhoon — Slow but steady development of a system in next several days —> Invest 92W

Moisture Transport — Next 10-days

Full Physics Ensemble Tracks — 2 systems likely … another following 92W