2025 Season to Date: 12 Named Storms, 4 Hurricanes, and 3 Majors | ACE = 100

Winter is approaching, and we’ll be transitioning to coverage of cold and snow.

Clear skies and warm temperatures across the South today (Wednesday)

A powerful upper-level trough connected to the Canadian Arctic tropospheric polar vortex continues to spin over California.

GFS Analysis 06z | California trough

The cut-off trough is remarkable for mid-October with very low geopotential heights at 500 mb — and cold temperatures in the mid-levels. The jet stream is highly amplified extending into southern California.

High Temperatures Today

Only in the 60s across California today … with 80s and 90s in the Plains into the Southeast — quite warm for October 15. Lower 48 average high is 68.1°F

North Pacific Wave Train next 8-days | 850 hPa Wind

I like showing this loop — so we’ll do it again. All aboard the North Pacific “wave train” with multiple sequential “hurricane force” extratropical cyclones “bombing” out in the Aleutians and then decaying over Alaska or the Gulf of Alaska.

The typical extratropical cyclone forms as a shallow frontal wave NE of Japan and then phases with the upper-level jet stream often “rapidly intensifying” with central pressures from the 930s to 960s mb. The entire lifecycle is 3-5 days, but may last longer if the mature or occluded stage becomes stationary or cuts off from the main storm track.

The result of these storms = atmospheric rivers into Alaska, Northwest Canada, and Pacific NW U.S. coast = mountain snowfall and heavy rainfall near sea level. We’ll that in the “Integrated Vapor Transport” maps.

North Pacific Jet Stream Next 10 Days > 200 knots

North America Precipitable Water next 8-Days | 00z ECMWF

Overview of the continent: Next 8-days

1. A series of weak/moderate atmospheric rivers descend the west coast from WA/OR into California for a great start to the 2025-26 Water Year as a strong jet stream from North Pacific “wave train” sends repeated “hurricane force” cyclones into the Aleutian Low region.

2. Weekend storm system for the central U.S. moves into Canada by Saturday and deepens to around 980 mb central pressure. Another storm then develops in the Great Lakes into Sunday and heads into the mid-Atlantic and Northeast for early next week — not quite cold enough for snowfall.

3. Risk of severe weather along the tail end of the cold fronts with these central U.S. weather systems.

4. Cool, dry Canadian air blasts through the Lower 48 behind these powerful storms this weekend and next week.

Look Ahead: Precipitation Type + MSLP | Next 8-days

Current Temperature | RTMA 8:45 AM ET

Current Temperature Anomaly | RTMA 8:45 AM ET

Lower 48 is +2.7°F above normal with California remaining chilly

Low Temperatures Thursday Morning

Lower 48 average low temperature of 46.9°F with 3.6 million at least freezing

High Temperatures on Thursday

Lower 48 average temperature of 68°F … with 90s in South Texas but only 2 Million population.

High Temperature Anomaly on Thursday

ECMWF Next 6-Days Integrated Vapor Transport | 06z cycle

Blend of Models 7-Day Precipitation through early next Tuesday

Snowfall Next 7-days | Blend of Models

Medium Range | AIFS 06z | 10-days Height Anomaly

Parade of troughs arriving from the North Pacific into the U.S. Northwest and then progressing across the northern tier of states = active pattern

Atlantic Basin Outlook | 8 AM ET Update

Tropical Storm Lorenzo (12L)

40 mph winds — poorly organized — and not expected to intensify further until dissipation within the next 24-hours.

Lorenzo did help the Atlantic ACE hit 100 for the 2025 season.

Central Atlantic GeoColor + IR Satellite Images

Atlantic Basin | Integrated Vapor Transport | Next 12-days

A tropical wave currently off the coast of Africa in the far eastern Atlantic will travel westward and could find more favorable environment conditions for development in the Caribbean in 8-10 days.

SST and Anomaly

NOAA Tropical Surface Analysis | 06z

Atlantic Tropical Waves = 3 + nearly gone TS Lorenzo mixed in

ECMWF EPS 00z | Active Storm Tracks Day 10

20% to 30% chance of development by Day 10 in the western Caribbean — extended range!

ECMWF EPS 00z | Active Storm Tracks Day 15

About half of the ensemble members develop the tropical wave — eventually and create a powerful hurricane into late October, with a northward track thereafter.

The Caribbean is a favored region, of course, so we will keep a very close eye for the next several days to see how this trends.

AIFS ENS at Day 12 and Day 15 Comparison | Active Storm Tracks

Much stronger signal today in the AIFS-ENS for the tropical wave development in the Caribbean.

GFS 00z Massive Category 5 Hurricane (one of many extended range solutions)

GFS continues to blow up a Category 5 hurricane out of the Caribbean — way down the line at Days 10 to 15 —way over the forecast predictability horizon. You’ll probably see this bad boy on social media — until it [hopefully] disappears.

This is possible/plausible but beyond our capability to accurately/skillfully forecast.

NOAA GEFS 06z (31-members) | Through 10-days

Active Caribbean from 06z GEFS ensemble members.

Summary:

We have low skill with location/intensity of tropical storm development more than 10-days into the future — BUT there are increasing signals for “something” to develop — probably a coin flip based upon current guidance.

What do you do with this information? Monitor the situation daily to look for trends up/down in the risk of hurricane development — nothing new/different than what you’d do during the rest of the season.

Eastern Pacific Tropical Weather Outlook | 8 AM ET

60% chance of formation of another tropical cyclone (next name is Sonia) in the next several days. However, convection is limited and any development looks “slow going” as the Eastern Pacific hurricane season winds down.

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