The Pacific Remains Extremely Active, Nor’easter Set to Impact the East Coast: AI Models Discussion 9-22-2026

We’ll take a look at some of the key systems in the Northern Hemisphere tropics, focusing especially on the Pacific, which remains very active with multiple threats.

West Pacific

The main system of note right now is Invest 91W, which is moving west to the West of the Mariana Islands. It is forecast to intensify into a typhoon over the next several days, and then likely recurve in the vicinity of the southern Japanese Islands (Figure 1).

The main track influence for this system will be a mid-upper-level ridge to its north and east (Figure 2). The exact strength and positioning of this ridge will be important for determining how sharp the turn is. This system will definitely be worth keeping an eye on in Okinawa and nearby islands of Southern Japan.

Behind this system, it looks like something else could form and intensify SE of Japan (Figure 1), but details are not clear at this point.

East/Central Pacific

The East and Central Pacific remain the most active basins, which is not surprising with the ongoing El Niño. Multiple systems are active, with more possibly forming in the coming days (Figure 3).

Going from west to east, the remnants of 15E are yet another threat to the Hawaiian Islands. The system is forecast to redevelop and intensify south of Hawaii, and could lift north due to forcing from an upper-level trough (Figure 4). It remains to be seen exactly how much it will intensify and how close it gets to the Big Island, but we can’t rule out an impact like Lala earlier this year.

Further East, the big storm is Polo, which has rapidly intensified to a Category 5 with 180-mph winds, one of the strongest storms ever seen in the East Pacific. The system is forecast to move westward to the south of Mexico for the next few days. In the medium range, there is some uncertainty as to whether it will continue west or be lifted northeast towards Baja California. The uncertainty seems to stem from a trough to the north of the storm and whether it will be able to lift it northeast or will leave it behind. Some of the uncertainty may also stem from interaction with Odalys further west, though that system might weaken as it gets close to Polo.

Finally, models are indicating that yet another system may develop south of Mexico, close to where Polo is now. Environmental conditions look generally favorable for development, with an anticyclone overhead (Figure 6). Upwelling from Polo could reduce the SST fuel somewhat, but the waters should still be warm enough to support intensification. This will definitely be something to watch after the other storms have moved out of the picture.

Atlantic

The Atlantic still does not have a hurricane, with Fay dissipating after coming up just short. The main system of note over the next several days is actually a non-tropical “nor’easter” that is forecast to impact the East Coast. Some WNV3 members are picking up on this system (Figure 7), showing that it may have some warm-core characteristics.

However, forecasts generally show that the system will remain non-tropical, with clear fronts, and would probably be a “warm seclusion” extratropical cyclone if it does become a warm core system (Figure 8). Thus, I would be surprised if this becomes a named storm, but it will be impactful in the NE, with strong gusty winds (Figure 9) and rain across the New England region.

Figure 9: FourCastNet-v3 forecast of MSLP and 10-meter wind initialized at 12 UTC September 22, 2026 and valid at 12 UTC September 27, 2026.