Maila and 91P form in the Southwest Pacific, a North Pacific Twin Coming?

The Southwest Pacific is heating up, with cyclone 30P (Maila) over the Solomon Sea and Invest 91P a little further east. 91P is forecast to become a TC and intensify, but thankfully looks like it should thread the gap between Vanuatu and Fiji (Figure 1).

Maila could be a bigger problem. It is moving very slowly, and forecast to continue to do so over the next several days as it meanders southeast of Papua New Guinea. If it continues to intensify as forecast, it could become a very rare event, as there have been extremely few strong cyclones in that region in the historical record (Figure 2), and none impacting mainland Papua New Guinea.

Regardless of landfall, Maila will be a major flooding threat for the islands in the region, as it intensifies and meanders, dropping copious amounts of rainfall (Figure 3).

The long-term fate of Maila is unclear. It may weaken over the Solomon Sea if it upwells too much cold water. Later, it could move SW towards NE Australia. This would allow for an opportunity to move over warmer water again, but there could also be some NE shear to contend with. Regardless, this system looks like it will be around for a while.

The possibility of “twin” TCs on both sides of the equator has been discussed for a while, and models are still showing a fairly strong signal for eventual development of a TC in the Northwest Pacific (Figure 1). In fact, upper-level winds could be favorable enough to allow a typhoon to form, with a favorable jet interaction possible (Figure 5).

As noted in previous blogs, the other impact of the TCs and convective activity across the Pacific will be to enhance an ongoing Westerly Wind Burst (WWB). If a TC forms in the NW Pacific, this WWB will be enhanced even further by the circulation around the storms to the north and south (Figure 6). This will continue to push the climate system towards a potentially strong El Niño event that begins to develop this summer.