Severe Tropical Cyclone Pat

[Somerset Squall]

The South Pacific is on fire (completely different to last year. In addition, the South Indian Ocean is unusually quiet when it wasn't last year)! Yet another tropical cyclone has formed, approx 500 nautical miles east-northeast of Pago Pago. Convection has consolidated around a well defined circulation, prompting the declaration of cyclone status. 14P is currently a 35kt tropical cyclone, and has the potential for some intensification over the next few days as shear is light and waters are in excess of 30C. As the system is well organised already, I can see this storm becoming similarly strong to Oli.

14P is moving east-southeastwards on the south side of an equatorial ridge. A new subtropical ridge building to the east should send 14P on a southward track over the next day or so, and then this ridge is expected to swing to the south of the storm, cradling it and sending 14P back towards the west by day 4 or 5. This track is highly dependant on the sormation of this second ridge and the movement to the south. Needless to say, this track forecast could change.

Once again, no main landmasses are threatened though Bora Bora and later on, Rarotonga need to be wary as 14P could approach both islands through the week.

[Cookie]

[Somerset Squall]

14P has strengthened and has become Tropical Cyclone Pat, with intensity now at 55kts. Pat has developed a solid central dense overcast feature and there are hints of an eye beginning to form. Pat is now swinging to the south as a ridge builds to the east. The ridge is expected to expand southwestwards, sending Pat towards the southwest too. Some further intensification is expected over the next day or so before shear gradually increases and sea temps decline a little, which should induce slow weakening by day 4 or 5.

[Somerset Squall]

Pat has steadily strengthened over the last 24hrs, and intensity has increased to 75kts, making Pat a cat 1 on the SS scale. Some further strengthening is likely over the next 24hrs in low shear and warm sea temps, but after this shear is set to increase and waters cool on the generally southward track. Pat is moving southwards at present on the western side of a subtropical ridge to the east, this general motion should continue. There is a smaller risk that Pat could instead veer westwards due to the potential interaction with invest 98P to the west, though this is currently considered unlikely.

[Somerset Squall]

Pat has significantly intensified today. A well defined, small eye emerged this morning, and even though this eye is a little more cloud obscured at present, Pat has been upgraded to Severe Tropical Cyclone status and intensity has risen to 105kts, a cat 3 on the SS scale. Pat is still moving southwards, but a turn to the southwest is expected as the ridge to the east builds southwestwards in tandem with the cyclone. This will take Pat over colder waters beyond 24hrs, before which Pat could get a little stronger. Rarotonga need to be prepared for this dangerous cyclone as it will pass very close by.

Edited February 10, 2010 by Somerset Squall

[Somerset Squall]

Pat has rapidly weakened over the last 24hrs. Very strong shear and colder waters have totally overwhelmed Pat who is now a meager 45kt tropical storm with a distorted LLC and patchy, disorganised convection. The destructive shear could finish Pat off tonight, as the system looks very fragile and conditions look set to remain very poor to sustain a tropical cyclone.