eastern pacific Hurricane Karina

[Somerset Squall]

Invest 99E, mentioned by Vorticity in the Eastern Pacific Hurricane thread, has become the season's eleventh tropical depression, a few hundred miles west-southwest of Manzanillo, Mexico. The depression has increasing convection near the LLCC, and banding features wrapping towards the centre. Shear is set to remain low for several days on the westward track, and waters warm. Though NHC only forecast a peak of 70kts, they say this a conservative forecast, and IMO, barring any premature rises in shear or jogging northwards into cooler water, 11E will probably get stronger than what is forecast. 11E is moving away from Mexico, so should be of no threat to land, at least yet. Who knows with this season? It seems the tropical cyclones are tending towards surviving much further north and moving into the Central Pacific basin, so this one still needs watching.

[Somerset Squall]

11E has become Tropical Storm Karina, with winds of 35kts. The storm has developed a central dense overcast, with the LLCC tucked underneath the eastern edge of the convective canopy. There is actually a little shear present, as evident by this structure. Any shear should ease, allowing Karina to become a hurricane. Just how strong Karina will get is uncertain.

[Somerset Squall]

Karina has steadily strengthened, and now has winds of 50kts. The central dense overcast has expanded a little, and fully covers the LLCC. Further strengthening is expected as Karina continues westwards. Ridging to the north will ensure this motion continues over the next couple of days. Beyond this, NHC mention possible interaction witglh a disturbance to the west, and possibly another to the east. This is causing a fair bit of model spread at days 4 and 5, with tracks ranging from a northerly component of motion to southerly. One thing this does suggest is that tje busy East Pacific season shows no signs of slowing down.

[Somerset Squall]

Karina has continued to strengthen, despite some moderate shear. Winds are now at 65kts, making Karina the sixth hurricane of the Eastern Pacific season. Karina has developed an eye this evening, though it is currently cloud filled and not very distinct on satellite imagery. Shear is forecast to increase a little further now over the next 24hrs, which argues against rapid intensification, but given how well Karina has handled the shear so far, some intensification is likely. NHC still mention the possibility of Karina interacting with a possible tropical cyclone to the west and another to the east by day 4 and 5 of the forecast. It'll be interesting to see if a) these cyclones both form and b) what will happen to Karina's track and intensity.

 

Edited August 14, 2014 by Somerset Squall

[Somerset Squall]

Persistant northeasterly shear has weakened Karina today, and winds have fallen to 55kts, meaning Karina has lost hurricane status. Convection is mostly confined to the western quadrant of the storm, and the eye is no longer apparent. Shear is not expected to let up for at least another 36hrs, meaning further weakening is now forecast. The track forecast after this time is highly uncertain, and will govern Karina's intensity. The NHC are so unsure of what is going to happen, they forecast no change in strength after 24hrs, which probably won't happen. Will Karina interact with disturbance to the east, and therefore head west-southwestwards and remain over warmer water? Or will the cyclone head west-northwestwards into cooler water? We will have to wait and see as there is very little model agreement currently, which means just about anything could happen!

Edited August 15, 2014 by Somerset Squall

[Somerset Squall]

Karina has continued to weaken, and winds are down to 35kts. Karina has dipped south of due west. Shear should ease and waters also warm along the west-southwesterly track. Therefore, Karina will probably begin to re strengthen soon.

[Somerset Squall]

Karina has strengthened slightly, to 40kts. Karina is still under some moderate shear, displacing convection to the west. Karina is heading west-southwestwards as ridging to the north is in control for now. It now appears the disturbance to the east (invest 91E) is going to become dominant due to it's size. This will probably drag Karina back to the northeast in a few days.

[Somerset Squall]

Karina has re-intensified today. Shear has eased as forecast, and Karina has moved over warmer water. As a consequence, convection has built directly over the LLCC, banding features have increased, and there has even been hints of an eye trying to reform again. Winds are back up to 50kts.

 

Karina could gain more strength over the next day or so, and even though not explicitly forecast by NHC, Karina has a shot at becoming a hurricane again in this time. Thereafter, as Karina gets dragged back northeastwards by TD12E, shear will increase, causing Karina to weaken once more.

 

 

 

 

 

 

 

[Somerset Squall]

Shear increased again over fickle Karina overnight. Winds have dropped back to 50kts from 55kts. Convection has collapsed quite considerably, and what little is left is sheared away from the LLCC. Karina has slowed down, and will probably slow further before being dragged back northeastwards in the southwesterly flow around the south quadrant of the larger Tropical Storm Lowell to the northeast.

Edited August 19, 2014 by Somerset Squall

[Vorticity0123]

Karina has slowed down, and will probably slow further before being dragged back northeastwards in the southwesterly flow around the south quadrant of the larger Tropical Storm Lowell to the northeast.

 

Latest forecast from the NHC suggests Karina will be making a small cyclonic loop, with a southward turm expected initially, before it gets surged northeastward toward the circulation of Lowell.

 

NHC forecast track of Karina

 

For the time being, it also seems that Lowell is the larger and dominant cyclone, and therefore, it is likely that Karina will be absorbed by Lowell.

 

The satellite presentation of Karina has improved some during the past few hours, though, as convection has become deeper over and to the southwest of the LLCC (low level circulation center). However, Karina continues to be affected by east-northeasterly shear, which leaves the LLCC at the northeastern edge of the convective envelope. The shear, possibly induced by the outflow of Lowell, is expected to remain and even become stronger once Karina draws closer to Lowell. This, in combination with cooler SSTS (sea surface temperatures) when Karina starts moving northward will induce a gradual weakening trend during the next few days, possibly also leading to dissipation.

 

Visible satellite image of loop Karina.

 

 

Source:

http://www.nhc.noaa.gov/text/refresh/MIATCDEP1+shtml/200841.shtml

[Somerset Squall]

Shear and dry air from TS Lowell have weaken ed Karina to 45kts this morning. The storm is barely moving, but will soon be dragged northeast in a Fujiwara Intetaction with Lowell. Lowell will eventually absorb Karina. As Karina nears Lowell, it will likely weaken further as Lowell continues to inflict shear on Karina.

[Somerset Squall]

Karina's intensity continues to yo-yo. Winds are up to 55kts as shear has once again eased. Convection has built closer to the LLCC, and there are hints of an eye again. Dare I say it, but Karina could approach hurricane intensity again, though I have said this before, for Karina to then just weaken again. In a day or so, a more firm weakening trend will begin as Karina gets drawn towards Lowell.

[Somerset Squall]

Karina remains a 55kt tropical storm in the latest NHC advisory. The track forecast has changed however. It now appears likely that Karina will be drawn towards Lowell, but Lowell should remain seperate from Karina, with absorption no longer expected. Karina could then go on to interact with TS Marie to the east of TS Lowell (though Karina will probably be a remnant low at this point). Karina has certainly been difficult to forecast, but then this is quite an unusual situation!

[Somerset Squall]

Karina is sporting an eye now, and the storm is now a 65kt hurricane, for the second time. This comes 9 days after Karina lost hurricane status for the first time. Karina is now moving east-northeastwards towards Lowell. However, as I mentioned earlier, it still appears that although the systems will get close to one another, they should remain seperate systems instead of merging now. Karina, or it's remnants, should remain south of Lowell, and drift westwards in the long run.

 

Track:

 

 

Edited August 22, 2014 by Somerset Squall

[Somerset Squall]

Karina has reached a new peak intensity, with winds now at 70kts. Karina is expected to remain a hurricane for about another 12-24hrs before weakening.

[Somerset Squall]

Karina is starting to feel the shear and also the lukewarm sea temps. The eye is no longer clearly visible in satellite imagery. Winds are down to 65kts. Karina is heading eastwards now, pretty much over the same area that it tracked westwards across initially. The steering motion is still being caused by the remnant low of Lowell to the north. Karina will interact with Hurricane Marie next, though whether Karina will escape absorption or not for the second time is open to question. However, due to shear and cooling sea temps, Karina should weaken anyway, particularly as Marie nears Karina and inflicts even stronger shear over Karina.

[Somerset Squall]

Karina is being heavily sheared by Marie. Convection is pulsing, but it is sheared away from the LLCC each time. Currently, there isn't much convection at all. Winds are down to 35kts, which barely makes Karina a tropical storm. The storm is drifitng southeastwards now to the southwest of Major Hurricane Marie. Karina should soon dissipate under the shear inflicted by the outflow of Marie.

 

[Somerset Squall]

Karina has weakened to a tropical depression. The depression is approaching Major Hurricane Marie, and will degenerate into a remnant low before being absorbed by the hurricane in a couple days. This image shows the two systems nicely (and the remnant low of Lowell to the north:

[Somerset Squall]

Karina is hanging on in there as a tropical depression, albeit one with only 25kt winds. Convection completely collapsed this afternoon, but a new band of convection has formed in the southwestern quadrant, just about sustaining Karina as a tropical cyclone. The depression is very close to Hurricane Marie now. Karina is moving south-southeastwards into the southern quadrant of Marie, so Karina isn't long for this world. According to NHC, Karina is the seventh longest lasting tropical cyclone on record in the Eastern Pacific in the satellite era.

[Somerset Squall]

Karina has degnerated into a remnant low. The naked swirl left behind can be seen orbiting weakening Hurricane Marie.