eastern pacific Hurricane Hernan

[Somerset Squall]

Tropical Storm Hernan has formed off the south coast of Mexico. Winds are at 35kts. The storm has well developed banding and deep convection over the LLCC. Hernan looks like it may rapidly intensify, as it is in an area of low shear and very warm water, and already has an impressive structure. Hernan is forecast to head northwestwards, and has a few days before reaching cooler waters, so the storm is likely to become a hurricane. The outer rainbands are affecting Mexico, but the storm will remain offshore.

[Somerset Squall]

Hernan has rapidly strengthened over the last 12 hours, and winds are now at 55kts. The storm has become more compact, developed a central dense overcast, and hints of an eye. Hernan is expected to attain hurricane status in the next 12 hours, before decreasing sea temps causes weakening. Hernan is forecast to weaken sooner than before as the storm's track has shifted to the north. NHC forecast a peak of 65kts, but I think Hernan could become a little stronger than this.

 

 

 

 

 

 

 

[Vorticity0123]

Hernan has rapidly strengthened over the last 12 hours, and winds are now at 55kts. The storm has become more compact, developed a central dense overcast, and hints of an eye. Hernan is expected to attain hurricane status in the next 12 hours, before decreasing sea temps causes weakening. Hernan is forecast to weaken sooner than before as the storm's track has shifted to the north. 

 

No sooner said than done, as Hernan has become the third hurricane of the 2014 Eastern Pacific hurricane season. In fact, a faint eye became visible around 18:30 UTC, but this feature has since dissipated. The eye feature can be seen in the imagery below: (note that the image updates itself)

 

Visible satellite loop of Hernan, showing the faint eye appearing and disappearing. (Courtesy: NOAA)

 

 NHC forecast a peak of 65kts, but I think Hernan could become a little stronger than this.

 

 

Agreed, especially given the appearance of the eye feature as mentioned above. Furthermore, it also appears that the center is located directly below the convection, indicative of favourable circumstances for intensification.

 

Hernan is currently located over SSTS (sea surface temperatures) which are warm enough to support a tropical cyclone. However, the forecast track brings the cyclone over cooler waters. This, along with increasing shear, will cause weakening in a day or so. There is also a small area of dry air to the west/southwest of Hernan, which can be seen in the Water Vapor image of Hernan below.

 

Water vapor image of Hernan (Courtesy: NOAA)

 

The dry air can be seen as the yellow colours to the west of Hernan. 

 

 

 

Sources:

http://www.nhc.noaa.gov/text/refresh/MIATCDEP3+shtml/272031.shtml

Edited July 27, 2014 by Vorticity0123

[Somerset Squall]

Hernan's peak ended up being 65kts. Shortly after Vorticity posted, Hernan began weakening as shear increased and the storm began to move over cooler waters. Winds are now down to 35kts. There is barely any convection left associated with Hernan, as the dry air, shear and sea temps below 24C take their toll. The storm is likely to weaken to a tropical depression this afternoon, and a remnant low soon thereafter as the shallowe cyclone veers to the west.

[Somerset Squall]

Hernan has been declared a remnant low. Regeneration is not expected.