eastern pacific Hurricane Guillermo

[Somerset Squall]

Tropical Storm Guillermo, the seventh named storm of the Eastern Pacific season has formed at quite low lattitude, about 1000 miles southwest of Socorro Island. Winds are at 35kts. Guillermo is in an environment of low shear and warm sea temperatures, so should strengthen into a hurricane in about 36hrs, before weakening occurs on the northwestwards track as Guillermo moves over cooler waters and into increased shear. There is the potential for rapid strengthening in the next 36hrs as the environment is very favourable.

Edited August 29, 2015 by Somerset Squall

[Somerset Squall]

Guillermo is strengthening quickly. Winds are up to 50kts. Strong banding features are encircling a central dense overcast, with the beginnings of an eye feature. It won't be long before Guillermo becomes a hurricane.

You can see the structural improvements of Guillermo by comparing the image of my last post to the one below:

[Somerset Squall]

Guillermo has continued to intensify, became a hurricane last night, and has since strengthened to 90kts, cat 2 on the SS scale. Guillermo is expected to become a major hurricane soon, but should begin to weaken beyond 24hrs.

[Somerset Squall]

Latest track continues to indicate a risk of impact to Hawaii in 5 days time, Guillermo should have weakened to a tropical storm by this point but will still be a coherent tropical cyclone. Track forecast can obviously still shift this far out but it worth watching.

[Somerset Squall]

Guillermo's peak may be 90kts after all. That is still the current wind speed so strengthening appears to have stopped. Although waters are still plenty warm beneath the hurricane, outflow is being surpressed in the western quadrant. Guillermo's banding features are not as well defined as last night, and the central dense overcast feature has become irregularly shaped due to the subsidence on the western side. Sea surface temperatures will gradually decline on the west-northwesterly track, and shear will gradually increase, becoming quite strong on approach to Hawaii. These factors will more than likely start a weakening trend soon, which will accelerate on approach to the Hawaiian Islands. Guillermo is still expected to probably impact Hawaii as a tropical storm in 4-5 days time however.

The image below shows the deterioration in Guillermo's cloud pattern, suggesting the hurricane has peaked:

[Somerset Squall]

Guillermo is barely a hurricane this morning, with winds down to 65kts. Strong westerly shear is affecting the hurricane, disrupting the inner core and making the associated convection disorganised. Further weakening is expected. Guillermo is still expected to impact Hawaii, though which islands bear the brunt of the storm is still uncertain.

[Somerset Squall]

Guillermo has slowly weakened, and is now a 60kt tropical storm. Shear is gradually eroding the convection, despite Guillermo still being over warm waters. The track has consistently shifted north since I last posted, which thankfully puts Hawaii at much less risk of impact. Further weakening is expected, as even stronger shear lies in Guillermo's track.

[Somerset Squall]

Guillermo is passing north of the Hawaiian Islands. Strong shear and dry air has continued to take it's toll on Guillermo, with the system being a weak 35kt tropical storm currently. Guillermo is not long for this world as shear is not set to abate and the air mass remains reletively dry.