eastern pacific Major Hurricane Julio

[Somerset Squall]

Invest 97E, located several hundred miles southwest of the southern tip of Baja California, has become Tropical Depression 10E, with winds of 30kts. The system has had a well defined circulation for a couple days now, but moderate shear has prevented convection from persisting. Convection has built closer to the LLCC now, prompting the upgrade to tropical depression.

10E is still under moderate shear, and this will slow the intensifcation of the depression, but isn't expected to stop it all together. In a couple days, shear is expected to ease on the westwards track along the south side of a strong ridge to the north. This should allow at least some steadier intensification at this time. NHC forecast 10E to become a hurricane as it moves toward the Central Pacific.

Edited August 9, 2014 by Somerset Squall

[summer blizzard]

Julio forecast to be a potential second hit in succession on Hawaii. Even if one or both is weak, they will get severe flooding if both hit.

[Somerset Squall]

10E became Tropical Storm Julio this afternoon, and has since continued to strengthen fairly quickly. Winds are now at 50kts. Julio has much deeper, more centralised convection and impressive banding features wrapping into the circulation from the west side. Shear doesn't seem to be much of an issue for now, so Julio is expected to become a hurricane soon. As Julio heads towards the west, it could pass over waters cooled by Major Hurricane Iselle, which could cause the cyclone to weaken. Before this however, Julio is expected to peak as a category 2 hurricane. As SB says, it looks like Julio could follow Iselle to Hawaii.

 

Edited August 5, 2014 by Somerset Squall

[Somerset Squall]

Shear rose again over Julio today, which has kept the storm is check. This evening however, the storm has become more tightly wrapped again, with some healthy convection over the LLCC, which indicates that shear is easing again. Winds are up to 55kts. Julio should become a hurricane tomorrow as it travels west in the wake of Major Hurricane Iselle. Track forecast has shifted northwards, which means latest thinking is that Julio may pass to the north of Hawaii, but still close enough to bring severe weather, unless it shifts even further north.

[Somerset Squall]

Julio has become a hurricane, with winds of 65kts. Convection is a little meager in association with Julio, but it does have a complete eyewall, prompting the upgrade. Although shear is low, Julio will be moving through cooler waters upwelled to the ocean surface by Major Hurricane Iselle, so only slight strengthening is forecast, with NHC expecting a peak of 80kts.

[Somerset Squall]

Julio is a compact hurricane with some moderately deep convection surrounding the fairly well defined eye. Winds are up to 85kts, category 2 on the SS scale. Julio is beginning to move over cooler water, but shear is low. A little more intensification is expected, followed by slow weakening. Julio is still forecast to move just north of the Hawaiian Islands, but not far enough north to not have an affect.

[Somerset Squall]

Julio has become a major hurricane overnight, with winds now at 100kts, cat 3 on the SS scale. Apart from the higher than expected intensity of the system, the intensity forecast remains the same. Slow weakening is expected to begin soon due to cool sea temps beneath the hurricane. However, NHC mention that Julio has some annular characteristics, so unless shear rises, Julio will continue to be stubborn despite the marginal environment.

[Somerset Squall]

Julio peaked at 105kts, but has weakened to 90kts as cooler waters take some affect on the system. Julio has redeveloped some banding features which does suggest it has lost annular characteristics. Track still points to Julio just moving north of Hawaii.

[Somerset Squall]

Julio is hanging on as a hurricane, with winds of 80kts. The eye remains apparent on satellite imagery, encircled by some moderately deep convection. Julio is moving well north of the Hawaiian Islands, so is no longer a threat. The hurricane is gaining some impressive lattitude for an East/Central Pacific hurricane, this is probably due to the anomalously warm sea temperatures north of Hawaii, 2-3 degrees warmer than normal according to CPHC. Julio is forecast to continue heading northwestwards and then turn to the north. In 5 days time, waters will finally cool and extratropical transition will begin- again, another unusual occurrence for a system in this basin.

 

Edited August 10, 2014 by Somerset Squall

[Typhoon43]

Julio is now a minimal 65 kt hurricane according to the best track.

[Vorticity0123]

In 5 days time, waters will finally cool and extratropical transition will begin- again, another unusual occurrence for a system in this basin.

 

Yes, like Genevieve, a very rare occurrence to see an Eastern Pacific hurricane recurving into the westerlies. Those abnormally warm SSTS (sea surface temperatures) definitely must have been aiding to this string of events. To show this, below is a SST anomaly chart as of 11 August 2014:

 

SST anomaly chart of the Eastern Pacific. Positive anomalies (warm) are indicated by yellow to red colours, while negative (cold) anomalies are indicated by blue colours.

 

Note the positive anomalies of about 3*C to the northeast of the main Hawaiian islands. Also worth noting is the pool of sharp negative SST anomalies over where Julio and Iselle passed (likely caused by upwelling).

 

Finally, also note the very weak El Nino signature present, with cool anomalies extending from Peru westward toward Indonesia, and weakly warm SSTS near the west of Mexico extending westward to about 120 deg. E.

 

Source:

http://www.ospo.noaa.gov/Products/ocean/sst/anomaly/

[Somerset Squall]

Julio continues to gain an impressive lattitude for an East/Central Pacific hurricane. Winds are down to 55kts currently. As shear is quite low, and waters aren't unfavourably cold, only slow weakening is expected before Julio recurves into the mid-lattitudes. It may hang on for another 4 days before becoming extratropical.

[Somerset Squall]

Julio has become a hurricane again with winds of 65kts. An eye has re-emerged, surrounded by a ring of deep convection. As shear remains low amd waters reletively warm for another 12-24hrs, CPHC mention the possibility of a little additional intensification, before stubborn Julio finally weakens as shear rises at this high lattitude.

[Somerset Squall]

Julio has re-strengthened further, with winds now at 70kts. The ring of convection persists around the clear eye of the compact hurricane. Satellite imagery clearly shows a very large trough approaching however, which will increase shear markedly over Julio tomorrow.

 

[Somerset Squall]

Shear has heavily impacted Julio today. The system is largely convectionless this evening, and the LLCC is completely exposed. Winds are down to 50kts. CPHC forecast Julio to become a remnant low in 48hrs, but unless convection returns soon, this will occur sooner.