Civicane49's WunderBlog

Alvin weakening, may become post-tropical cyclone sooner than expected

Posted by: Civicane49, Saat: 04:43 AM GMT Tarih: 17 Mayıs 2013

East Pacific’s Tropical Storm Alvin is weakening. The combination of strong west-southwesterly shear and interaction of the monsoon trough has disrupted the cyclone from organizing further. The latest National Hurricane Center (NHC) advisory stated that Alvin is barely a tropical storm with winds of 40 mph and central pressure of 1006 mb. Satellite images depict a poorly organized tropical storm with a disorganized cloud pattern. Satellite imagery also shows a cyclone interacting with the monsoon trough. The storm appears to be in the process of becoming a post-tropical cyclone or an open trough. In fact, the latest ASCAT pass suggests that the surface center has become an open circulation. If it remains that way for several hours, the NHC will likely end the advisories of this cyclone. (One of the requirements of a tropical cyclone is that it must have a closed surface circulation center).

Figure 1. Evening infrared satellite image of Tropical Storm Alvin. Image credit: NOAA/RAMMB.

Forecast for Alvin
Alvin should continue to meet its demise. An upper-level trough located just off of the western coast of Baja California has resulted strong west-southwesterly shear of 20 knots over the storm, and the shear is not expected to abate significantly in the next few days. In addition, the interaction of the monsoon trough will keep Alvin from organizing further but rather weakening it. Thus, I expect additional weakening of the storm before degenerating into an open trough by 72 hours. Though, I would not be surprised to see Alvin becoming an open trough sooner than the NHC expected. The system is currently moving west-northwestward and should remain in this motion for couple of days under the influence of a mid-level ridge over southwestern Mexico. Global models forecast the low-level and mid-level centers of the cyclone to split when the storm will degenerate. The low-level center is predicted to move westward within the easterly flow, while the mid-level center is expected to shift poleward toward the trough. Alvin is not anticipated to threaten any land masses.

Civicane49

Categories:Hurricane

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First East Pacific Invest (90E) has a potential to develop

Posted by: Civicane49, Saat: 04:54 AM GMT Tarih: 14 Mayıs 2013

The first invest of the year in the eastern Pacific is here and has a chance to become the first tropical depression of the East Pacific hurricane season, which the official start will be on this Wednesday. Earlier today, the National Hurricane Center (NHC) has designated an area of low pressure in the far eastern Pacific; the NHC tagged it as “Invest 90E”. (For those unfamiliar with the term “Invest”, the information can be found on the Hurricane FAQ). Sate...

Categories:Hurricane

Updated: Saat: 05:03 AM GMT Tarih: 14 Mayıs 2013

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Cold front approaching Hawaii, expected to bring wet weather

Posted by: Civicane49, Saat: 11:17 AM GMT Tarih: 27 Ocak 2013

Calm, dry weather should end for some of the main Hawaiian Islands later today as the cold front will creep in and move down the island chain, bringing the threat for locally heavy rain and thunderstorms. Satellite imagery shows a cold front associated with a robust storm system located northwest of Hawaii. The approaching front should reach the islands of Niihau and Kauai by the next several hours. In fact, the radar data depicts areas of moderate to heavy rain loc...

Categories:Severe Weather Flood Hawaii

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Wet weather for Hawaii on Christmas holidays?

Posted by: Civicane49, Saat: 08:48 PM GMT Tarih: 23 Aralık 2012

Trade winds that have been keeping the Hawaiian Islands cool in the past week has weakened as the high pressure ridge weakened and shifted eastward ahead of the approaching frontal system from the west. It caused the winds to shift from easterly to southeasterly. Showers will continue to favor in windward and mauka areas. There will be widespread sea breezes that would produce afternoon cloud buildups throughout the leeward portions of all islands, but conditions sh...

Categories:Hawaii

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91L could develop over the central Atlantic; Bopha in the Western Pacific

Posted by: Civicane49, Saat: 10:29 PM GMT Tarih: 01 Aralık 2012

Even though hurricane season officially ended yesterday in the Atlantic, there is a low pressure system that could briefly become a subtropical or tropical cyclone. It is situated over the central Atlantic roughly 1150 miles southwest of the Azores Island. The low pressure system was designated as Invest 91L by the National Hurricane Center (NHC). Satellite imagery depicts that the system is producing some shower and thunderstorm activity and has an asymmetric struc...

Categories:Hurricane

Updated: Saat: 10:38 PM GMT Tarih: 01 Aralık 2012

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