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Yellow Evan wrote:TheStormExpert wrote:Maybe Hawaii will get fortunate and it will pull an Iselle and weaken a good bit right before hitting or coming close to the Big Island.
The angle of approach from Ana is different than the angle from Iselle.
TheStormExpert wrote:Yellow Evan wrote:TheStormExpert wrote:Maybe Hawaii will get fortunate and it will pull an Iselle and weaken a good bit right before hitting or coming close to the Big Island.
The angle of approach from Ana is different than the angle from Iselle.
True, but the volcanic mountains could once again impact the circulation several hours prior to landfall or her closest approach to the Big Island.
Yellow Evan wrote:TheStormExpert wrote:Yellow Evan wrote:The angle of approach from Ana is different than the angle from Iselle.
True, but the volcanic mountains could once again impact the circulation several hours prior to landfall or her closest approach to the Big Island.
I can't see the Big Island spitting it out if it passes E of the islands. The Big Island clearly did not bother Iniki.
During late July 1996 the tropical atmosphere of the western North Pacific was dominated by an active monsoon trough. On 23 July, three TCs were developing along the axis of this trough: Frankie (in the South China Sea), Gloria (in the Philippine Sea, east of Luzon), and Herb (northeast of Guam) (Fig. 1). Gloria had been developing as a monsoon depression, defined by the Joint Typhoon Warning Center (JTWC) as a large (but relatively weak) cyclone in the monsoon trough that is composed of an ensemble of mesoscale convective systems (MCSs) (JTWC 1993). During the evening hours of 23 July, a cluster of small cold-topped MCSs began to grow near the estimated center position of Gloria. During a 6-h period, this cluster of MCSs mushroomed into an enormous CCC. By local midnight, the average diameter of the area within which the cloud-top temperature was at or below −70°C was approximately 780 km (Fig. 2).
In relation to published statistics of convective cloud sizes, Gloria’s CCC is extraordinarily large. The area of that portion of Gloria’s CCC (see Fig. 2) that is colder than −70°C is nearly 500 000 km2. For ease of visualization, one sees from Fig. 3 that this is nearly as large as the state of Texas (which encompasses 692 402 km2). In a study of 43 mesoscale convective complexes (MCCs) occurring over the central United States during 1978, Maddox (1980) measured the areal extent of cloud-top temperatures at, or below, −52°C. Only one of these 43 MCCs possessed a cold cloud shield (at, or below, −52°C) that was bigger than the portion of Gloria’s CCC that was at, or below, −70°C. In a study of winter monsoon cloud clusters in the region of Borneo and surrounding seas, Williams and Houze (1987) found no cluster elements (i.e., an individual cloud mass) meeting the area and temperature thresholds of at least 50 000 km2 of contiguous cloud below −60°C with a size greater than 300 000 km2. Mapes and Houze (1993) examined maritime tropical cloud clusters as defined by the very cold threshold of −65°C (which matches the instantaneous precipitation area in radar-sampled mature MCSs fairly well). In their study, a cloud cluster was identified on geostationary IR imagery by an algorithm that searched for connected areas of cold cloudiness. This algorithm required horizontal (along the satellite scan line) connectivity as well as a columnar (not merely touching diagonally) connectivity. Less than 0.1% of all cloud clusters at the temperature threshold of −65°C had sizes greater than 500 000 km2.
Gloria’s CCC was not only large but also exceptionally cold. Roughly half of the area of Gloria’s CCC was colder than −90°C. The coldest IR pixel, with an equivalent blackbody temperature of −100°C, was located near the geometric center of the CCC. This is an extremely cold cloud-top temperature that is rarely seen. It is only 2°C shy of the record cold cloud-top temperature of −102°C reported by Ebert and Holland (1992) in the deep convection associated with a TC near Australia.
By the early daylight hours of 24 July, the periphery of the CCC began to warm on IR imagery, and a new smaller CCC mushroomed into the preexisting cold cirrus canopy. As the day progressed, the underlying structure of Gloria gradually emerged in VIS imagery as the supporting convection of the CCC ended and the large cirrus canopy of the CCC thinned. By midafternoon, the cold cirrus of the CCC became nearly transparent, and a ragged eye accompanied by some peripheral convective cloud bands of the intensifying Gloria was then seen.
That a CCC indicates arrested development is a finding by Dvorak. This is generally accepted as valid and is used in operational application of Dvorak’s techniques. While it is true that there were no in situ measurements of the intensity of Gloria before, during, or after it possessed a CCC, the satellite imagery does provide evidence that little intensification took place. The JTWC best track (largely dependent upon satellite intensity estimates) shows little intensification during this time period. Prior to the formation of Gloria’s CCC, satellite intensity estimates (supported by ship observations) indicated that Gloria’s peak winds had increased to approximately 55 kt. During the afternoon hours of the following day, as the dense cirrus of Gloria’s CCC thinned to allow a view of the underlying central cloud structure, a very poorly defined eye was observed on VIS imagery, indicating that Gloria had become a minimal typhoon. By the morning hours of the next day, Gloria acquired a well-defined CDO within which there was a small cloud-filled eye. Applications of Dvorak’s techniques to the satellite imagery indicated that Gloria had reached 90 kt (its peak estimated intensity), representing a rise of only 35 kt during the 36-h interval following the onset of its CCC—hardly a remarkable change considering the extreme changes in the cloud pattern. This is consistent with Dvorak’s findings that the appearance of a CCC signals arrested development that is renewed as the eye pattern of the T4 (minimal hurricane) emerges beneath the thinning cirrus. It is an irony that the most significant convective event that may be observed during the life of a TC has little immediate effect upon the intensity.
hawaiigirl wrote:whats the chances of Ana hitting Oahu as a Cat 2+ ?
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ADT is being ignored completely by the cphc.
