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Hurricane DOLORES Forecast Discussion Number 10

2015-07-13 22:34:22| National Hurricane Center (East Pacific)

Issued at 300 PM MDT MON JUL 13 2015 000 WTPZ45 KNHC 132034 TCDEP5 HURRICANE DOLORES DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052015 300 PM MDT MON JUL 13 2015 Dolores is strengthening. Visible satellite imagery shows the inner core of the cyclone becoming better organized, and a ragged eye has become evident during the past few hours. There is also a long curved band wrapping entirely around the circulation. The upper-level outflow continues to be restricted to the west, likely the result of a persistent west-northwesterly flow associated with a trough to the northwest. A Dvorak classification of T4.0 from SAB and a UW-CIMSS ADT value of 4.5 are used to raise the initial intensity to 65 kt. Recent fixes suggest that Dolores' forward speed has decreased considerably since this morning, and the initial motion estimate is 295/08. Dolores is about to reach the western edge of a subtropical ridge over the south-central United States, which should result in continued west-northwestward motion but at an even slower forward speed. The subtropical ridge is forecast to rebuild some in 48 to 72 hours, but the ECMWF and GFS are still at odds on exactly how much. These models and the remaining model suite have track solutions that are significantly divergent late in the period, and the official track forecast has been adjusted close to the multi-model consensus, which is nearly midway between the ECWMF and GFS. The track forecast has also been slowed down throughout the forecast period, following the trends of the latest guidance. Nearly optimal thermodynamic parameters such as sea surface temperatures of 29-30 deg C and high tropospheric moisture in the near-storm environment should promote further strengthening. Only some west-northwesterly shear could slow the rate of intensification during the next 12 to 24 hours. After that time, Dolores seems poised to reach major hurricane strength and could potentially intensify more than forecast as a result of the very conducive environmental factors. A gradual spin-down of the vortex is forecast after 72 hours once the cyclone reaches cooler waters and a drier and more stable atmosphere. The statistical guidance has responded to the current intensification and shows Dolores reaching a peak intensity of around 105 kt in 48-72 hours, and the official forecast follows suit. The official forecast continues to be above the multi-model intensity consensus. FORECAST POSITIONS AND MAX WINDS INIT 13/2100Z 17.2N 106.5W 65 KT 75 MPH 12H 14/0600Z 17.5N 107.1W 75 KT 85 MPH 24H 14/1800Z 17.8N 108.0W 85 KT 100 MPH 36H 15/0600Z 18.1N 108.8W 95 KT 110 MPH 48H 15/1800Z 18.6N 109.9W 105 KT 120 MPH 72H 16/1800Z 19.8N 112.2W 105 KT 120 MPH 96H 17/1800Z 21.0N 115.4W 90 KT 105 MPH 120H 18/1800Z 22.2N 118.9W 70 KT 80 MPH $$ Forecaster Kimberlain

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Tropical Storm CLAUDETTE Forecast Discussion Number 1

2015-07-13 19:03:54| National Hurricane Center (Atlantic)

Issued at 100 PM AST MON JUL 13 2015 000 WTNT43 KNHC 131703 TCDAT3 TROPICAL STORM CLAUDETTE SPECIAL DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032015 100 PM AST MON JUL 13 2015 The small low pressure area that moved off the coast of North Carolina over the weekend has lost its frontal characteristics and acquired organized deep convection overnight. The convection, albeit primarily over the eastern semicircle of the sheared system, has persisted for more the 12 hours. Recent ASCAT data indicated that the cyclone has maximum winds of 40 to 45 kt and a well-defined circulation. Based on these data, advisories are being initiated on Tropical Storm Claudette, the third tropical storm of the 2015 Atlantic hurricane season. Claudette is expected to be a short-lived tropical cyclone since it will be moving over much cooler waters and into an area of increasing southwesterly shear tonight. The cyclone could strengthen slightly in the very near term, but is expected to weaken later tonight and become post-tropical shortly thereafter. The post-tropical cyclone is forecast to dissipate within 2 to 3 days as it accelerates northeastward. The global models are in good agreement, and the NHC track forecast is near the middle of the tightly clustered guidance. FORECAST POSITIONS AND MAX WINDS INIT 13/1700Z 37.4N 68.1W 45 KT 50 MPH 12H 14/0000Z 38.5N 66.8W 45 KT 50 MPH 24H 14/1200Z 41.0N 64.0W 40 KT 45 MPH 36H 15/0000Z 43.9N 61.2W 35 KT 40 MPH...POST-TROPICAL 48H 15/1200Z 47.2N 58.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 72H 16/1200Z...DISSIPATED $$ Forecaster Brown

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Tropical Storm ENRIQUE Forecast Discussion Number 5

2015-07-13 16:53:59| National Hurricane Center (East Pacific)

Issued at 800 AM PDT MON JUL 13 2015 000 WTPZ41 KNHC 131453 TCDEP1 TROPICAL STORM ENRIQUE DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL EP062015 800 AM PDT MON JUL 13 2015 Enrique's convective structure consists of a large band that wraps about halfway around the cyclone in its southern semicircle. Unlike the convectively uninhibited nature of Tropical Storm Dolores to its east, the showers and thunderstorm activity of Enrique have warmer cloud tops and the band is somewhat fragmented. As the TAFB, SAB, and ADT Dvorak classifications remain unchanged at 2.5, the intensity for Enrique remains 35 kt. It appears that Enrique will continue to be convectively challenged as the atmosphere in which it is embedded has limited thermodynamical instability, and the SSTs should drop below 26.5 deg C in less than two days. Additionally, the vertical shear - which is low now - is anticipated to increase to 10-15 kt out of the south in about two days, as Enrique reaches the western periphery of an upper-level high. The combination of these effects should result in gradual weakening of the cyclone after about two days and the system becoming a remnant low in about five days. The official intensity forecast is closest to the GHMI dynamical model - the model that anticipates the most development - but the NHC prediction represents a modest reduction from the forecast issued previously. Enrique is moving toward the north-northwest at about 9 kt, primarily due to a deep-layer ridge to its north. The dynamical models have been unanimously in agreement that Enrique should have already taken a west-northwestward turn, which the cyclone has stubbornly resisted thus far. Once such a turn does materialize, Enrique should move toward the west-northwest at about the same rate of speed for about three to four days. After that time, it is anticipated that Enrique's movement should decrease as the steering flow weakens. The official track forecast is north of the consensus at 12 and 24 hours due to the continued right-of-track movement currently occurring and then close to the TVCN multi-model consensus thereafter. This NHC prediction is consistently north of that from the previous advisory because of the continued unanticipated northerly movement of Enrique currently. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 15.9N 126.6W 35 KT 40 MPH 12H 14/0000Z 16.9N 127.3W 40 KT 45 MPH 24H 14/1200Z 17.6N 128.8W 45 KT 50 MPH 36H 15/0000Z 17.9N 130.6W 45 KT 50 MPH 48H 15/1200Z 18.3N 132.3W 40 KT 45 MPH 72H 16/1200Z 19.1N 135.0W 35 KT 40 MPH 96H 17/1200Z 20.0N 137.0W 30 KT 35 MPH 120H 18/1200Z 19.5N 137.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Landsea

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Tropical Storm DOLORES Forecast Discussion Number 9

2015-07-13 16:50:52| National Hurricane Center (East Pacific)

Issued at 900 AM MDT MON JUL 13 2015 000 WTPZ45 KNHC 131450 TCDEP5 TROPICAL STORM DOLORES DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052015 900 AM MDT MON JUL 13 2015 Dolores is gradually intensifying. The cyclone is maintaining a symmetric and very cold-topped central dense overcast, with the center fully underneath the deepest convection. Very recently the cyclone has also shed its outer bands while the inner core has increased in organization. The outflow remains somewhat restricted to the west, however, and there still is some evidence of west- northwesterly shear as a result of an upper-level trough to the northwest. Dvorak classifications were T3.5/55 kt from both TAFB and SAB at 1200 UTC. Since that time, there has been some further increase in organization, and thus the initial intensity is set to 60 kt. The initial motion estimate continues to be a steady 295/11. Dolores should continue to be steered west-northwestward by a subtropical ridge over the south-central United States during the next couple of days. As the cyclone approaches the western periphery of this ridge, the forward motion should decrease and the heading should become west-northwestward to northwestward in 48 to 72 hours. After that time, the ridge should rebuild somewhat to the northeast, which should result in a slightly faster forward speed late in the forecast period. The GFS and ECMWF model solutions diverge considerably after 72 hours, owing to the strength of the subtropical ridge. The official forecast is a little right of the previous one through 36 hours and very close to the multi-model consensus after that time since the strength of the subtropical ridge is still uncertain late in the forecast period. Although environmental thermodynamics are quite conducive for intensification, global models continue to show a persistent west- northwesterly shear over Dolores during the next 24 hours. The shear, however, has not been enough to impede strengthening, with the cyclone developing at about the standard T-number/day climatological average. SHIPS model output indicates a decrease in shear in about 36 hours, and Dolores is expected to become a major hurricane not long after that time. With decreasing SSTs and a drier and more stable atmosphere along Dolores' path after 96 hours, the cyclone is forecast to gradually spin down. Ultimately, the rate of decay will depend on how quickly Dolores gains latitude late in the forecast period. The official intensity forecast is generally above the multi-model consensus and closest to SHIPS model output. FORECAST POSITIONS AND MAX WINDS INIT 13/1500Z 17.1N 106.0W 60 KT 70 MPH 12H 14/0000Z 17.5N 107.0W 70 KT 80 MPH 24H 14/1200Z 17.8N 108.0W 80 KT 90 MPH 36H 15/0000Z 18.1N 109.0W 90 KT 105 MPH 48H 15/1200Z 18.4N 109.8W 100 KT 115 MPH 72H 16/1200Z 19.7N 112.0W 105 KT 120 MPH 96H 17/1200Z 21.2N 115.0W 90 KT 105 MPH 120H 18/1200Z 22.7N 118.3W 70 KT 80 MPH $$ Forecaster Kimberlain

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Tropical Storm DOLORES Forecast Discussion Number 8

2015-07-13 10:44:23| National Hurricane Center (East Pacific)

Issued at 400 AM CDT MON JUL 13 2015 000 WTPZ45 KNHC 130844 TCDEP5 TROPICAL STORM DOLORES DISCUSSION NUMBER 8 NWS NATIONAL HURRICANE CENTER MIAMI FL EP052015 400 AM CDT MON JUL 13 2015 Dolores' convective cloud pattern has continued to improve overnight with a distinct CDO now evident along with a large curved band in the eastern semicircle. In addition, a warm spot has recently appeared near the center of the CDO, a possible precursor to the development of an eye. The ship Asia Excellence, call sign C6AX5, traversed the northeastern quadrant during the past several hours and reported winds of 55 kt. Based on that report and a UW-CIMSS ADT intensity estimate of T3.7/59 kt, the intensity of Dolores has been increased to 55 kt. The initial motion estimate is 290/11 kt, and is based on continuity with the previous forecast and limited microwave fix data. The NHC model guidance is in decent agreement on Dolores maintaining a west-northwestward motion along with a decrease in forward speed through the forecast period as a strong ridge to its north holds steady. Some spread in the models occurs after 48 hours due to differences in how they handle the large trough along the U.S. west coast and how much it erodes the western portion of the ridge over the U.S. desert southwest and northwestern Mexico. The reliable ECMWF and GFS global models, and the regional HWRF model, keep the ridge intact across Baja California, and the official track forecast follows this scenario by keeping Dolores well to the south and southwest of Baja California. The latest NHC forecast lies close to a blend of those three model tracks. Dolores is expected to remain over SSTs greater than 28C for the next 48 hours or so, during which time the deep-layer vertical shear is expected to gradually weaken, especially after 24 hours when the shear is forecast to decrease to less than 5 kt. This combination, along with a moist mid-level environment, should allow for Dolores to continue to strengthen into a significant hurricane. Around 96-120 hours, Dolores is forecast to move over SSTs less than 26C, which should induce gradual weakening. The NHC intensity forecast is similar to the previous advisory and follows the trend of the Decay-SHIPS intensity model, which essentially brings Dolores to major hurricane status by 48-72 hours. FORECAST POSITIONS AND MAX WINDS INIT 13/0900Z 16.6N 105.0W 55 KT 65 MPH 12H 13/1800Z 16.9N 106.1W 65 KT 75 MPH 24H 14/0600Z 17.1N 107.3W 75 KT 85 MPH 36H 14/1800Z 17.4N 108.2W 80 KT 90 MPH 48H 15/0600Z 17.9N 109.1W 85 KT 100 MPH 72H 16/0600Z 19.2N 111.0W 100 KT 115 MPH 96H 17/0600Z 20.6N 113.6W 90 KT 105 MPH 120H 18/0600Z 21.8N 116.6W 75 KT 85 MPH $$ Forecaster Stewart

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