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Hurricane Kiko Forecast Discussion Number 11

2019-09-15 04:17:10| National Hurricane Center (East Pacific)

Issued at 800 PM PDT Sat Sep 14 2019 000 WTPZ43 KNHC 150216 TCDEP3 Hurricane Kiko Discussion Number 11 NWS National Hurricane Center Miami FL EP132019 800 PM PDT Sat Sep 14 2019 Kiko has undergone a remarkable intensification over the past 24 hours. The initial intensity for this advisory is 100 kt, 55 kt higher than last night's estimate at the same time. The hurricane briefly developed a very clear eye earlier today, and although the eye has become slightly obscured by an increase in eyewall convection, it still has a very impressive satellite appearance. The 100 kt intensity is based on a blend of recent subjective and objective estimates that range from 90 to 105 kt. There is no obvious reason why Kiko would stop strengthening in the short term. The hurricane is clearly not being affected by any of the dry air to its east, SSTs beneath the cyclone are warm, and the shear is quite low. This should be the case for the next 36 h or so, and Kiko is expected to at least maintain its current strength through that period. Beyond that time, the intensity forecast is quite complicated. Kiko will be moving nearly parallel to a strong SST gradient. If the hurricane moves farther south than forecast, it could maintain its strength for longer than indicated. But if it moves farther north, it will likely weaken quickly. Kiko is also forecast to slow down, and upwelling of colder water could also become a factor in a few days, even if the hurricane stays on the warm side of the SST gradient. The NHC forecast continues to show gradual weakening beyond 36 h, but is on the high side of the intensity guidance, most of which is tied to a forecast track north of the latest NHC forecast. The hurricane has slowed a little but is still moving west with a motion of 270/8 kt. For the next couple of days a mid-level ridge should keep Kiko moving generally westward at a similar forward speed. Beyond that time, there is significant divergence between the models. The GFS and regional hurricane models all show the ridge weakening, allowing Kiko to turn northwestward. The ECMWF and UKMET (as well as a clear majority of their ensembles) show no such weakness forming and keep Kiko moving steadily westward through mid-week. Unfortunately, no one solution appears superior at this point, so the NHC forecast isn't fully following either group of models. Instead it has been adjusted only modestly southward, and remains close to the multi-model consensus. Needless to say, confidence in the forecast is quite low. FORECAST POSITIONS AND MAX WINDS INIT 15/0300Z 17.0N 120.1W 100 KT 115 MPH 12H 15/1200Z 17.0N 121.2W 110 KT 125 MPH 24H 16/0000Z 17.2N 122.4W 105 KT 120 MPH 36H 16/1200Z 17.6N 123.6W 100 KT 115 MPH 48H 17/0000Z 17.8N 124.5W 95 KT 110 MPH 72H 18/0000Z 18.2N 126.2W 80 KT 90 MPH 96H 19/0000Z 18.5N 128.0W 60 KT 70 MPH 120H 20/0000Z 18.5N 130.5W 45 KT 50 MPH $$ Forecaster Zelinsky

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Hurricane Kiko Forecast Discussion Number 10

2019-09-14 22:37:05| National Hurricane Center (East Pacific)

Issued at 200 PM PDT Sat Sep 14 2019 000 WTPZ43 KNHC 142036 TCDEP3 Hurricane Kiko Discussion Number 10 NWS National Hurricane Center Miami FL EP132019 200 PM PDT Sat Sep 14 2019 Kiko has continued to quickly strengthen today, with an eye becoming apparent in geostationary and microwave satellite imagery. The latest subjective Dvorak intensity estimates from TAFB and SAB are T4.5 (77 kt), and objective estimates from UW/CIMSS ADT and SATCON are around 75 kt. On this basis, the initial wind speed as been raised to 75 kt for this advisory, and Kiko becomes the sixth hurricane in the eastern Pacific basin this season. Some additional strengthening is possible during the next day or so while Kiko remains over warm water and within low vertical wind shear conditions. After that time, slightly cooler waters and a little increase in shear are likely to cause gradual weakening. A faster rate of filling is expected after 72 hours when Kiko is forecast to encounter stronger westerly shear. The new NHC intensity forecast is near the upper end of the guidance, once again in best agreement with the HFIP corrected consensus model. Recent microwave fixes show that the center of Kiko is a little south of the previous estimates, which results in a more westward initial motion estimate of 270/10 kt. Kiko is currently being steered westward by a mid-level ridge that extends westward over the eastern Pacific from northern Mexico. The western portion of the ridge is forecast to weaken over the next couple of days which should cause Kiko to slow down and gain some latitude. There continues to be usually large spread in the track guidance, with the spread over 400 n mi by day 5. The latest trend in the guidance is slower and farther southward after 48 hours, so the NHC track has been adjusted in the direction. The new track forecast is not as slow as the lastest consensus models, so additional adjustment may be required in future advisories. In summary, the confidence in the track forecast remains quite low. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 17.1N 119.3W 75 KT 85 MPH 12H 15/0600Z 17.2N 120.6W 85 KT 100 MPH 24H 15/1800Z 17.4N 122.0W 85 KT 100 MPH 36H 16/0600Z 17.7N 123.0W 80 KT 90 MPH 48H 16/1800Z 18.0N 123.8W 75 KT 85 MPH 72H 17/1800Z 18.7N 126.0W 55 KT 65 MPH 96H 18/1800Z 19.3N 128.0W 40 KT 45 MPH 120H 19/1800Z 20.0N 130.0W 30 KT 35 MPH $$ Forecaster Brown

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Tropical Storm Humberto Forecast Discussion Number 9

2019-09-14 22:36:32| National Hurricane Center (Atlantic)

Issued at 500 PM EDT Sat Sep 14 2019 000 WTNT44 KNHC 142036 TCDAT4 Tropical Storm Humberto Discussion Number 9 NWS National Hurricane Center Miami FL AL092019 500 PM EDT Sat Sep 14 2019 An Air Force Hurricane Hunter plane extensively investigated Humberto during the past several hours. Data from the plane indicated that the circulation was much better defined than yesterday and the winds increased to 45 kt. Since the plane left, satellite images revealed that the cloud pattern has continued to become better organized, and the low-level center is now under the convection. However, the Dvorak numbers still support keeping the same intensity of 45 kt at this time. Now that the shear appears to be decreasing and Humberto will be moving over warm waters, the NHC forecast continues to call for strengthening. Humberto is anticipated to become a hurricane in about 36 hours over the western Atlantic well east of the Florida east coast, and well away from the Bahamas. The intensity forecast continues to be consistent with the solutions of the consensus model and the corrected consensus HCCA. In addition, all global models intensify Humberto and show an increase in the size of the storm. Satellite and reconnaissance fixes indicate that Humberto has begun to move very slowly toward the north-northwest or 330 degrees at 6 kt. The ridge over the western Atlantic that has been trapping Humberto is already weakening, and this should result in a slow motion toward the north-northwest and then north during the next day or so. After that time, the cyclone will encounter the mid-latitude westerlies, and Humberto, by then a hurricane, is forecast to sharply recurve northeastward away from the United States with no significant increase in forward speed. Only by the end of the forecast period, Humberto should begin to accelerate. The NHC forecast is very consistent with the track guidance which once again clearly depict the slow motion of the system, and then a sharp right turn in 2 or 3 days. FORECAST POSITIONS AND MAX WINDS INIT 14/2100Z 27.4N 77.3W 45 KT 50 MPH 12H 15/0600Z 28.2N 77.9W 55 KT 65 MPH 24H 15/1800Z 29.3N 78.3W 60 KT 70 MPH 36H 16/0600Z 29.9N 77.9W 65 KT 75 MPH 48H 16/1800Z 30.5N 76.7W 75 KT 85 MPH 72H 17/1800Z 31.2N 73.5W 85 KT 100 MPH 96H 18/1800Z 32.5N 67.5W 90 KT 105 MPH 120H 19/1800Z 36.0N 61.0W 80 KT 90 MPH $$ Forecaster Avila

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Tropical Storm Kiko Forecast Discussion Number 9

2019-09-14 16:55:32| National Hurricane Center (East Pacific)

Issued at 800 AM PDT Sat Sep 14 2019 000 WTPZ43 KNHC 141455 TCDEP3 Tropical Storm Kiko Discussion Number 9 NWS National Hurricane Center Miami FL EP132019 800 AM PDT Sat Sep 14 2019 Kiko's cloud pattern has continued to quickly organize overnight and this morning. A couple of high-resolution microwave overpass from several hours ago revealed significant banding around the center, and that a banded eye had formed. Dvorak intensity estimates from TAFB and SAB at 1200 UTC were 55 kt, and the UW/CIMSS ADT is now up to about 60 kt. Based on the continued increase in organization, the initial intensity has been raised to 60 kt. Kiko is forecast to remain over warm water and in a low wind shear environment during the next day or so. This should allow for additional intensification, and Kiko is expected to become a hurricane later today. The new NHC intensity forecast shows a slightly higher peak intensity and is in best agreement with the HFIP corrected consensus model, which is at the upper-end of the guidance envelope. By 72 hours, Kiko will be moving into an area of increasing westerly shear and over slightly cooler waters. As a result, steady weakening is anticipated later in forecast period. The tropical storm is moving westward (280/9 kt) to the south of a mid-level ridge that extends westward from northern Mexico. The track models still exhibit an usually large spread after 48 hours, especially for a system in the eastern Pacific basin. This appears to be the result of the forecast vertical depth of Kiko and how the cyclone responds to a developing weakness in the ridge. The GFS, GFS ensemble mean, and HWRF show a more northerly track, with a stronger Kiko heading toward the break in the ridge. Meanwhile, the ECMWF and UKMET take a weaker Kiko on a more westerly heading. Since the NHC forecast shows Kiko a stronger and vertically deep system during the next couple of days, the track forecast lies a little north of the consensus models. After that time, Kiko is likely to weaken and the official forecast shows a turn back toward the west, as Kiko comes under the influence of the low-level easterly flow. As a result of the large model spread, the confidence in the track forecast remains lower than normal. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 17.4N 118.3W 60 KT 70 MPH 12H 15/0000Z 17.6N 119.5W 70 KT 80 MPH 24H 15/1200Z 17.9N 120.9W 75 KT 85 MPH 36H 16/0000Z 18.3N 122.1W 75 KT 85 MPH 48H 16/1200Z 18.8N 123.3W 70 KT 80 MPH 72H 17/1200Z 19.6N 125.5W 55 KT 65 MPH 96H 18/1200Z 20.3N 128.0W 40 KT 45 MPH 120H 19/1200Z 20.7N 131.0W 30 KT 35 MPH $$ Forecaster Brown

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Tropical Storm Humberto Forecast Discussion Number 8

2019-09-14 16:49:26| National Hurricane Center (Atlantic)

Issued at 1100 AM EDT Sat Sep 14 2019 202 WTNT44 KNHC 141449 TCDAT4 Tropical Storm Humberto Discussion Number 8 NWS National Hurricane Center Miami FL AL092019 1100 AM EDT Sat Sep 14 2019 The center of Humberto is better defined today, but due to shear, it is still located south of the main area of deep convection. Satellite images indicate that a cyclonically-curved convective band is also developing southeast of the center. Recent reports from an Air Force reconnaissance plane indicate that the winds have increased, and the maximum intensity has been adjusted upward to 45 kt. These strong winds are confined to the north and east of the center of the cyclone. The current unfavorable shear over Humberto is forecast to weaken, and since the cyclone is expected to move over warm waters, the NHC forecast calls for strengthening. Humberto is anticipated to become a hurricane in about 36 hours over the western Atlantic well east of the Florida east coast and well away from the Bahamas. The intensity forecast is consistent with the solutions of the consensus model and the corrected consensus HCCA. In addition, all global models intensify Humberto and show an increase in the size of the storm. Satellite and reconnaissance fixes indicate that Humberto has barely moved during the past few hours. Humberto is being trapped by a ridge to the north, but this feature is forecast to weaken. The expected flow pattern should steer the cyclone very slowly toward the northwest and north during the next 24 to 36 hours. After that time, the cyclone will encounter the mid-latitude westerlies, and most likely, Humberto will sharply recurve northeastward away from the United States with no significant increase in forward speed. Only by the end of the forecast period, Humberto should begin to accelerate. The NHC forecast is very consistent with the track guidance which clearly depict the slow motion of the system and the sharp turn to the right in 2 or 3 days. Key Messages: 1. Humberto will likely bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas today. Significant storm surge is not expected in the northwestern Bahamas from this system. Residents there should follow any advice given by local officials. FORECAST POSITIONS AND MAX WINDS INIT 14/1500Z 26.6N 76.7W 45 KT 50 MPH 12H 15/0000Z 27.6N 77.6W 55 KT 65 MPH 24H 15/1200Z 28.7N 78.1W 60 KT 70 MPH 36H 16/0000Z 29.5N 78.0W 65 KT 75 MPH 48H 16/1200Z 30.0N 77.0W 70 KT 80 MPH 72H 17/1200Z 30.5N 74.5W 80 KT 90 MPH 96H 18/1200Z 31.5N 70.0W 85 KT 100 MPH 120H 19/1200Z 34.5N 63.0W 90 KT 105 MPH $$ Forecaster Avila

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