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Tropical Storm Jerry Forecast Discussion Number 5

2019-09-18 16:54:50| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Wed Sep 18 2019 000 WTNT45 KNHC 181454 TCDAT5 Tropical Storm Jerry Discussion Number 5 NWS National Hurricane Center Miami FL AL102019 1100 AM AST Wed Sep 18 2019 Satellite images indicate that Jerry continues to become better organized, with a large curved band wrapping around the center. While microwave data does not show an inner core yet, the overall satellite presentation has improved during the past several hours. The initial wind speed is set to 45 kt, which closely matches almost all of the available Dvorak estimates and a just-arrived ASCAT-C scatterometer pass. Further intensification of Jerry is expected during the next day or two as the cyclone moves over very warm waters within light shear. While this type of environment could support even more strengthening than forecast, there is some substantial dry air around the cyclone, which is forecast to limit the intensification rates for now. This forecast leans heavier on the regional hurricane models HWRF, HMON and COAMPS-TC, which all show a weaker cyclone than the statistical/dynamical LGEM and SHIPS models. Most of the guidance shows increasing shear in a couple of days, and the shear could become somewhat strong by next week. While little change in strength is indicated beyond Friday, this usually doesn't happen in reality, and further changes will be necessary as the environmental factors become more clear. The initial motion continues to be west-northwestward, or 290/12 kt. The subtropical ridge to the north should steer Jerry at a faster forward speed for the next couple of days. Afterward, a northwest to north-northwestward turn, influenced by a weakness in the aforementioned ridge left behind by Humberto, is expected. The NHC track forecast is basically an update from the previous advisory and lies on the left side of the guidance suite, nearest the ECMWF model and the corrected-consensus forecasts. Key Messages: 1. Jerry is expected to strengthen and be a hurricane when it moves near the northern Leeward Islands Friday, although it is too soon to determine the direct impacts to the islands. Interests there should ensure they have their hurricane plan in place and monitor the progress of this system. Watches could be issued for a portion of this area this afternoon or evening. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 14.6N 49.2W 45 KT 50 MPH 12H 19/0000Z 15.3N 51.0W 55 KT 65 MPH 24H 19/1200Z 16.3N 53.7W 60 KT 70 MPH 36H 20/0000Z 17.3N 56.5W 65 KT 75 MPH 48H 20/1200Z 18.4N 59.5W 65 KT 75 MPH 72H 21/1200Z 20.5N 65.3W 65 KT 75 MPH 96H 22/1200Z 23.3N 69.1W 65 KT 75 MPH 120H 23/1200Z 26.5N 70.5W 60 KT 70 MPH $$ Forecaster Blake

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Tropical Storm Lorena Forecast Discussion Number 5

2019-09-18 16:52:20| National Hurricane Center (East Pacific)

Issued at 1000 AM CDT Wed Sep 18 2019 000 WTPZ45 KNHC 181452 TCDEP5 Tropical Storm Lorena Discussion Number 5 NWS National Hurricane Center Miami FL EP152019 1000 AM CDT Wed Sep 18 2019 Lorena's cloud pattern has improved this morning, with the development of a central dense overcast feature, and several bands wrapping around the circulation. The initial intensity has been increased to 55 kt, which is in agreement subjective satellite estimates from SAB, and objective estimates from UW/CIMSS. Lorena is located within favorable oceanic and atmospheric conditions, and additional strengthening is forecast during the next 12 to 24 hours. After that time, Lorena's intensity will depend on how much interaction occurs with the mountainous terrain of southwestern Mexico. The latest NHC forecast takes the center along the immediate coast and shows some slight weakening as this occurs. After that time, re-strengthening is possible as Lorena is forecast to traverse warm waters to the southeast of the Baja California peninsula. It should be noted that the intensity forecast is more uncertain than normal due to the potential for land interaction. Lorena has moved a little right of the previous track. Recent microwave fixes indicated a northwestward motion of 325/11 kt. Lorena is forecast to move northwestward around the southwestern portion of mid-level ridge. The overall track envelope has nudged eastward, closer to the coast of southwestern Mexico. In fact, the ECMWF brings the center of Lorena onshore tonight, and that is a distinct possibility. The early portion of the NHC track has been nudged eastward, and lies between the aforementioned ECMWF model track and the various consensus aids. After 24 hours, most of the guidance turns Lorena west-northwestward as a narrow ridge builds to the north of the cyclone. During this portion of the track forecast, the guidance has shifted to the right, and the NHC forecast has been adjusted accordingly. Key Messages: 1. Lorena is forecast to become a hurricane and move dangerously close to the coast of southwestern Mexico later today and tonight. A hurricane warning has been issued for this area and preparations to protect life in property should be rushed to completion. 2. Lorena is forecast to cause heavy rain over portions of the Mexican states of Guerrero, Michoacan, Colima, and Jalisco during the next few days. This rainfall may produce life-threatening flash flooding and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 17.4N 103.5W 55 KT 65 MPH 12H 19/0000Z 18.6N 104.4W 65 KT 75 MPH 24H 19/1200Z 19.8N 105.4W 70 KT 80 MPH 36H 20/0000Z 20.5N 106.2W 60 KT 70 MPH 48H 20/1200Z 21.2N 107.4W 65 KT 75 MPH 72H 21/1200Z 22.4N 110.0W 65 KT 75 MPH 96H 22/1200Z 24.0N 112.4W 55 KT 65 MPH 120H 23/1200Z 26.7N 114.2W 40 KT 45 MPH $$ Forecaster Brown

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Hurricane Humberto Forecast Discussion Number 24

2019-09-18 16:44:20| National Hurricane Center (Atlantic)

Issued at 1100 AM AST Wed Sep 18 2019 000 WTNT44 KNHC 181444 TCDAT4 Hurricane Humberto Discussion Number 24 NWS National Hurricane Center Miami FL AL092019 1100 AM AST Wed Sep 18 2019 An Air Force Reserve Hurricane Hunter aircraft conducting a reconnoiter of Humberto this morning found that the intensity of the major hurricane had increased slightly, but that the inner-core 64- and 50-kt wind fields had expanded significantly, now extending outward up to at least 90 n mi and 110 n mi, respectively, in the southeastern quadrant. During their pass through the southeastern quadrant, the aircraft measured 700-mb flight-level winds of 120 kt, but peak SFMR winds of only 97 kt. Given that convection is minimal in that quadrant, the normal downward mixing is likely not occurring, the intensity has only been increased to 105 kt. The aircraft also measured a central pressure of 952 mb with a dropsonde, which is close to the pressure of 954.2 mb with 30-kt winds that NOAA buoy 41048 measured in the eye around 0930 UTC. The initial motion estimate remains 065/14 kt. Humberto is beginning to feel the effects of a deep-layer trough approaching from the west, and the hurricane should continue to accelerate toward the east-northeast through tonight, passing just north and northwest of Bermuda, followed by a turn toward the northeast by early Thursday afternoon. By 48 hours or so, Humberto is forecast to turn back toward the east-northeast and maintain that motion through day 5 as a ridge to the east of the cyclone weakens and flattens out. The new NHC track forecast is very similar to the previous one for the first 36 hours, and then is a little faster and to the left of the previous advisory thereafter, closer to the tightly packed consensus track model guidance. Humberto may have peaked in intensity based on the cloud pattern in satellite imagery beginning to take on the appearance of an extratropical cyclone. Thus, some fluctuations in strength could occur during the next 12 hours or so. Thereafter, very strong southwesterly vertical wind shear and cold upwelling beneath the hurricane should disrupt the inner-core convection and organization, resulting in steady weakening. By 72 hours, the global models continue to show Humberto merging with a frontal system, and the NHC intensity forecast calls for extratropical transition by that time. The official intensity forecast follows the corrected- consensus models HCCA and FSSE through the next 12-24 hours, and then is above that guidance through the remainder of the forecast period, closer to an average of the global models. Key Messages: 1. A prolonged period of dangerous winds is expected on Bermuda from late this afternoon through Thursday morning, with hurricane-force winds expected overnight tonight. Preparations to protect life and property should be rushed to completion. 2. Storm surge and dangerous breaking waves could cause coastal flooding tonight and Thursday along the southern coast of Bermuda. 3. Swells will continue to affect the northwestern Bahamas and the southeastern coast of the United States from east-central Florida to North Carolina during the next couple of days, creating life- threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 32.2N 68.1W 105 KT 120 MPH 12H 19/0000Z 33.5N 65.4W 100 KT 115 MPH 24H 19/1200Z 36.1N 62.1W 90 KT 105 MPH 36H 20/0000Z 38.6N 60.5W 75 KT 85 MPH 48H 20/1200Z 40.7N 59.5W 60 KT 70 MPH 72H 21/1200Z 43.3N 50.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 22/1200Z 47.2N 33.4W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 23/1200Z 54.0N 20.0W 45 KT 50 MPH...POST-TROP/EXTRATROP $$ Forecaster Stewart

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Tropical Storm Mario Forecast Discussion Number 5

2019-09-18 16:33:24| National Hurricane Center (East Pacific)

Issued at 900 AM MDT Wed Sep 18 2019 000 WTPZ44 KNHC 181433 TCDEP4 Tropical Storm Mario Discussion Number 5 NWS National Hurricane Center Miami FL EP142019 900 AM MDT Wed Sep 18 2019 Recent microwave imagery shows that the inner core of Mario has become better defined overnight. Both GPM and SSMI overpasses reveal a small low- to mid-level eye feature that is fairly aligned with the low-level center. This places the center well within the convective mass seen in conventional satellite imagery. Based on this recent improvement in organization, the initial intensity is raised to 55 kt, in agreement with the latest SAB Dvorak estimate and UW/CIMSS ADT. Mario has managed to fight off moderate northeasterly shear so far, and with the cyclone traversing warm SSTs during the next day or so, additional strengthening is forecast. The new intensity forecast is above the previous advisory in the short term and brings Mario to hurricane strength within 24 hours. After that time, the anticipated slow motion of the storm could cause some upwelling, so little change in strength is shown in the middle portion of the forecast period, followed by slow weakening. Mario is moving northwestward at about 10 kt. A mid-level ridge to the northeast of the cyclone should continue to steer it northwestward during the next day or so. After that time, the track forecast becomes much more uncertain as some of the dynamical models suggest some binary interaction between Mario and Lorena, with Mario turning northeastward as Lorena passes to the northeast and north of Mario. For now, the NHC forecast anticipates less interaction between the two tropical cyclones, and the official forecast is closest to the ECMWF and ECMWF ensemble mean. The medium- to long-range track forecast for Mario is much more uncertain than normal. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 14.5N 111.0W 55 KT 65 MPH 12H 19/0000Z 15.4N 112.0W 60 KT 70 MPH 24H 19/1200Z 16.2N 112.6W 65 KT 75 MPH 36H 20/0000Z 17.0N 113.0W 70 KT 80 MPH 48H 20/1200Z 17.4N 113.1W 70 KT 80 MPH 72H 21/1200Z 18.3N 113.1W 60 KT 70 MPH 96H 22/1200Z 20.2N 114.1W 55 KT 65 MPH 120H 23/1200Z 22.3N 115.6W 50 KT 60 MPH $$ Forecaster Brown

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Tropical Storm Kiko Forecast Discussion Number 25

2019-09-18 16:32:22| National Hurricane Center (East Pacific)

Issued at 800 AM PDT Wed Sep 18 2019 000 WTPZ43 KNHC 181432 TCDEP3 Tropical Storm Kiko Discussion Number 25 NWS National Hurricane Center Miami FL EP132019 800 AM PDT Wed Sep 18 2019 Kiko appears to be stronger this morning with very deep convection near the center, although the cloud pattern is somewhat distorted. The initial wind speed is conservatively raised to 50 kt on this advisory, since the subjective satellite estimates have been running a little hot recently. The storm continues to move west-southwest, or 245/05 kt. A track resembling on roller coaster (which seems appropriate for the ups and downs trying to forecast Kiko this past week) is anticipated during the next several days due to fluctuations in the strength of a mid-level ridge to the north. The guidance is actually in pretty good agreement on this unusual track, so little change was made to the previous NHC forecast. Kiko is expected to remain in a low-shear and marginally warm-water environment for the next few days. After that time, some dry air entrainment and a possible increase in shear could level off the intensity. The latest forecast is essentially an update of the previous one, adjusted for the higher initial wind speed, but this is a fairly low confidence forecast at long range due to some large changes in the guidance at that time. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 16.0N 126.7W 50 KT 60 MPH 12H 19/0000Z 15.9N 127.5W 55 KT 65 MPH 24H 19/1200Z 15.8N 128.4W 55 KT 65 MPH 36H 20/0000Z 16.1N 129.2W 60 KT 70 MPH 48H 20/1200Z 16.6N 129.8W 65 KT 75 MPH 72H 21/1200Z 17.0N 131.2W 70 KT 80 MPH 96H 22/1200Z 16.0N 133.5W 70 KT 80 MPH 120H 23/1200Z 15.5N 136.5W 65 KT 75 MPH $$ Forecaster Blake

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