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Tropical Storm Mario Forecast Discussion Number 10

2019-09-19 22:53:38| National Hurricane Center (East Pacific)

Issued at 300 PM MDT Thu Sep 19 2019 000 WTPZ44 KNHC 192053 TCDEP4 Tropical Storm Mario Discussion Number 10 NWS National Hurricane Center Miami FL EP142019 300 PM MDT Thu Sep 19 2019 It's become clear since the issuance of the last advisory that the low level center of Mario is displaced well east of its convection. In fact, a good portion of the center has been exposed this afternoon. The intensity has been lowered to 50 kt based on a blend of the most recent Dvorak Final-T and Current Intensity numbers from TAFB. A significant change to the track forecast was required based on the adjusted initial position of Mario, and the cyclone is now forecast to move much farther east during the next couple of days. The track models are still in extremely poor agreement on how much Mario and Lorena will interact over the next 2 days, and this is further complicated by the fact that Lorena will move over or very near the Baja California peninsula during that time. The NHC forecast still carries Mario as an independent system through 5 days, but confidence in the forecast remains low. For better or worse, the NHC forecast is close to TVCE at most of the forecast period, but is now just east of the consensus for the first 24 h, given current trends. Merger or not, shear from Lorena will likely affect Mario for the next couple of days. As long as Lorena continues to produce substantial convection, this shear should prevent Mario of significantly strengthening, though small short-term fluctuations are still possible. By the end of the forecast period, Mario is forecast to reach cooler waters and encounter dry air, and will likely become post-tropical. The new official intensity forecast is close to the intensity consensus IVCN throughout the forecast period. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 17.1N 110.4W 50 KT 60 MPH 12H 20/0600Z 17.8N 109.7W 50 KT 60 MPH 24H 20/1800Z 19.0N 109.4W 50 KT 60 MPH 36H 21/0600Z 20.3N 110.2W 50 KT 60 MPH 48H 21/1800Z 21.2N 111.6W 50 KT 60 MPH 72H 22/1800Z 22.9N 114.3W 40 KT 45 MPH 96H 23/1800Z 24.5N 116.5W 35 KT 40 MPH 120H 24/1800Z 25.0N 118.0W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ Forecaster Zelinsky

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Tropical Storm Kiko Forecast Discussion Number 30

2019-09-19 22:46:08| National Hurricane Center (East Pacific)

Issued at 200 PM PDT Thu Sep 19 2019 000 WTPZ43 KNHC 192045 TCDEP3 Tropical Storm Kiko Discussion Number 30 NWS National Hurricane Center Miami FL EP132019 200 PM PDT Thu Sep 19 2019 In terms of organization (and latitude) Kiko appears to have hit rock bottom and may now be on its way back up (and north). After the last advisory, Kiko briefly lost all of its central deep convection and consisted of a low-level swirl of clouds. Since then, convective activity has increased substantially and now a rain band appears to be trying to wrap around the northern semicircle of the tropical storm. ASCAT data around 1800 UTC showed max winds of only 35-40 kt, but given the improvement in the structure of Kiko since that time, the initial intensity is conservatively lowered to 45 kt. Aside from small adjustments due to the lower initial intensity, little change was made to the intensity forecast. Most of the guidance calls for at least slight strengthening, and the dynamical models are still calling for Kiko to become a hurricane again. Dry air is still the primary limiting factor, and if Kiko can ever reform a well-defined inner-core, it could strengthen more quickly than forecast. By the end of the forecast period, Kiko could encounter an even drier environment and most of the guidance calls for weakening. Kiko is beginning to turn west-northwestward, and a turn toward the northwest is expected soon. The tropical storm is still forecast to move slowly westward on a wave-like path due to fluctuations in the strength of a mid-level ridge to the north. The track guidance is in particularly poor agreement on the speed Kiko will move west and by day 5 the ECMWF and GFS are 750 mi apart. Although only minor changes were made to the NHC forecast, which remains near the model consensus, confidence in the track forecast is much lower than usual. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 16.3N 129.3W 45 KT 50 MPH 12H 20/0600Z 16.8N 130.0W 50 KT 60 MPH 24H 20/1800Z 17.5N 130.6W 55 KT 65 MPH 36H 21/0600Z 17.9N 131.4W 55 KT 65 MPH 48H 21/1800Z 17.8N 132.2W 55 KT 65 MPH 72H 22/1800Z 17.0N 134.5W 60 KT 70 MPH 96H 23/1800Z 17.0N 136.5W 70 KT 80 MPH 120H 24/1800Z 18.0N 138.5W 55 KT 65 MPH $$ Forecaster Zelinsky

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Hurricane Jerry Forecast Discussion Number 10

2019-09-19 22:43:07| National Hurricane Center (Atlantic)

Issued at 500 PM AST Thu Sep 19 2019 000 WTNT45 KNHC 192043 TCDAT5 Hurricane Jerry Discussion Number 10 NWS National Hurricane Center Miami FL AL102019 500 PM AST Thu Sep 19 2019 Jerry is a compact hurricane on satellite imagery with the central dense overcast becoming more symmetric during the past few hours. Before the Air Force plane departed, the crew recorded 700-mb flight-level winds of 97 kt and SFMR winds of about 70 kt, suggesting maximum winds of about 75 kt. Since that time, an eye feature has been noted on the last-light visible images, indicating that the earlier intensification has probably continued. Thus, the initial wind speed is set to 80 kt, and the next aircraft is scheduled to investigate Jerry around 0000 UTC to obtain a better estimate. The hurricane still has some time to strengthen before northwesterly shear increases by tomorrow morning. The shear increase will also probably allow some environmental dry air to be entrained into the central core and help weaken the cyclone. Thus weakening is anticipated by late tomorrow continuing into Saturday. Some re-strengthening is possible early next week as Jerry could find a lower shear region due to a mid-latitude trough interaction. The new NHC wind speed prediction has not changed too much, but is a little higher at longer range to reflect the above possibility. The initial motion is still west-northwestward, or 295/15 kt. A large subtropical ridge to the northeast of Jerry should continue to steer the hurricane at about the same direction and speed during the next day or two. The models have generally trended a bit to the north on this cycle at short range, and the official forecast follows suit. Thereafter, Jerry is forecast to move around the then-weakening ridge, turning to the northwest on Saturday, north-northwest on Sunday, and then northward and north- northeastward by Monday/Tuesday. The guidance has moved to the northeast at longer range on this cycle, possibly due to a stronger mid-latitude trough helping to weaken the ridge. The NHC forecast is adjusted to the northeast on this advisory, although is still on the western side of the guidance envelope. Key Messages: 1. Although the core of Jerry is expected to move north of the northern Leeward Islands, life-threatening flash floods are possible, along with tropical-storm-force winds in some areas. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 17.5N 55.8W 80 KT 90 MPH 12H 20/0600Z 18.4N 57.9W 85 KT 100 MPH 24H 20/1800Z 19.5N 60.8W 75 KT 85 MPH 36H 21/0600Z 20.7N 63.6W 70 KT 80 MPH 48H 21/1800Z 21.9N 65.8W 65 KT 75 MPH 72H 22/1800Z 24.9N 68.7W 65 KT 75 MPH 96H 23/1800Z 28.0N 68.5W 65 KT 75 MPH 120H 24/1800Z 33.0N 65.0W 70 KT 80 MPH $$ Forecaster Blake

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Tropical Storm Lorena Forecast Discussion Number 10

2019-09-19 22:37:35| National Hurricane Center (East Pacific)

Issued at 300 PM MDT Thu Sep 19 2019 000 WTPZ45 KNHC 192037 TCDEP5 Tropical Storm Lorena Discussion Number 10 NWS National Hurricane Center Miami FL EP152019 300 PM MDT Thu Sep 19 2019 The center and structure of Lorena was extremely difficult to determine this morning after the core of the tropical cyclone interacted with the mountainous terrain of southwestern Mexico. The aircraft that was scheduled to investigate Lorena had mechanical issues and was unable to complete its mission. Thankfully, a fortuitous GMI microwave overpass around 1800 UTC and more recent ASCAT data has provided some clarity on the location and structure of the cyclone. According to that data, the center is located just southwest of the Islas Marias, and the ASCAT revealed peak winds of 45-50 kt. Given the typical undersampling of the ASCAT for in small tropical cyclones, the initial intensity is set at 60 kt, which is between the peak scatterometer winds and the higher satellite estimates. Since the microwave data suggests that the inner core appears to be somewhat intact, some strengthening is expected while the cyclone moves over warm water and remains in a low shear environment during the next 24 hours or so. As a result, Lorena is forecast to be a hurricane when it pass near or over the southern Baja peninsula. After that time, interaction with land is likely to cause some decrease in wind speed. Lorena has been moving faster than expected, and the initial motion estimate is 315/11 kt. The cyclone should turn west-northwestward tonight as it moves between a mid-level ridge to its northeast and Tropical Storm Mario to the southwest. If Lorena remains separated from Mario (as shown by the latest ECMWF), a turn back toward the northwest is expected as the storm moves around the southwestern portion of the ridge. The new NHC track forecast lies between the HFIP corrected consensus model and the latest ECMWF. Although there is still quite a bit of uncertainty regarding the exact track and intensity of Lorena, the government of Mexico has issued a Hurricane Warning for a portion of the southern Baja California peninsula. Key Messages: 1. Heavy rainfall will continue over portions of the Mexican states of Michoacan, Colima, and Jalisco during the next day or so. This rainfall may produce life-threatening flash flooding and mudslides. 2. Tropical-storm-force winds are expected to continue along a portion of the coast of southwestern Mexico through this evening. 3. Lorena is forecast to re-strengthen into a hurricane and bring hurricane-force winds and heavy rainfall to a portion of the southern Baja California peninsula beginning on Friday. A Hurricane Warning has been issued, and preparations to protect life and property should be rushed to completion. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 21.6N 107.0W 60 KT 70 MPH 12H 20/0600Z 22.4N 108.3W 65 KT 75 MPH 24H 20/1800Z 22.8N 109.8W 70 KT 80 MPH 36H 21/0600Z 23.5N 111.1W 70 KT 80 MPH 48H 21/1800Z 24.4N 112.2W 60 KT 70 MPH 72H 22/1800Z 27.0N 114.2W 45 KT 50 MPH 96H 23/1800Z 29.0N 115.5W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 24/1800Z...DISSIPATED $$ Forecaster Brown

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Hurricane Humberto Forecast Discussion Number 29

2019-09-19 22:34:08| National Hurricane Center (Atlantic)

Issued at 500 PM AST Thu Sep 19 2019 000 WTNT44 KNHC 192033 TCDAT4 Hurricane Humberto Discussion Number 29 NWS National Hurricane Center Miami FL AL092019 500 PM AST Thu Sep 19 2019 Humberto is almost a post-tropical cyclone. Satellite images show a well-defined cold and warm front, but they do not appear to be fully connected to the center of circulation yet. In addition, the cyclone is still producing an area of deep convection to the northwest of the exposed low-level center. ASCAT data from earlier today indicated that the wind field of Humberto is very large with tropical-storm-force winds extending up to 330 n mi from the center and hurricane-force winds extending out to 70 n mi from the center. The initial intensity is lowered a little to 90 kt for this advisory. The cyclone is anticipated to become fully extratropical soon, within the next 6 to 12 hours. Although weakening is forecast, Humberto is expected to be a large and powerful extratropical cyclone for a couple of days before it is absorbed by another extratropical low over the north Atlantic. The NHC intensity forecast generally follows the guidance of the GFS model, which typically handles extratropical lows better than the tropical cyclone intensity guidance. Humberto is moving northeastward at 21 kt. A slight turn to the left and a decrease in forward speed are expected during the next 12 to 24 hours as the cyclone rotates around the east and north sides of a mid- to upper-level low to its west. After that time, a faster east-northeast or east motion is expected when the cyclone becomes embedded in the mid-latitude westerlies. The NHC track forecast is largely an update of the previous one and near the various consensus aids. Key Messages: 1. Large swells will continue to affect Bermuda, the northwestern Bahamas, and the east coast of the United States from east-central Florida to the Mid-Atlantic States during the next couple of days. These swells could create life-threatening surf and rip current conditions. FORECAST POSITIONS AND MAX WINDS INIT 19/2100Z 38.5N 58.7W 90 KT 105 MPH 12H 20/0600Z 40.4N 57.5W 75 KT 85 MPH...POST-TROP/EXTRATROP 24H 20/1800Z 42.8N 55.5W 60 KT 70 MPH...POST-TROP/EXTRATROP 36H 21/0600Z 44.6N 51.2W 55 KT 65 MPH...POST-TROP/EXTRATROP 48H 21/1800Z 45.6N 44.6W 50 KT 60 MPH...POST-TROP/EXTRATROP 72H 22/1800Z...DISSIPATED $$ Forecaster Cangialosi

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