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Hurricane Felicia Forecast Discussion Number 9

2021-07-16 10:59:18| National Hurricane Center (East Pacific)

Issued at 200 AM PDT Fri Jul 16 2021 000 WTPZ41 KNHC 160859 TCDEP1 Hurricane Felicia Discussion Number 9 NWS National Hurricane Center Miami FL EP062021 200 AM PDT Fri Jul 16 2021 Tiny Felicia has continued to intensify tonight. Earlier SSMIS microwave imagery showed that the hurricane was maintaining a closed circular eyewall and cloud-top temperatures surrounding the eye on infrared satellite have continued to cool below -70 C. Scatterometer data from an ASCAT-A pass at 0418 UTC also indicated the small size of Felicia's wind field, with peak 34-kt wind radii only extending roughly 50 nm from the center in the northern semicircle. Subjective Dvorak estimates at 0600 UTC were both T5.5/102 kt from TAFB and SAB while the latest UW-CIMSS ADT objective estimate was T5.4/100 kt. A blend of these intensity estimates support a current intensity of 100 kt, making Felicia the first major hurricane in the East Pacific basin this year. Felicia now appears to be moving slightly south of due west with the latest estimated motion at 260/8 kt. Now that the strongest deep-layer ridging is positioned northwest of the hurricane, a west-southwestward motion is expected to continue for the next day or so. Afterwards, a narrow ridge axis shifts back north of Felicia, and the cyclone is expected to resume a more due westward motion between 24 to 72 hours. In the latter portion of the track forecast, the hurricane will come under the influence of a stronger mid-level ridge located north of Hawaii, resulting in another leftward turn by the end of the forecast period. The latest track guidance remains in good agreement for the majority of the forecast. The official NHC forecast is a touch south of the previous track and lies between the HCCA and TVCE consensus aids. Additional short-term intensification is forecast while Felicia remains in a favorable environment of low vertical wind shear between 5-10 kt and warm sea-surface temperatures (SSTs) between 27-28 C. Thereafter, mid-level humidity values are forecasted by the ECMWF-SHIPS guidance to drop below 50 percent as SSTs also gradually decrease. However, both deep-layer (200-850 hPa) and mid-level vertical wind shear are expected to remain light and easterly through at least the next 72 hours. Light easterly shear in combination with marginally warm SSTs are common environmental factors associated with major hurricanes that develop annular characteristics, and these storms are known to weaken at a slower than typical rate. To account for this possibility, the intensity forecast only shows very gradual weakening between 24 to 48 hours which is above the majority of the intensity guidance but lies closest to CTCI (COAMPS-TC). Afterwards, Felicia's weakening rate is forecast to increase as SSTs cool further, and northwesterly vertical-wind shear impinges on the cyclone by the end of the forecast period. The latter portion of the intensity forecast is closer to the mean of the intensity guidance and is near the HCCA intensity consensus aid at 120 hours. FORECAST POSITIONS AND MAX WINDS INIT 16/0900Z 15.1N 121.0W 100 KT 115 MPH 12H 16/1800Z 14.9N 122.0W 110 KT 125 MPH 24H 17/0600Z 14.6N 123.4W 105 KT 120 MPH 36H 17/1800Z 14.5N 125.1W 100 KT 115 MPH 48H 18/0600Z 14.6N 126.8W 95 KT 110 MPH 60H 18/1800Z 14.7N 128.7W 85 KT 100 MPH 72H 19/0600Z 14.8N 130.5W 80 KT 90 MPH 96H 20/0600Z 14.6N 134.2W 65 KT 75 MPH 120H 21/0600Z 13.8N 137.6W 55 KT 65 MPH $$ Forecaster Papin/Beven

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Hurricane Felicia Forecast Discussion Number 8

2021-07-16 04:53:14| National Hurricane Center (East Pacific)

Issued at 800 PM PDT Thu Jul 15 2021 000 WTPZ41 KNHC 160253 TCDEP1 Hurricane Felicia Discussion Number 8 NWS National Hurricane Center Miami FL EP062021 800 PM PDT Thu Jul 15 2021 Satellite imagery indicates that Felicia has continued to rapidly strengthen this evening. Infrared temperatures have significantly warmed within the eye during the past couple hours, and deep convection within the eyewall has become more symmetric. A closed ring of infrared cloud top temperatures colder than -65 to -70 deg Celsius now completely surrounds the eye of Felicia. Based on these current satellite trends, the initial intensity is raised to 95 kt for this advisory. This lies between the TAFB subjective Dvorak current intensity estimate of 90 kt and UW-CIMSS ADT objective estimates of around 100 kt. Warm sea-surface temperatures and low vertical wind shear along Felicia's forecast track are expected to allow for some additional strengthening in the short-term, especially since dry air in the surrounding environment has had minimal impact on the cyclone's intensification up to this point. The official NHC intensity forecast has been adjusted upward and now brings Felicia to major hurricane status (Category 3 on the Saffir-Simpson Hurricane Wind Scale) within 12 h. The NHC forecast remains higher than the guidance consensus through the first 72 h, then generally follows the HFIP corrected consensus approach (HCCA) thereafter. The cyclone is forecast to slowly weaken this weekend within a drier, more stable mid-level environment. However, the forecast track keeps Felicia south of the 26 deg C isotherm, which should allow the cyclone to maintain its hurricane intensity through much of the forecast period. Felicia is still moving almost due west at around 8 kt. As the steering ridge becomes positioned to the northwest of Felicia, the cyclone is expected to move west-southwestward during the next day or so. Then, Felicia is forecast to resume a more westward motion for the next several days as the cyclone moves to the south of a subtropical ridge. The track guidance remains tightly clustered through much of the period. The official NHC forecast is adjusted just a bit slower and slightly farther north than the previous one, bringing it closer to the usually reliable consensus aids TVCE and HCCA. FORECAST POSITIONS AND MAX WINDS INIT 16/0300Z 15.2N 120.2W 95 KT 110 MPH 12H 16/1200Z 15.1N 121.3W 110 KT 125 MPH 24H 17/0000Z 14.9N 122.6W 105 KT 120 MPH 36H 17/1200Z 14.7N 124.2W 95 KT 110 MPH 48H 18/0000Z 14.7N 126.0W 90 KT 105 MPH 60H 18/1200Z 14.9N 127.8W 85 KT 100 MPH 72H 19/0000Z 15.0N 129.7W 80 KT 90 MPH 96H 20/0000Z 14.9N 133.3W 65 KT 75 MPH 120H 21/0000Z 14.5N 137.0W 60 KT 70 MPH $$ Forecaster Reinhart/Blake

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Hurricane Felicia Forecast Discussion Number 7

2021-07-15 22:35:37| National Hurricane Center (East Pacific)

Issued at 200 PM PDT Thu Jul 15 2021 000 WTPZ41 KNHC 152035 TCDEP1 Hurricane Felicia Discussion Number 7 NWS National Hurricane Center Miami FL EP062021 200 PM PDT Thu Jul 15 2021 The evolution of Felicia's satellite imagery since last night suggested that an eyewall replacement cycle had occurred, and recently has completed. For the past several hours, an eye has been occasionally appearing while surrounded by cloud tops as cold as -80 degrees C. With this eye feature becoming somewhat clearer, the corresponding Dvorak-T numbers have increased. Based on a blend of these latest intensity estimates from TAFB, SAB, and the UW-CIMSS ADT, the initial advisory intensity has been increased to 85 kt. Felicia continues to move west, or 270/09kt. The ridge currently to the north of the hurricane is forecast to shift the northwest of Felicia by tonight, which will force the cyclone west-southwestward for a couple of days. By early next week, the hurricane should once again become positioned to the south of the ridge, which would result in a westward motion through the end of the forecast period. The latest NHC track forecast is little changed from the previous one, and is near the tightly clustered track guidance. The small inner-core structure of Felicia is well established, and the cyclone should remain in an environment of low shear and over warm sea surface temperatures (SSTs) over the next 12-24 h. This should allow for some additional strengthening. By late Friday, Felicia is forecast to move into a drier airmass which may begin to disrupt the convection, while the cyclone also begins to move over slowly decreasing SSTs. This should cause the system to gradually weaken through the remainder of the forecast period. The latest NHC intensity forecast remains slightly above the bulk of the guidance through 24 h due to the aforementioned favorable conditions currently in place for strengthening. Thereafter, the forecast is close to the HFIP Corrected Consensus Approach model HCCA. FORECAST POSITIONS AND MAX WINDS INIT 15/2100Z 15.2N 119.4W 85 KT 100 MPH 12H 16/0600Z 15.1N 120.6W 95 KT 110 MPH 24H 16/1800Z 14.9N 122.0W 90 KT 105 MPH 36H 17/0600Z 14.6N 123.6W 90 KT 105 MPH 48H 17/1800Z 14.5N 125.3W 85 KT 100 MPH 60H 18/0600Z 14.5N 127.0W 80 KT 90 MPH 72H 18/1800Z 14.5N 128.9W 75 KT 85 MPH 96H 19/1800Z 14.5N 132.8W 65 KT 75 MPH 120H 20/1800Z 14.5N 136.5W 60 KT 70 MPH $$ Forecaster Latto

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Hurricane Felicia Forecast Discussion Number 6

2021-07-15 16:37:36| National Hurricane Center (East Pacific)

Issued at 800 AM PDT Thu Jul 15 2021 000 WTPZ41 KNHC 151437 TCDEP1 Hurricane Felicia Discussion Number 6 NWS National Hurricane Center Miami FL EP062021 800 AM PDT Thu Jul 15 2021 Earlier this morning, an eye began to appear in satellite imagery. However, since that time the convection has eroded slightly over the southwestern portion of the circulation, making that feature somewhat obscured. This could be a sign that an eyewall replacement cycle (ERC) is underway. Although the eye is not readily apparent in satellite, Felicia has a well-defined inner core structure with persistent and very cold cloud tops surrounding much of the center. The Dvorak T-numbers continue to rise, and the latest blend of the available values from TAFB, SAB, and the UW-CIMSS ADT support increasing the initial intensity to 80 kt for this advisory. Felicia continues to make a gradual turn to the left, and the initial motion is now 270/10 kt. The ridge currently to the north of the hurricane is foreast to shift to its northwest over the next day or so, which will force the cyclone west-southwestward for a couple of days. By early next week, Felicia should once again become positioned to the south of the ridge, which would result in a westward motion through the end of the forecast period. The latest NHC track forecast is little changed from the previous one, and is near the tightly clustered track guidance. Rapid intensification (RI) has continued, and Felicia's winds have increased by 50 kt since early yesterday morning. Aside from a possible pause in the cyclone's intensification in the near-term due to the ERC, the environment of low shear and warm sea surface temperatures (SSTs) that have been supporting the strengthening should continue around the cyclone over the next 24 h. By late Friday, Felicia is forecast to move into a drier airmass which may begin to disrupt the convection, while the cyclone also begins to move over slowly decreasing SSTs. This should cause the system to gradually weaken through the remainder of the forecast period. The latest NHC intensity forecast is slightly above the bulk of the guidance through 24 h due to the RI factors currently in place. Thereafter, the forecast is close to the HFIP Corrected Consensus Approach model HCCA. FORECAST POSITIONS AND MAX WINDS INIT 15/1500Z 15.2N 118.6W 80 KT 90 MPH 12H 16/0000Z 15.3N 119.8W 90 KT 105 MPH 24H 16/1200Z 15.1N 121.5W 95 KT 110 MPH 36H 17/0000Z 14.8N 123.0W 90 KT 105 MPH 48H 17/1200Z 14.6N 124.7W 85 KT 100 MPH 60H 18/0000Z 14.4N 126.3W 80 KT 90 MPH 72H 18/1200Z 14.4N 128.2W 80 KT 90 MPH 96H 19/1200Z 14.5N 132.1W 70 KT 80 MPH 120H 20/1200Z 14.5N 136.0W 65 KT 75 MPH $$ Forecaster Latto

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Hurricane Felicia Forecast Discussion Number 5

2021-07-15 10:58:30| National Hurricane Center (East Pacific)

Issued at 200 AM PDT Thu Jul 15 2021 000 WTPZ41 KNHC 150858 TCDEP1 Hurricane Felicia Discussion Number 5 NWS National Hurricane Center Miami FL EP062021 200 AM PDT Thu Jul 15 2021 Overnight, Felicia has maintained a small, but circular central dense overcast near its estimated center. A fortuitous GMI microwave pass at 0545 UTC depicted a well-defined mid-level eye on the 89 GHz channel, with deep convection wrapped three-fourths around the south and east sides of Felicia's center. Since that time, the storm's infrared satellite structure has improved further, with a distinct warm spot apparent near Felicia's center with colder than -70 C cloud tops wrapping around this feature. Subjective Dvorak estimates from TAFB and SAB were both T4.0/65 kt at 0600 UTC, but a more recent objective ADT estimate was up to T4.4/75 kt. Given the additional improvement seen on geostationary satellite imagery since 0600 UTC, the latest initial intensity was raised to 75 kt this advisory, making Felicia a hurricane. Felicia appears to be starting a leftward turn, with the latest estimated motion at 280/10 kt. Over the next 24-36 hours, a weak upper-level trough currently centered over Baja California is forecast to cutoff and shift the mid-level ridging, currently north of Felicia, to the northwest ahead of the cyclone. This ridge reorientation is expected to result in a slow west-southwestward motion of Felicia beginning in the next 24 hours. Afterwards, the mid-level ridging becomes reestablished north of the cyclone, allowing a resumption of a more westward motion after 60 hours. The latest track guidance remains in good agreement, but has shifted a bit more southward this cycle. The official NHC track forecast is also a little south of the previous forecast, blending the latest track forecasts from the TVCE and HCCA consensus aids. Felicia has rapidly intensified over the last 24 hours from a tropical depression to a category one hurricane. In the short term, Felicia remains in an environment of low (5-10 kt) vertical wind shear and warm (27-28 C) sea surface temperatures. Now that the hurricane appears to have developed an inner core with convection axis-symmetric around it, additional intensification is expected with a new peak intensity of 95 kt forecasted in 24 to 36 hours. The first part of the NHC intensity forecast is on the upper end of the intensity guidance due to the higher initial intensity, and also given the possibility rapid intensification continues, as suggested by SHIPS-RII guidance, which gives Felicia a one-in-three chance of a 25 kt intensity increase over the next 24 hours. Afterwards, while vertical wind shear is expected to remain low, mid-level relative humidity is expected to decrease, leaving the small tropical cyclone susceptible to dry-air intrusions as sea surface temperatures also gradually decrease. A combination of these environmental factors are expected to lead to gradual weakening beginning after 36 hours through the end of the forecast. The latter portion of the NHC intensity forecast is in better agreement with the intensity guidance and closely follows the HCCA consensus aid. FORECAST POSITIONS AND MAX WINDS INIT 15/0900Z 15.2N 117.6W 75 KT 85 MPH 12H 15/1800Z 15.3N 118.9W 85 KT 100 MPH 24H 16/0600Z 15.2N 120.6W 95 KT 110 MPH 36H 16/1800Z 14.9N 122.1W 95 KT 110 MPH 48H 17/0600Z 14.6N 123.6W 85 KT 100 MPH 60H 17/1800Z 14.4N 125.3W 80 KT 90 MPH 72H 18/0600Z 14.3N 127.1W 75 KT 85 MPH 96H 19/0600Z 14.4N 131.1W 75 KT 85 MPH 120H 20/0600Z 14.5N 135.1W 65 KT 75 MPH $$ Forecaster Papin/Beven

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