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Tropical Storm Guillermo Forecast Discussion Number 8

2021-07-19 10:38:17| Tropical Depression LIDIA

Issued at 1100 PM HST Sun Jul 18 2021

Hurricane Felicia Forecast Discussion Number 20

2021-07-19 04:32:39| National Hurricane Center (East Pacific)

Issued at 500 PM HST Sun Jul 18 2021 000 WTPZ41 KNHC 190232 TCDEP1 Hurricane Felicia Discussion Number 20 NWS National Hurricane Center Miami FL EP062021 500 PM HST Sun Jul 18 2021 Felicia continues to decline over water temperatures near or just below 26C. The eye is gradually becoming more difficult to locate in satellite imagery, and the CDO, while already small to begin with, has shrunk in size over the past several hours. A blend of the latest Dvorak T- and CI-numbers from TAFB and SAB suggest that the hurricane has weakened to 90 kt. However, given that environment is not too hostile at the moment, is it reasonable to believe that the vortex of this mature tropical cyclone will take time to spin down despite the degradation in satellite images. Therefore, the initial intensity is being lowered to a perhaps generous 95 kt for this advisory. The cooler waters alone should continue to take a toll on Felicia over the next couple of days by gradually eroding the deep convection. After 48 h, increasing northwesterly shear should help to inject dry and stable air into what remains of the core of the cyclone. By 96 h, if not sooner, Felicia is expected to have lost all of its deep convection and decay into a remnant low. The latest NHC intensity forecast has been lowered from the previous one through the first few days of the forecast period due to the rapidly decreasing wind speeds, and is near the ICON intensity consensus model. Thereafter, the NHC intensity forecast is little changed from the previous one. Felicia continues its 10-kt west-northwestward trek to the south of a subtropical ridge. There is no change to the track forecast reasoning. Model guidance is in good agreement on the cyclone turning westward by Monday then perhaps west-southwestward later in the forecast period as the ridge expands and becomes oriented NE-SW. The NHC track forecast is little changed from the previous one, and lies in the middle of the consensus guidance. Based on this track, Felicia should cross over into the central Pacific basin Tuesday night. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 16.3N 130.1W 95 KT 110 MPH 12H 19/1200Z 16.4N 131.7W 80 KT 90 MPH 24H 20/0000Z 16.5N 133.8W 70 KT 80 MPH 36H 20/1200Z 16.3N 136.1W 60 KT 70 MPH 48H 21/0000Z 15.8N 138.8W 50 KT 60 MPH 60H 21/1200Z 15.3N 141.5W 40 KT 45 MPH 72H 22/0000Z 14.9N 144.1W 30 KT 35 MPH 96H 23/0000Z 14.1N 149.7W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 24/0000Z 13.3N 155.4W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Latto

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Tropical Storm Guillermo Forecast Discussion Number 6

2021-07-18 22:33:03| Tropical Depression LIDIA

Issued at 300 PM MDT Sun Jul 18 2021

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Hurricane Felicia Forecast Discussion Number 18

2021-07-18 16:35:27| National Hurricane Center (East Pacific)

Issued at 500 AM HST Sun Jul 18 2021 000 WTPZ41 KNHC 181435 TCDEP1 Hurricane Felicia Discussion Number 18 NWS National Hurricane Center Miami FL EP062021 500 AM HST Sun Jul 18 2021 Some changes have been seen with Felicia during the past several hours. The eye is not quite as warm in satellite pictures, and there are banding features present in the eastern semicircle of the hurricane. Overall, Felicia's previously very symmetric appearance has become a little distorted to the northeast. Both SAB and TAFB give an initial wind estimate of 115 kt, and that value is used for this advisory. The big question is when will Felicia begin to weaken more significantly. Any environmental changes are fairly subtle during the next couple of days, with somewhat cooler waters and a slight increase in upper-level shear likely. While annular structure tends to be more stable, Felicia is a very small tropical cyclone, and those petite systems usually weaken quickly in marginal environments. Additionally, the latest microwave data has some suggestion of the early stages of an eyewall cycle (although it showed the same thing yesterday without much impact). All of these complex factors lead to this being a low confidence forecast during the next day or two. The new intensity forecast is a bit lower than the previous one, owing to the recent degradation in structure, but is still above the guidance mean. In about 3 days, much stronger shear should impact Felicia, leading to a quick death near or just after day 4. Felicia is moving west-northwestward at about 10 kt. The cyclone is expected to turn westward by Monday, then move west-southwestward through midweek as Felicia becomes steered by a large ridge across the central Pacific. There is a little more spread in the guidance this morning, partially related to exactly how quickly Felicia weakens. The ECMWF, for instance, shows a faster decrease in wind speed, and is more to the southwest of the other guidance, consistent with the low-level steering flow. The GFS has the system moving slower and a little more poleward due to its stronger depiction of Felicia. The new forecast is slightly weighted toward the GFS solution, near the TCVN consensus, resulting in a small northward adjustment. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 15.7N 128.1W 115 KT 130 MPH 12H 19/0000Z 16.1N 129.6W 105 KT 120 MPH 24H 19/1200Z 16.3N 131.7W 95 KT 110 MPH 36H 20/0000Z 16.4N 133.9W 85 KT 100 MPH 48H 20/1200Z 16.2N 136.3W 75 KT 85 MPH 60H 21/0000Z 15.8N 139.0W 60 KT 70 MPH 72H 21/1200Z 15.2N 141.6W 45 KT 50 MPH 96H 22/1200Z 14.2N 146.8W 30 KT 35 MPH 120H 23/1200Z 13.5N 152.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ Forecaster Blake

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