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Tropical Storm Felicia Forecast Discussion Number 26

2021-07-20 16:49:15| National Hurricane Center (East Pacific)

Issued at 500 AM HST Tue Jul 20 2021 000 WTPZ41 KNHC 201449 TCDEP1 Tropical Storm Felicia Discussion Number 26 NWS National Hurricane Center Miami FL EP062021 500 AM HST Tue Jul 20 2021 After being devoid of deep convection for 9-12 hours overnight, Felicia managed to redevelop a small area of convection near and north of its estimated low-level center. However, this convective activity is poorly-organized and already appears to be waning. Subjective Dvorak satellite estimates at 1200 UTC were T2.5/35 kt from SAB and T2.0/30 kt from TAFB, while the latest objective ADT estimate was T1.5/25 kt. Given the earlier scatterometer data and that convection had increased somewhat since that time, the initial intensity is only being lowered to a possibly generous 35 kt for this advisory. The latest estimated motion continues to be south of due west but a little faster, at 260/14 kt. Felicia is primarily being steered by a large subtropical ridge to its north, which should maintain the cyclone on a west-southwest heading over the remainder of its lifespan. The latest NHC track forecast remains very similar to the previous one, but is a touch faster, in agreement with the most recent GFS and ECMWF forecasts. On the latest forecast track, Felicia is expected to move into the central Pacific basin later today, just after 2100 UTC. Despite the recent small convective burst, Felicia's large-scale environment remains dominated by moderate to strong northwesterly vertical wind shear within a dry and stable airmass over 25-26 C sea-surface temperatures. Consequently, a good chunk of the deterministic model guidance (e.g., GFS/ECWMF/HWRF) depict Felicia struggling to produce much, if any, additional organized convection near its center. The official NHC intensity forecast shows Felicia weakening into a tropical depression later today and then degenerating into a remnant low by 24 hours, in close agreement with the multi-model consensus. The remnant low is then forecast to open up into a trough while moving well south of the Hawaiian islands by 60 hours. FORECAST POSITIONS AND MAX WINDS INIT 20/1500Z 15.8N 138.0W 35 KT 40 MPH 12H 21/0000Z 15.3N 140.2W 30 KT 35 MPH 24H 21/1200Z 14.7N 143.1W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 22/0000Z 14.1N 145.9W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 22/1200Z 13.6N 148.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 23/0000Z...DISSIPATED $$ Forecaster Papin/Cangialosi

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Tropical Depression Guillermo Forecast Discussion Number 12

2021-07-20 10:45:39| Tropical Depression LIDIA

Issued at 200 AM PDT Tue Jul 20 2021

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Tropical Storm Felicia Forecast Discussion Number 25

2021-07-20 10:37:07| National Hurricane Center (East Pacific)

Issued at 1100 PM HST Mon Jul 19 2021 000 WTPZ41 KNHC 200836 TCDEP1 Tropical Storm Felicia Discussion Number 25 NWS National Hurricane Center Miami FL EP062021 1100 PM HST Mon Jul 19 2021 Felicia is a rapidly weakening tropical cyclone. The system has been reduced to a low- to mid-level cloud swirl in satellite imagery, with no deep and organized convection near its center since about 0100 UTC. A couple of recent scatterometer passes show several 35-kt vectors in the northern semicircle of the compact cyclone, which supports lowering the initial intensity to 40 kt with this advisory. The cyclone is moving just south of due west, or 265/13 kt. It is expected to turn slightly more west-southwestward later today and maintain this heading for the next several days as it is steered by a subtropical ridge to its northwest. The NHC track forecast is basically an update of the previous one and lies near the center of the tightly clustered guidance envelope. Based on this forecast, Felicia will move into the central Pacific basin by Tuesday night. Felicia is embedded within a dry and stable airmass over SSTs of around 25 deg C, and the cyclone will move under the influence of strong northwesterly vertical wind shear during the next day or so. Thus, it appears very unlikely that Felicia will be able to sustain any organized convection near its center, even as it moves deeper into the tropics over slightly warmer SSTs. The official NHC intensity forecast follows the multi-model consensus and weakens Felicia to a tropical depression in 12 h, and to a remnant low by 36 h. However, this could occur even sooner based on recent trends and the latest model-simulated satellite imagery. The remnant low is forecast to open up into a trough by Thursday night as it passes well to the south of the Hawaiian Islands. FORECAST POSITIONS AND MAX WINDS INIT 20/0900Z 15.9N 136.3W 40 KT 45 MPH 12H 20/1800Z 15.5N 138.4W 30 KT 35 MPH 24H 21/0600Z 14.9N 141.2W 25 KT 30 MPH 36H 21/1800Z 14.3N 144.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 48H 22/0600Z 13.7N 146.7W 25 KT 30 MPH...POST-TROP/REMNT LOW 60H 22/1800Z 13.2N 149.3W 20 KT 25 MPH...POST-TROP/REMNT LOW 72H 23/0600Z...DISSIPATED $$ Forecaster Reinhart/Pasch

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Tropical Storm Felicia Forecast Discussion Number 24

2021-07-20 04:37:31| National Hurricane Center (East Pacific)

Issued at 500 PM HST Mon Jul 19 2021 423 WTPZ41 KNHC 200237 TCDEP1 Tropical Storm Felicia Discussion Number 24 NWS National Hurricane Center Miami FL EP062021 500 PM HST Mon Jul 19 2021 Felicia continues to rapidly weaken over sea-surface temperatures (SST) of around 25 deg C and within a cooler and drier air mass. After an earlier burst of strong convection, all that remains of it is limited to the northeastern quadrant along with cloud tops now having warmed to -55C to -60C. The latest satellite intensity estimates from TAFB and SAB were 45 kt, and that is the intensity assigned for this advisory. Additional weakening is forecast through the remainder of the 72-h forecast period due to the cyclone remaining over SSTs near 25C, westerly vertical wind shear increasing to more than 30 kt by 24 hours, and continued entrainment of drier and cooler low- to mid-level air. The new NHC intensity forecast is similar to the previous advisory, and closely follows a blend of the IVCN and HCCA intensity consensus models. The initial motion estimate remains a little south of due west, or 265/13 kt. A low- to mid-level subtropical ridge to the north of the cyclone is expected to steer Felicia west-southwestward to westward over the next few days until the small cyclone dissipates by 96 hours, if not sooner. Felicia will likely cross into the Central Pacific basin by Tuesday night. The new official track forecast is similar to the previous advisory track, and lies between the tightly packed TVCE and NOAA-HCCA track forecast models. FORECAST POSITIONS AND MAX WINDS INIT 20/0300Z 16.1N 134.8W 45 KT 50 MPH 12H 20/1200Z 15.9N 136.7W 35 KT 40 MPH 24H 21/0000Z 15.3N 139.5W 25 KT 30 MPH 36H 21/1200Z 14.7N 142.3W 25 KT 30 MPH 48H 22/0000Z 14.2N 145.0W 20 KT 25 MPH...POST-TROP/REMNT LOW 60H 22/1200Z 13.6N 147.5W 15 KT 15 MPH...POST-TROP/REMNT LOW 72H 23/0000Z 13.0N 150.1W 15 KT 15 MPH...POST-TROP/REMNT LOW 96H 24/0000Z...DISSIPATED $$ Forecaster Stewart

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