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Tropical Storm Dolores Forecast Discussion Number 2
2021-06-18 16:49:46| National Hurricane Center (East Pacific)
Issued at 1000 AM CDT Fri Jun 18 2021 464 WTPZ44 KNHC 181449 TCDEP4 Tropical Storm Dolores Discussion Number 2 NWS National Hurricane Center Miami FL EP042021 1000 AM CDT Fri Jun 18 2021 Recent SSMIS microwave imagery indicates that convective banding continues to become established to the north and west of the cyclone's center, while the overall area of deep convection is gradually expanding. Dvorak satellite classifications have increased to T2.0/30 kt from TAFB and T2.3/35 kt from SAB, and the depression is therefore being upgraded to a tropical storm with maximum winds of 35 kt. Dolores is moving toward the west-northwest (285/9 kt), to the south of a weak mid-level ridge which extends from the northwestern Caribbean Sea to central Mexico. Since Dolores is now reaching the western extent of this ridge, the storm is expected to turn northwestward and then north-northwestward around the ridge later today and into Saturday, reaching the coast of Colima or Jalisco by Saturday evening. The track models agree on this general scenario, although there is some spread on exactly where and if the center makes landfall. The GFS and HWRF models show a sharper turn toward the north, with the center moving inland near or south of the Manzanillo area, while the ECMWF and UKMET models depict a wider sweeping turn, keeping the center near or just off the coast in the vicinity of Cabo Corrientes. The updated NHC track forecast is between these two scenarios, near the TVCE and HCCA consensus aids, depicting a potential landfall along the Colima or Jalisco coasts Saturday evening. The new NHC track forecast is not too different than the previous forecast, although it does show Dolores reaching the coast a little sooner than previously expected. Additional strengthening is anticipated up until Dolores's potential landfall due to very warm sea surface temperatures (29 to 30 degrees Celsius), a moist environment, and significant upper-level divergence. The intensity models agree on this strengthening, although since several of the track models already have Dolores inland by 36 hours (which the NHC official forecast does not), they're showing the cyclone's intensity too low at that time. The NHC intensity forecast is close to the HCCA consensus aid through 24 hours, but then it is above all of the guidance at 36 hours in order to show at least some additional strengthening before Dolores reaches the coast. Based on this forecast, Dolores is expected to be near or just below hurricane strength when it reaches the coast. This new forecast necessitates the issuance of a tropical storm warning and a hurricane watch for a portion of the west-central coast of Mexico. Depending on the amount of land interaction after 36 hours, Dolores is expected to weaken fast as it continues moving northward along the west-central coast of Mexico. Key Messages: 1. Dolores is expected to continue strengthening today and on Saturday, and it could be near hurricane strength when it reaches the coast of west-central Mexico by Saturday evening. A tropical storm warning and a hurricane watch are now in effect for portions of the southwestern and west-central coasts of Mexico. 2. Heavy rains are forecast over coastal sections of the Mexican states of Oaxaca, Guerrero, Michoacan, Colima, Jalisco, and Nayarit during the next few days, which could result in life-threatening flash flooding and mudslides. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 14.7N 102.5W 35 KT 40 MPH 12H 19/0000Z 15.3N 103.3W 45 KT 50 MPH 24H 19/1200Z 16.8N 104.3W 55 KT 65 MPH 36H 20/0000Z 19.2N 105.0W 60 KT 70 MPH 48H 20/1200Z 22.1N 105.6W 35 KT 40 MPH...INLAND 60H 21/0000Z 24.4N 106.2W 25 KT 30 MPH...POST-TROP/INLAND 72H 21/1200Z...DISSIPATED $$ Forecaster Berg
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