Early Sunday, Tropical Depression Four-E strengthened into Tropical Storm Dora, becoming the fourth named storm of the 2017 Pacific hurricane season. Dora has continued to strengthen this morning, although its circulation center has become partially exposed to the north of the main convective mass. Dora is likely to strengthen to a minimal hurricane by Tuesday before weakening commences as the cyclone moves over cooler waters.

As of 10:00 a.m. CDT  (11:00 a.m. EDT), Dora was centered near 15.0°N 101.8°W and was moving west-northwest at 12 mph. Maximum sustained winds were 45 knots (50 mph) with an estimated minimum pressure of 1001 mb. This intensity is based off a Dvorak classification of T3.0/45 kt from TAFB (slightly above the ADT value of T2.8/41 kt from the University of Wisconsin). This makes Dora the strongest storm so far of the 2017 Pacific hurricane season. Dora was strengthening quickly this morning, developing distinct convective banding features. However, during the past few hours, Dora’s intensification seems to have slowed with the circulation now being partially exposed. The main convective mass is located to the south of Dora’s center. While wind shear near the surface is light, mid-level wind shear and dry air from Mexico is likely slowing Dora’s intensification process.

Overall, conditions for Dora are expected to be favorable for intensification during the next 36 hours or so. Wind shear is expected to remain light, about 5 to 10 knots, for the next few days. Sea surface temperatures are currently very favorable, near 28.5°C (83.3°F). However, Dora will be moving over progressively cooler sea surface temperatures during the next few days, with sea surface temperatures falling below the threshold of 26°C (78.8°F) by 36-48 hours. Most of the intensity guidance indicates that Dora will likely be a category 1 hurricane tomorrow. The GFS and HWRF models bring Dora to category 1 strength, but the ECMWF model predicts that Dora will peak as a tropical storm. The SHIPS model indicates an above-normal probability of rapid intensification in the short term, but based on the cyclone’s current structure, it seems unlikely that Dora will strengthen past category 1 strength. I expect Dora to peak around 75-80 mph tomorrow evening before weakening commences on Tuesday. Dora is expected to degenerate into a post-tropical remnant low by Thursday or Friday.

The track forecast for Dora is straightforward with a west-northwest to northwest motion favored over the next few days. Dora is expected to remain parallel to the coast of Mexico but landfall is not expected. However, it should be noted that heavy rains are possible along western Mexico from Dora’s outer bands. No watches or warnings are currently in effect with Dora. I will be back tomorrow for another post on Dora.