(BIVN) – Tropical Storm Norbert has formed in the Eastern Pacific, and is expected to gradually strengthen as it moves west over the next several days.
Norbert is far from Hawaiʻi. As of Thursday morning, the storm was located about 755 miles southwest of the southern tip of Baja California.
At its current distance, Norbert is not an immediate threat to Hawaiʻi. However, some long term models are already showing Norbert approaching the Hawaiian islands as a hurricane later this month.
From the National Hurricane Center discussion on Thursday morning:
An AMSR-3 microwave pass over Norbert and GOES-West Infrared satellite imagery indicate that the low-level center of Norbert is underneath the western side of main burst of convection associated with Norbert’s developing core. Moderate westerly wind shear is having a significant affect on the cyclone by pushing the majority of the convection to the east of the low-level center. Given that the center is underneath the convection, gradual intensification seems possible in the short term. The latest subjective Dvorak classification from TAFB is T2.5/35 kt, and recent objective intensity estimates from UW-CIMSS range from 35-40 kt. The initial intensity is held at 35 kt.
The initial motion estimate is westward, or 275/12 kt. A well-established mid-level ridge to the north of Norbert should keep the cyclone moving in a direction between westward and west-northwestward for the next several days. The NHC track forecast is similar to the previous one, and lies close to the HCCA.
The sheared structure of Norbert and the proximity of drier air to the west of the system suggests that only modest near-term strengthening should be expected. However, the shear is forecast to weaken over the next few days while the system moves into a sufficiently moist environment over waters near 28C. Despite these seemingly favorable conditions, there are mixed signals in the guidance regarding how much strengthening may occur. There is also a large spread in some of the ensemble intensity guidance. For example, the Google DeepMind ensemble has a spread at day 4 that ranges from 30 to 120 kt. The HAFS-A keeps it a tropical storm through the forecast period. The HAFS-B briefly makes it a category 1 hurricane within the next 60 hours before weakening the system back to a low-end tropical storm by day 4-5. The NHC intensity forecast is similar to the previous one, showing a slightly faster intensification in the first 48 hours, but then a slower rate of strengthening thereafter. The NHC intensity forecast still lies on the higher end of the guidance envelope and calls for Norbert to reach hurricane strength by early next week.
