(BIVN) – Hurricane Fausto, as of 5 a.m. Monday morning, was 580 miles east of Hilo, and moving west northwest at 14 mph.
Although Fausto has maintained hurricane strength overnight, with maximum sustained winds near 80 mph, gradual weakening is still forecast during the next several days, as Fausto passes north of the Hawaiian Islands Tuesday night into Wednesday.
“The environment ahead of Fausto grows more unfavorable on approach to the islands and we expect it to weaken into a tropical storm before arrival in the vicinity of the Hawaiian Islands,” the National Weather Service wrote early Monday morning. “That said, we remain cautious at this stage that even subtle southern shifts in the track or delayed weakening trends may still produce changes to our island by island impacts. We strongly encourage the public to pay close attention to this passing storm system as weather impacts over the Hawaiian Islands will evolve the closer Fausto gets.”
High surf is expected along east-facing shores, where a High Surf Advisory has already been issued.
“Although the current forecast indicates that the strongest winds and heaviest rainfall will remain north of the islands, interests across Hawaii should continue to monitor the progress of Fausto,” stated the NWS Central Pacific Hurricane Center.
From the NWS Central Pacific Hurricane Center discussion posted at 5 a.m. HST:
Before departing, the last leg of the overnight Air Force Reconnaissance mission found that Fausto was more or less steady state, with the surface pressure in the 986-988 mb range and enough flight level winds to support maintaining the intensity of at least 70 kt. Since the plane departed, the hurricane’s satellite structure has also held steady, with an irregular central dense overcast near and to the north of the estimated center. While there is no lack of upper-level outflow, increasing mid-level vertical wind shear appears to be undercutting the outflow, with increasing tilt also noted on microwave imagery from a 12 UTC GPM pass. Satellite intensity estimates have not changed appreciably since the last aircraft mission, so the initial intensity remains 70 kt for this advisory.
Fausto continues to move west-northwestward, estimated at 285/12 kt. The track reasoning remains unchanged, with the hurricane being steered by a low- to mid-level ridge parked north of the system. This feature should keep Fausto on a steady west-northwest heading through the middle part of the week. Some wobbles in this general track could occur in the 24-60 h period as shear increases and Fausto’s convective structure becomes increasingly asymmetric. Regardless, the track guidance has remained consistent over the last few cycles, and the NHC track forecast is very close to the prior one, once again blending the HFIP corrected consensus approach (HCCA) and Google DeepMind ensemble mean (GDMI). On this track, Fausto should pass north of the Hawaiian Islands Tuesday night into Wednesday.
The mid-level shear affecting Fausto this morning is an early sign that shear is beginning to disrupt its structure. Westerly vertical wind shear increases above 30 kt in 24-36 h, which is expected to cause the convection to become increasingly displaced northeast of the center. As Fausto passes north of the Hawaiian Islands, it is forecast to be a steadily weakening tropical storm. Simulated satellite imagery from the GFS, ECMWF, and HAFS models show the tropical cyclone losing organized convection between days 2 and 3, and the latest NHC intensity forecast now shows Fausto becoming a remnant low in 72 h, with dissipation shortly thereafter. The NHC intensity forecast is similar to the prior one, near the middle to upper portion of the guidance.
Key Messages:
1. Fausto is expected to continue weakening as it approaches the Hawaiian Islands this week. Although the current forecast indicates that the strongest winds and heaviest rainfall will remain north of the islands, interests across Hawaii should continue to monitor the progress of Fausto.
2. Surf generated by Fausto will continue to build westward across Hawaii along exposed east-facing shores through Tuesday as Fausto approaches and begins to pass north of the islands. Large surf and strong currents will lead to dangerous conditions along exposed shores. Please consult products from your local weather office.
