1. Humberto will likely bring tropical-storm-force winds and heavy rainfall to portions of the northwestern Bahamas today. Significant storm surge is not expected in the northwestern Bahamas from this system. Residents there should follow any advice given by local officials.

2. Since the forecast track has shifted farther to the east, the chance of heavy rainfall affecting the southeastern United States has diminished.

WHAT'S NEW:

None.

SUMMARY OF ALERTS:

A Tropical Storm Warning is in effect for...
- Northwestern Bahamas excluding Andros Island

A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. Interests along the east coast of Florida should monitor the progress of this system. For storm information specific to your area, please monitor products issued by your national meteorological service.

WIND: [TOP] Tropical storm conditions are expected within the warning area in the northwestern Bahamas today.

RAINFALL: [TOP] Humberto is expected to produce the following total rainfall accumulations through Monday:

The Bahamas...2 to 4 inches, isolated maximum amounts 6 inches. Portions of the Florida and Georgia coasts...1 to 2 inches.

STORM SURGE: [TOP] Humberto is not expected to product significant storm surge in the northwestern Bahamas.

SURF: [TOP] Swells generated by Humberto are expected to increase and effect the coast from east-central Florida to South Carolina late this weekend and early next week. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

At 500 AM EDT (0900 UTC), the center of Tropical Storm Humberto was located near latitude 26.3 North, longitude 76.0 West. Humberto is moving toward the northwest near 7 mph (11 km/h), and this motion is expected to continue through tonight. A turn toward the north-northwest is expected by Sunday, with a slower northward to northeastward motion forecast to occur by Monday. On the forecast track, the system is anticipated to move near or over the northwestern Bahamas today, and offshore of the east coast of Florida this weekend and early next week.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts. Gradual strengthening is forecast, and Humberto is expected to become a hurricane by Sunday night.

Tropical-storm-force winds extend outward up to 90 miles (150 km) from the center.

The estimated minimum central pressure is 1007 mb (29.74 inches).

Convection associated with Humberto has increased a little since the last advisory, as a new burst has occurred to the north of the center. Other convection continues in a large curved band in the eastern semicircle. Reports from an Air Force Reserve Hurricane Hunter aircraft near 0500 UTC indicated that the maximum sustained winds were near 35 kt, and that will be the initial intensity for this advisory. It should be noted that an upper-level trough is located just south of Humberto, and the storm may have some subtropical characteristics due to interaction with this trough.

While the motion is still a bit erratic, Humberto now seems to be moving a little faster toward the northwest or 315/6 kt. During the next few days, a low- to mid-level ridge over the eastern United States and the western Atlantic is expected to slide southeastward, with a weakness in the ridge developing due to a mid- to upper-level trough over the northeastern U.S. This change in the steering pattern should cause the storm to slow down and turn northward off the east coast of Florida in 36 to 48 hours. Subsequently, the northeastern U.S. trough should dig southward, and this change should turn Humberto northeastward and then eastward away from the U.S. The track guidance has shifted a little more to the east during the first 72 h, and the new NHC track has been nudged eastward as well during this time. The new forecast track lies near the various consensus models.

Southwesterly vertical shear and dry air entrainment caused by the upper-level trough to the south is forecast to diminish during the next 2-3 days while Humberto moves near or over the warm waters of the Gulf Stream. This should allow intensification, and Humberto is expected to become a hurricane in about 48 h. The intensity forecast becomes more uncertain between 72-120 h. Strong upper-level winds associated with the mid-latitude trough over the eastern United States should cause strong shear over Humberto. However, there is a chance that baroclinic forcing from the trough could compensate for the shear, and the GFS, ECMWF, UKMET, Canadian, and HWRF models all show the central pressure falling during this time. The intensity forecast will follow this guidance and show some additional strengthening through 96 h. Overall, the new intensity forecast is similar to, but slightly higher than, the previous forecast.