Visible satellite image of Tropical Storm Flossie on Friday afternoon.
Flossie:
All signs are pointing to a period of showers and wind early next week in parts of Hawaii, as Tropical Storm Flossie is expected to make landfall on the Big Island as a tropical depression sometime on Tuesday. Tropical systems don't impact Hawaii too often -- impacts are usually confined to the remnants of tropical systems -- but a named storm will impact parts of the state every couple of years.
The most recent landfall of a named system was Hurricane Neki back in 2009, and the worst system to make landfall in Hawaii was Hurricane Iniki in 1992, which hit Kaua'i as a Category 4.
Here's the National Hurricane Center's forecast track of Flossie as of this afternoon's advisory, showing the storm making landfall on the Big Island as a tropical storm sometime on Tuesday:
The models are in fairly good agreement that the storm will track towards Hawaii over the next couple of days, though there is some variation on exactly where the center will wind up. Regardless, the system is sizable, so even if the center passes north or south of the islands, some heavy showers, wind, and higher waves are likely.
The system is expected to strengthen to a minimal tropical storm or tropical depression by the time it reaches the state next week. One of the big battles Flossie has to deal with for the remainder of its life is dry air, seen below on water vapor imagery. Tropical systems ingesting dry air is a death sentence if they can't escape to a more moist environment. According to the NHC, the dry air mixed with some wind shear and slightly cooler sea surface temperatures (hovering in the upper 70s), the storm should weaken markedly by the time it reaches Hawaii.
5PM ET FLOSSIE UPDATE: NHC finds that Flossie is a little stronger and has updated their forecast accordingly. The storm may make landfall in Hawaii as a tropical storm, after all. Track map updated to reflect the new advisory.
Dorian:
Over in the Atlantic, the NHC is still keeping an eye on Tropical Storm Dorian, which is struggling to survive against wind shear. Here's the forecast track as of 11AM today:
Since Dorian doesn't have very much thunderstorm activity around the center of the storm, the storm is more influenced by the lower- to mid-levels of the atmosphere than the upper-level winds. The upper-level winds in the vicinity of Dorian are rather calm right now (around 5-10 knots), whereas the lower- to mid-level winds are between 15 and 20 knots.
This is causing two things to happen. The first, the storm is struggling to keep from shredding apart. The second, blocked by the high from moving more towards the north and out to sea, the storm is going to continue moving west towards the Caribbean. The result is pretty clear on this afternoon's visible satellite imagery from the central Atlantic. Dorian looks more like a blob of disorganized clouds than a tropical system:
I think the NHC and the models are being too generous with the forecast. I have a feeling Dorian is going to degenerate into a tropical wave well before it reaches the Caribbean, given how disorganized it is right now. It's worth watching regardless, because stranger things have happened.
5PM ET DORIAN UPDATE: The NHC is surprisingly still calling Dorian a tropical storm, even with its incredibly raggedy appearance, but lowered the winds to 45 MPH. Their forecast discussion strongly hints at declaring it degenerated within a couple of advisories if it continues to grow more disorganized.
It's worth noting that July isn't the most active month for tropical systems. The peak of hurricane season is September 10th, so don't let your guard down yet that it's been a relatively quiet year -- we're just getting started. Here's some monthly hurricane climatology from the NHC.