close
close

Yiamastaverna

Trusted News & Timely Insights

    • TD 18, Rafael route means rain, not a storm
    New Jersey

    TD 18, Rafael route means rain, not a storm

    Seren Anwen Posted on

    Ryan Truchelut
    | WeatherTiger

    play

    Tropical Depression 18, soon-to-be Tropical Storm Rafael, has come to life as expected in the central Caribbean south of Jamaica. The system is expected to enter the southern Gulf of Mexico as a hurricane by midweek.

    While that’s an alarming statement, the risk of damaging winds or storm surge along the U.S. Gulf Coast remains quite low due to hostile conditions near the coast, and increased rain chances are likely to be the only significant impact of TD 18 on Florida and surrounding areas.

    Tropical Storm Rafael could peak as a Category 2 hurricane before weakening

    According to the NHC advisory at 10 a.m., the storm has maximum sustained winds of 35 mph and is moving north at about 10 mph. Once the storm begins to feel the influence of a ridge of high pressure centered over Florida, which will move the storm further northwest through Thursday, a curve to the left should begin.

    Since the low circulation of the future Rafael is developing in the middle range of possibilities, the short-term orientation is becoming more of a focus.

    Look for the center of Rafael to cross western Cuba or the Yucatan Channel and enter the southeastern Gulf late Wednesday. The system is located on the east side of a high low that will increase its outflow and keep wind shear at favorable to manageable levels over the next few days. Therefore, strengthening is expected through midweek as the system continues to transit Caribbean waters in the mid-80s. Therefore, the storm will likely peak as a Category 1 or 2 storm by Thursday if it can avoid landfall.

    That’s the scary part.

    The good news is that while Rafael could enter the Gulf as a hurricane by midweek, the chance of a storm is very low to reach land like a hurricane. As I discussed last week, a Gulf hurricane in November would require a strengthened steering trough or boundary low over the Mississippi Valley, allowing a storm to quickly track north or northeast over a hostile Gulf without weakening much.

    In this case, a front that descends into the Deep South later this week will be weak and focused primarily east-west. This front will push the steering ridge east into the Atlantic, but the western flank of the high will continue to extend over Florida and the northern Gulf Coast.

    That means Rafael will likely slow down Friday and Saturday, turning west-northwest or northwest into the central or north-central Gulf instead of accelerating north toward Florida.

    This slowdown will also be accompanied by a weakening. While Gulf water temperatures are in the low 80s away from the immediate coast and still capable of sustaining a hurricane, Rafael will draw a very dry continental air mass into its circulation later this week while being sandblasted by wind shear of 30 knots or more . The further north and closer to land the storm gets, the worse the conditions for it will become, meaning the weakening could be dramatic on Friday and Saturday.

    Ultimately, it’s still too early to say whether the storm will technically make landfall on the central or east-central Gulf Coast as a tropical storm, but I don’t think it will make much of a difference in terms of weather impacts if it does does or not.

    What Florida can expect from Rafael: Mostly beneficial rain with little risk of coastal flooding

    For the Florida peninsula, Rafael will reach closest approach late Wednesday and Thursday. If the storm continues to strengthen through Wednesday, it will likely pass a little closer to Florida, but should remain well southwest of the Keys under all scenarios.

    The storm’s main impact on Florida will be an increase in the chance of rain between Wednesday and the weekend. While the tropical cyclone remains well off Florida’s Gulf Coast, it will move tropical moisture from the Caribbean north and across most of the state, producing intermittent showers and thunderstorms of 1 to 3 inches through Saturday.

    Since there has been little rain on the Peninsula since Milton and virtually no rain on the Panhandle since Helene, this rainfall will be a net benefit outside of Central Florida’s river basins that are still in flood stage. Similar precipitation amounts are expected to extend across eastern Alabama and most of Georgia and South Carolina.

    As the storm moves west-northwest or northwest across the southeastern and central Gulf, there is little to no threat of flooding or coastal flooding due to offshore winds along Florida’s Gulf Coast.

    Conditions across Florida will be windy inland and gusty along the coast later this week, but the storm will initially be too far from Florida to pose a wind threat and then too weak to cause major windsorage as it moves approaching or across the central Gulf Coast on weekends. (The Keys may experience more frequent, weak tropical storm squalls midweek.)

    Rafael should also be too far offshore to trigger any large-scale tornado outbreak, although isolated spin-ups in bands far east of even modest tropical systems are always possible.

    With things largely going according to plan, I remain broadly low on the larger impacts of this late-season tropical threat: The depression has not developed any faster than expected, has (yet, anyway) not quickly reinforced, and the controls are characterized by a safe haven I didn’t move while modeling. That means the eastern halves of the U.S. Gulf Coast and the Deep South will likely see needed rainfall, but little other impact.

    After Rafael, another low-threat system could also be eyeing Florida

    One final note: Another tropical system could develop near Hispaniola this weekend and also approach South Florida from the east early next week. Conditions for this aren’t conducive to becoming a big deal either, but it could keep rain chances high in Florida longer term.

    Our hope is that the flurry of late-season tropical activity remains in positive or at least irritating impact territory, which appears to be the case so far. Keep watching the sky.

    Dr. Ryan Truchelut is chief meteorologist at WeatherTiger, a Tallahassee company that provides forensic meteorological expert services as well as subscription agricultural and hurricane forecasts. Visit Weathertiger.com for more information. Email Ryan Truchelut at [email protected].

    Tagged:

    LEAVE A RESPONSE

    Your email address will not be published. Required fields are marked *

    Seren Anwen
    View all posts

    You Might Also Like

    ads