• TS Helene Forms - Watches

    From Dumas Walker@21:1/175 to All on Tue Sep 24 12:45:00 2024
    062
    WTNT34 KNHC 241458
    TCPAT4

    BULLETIN
    Tropical Storm Helene Advisory Number 5
    NWS National Hurricane Center Miami FL AL092024
    1100 AM EDT Tue Sep 24 2024

    ...TROPICAL STORM HELENE FORMS OVER THE NORTHWESTERN CARIBBEAN SEA...

    ...HURRICANE AND STORM SURGE WATCHES REMAIN IN EFFECT FOR PORTIONS
    OF THE FLORIDA GULF COAST...


    SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION -----------------------------------------------
    LOCATION...19.5N 84.3W
    ABOUT 180 MI...295 KM ESE OF COZUMEL MEXICO
    ABOUT 170 MI...275 KM SSE OF THE WESTERN TIP OF CUBA
    MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
    PRESENT MOVEMENT...NW OR 310 DEGREES AT 12 MPH...19 KM/H
    MINIMUM CENTRAL PRESSURE...1000 MB...29.53 INCHES


    WATCHES AND WARNINGS
    --------------------
    CHANGES WITH THIS ADVISORY:

    A Tropical Storm Warning has been issued for the Lower Florida Keys
    west of the Seven Mile Bridge and for the Dry Tortugas.

    A Tropical Storm Watch has been issued for the Middle Florida Keys
    from the Seven Mile Bridge to the Channel 5 Bridge.

    SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

    A Storm Surge Watch is in effect for...
    * Indian Pass southward to Flamingo
    * Tampa Bay
    * Charlotte Harbor

    A Hurricane Watch is in effect for...
    * Cabo Catoche to Tulum, Mexico
    * Cuban province of Pinar del Rio
    * Englewood to Indian Pass
    * Tampa Bay

    A Tropical Storm Warning is in effect for...
    * Dry Tortugas
    * Lower Florida Keys west of the Seven Mile Bridge
    * Grand Cayman
    * Rio Lagartos to Tulum, Mexico
    * Cuban provinces of Artemisa, Pinar del Rio, and the Isle of Youth

    A Tropical Storm Watch is in effect for...
    * Middle Florida Keys from the Seven Mile Bridge to the Channel 5 Bridge
    * Flamingo to south of Englewood
    * West of Indian Pass to Walton Bay County line

    A Storm Surge Watch means there is a possibility of life-
    threatening inundation, from rising water moving inland from the
    coastline, in the indicated locations during the next 48 hours.
    For a depiction of areas at risk, please see the National Weather
    Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov.

    A Tropical Storm Warning means that tropical storm conditions are
    expected somewhere within the warning area within the next 36 hours.

    A Hurricane Watch means that hurricane conditions are possible
    within the watch area. A watch is typically issued 48 hours
    before the anticipated first occurrence of tropical-storm-force
    winds, conditions that make outside preparations difficult or dangerous.

    A Tropical Storm Watch means that tropical storm conditions are
    possible within the watch area, generally within 48 hours.

    Wind and storm surge warnings will likely be required for the
    U.S. later today.

    For storm information specific to your area in the United
    States, including possible inland watches and warnings, please
    monitor products issued by your local National Weather Service
    forecast office. For storm information specific to your area
    outside of the United States, please monitor products issued by
    your national meteorological service.


    DISCUSSION AND OUTLOOK
    ----------------------
    At 1100 AM EDT (1500 UTC), the center of Tropical Storm Helene was
    located near latitude 19.5 North, longitude 84.3 West. Helene is
    moving toward the northwest near 12 mph (19 km/h), and this
    general motion is expected to continue through early Wednesday. A
    northward to north-northeastward motion at a faster forward speed
    is expected on Wednesday and Thursday. On the forecast track, the
    center of Helene will move across the far northwestern Caribbean
    Sea through tonight, and then move across the eastern Gulf of
    Mexico Wednesday and Thursday, potentially reaching the Gulf coast
    of Florida late Thursday.

    Data from an Air Force Reserve Hurricane Hunter aircraft indicate
    that the system has acquired a well-defined center of circulation,
    and maximum sustained winds have increased to near 45 mph (75 km/h)
    with higher gusts. Additional strengthening is forecast, and
    Helene is expected to become a hurricane on Wednesday. Continued
    strengthening is anticipated after that time, and Helene could
    become a major hurricane on Thursday.

    Tropical-storm-force winds extend outward up to 140 miles (220 km)
    to the east of the center.

    Data from the Hurricane Hunter aircraft indicate that the minimum
    central pressure is 1000 mb (29.53 inches).


    HAZARDS AFFECTING LAND
    ----------------------
    Key Messages for Helene can be found in the Tropical Cyclone
    Discussion under AWIPS header MIATCDAT4 and WMO header WTNT44 KNHC
    and on the web at hurricanes.gov/text/MIATCDAT4.shtml

    RAINFALL: Helene is expected to produce total rain accumulations of
    4 to 8 inches over western Cuba and the Cayman Islands with isolated
    totals around 12 inches. Over the eastern Yucatan Peninsula, 4 to 6
    inches of rain are expected with isolated totals over 8 inches. This
    rainfall brings a risk of considerable flooding.

    Over the Southeastern U.S., Helene is expected to produce total rain accumulations of 4 to 8 inches with isolated totals around 12
    inches. This rainfall will likely result in areas of considerable
    flash and urban flooding, with minor to moderate river flooding
    likely, and isolated major river flooding possible.

    For a complete depiction of forecast rainfall associated with
    Helene, please see the National Weather Service Storm Total Rainfall
    Graphic, available at hurricanes.gov/graphics_at4.shtml?rainqpf and
    the Flash Flood Risk graphic at
    hurricanes.gov/graphics_at4.shtml?ero.

    STORM SURGE: The combination of a dangerous storm surge and the
    tide will cause normally dry areas near the coast to be flooded by
    rising waters moving inland from the shoreline. The water could
    reach the following heights above ground somewhere in the indicated
    areas if the peak surge occurs at the time of high tide...

    Ochlockonee River, FL to Chassahowitzka, FL...10-15 ft
    Chassahowitzka, FL to Anclote River, FL...6-10 ft
    Indian Pass, FL to Ochlockonee River, FL...5-10 ft
    Anclote River, FL to Middle of Longboat Key, FL...5-8 ft
    Tampa Bay...5-8 ft
    Middle of Longboat Key, FL to Englewood, FL...4-7 ft
    Englewood, FL to Bonita Beach, FL...3-5 ft
    Charlotte Harbor...3-5 ft

    For a complete depiction of areas at risk of storm surge inundation,
    please see the National Weather Service Peak Storm Surge Graphic,
    available at hurricanes.gov/graphics_at4.shtml?peakSurge.

    Storm surge could raise water levels by as much as 2 to 4 feet above
    normal tide levels in areas of onshore winds along the southern
    coast of Pinar del Rio, Cuba, including the Isle of Youth.

    Storm surge could raise water levels by as much as 2 to 4 feet above
    ground level in areas of onshore winds within the warning area along
    the east coast of the Yucatan Peninsula.

    WIND: Hurricane conditions are possible within the watch areas in
    Cuba and Mexico by early Wednesday. Hurricane conditions are
    possible within the U.S. watch areas Wednesday night and early
    Thursday. Tropical storm conditions are expected in the warning
    areas in the Cayman Islands, Cuba, and Mexico today. Tropical
    storm conditions are expected in the warning area in the Lower
    Florida Keys beginning on Wednesday, and are possible in the watch
    area in the Middle Florida Keys beginning late Wednesday.

    SURF: Swells generated by Helene will affect the southern coast
    of Cuba and the Yucatan Peninsula of Mexico during the next couple
    of days. Swells will spread northward toward the west coast of
    Florida and the northeastern Gulf Coast on Wednesday and Thursday.
    These swells are likely to cause life-threatening surf and rip
    current conditions. Please consult products from your local weather
    office.


    NEXT ADVISORY
    -------------
    Next intermediate advisory at 200 PM EDT.
    Next complete advisory at 500 PM EDT.

    $$
    Forecaster Berg
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