• STRMDISC: Tropical Storm Fernand Discussion Number 15

    From COD Weather Processor@1:2320/105 to wx-atlan@lists.illinois.edu on Wednesday, August 27, 2025 08:40:29
    524
    WTNT41 KNHC 270840
    TCDAT1

    Tropical Storm Fernand Discussion Number 15
    NWS National Hurricane Center Miami FL AL062025
    500 AM AST Wed Aug 27 2025

    Fernand continues to sputter along as a lopsided tropical storm,
    producing deep convection primarily along its southern semicircle.
    This convective activity has not been particularly well organized on
    either geostationary or microwave satellite images. In fact,
    overnight Proxy-Vis satellite imagery suggests this convective
    activity has been stretching the low-level vortex of the tropical
    cyclone, making it somewhat elongated. Satellite intensity estimates
    this morning have a wide range between 30 kt to 51 kt. Out of
    deference to the earlier scatterometer data, Fernand's initial
    intensity remains 40 kt this advisory, which is also roughly in the
    middle of the various estimates.

    The ongoing deep convection appears to be impacting Fernand's
    short-term motion, which is east of the prior forecast track, moving
    at an estimated 080/10 kt. This motion could persist a little longer
    given the tropical cyclone's ongoing convective asymmetry. Still,
    Fernand is expected to resume an accelerating east-northeastward
    motion later today, caught up in deep-layer southwesterly flow
    downstream of a large mid-latitude trough over eastern North
    America. Given the short-term motion, the track guidance has shifted
    a little east of the prior cycle, and the latest NHC track forecast
    has elected to go along the eastern edge of this track envelope,
    close to the latest HCCA and EC-AIFS solutions. The ongoing deep
    convection has also bought Fernand a little more time as a tropical
    cyclone, though probably only another 24 hours since the cyclone
    will soon cross a sharp sea-surface temperature gradient as it
    passes the north wall of the Gulf Stream. The NHC intensity forecast
    shows Fernand becoming post-tropical in about 24 h, and opening up
    into a trough and dissipating in 60 h.


    FORECAST POSITIONS AND MAX WINDS

    INIT 27/0900Z 38.3N 50.8W 40 KT 45 MPH
    12H 27/1800Z 39.3N 48.2W 40 KT 45 MPH
    24H 28/0600Z 41.3N 44.0W 35 KT 40 MPH...POST-TROPICAL
    36H 28/1800Z 43.3N 38.3W 35 KT 40 MPH...POST-TROPICAL
    48H 29/0600Z 45.2N 30.9W 30 KT 35 MPH...POST-TROP/REMNT LOW
    60H 29/1800Z...DISSIPATED

    $$
    Forecaster Papin


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