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Tropical Storm Gabrielle Discussion Number 25
NWS National Hurricane Center Miami FL AL082019
Issued by the NWS Weather Prediction Center College Park MD
1100 AM AST Mon Sep 09 2019
Satellite images indicate that deep convection has increased
overnight and become more symmetric around the center of Gabrielle.
Still, ASCAT data show maximum winds of only about 40 kt,
suggestive that this convective burst hasn't changed the intensity
much. The initial wind speed is set to 45 kt, near the TAFB
satellite estimate and a little above the ASCAT data to account for
Gabrielle has turned northeastward and picked up some speed.
The system is expected to move at an increasing pace in a similar
direction over the next few days as it is picked up by a
mid-latitude trough. Model guidance is tightly clustered around
the previous NHC prediction, and no significant changes were made
to the prior NHC track forecast.
The storm has about a day over marginally warm waters before it
crosses the north wall of the Gulf Stream into much colder waters.
Gabrielle is forecast to transition into an extratropical low by
Tuesday due to an increase in shear and baroclinicity from an
approaching cold front. The intensity forecast was reduced
slightly from the previous one and is in close agreement with a
blend of the GFS/ECMWF wind speed forecasts, which should best
handle this extratropical transition scenario.
FORECAST POSITIONS AND MAX WINDS
INIT 09/1500Z 39.0N 47.3W 45 KT 50 MPH
12H 10/0000Z 40.9N 44.7W 45 KT 50 MPH
24H 10/1200Z 43.4N 40.2W 45 KT 50 MPH
36H 11/0000Z 46.4N 34.7W 40 KT 45 MPH...POST-TROP/EXTRATROP
48H 11/1200Z 50.1N 26.9W 35 KT 40 MPH...POST-TROP/EXTRATROP
72H 12/1200Z 57.5N 5.5W 30 KT 35 MPH...POST-TROP/EXTRATROP