ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
Tropical Storm Gabrielle Discussion Number 10
NWS National Hurricane Center Miami FL AL082019
1100 PM AST Thu Sep 05 2019
The center of Gabrielle has been devoid of deep convection since
late this morning, as dry air and southerly shear have taken their
toll. If this trend continues, then advisories may be discontinued
Friday morning. For the time being, a recent scatterometer pass
showed that 35 kt winds are still occurring in association with
Gabrielle's circulation, and that will be the initial intensity for
this advisory.
SHIPS intensity guidance indicates strong shear will continue to
affect the cyclone for the next 24 to 36 hours. If the circulation
survives this, the shear will diminish. However, it appears that
there will still be dry air to contend with. The forecast calls for
a steady intensity through 36 hours, followed by slow strengthening
as the shear becomes negligible. Late in the forecast period, the
cyclone will move over cooler waters as it begins to transition to
an extratropical cyclone, which should limit any non-baroclinic
intensification beyond 96 hours. The intensity forecast is highly
uncertain, as Gabrielle very well could become a post-tropical
remnant low tomorrow. The convection will have to recover once the
wind shear subsides, and I am skeptical that this will do so with
any haste due to the dry air that is forecast to be in place. The
official intensity forecast is similar to the previous one, and is
below the various consensus aids beyond 36 hours.
Gabrielle has begun to accelerate to the northwest. The forward
speed will increase a little more through Friday morning as the
cyclone is steered between a mid- to upper-level low to its west,
and a subtropical ridge to its east. Later in the forecast period,
Gabrielle will begin to turn northward then northeastward and
accelerate as a mid-latitude trough approaches the cyclone. The
official track forecast is very close to the previous one through 72
hours, and then was nudged slightly to the left beyond that time due
to a shift in the global models and consensus guidance.
FORECAST POSITIONS AND MAX WINDS
INIT 06/0300Z 24.3N 36.6W 35 KT 40 MPH
12H 06/1200Z 25.7N 38.0W 35 KT 40 MPH
24H 07/0000Z 27.9N 40.2W 35 KT 40 MPH
36H 07/1200Z 29.7N 42.7W 40 KT 45 MPH
48H 08/0000Z 31.1N 45.3W 45 KT 50 MPH
72H 09/0000Z 34.3N 48.2W 55 KT 65 MPH
96H 10/0000Z 38.5N 45.5W 60 KT 70 MPH
120H 11/0000Z 44.5N 38.0W 60 KT 70 MPH
$$
Forecaster Latto
NNNN