[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT42 KNHC 012035
TCDAT2

Tropical Storm Gert Discussion Number  16
NWS National Hurricane Center Miami FL       AL062023
500 PM AST Fri Sep 01 2023

Gert appears to have strengthened and has become a tropical storm
once again. Satellite intensity estimates range from 30 kt (1800 UTC
SAB Dvorak Current Intensity) to 46 kt (1701 UTC UW-CIMSS SATCON),
so the intensity has been raised to 35 kt in this advisory. AMSR
microwave imagery from a few hours ago revealed Gert has a tight
well-defined low-level inner-core, and it's possible the 35-kt
estimate is conservative.

The AMSR pass was also the first clear indication that Gert is
centered a little farther south than previously estimated. It's
possible that Gert's deep convection, which is limited to the
southeast quadrant, is pulling the center slowly in that direction
in the absence of other strong steering currents right now. In a
couple days, Gert should move a little quicker toward the northeast,
steered by a combination of Idalia to its northwest and a low- to
mid-level ridge over the eastern and central Atlantic. The NHC track
forecast is very close to the multi-model consensus aids TVCN and
HCCA, but is a little slower than the previous advisory.

Although continued shear should prevent Gert from strengthening
much, additional slight intensification is possible today or
tomorrow. Most models show the cyclone becoming post-tropical in 48
to 60 hours, and absorbed into the much larger circulation of Idalia
soon after. The NHC intensity forecast has been adjusted slightly
higher but is still very similar to the previous advisory. One thing
to note, the model trackers used to help NHC make track and
intensity forecasts appear to be following Idalia at the end of the
forecast instead of Gert in many cases. Users should be aware that
the tracks and intensities in the NCEP tracker or ATCF files may not
be representative of the model depiction of Gert beyond 60-72 h.


FORECAST POSITIONS AND MAX WINDS

INIT  01/2100Z 27.8N  54.4W   35 KT  40 MPH
 12H  02/0600Z 27.7N  53.9W   40 KT  45 MPH
 24H  02/1800Z 28.4N  53.2W   40 KT  45 MPH
 36H  03/0600Z 29.0N  52.7W   35 KT  40 MPH
 48H  03/1800Z 30.6N  51.9W   35 KT  40 MPH
 60H  04/0600Z 33.0N  51.2W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  04/1800Z...DISSIPATED

$$
Forecaster D. Zelinsky
This weather bulletin was brought to you by:
www.nashvilleweather.net