[Tropical] Tropical Cyclone Discussion

EMWIN Server emwin at nashvilleweather.net
Thu Sep 2 03:46:16 CDT 2021


WTNT42 KNHC 020846
TCDAT2

Hurricane Larry Discussion Number   7
NWS National Hurricane Center Miami FL       AL122021
500 AM AST Thu Sep 02 2021

Larry's cloud pattern has gradually become better organized, with
deep convection increasing in coverage and intensity near the
center and a banding-type eye trying to form.  Upper-level outflow
is most prominent over the western and northern portions of the
circulation.  A well-defined low-level eye was apparent on an
AMSR-2 image from a few hours ago.  Dvorak final T- and Current
Intensity-numbers from both TAFB and SAB are 4.0/4.0, corresponding
to an intensity of 65 kt.  Based on these estimates, Larry is
upgraded to a hurricane, the fifth of the 2021 Atlantic season.

The hurricane is moving just slightly north of west, or 280/17 kt.
There are no important changes to the track forecast scenario from
the previous advisory.  Larry is likely to move along the southern
and southwestern periphery of a strong deep-layer subtropical high
pressure area over the east-central Atlantic during the next few
days.  This should result in a gradual turn toward the
west-northwest during the next 48-72 hours.  A turn toward the
northwest is likely in 4-5 days as the system approaches a weakness
in the ridge.  The track models are fairly well clustered on this
future direction of motion with some differences in forward speed.
The official track forecast is quite similar to the previous one
and is also very close to the latest dynamical model consensus,
TVCA.

Larry is expected to remain in an environment conducive for
strengthening over the next few days, with marginally warm
SSTs, low vertical shear, and surrounded by broad-scale anticyclonic
upper-level flow.  Therefore, strengthening is likely, and the
official forecast calls for Larry to become a major hurricane in 48
hours or so.  Some fluctuations in intensity due to eyewall
replacements are possible around and after that time.  Late in the
forecast period, slightly drier air in the environment could limit
further intensification.  The official intensity forecast is close
to the latest NOAA corrected consensus, HCCA, guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 13.0N  32.3W   65 KT  75 MPH
 12H  02/1800Z 13.4N  34.7W   75 KT  85 MPH
 24H  03/0600Z 14.0N  37.9W   85 KT 100 MPH
 36H  03/1800Z 14.8N  40.9W   95 KT 110 MPH
 48H  04/0600Z 15.8N  43.6W  100 KT 115 MPH
 60H  04/1800Z 16.9N  46.1W  105 KT 120 MPH
 72H  05/0600Z 18.3N  48.3W  110 KT 125 MPH
 96H  06/0600Z 20.9N  52.1W  115 KT 130 MPH
120H  07/0600Z 23.8N  55.4W  110 KT 125 MPH

$$
Forecaster Pasch
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