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#1094225 (Received by flhurricane at: 5:06 AM 05.Jun.2022)
TCDAT1

Tropical Storm Alex Discussion Number 11
NWS National Hurricane Center Miami FL AL012022
500 AM EDT Sun Jun 05 2022

After the previous advisory, data from the Air Force Reserve
Hurricane Hunters and GOES-16 Proxy-Vis satellite imagery indicated
that a well-defined center had formed in association with what is
now Tropical Storm Alex. With that said, the satellite structure of
the storm is hardly classical, with the coldest convective cloud
tops all shunted east of the low-level center which is still
occasionally reforming northeastward where the strongest convection
is located. Earlier, the reconnaissance aircraft found 850-mb
flight-level winds up to 72 kt in the southeast quadrant of the
circulation. A nearby released dropsonde, however, suggested that
these flight-level winds were not mixing down to the surface at the
standard reduction factor, and the highest SFMR winds were only
between 35-40 kt. Thus, the initial intensity was set to only 45 kt
at 0600 UTC and that remains the intensity this advisory. Another
reconnaissance aircraft will sample the storm later today.

Alex`s general motion continues off to the northeast at 065/19 kt.
This motion, with some further acceleration, is expected
during the next day or two as the system remains well embedded in
the mid-latitude westerly flow off the eastern US coastline. The
current track continues to indicate that Alex will make its closest
approach to Bermuda Monday afternoon or evening while the cyclone`s
track gradually bends eastward. Thereafter, both the GFS and ECMWF
suggest Alex`s surface circulation will decouple from the dwindling
convection and slow down as it becomes a shallow and stretched-out
vortex. The new NHC track maintains the slowdown trend made from
the previous advisory after 48 hours following this general shift
in the consensus track aids.

Some additional short-term strengthening is possible over the next
12 hours as long as Alex remains closely tied to the deep
convection. This convection is being aided by strong upper-level
difluent flow over the anomalously warm Gulf Stream. However, nearby
dry air combined with more than 30 kt of vertical wind shear is
forecast to disrupt this convective structure, and the global model
guidance suggests the convection could separate from the low-level
circulation after 24 hours. Thus, weakening is anticipated to start
on Monday. Continuing the trend from the previous forecast cycle,
the latest round of guidance suggests that Alex will complete
extratropical transition sooner as its circulation loses fidelity in
an increasingly baroclinic environment. The latest NHC forecast now
indicates the cyclone becoming post-tropical by 48 hours with
complete dissipation by 120 hours. However, the latest GFS and ECMWF
suggest Alex`s remnant circulation could open up into a trough even
sooner than the current forecast.

KEY MESSAGES:

1. Alex is forecast to pass near or just north of Bermuda on Monday,
and tropical storm conditions are expected on the island on Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 05/0900Z 29.1N 76.3W 45 KT 50 MPH
12H 05/1800Z 30.5N 74.0W 50 KT 60 MPH
24H 06/0600Z 32.0N 70.0W 50 KT 60 MPH
36H 06/1800Z 33.2N 65.3W 45 KT 50 MPH
48H 07/0600Z 34.0N 60.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
60H 07/1800Z 34.3N 56.4W 35 KT 40 MPH...POST-TROP/EXTRATROP
72H 08/0600Z 34.2N 52.6W 30 KT 35 MPH...POST-TROP/EXTRATROP
96H 09/0600Z 34.7N 49.0W 30 KT 35 MPH...POST-TROP/EXTRATROP
120H 10/0600Z...DISSIPATED

$$
Forecaster Papin/Blake