[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT45 KNHC 030852
TCDAT5

Tropical Storm Danielle Discussion Number   9
NWS National Hurricane Center Miami FL       AL052022
900 AM GMT Sat Sep 03 2022

Convection associated with Danielle has continued to decrease this
morning, with a corresponding decrease in satellite intensity
estimates.  Based on this decrease, it is estimated that Danielle
has weakened to a tropical storm with an initial intensity of 60 kt.
While it is not known why the storm has weakened, one possibility
is that the slow motion has allowed the cyclone to upwell cold
water underneath it.

Danielle is essentially stationary with a 12-h motion of 270/1 kt.
The cyclone is still caught south of a blocking high over the North
Atlantic.  This pattern is expected to hold firm for a couple of
days, with the system forecast to drift westward and then drift
northward.  After 48-60 h, the block will weaken and allow the
southern edge of the mid-latitude westerlies to steer Danielle
generally northeastward at a faster forward speed.  There are no
significant changes to the forecast track for the first 48-60 h.
After that, the forecast has been nudged eastward due to a shift
in the guidance envelope.

The intensity guidance is still calling for Danielle to strengthen
for 72 h or so.  Given the possibility of upwelling and the
forecast continued slow motion, the guidance might be a bit
optimistic on that.  The new intensity forecast calls for little
change in strength for 12 h or so, followed by slow strengthening
on the premise that the storm will move over somewhat warmer water.
After 72 h, the storm is likely to interact with an upper-level
trough, which could help maintain the intensity even as Danielle
moves toward much colder water in the North Atlantic.  This trough
will also start extratropical transition, although this will
likely not be complete by 120 h.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 38.0N  43.8W   60 KT  70 MPH
 12H  03/1800Z 38.0N  44.1W   60 KT  70 MPH
 24H  04/0600Z 38.1N  44.7W   65 KT  75 MPH
 36H  04/1800Z 38.5N  44.7W   70 KT  80 MPH
 48H  05/0600Z 39.1N  44.3W   75 KT  85 MPH
 60H  05/1800Z 39.9N  43.6W   75 KT  85 MPH
 72H  06/0600Z 40.7N  42.6W   75 KT  85 MPH
 96H  07/0600Z 43.0N  39.5W   70 KT  80 MPH
120H  08/0600Z 46.5N  35.5W   65 KT  75 MPH

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