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Tropical Storm Danielle Forecast Discussion


655 
WTNT45 KNHC 020845
TCDAT5

Tropical Storm Danielle Discussion Number   5
NWS National Hurricane Center Miami FL       AL052022
900 AM GMT Fri Sep 02 2022

Satellite imagery shows that Danielle is continuing to strengthen, 
with convective bands wrapping around the center and attempts at 
eye formation.  The various satellite intensity estimates have a 
wide range from 45-77 kt, and the consensus of the estimates is 
that Danielle is not quite a hurricane yet.  Based on these 
estimates, the initial intensity is increased to a possibly 
conservative 60 kt.

Danielle continues to move slowly eastward, with the initial motion 
100/3 kt.  The cyclone is situated within an area of light steering
flow on the south side of an omega block mid-level anticyclone, and 
this pattern is expected to cause Danielle to meander during the 
next couple of days.  After that, the blocking anticyclone should 
move eastward and weaken, allowing the southern edge of the 
mid-latitude westerlies to become the primary steering mechanism.  
The large-scale models differ in the details of the shortwave 
troughs in the westerlies that could affect Danielle, and due to 
this the track guidance becomes somewhat divergent, with the ECMWF 
calling for a more northward motion than the other guidance.  The 
new forecast track is similar to the previous forecast through 72 
h, then is shifted a little to the north of the previous forecast.

The cyclone should remain over 26-27C sea surface temperatures for 
about 72 h in an environment of light- to moderate westerly shear.  
This should allow continued strengthening, with the main negative 
factor being that the mid-level relative humidities near the 
storm are low.  After 72 h, movement over cooler water and 
increased shear should cause weakening.   However, the large-scale 
models are in good agreement that the cyclone will not undergo 
extratropical transition before the end of the forecast period.  
The new intensity forecast is an update of the previous forecast 
and lies near the intensity consensus.


FORECAST POSITIONS AND MAX WINDS

INIT  02/0900Z 37.9N  43.4W   60 KT  70 MPH
 12H  02/1800Z 37.8N  43.4W   65 KT  75 MPH
 24H  03/0600Z 37.8N  43.7W   70 KT  80 MPH
 36H  03/1800Z 37.9N  44.2W   75 KT  85 MPH
 48H  04/0600Z 38.2N  44.6W   80 KT  90 MPH
 60H  04/1800Z 38.6N  44.4W   85 KT 100 MPH
 72H  05/0600Z 39.2N  43.7W   85 KT 100 MPH
 96H  06/0600Z 41.0N  41.4W   80 KT  90 MPH
120H  07/0600Z 42.5N  38.0W   75 KT  85 MPH

$$
Forecaster Beven




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