Tropical Storm Earl Forecast Discussion Number 9

By | September 5, 2022

000
WTNT41 KNHC 050245
TCDAT1

Tropical Storm Earl Discussion Number   9
NWS National Hurricane Center Miami FL       AL062022
1100 PM AST Sun Sep 04 2022

Earl continues to produce intense deep convection with tops colder 
than -80 deg C over the eastern portion of its circulation,  
but the system still lacks clear-cut banding features.  A 2306 UTC 
SSMIS microwave image showed that the low-level center is displaced 
to the west-southwest of the main area of convection.  Dvorak 
intensity estimates range from 45 kt to 55 kt, and given that there 
has been no obvious change in organization since the aircraft 
missions earlier today, the current intensity estimate is held at 45 
kt for this advisory.

The storm is still being affected by southwesterly vertical wind 
shear associated with an upper-level trough located several hundred 
miles to the west and northwest.  However, Earl's upper-level 
outflow pattern is gradually becoming better defined, and global 
model predictions suggest a slow relaxation of the shear over the 
next several days as the trough shifts a little to the northwest.  
Since the other environmental factors appear conducive for 
strengthening, gradual intensification is likely.  The official 
intensity forecast is close to both the simple and corrected model 
consensus and also very similar to the previous NHC forecast.  Earl 
could become the first major hurricane of this Atlantic season.

Earl's motion is a somewhat uncertain but slow 305/3 kt.  The storm 
remains in a region of weak steering currents with mid-level 
anticyclones currently located to the west, northwest and east.  By 
tomorrow, however, Earl should begin to move northward into a 
weakness in the subtropical ridge.  Later in the forecast period, 
the cyclone is expected to start coming under the influence of a 
trough in the southern portion of the mid-latitude westerlies and 
turn toward the north-northeast and northeast.  The official track 
forecast is just slightly left of the previous NHC track and close 
to the latest dynamical model consensus.  This is roughly in the 
middle of the rather tightly clustered track guidance model suite.

While tropical-storm-force winds are still forecast to stay north of
the northern Leeward Islands, the Virgin Islands, and Puerto Rico,
training rainbands are producing heavy rainfall over portions of 
these islands.  Users should refer to products issued by local 
weather offices in these areas.

KEY MESSAGES:

1.  Heavy rainfall from Earl is expected to lead to limited flash,
urban, and small stream flooding impacts over the Leeward Islands,
U.S. and British Virgin Islands, and Puerto Rico today. Rapid rises
on rivers and mudslides in areas of steep terrain are possible in
Puerto Rico.  Considerable flood impacts cannot be ruled out in 
areas that receive heavier rainfall totals.

2.  Earl is forecast to remain to the north of the the Virgin 
Islands and Puerto Rico tonight, but gusty winds, especially in 
squalls, remain possible on those islands overnight.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0300Z 20.2N  65.4W   45 KT  50 MPH
 12H  05/1200Z 21.3N  65.6W   50 KT  60 MPH
 24H  06/0000Z 22.5N  65.7W   55 KT  65 MPH
 36H  06/1200Z 23.6N  65.8W   60 KT  70 MPH
 48H  07/0000Z 24.5N  65.9W   65 KT  75 MPH
 60H  07/1200Z 25.4N  65.8W   70 KT  80 MPH
 72H  08/0000Z 26.4N  65.5W   75 KT  85 MPH
 96H  09/0000Z 28.7N  64.4W   90 KT 105 MPH
120H  10/0000Z 32.0N  61.5W  105 KT 120 MPH

$$
Forecaster Pasch

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