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Hurricane Larry Discussion Number  11
NWS National Hurricane Center Miami FL       AL122021
500 AM AST Fri Sep 03 2021
 
Larry continues to gradually become better organized. Satellite 
images show a fairly compact central dense overcast feature with an 
eye occasionally evident. Beyond the inner core, banding features 
are gradually becoming more distinct, especially to the south of the 
center.  The latest Dvorak classifications at 0600 UTC was 4.5/77 kt 
from TAFB and SAB, and based on those estimates and the improving 
trend, the initial intensity is nudged upward to 80 kt.
 
Larry is moving west-northwestward at 17 kt.  There has been no
change to the track forecast reasoning.  A continued westward to
west-northwestward motion is expected on Friday and through the
weekend as the hurricane remains on the south side of a mid-level
ridge.  By early next week, Larry is expected to slow down and turn
northwestward when it reaches the southwestern periphery of the
ridge.  The models are in fairly good agreement, and the NHC track 
forecast lies near the middle of the guidance envelope.  This 
forecast is largely an update of the previous one.
 
The environmental factors appear favorable for steady strengthening
during the next few days with wind shear remaining low and mid-level
moisture fairly high.  The only slightly negative factor is
marginally warm 26-27 deg C waters that Larry will be moving over
during the next couple of days, which should prevent rapid
intensification.  All of the models are in general agreement that
Larry will become a major hurricane in a day or so with continued
strengthening through day 3, and the NHC intensity forecast follows
suit.  Some weakening is shown by the end of the forecast period
when the wind shear could increase a little.  This forecast is very
similar to the previous one and lies near the high end of the
guidance envelope.  It should be noted that eyewall replacement
cycles are possible, which could cause intensity fluctuations that
are challenging to predict.
 
The leading swell front from Larry is expected to reach the Lesser
Antilles on Sunday, increasing the risk of life-threatening rip
currents and high surf conditions on those islands early next week.
Large swells are likely to spread to areas surrounding the western
Atlantic later in the week as well.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  03/0900Z 14.6N  38.9W   80 KT  90 MPH
 12H  03/1800Z 15.2N  41.1W   90 KT 105 MPH
 24H  04/0600Z 16.2N  43.8W  100 KT 115 MPH
 36H  04/1800Z 17.3N  46.2W  105 KT 120 MPH
 48H  05/0600Z 18.6N  48.5W  115 KT 130 MPH
 60H  05/1800Z 19.8N  50.5W  120 KT 140 MPH
 72H  06/0600Z 21.1N  52.5W  120 KT 140 MPH
 96H  07/0600Z 23.8N  55.8W  115 KT 130 MPH
120H  08/0600Z 27.1N  58.9W  110 KT 125 MPH
 
$$
Forecaster Cangialosi
 
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