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Tropical Storm Omar Discussion Number   7
NWS National Hurricane Center Miami FL       AL152020
500 AM AST Wed Sep 02 2020
 
UW-CIMSS analyses and SHIPS model diagnostics all indicate that 
Omar is being blasted by 40-50 kt of northwesterly shear, and yet a 
sizable area of deep convection has been hanging close to the 
low-level center for some time now.  Based on last evening's ASCAT 
pass and the most recent satellite classifications, Omar's initial 
intensity remains 35 kt.  Despite the shear magnitude, Omar could 
maintain tropical storm intensity for another 24 hours or so while 
the shear direction remains out of the northwest and the cyclone is 
over the warm Gulf Stream.  During this period, the NHC forecast is 
close to the ICON intensity consensus and the HCCA aid.  After 24 
hours, Omar should begin moving over waters with lower ocean heat 
content, and the shear is forecast to veer more out of the north.  
Both of these factors are expected to cause weakening, with Omar 
likely to lose its deep convection and become a remnant low in about 
2 days.  Global models indicate that the remnant low should 
dissipate ahead of a cold front by day 4, which is now shown in the 
NHC forecast, although the ECMWF shows this happening a day earlier.

Omar is moving toward the east-northeast (070/12 kt), embedded 
within the mid-latitude westerlies north of the subtropical ridge.  
This steering pattern is forecast to keep Omar on an 
east-northeastward or eastward path until it dissipates, but a 
breakdown of the zonal flow should cause the cyclone's forward 
speed to slow down gradually during the next 2-3 days.  The updated 
NHC track forecast has been shifted southward a bit in the 
direction of the multi-model consensus aids and the GFS and ECMWF 
solutions, which both lie along the southern edge of the guidance 
envelope.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0900Z 36.2N  68.7W   35 KT  40 MPH
 12H  02/1800Z 36.6N  66.8W   35 KT  40 MPH
 24H  03/0600Z 36.8N  64.0W   35 KT  40 MPH
 36H  03/1800Z 36.6N  61.3W   30 KT  35 MPH
 48H  04/0600Z 36.3N  59.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  04/1800Z 36.5N  57.6W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  05/0600Z 37.1N  56.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  06/0600Z...DISSIPATED
 
$$
Forecaster Berg
 
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