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Tropical Storm Blanca Discussion Number   7
NWS National Hurricane Center Miami FL       EP022021
300 AM MDT Tue Jun 01 2021
 
Blanca's satellite appearance has changed little tonight, as the 
cyclone has maintained deep convection near its center with a couple 
of banding elements observed in recent imagery. Overnight ASCAT data 
indicate Blanca remains a compact tropical cyclone with a small 
radius of tropical-storm-force winds. The 35-40 kt winds shown by 
the scatterometer are likely not representative of the cyclone's 
peak intensity given the small size of the wind field. The initial 
advisory intensity of 50 kt is supported by a blend of the objective 
UW-CIMSS ADT and SATCON intensity estimates and subjective Dvorak 
classifications of T3.5/55 kt from SAB and T3.0/45 kt from TAFB.
 
The cyclone's estimated motion is 305/6 kt, as it continues to move 
around the southwestern extent of a mid-level ridge that extends 
across central Mexico. A mid- to upper-level trough near the Baja 
California peninsula is beginning to weaken the steering ridge, and 
so Blanca is expected to move generally west-northwestward with a 
continued decrease in forward speed over the next couple of days.  
Afterwards, the system is forecast to slowly turn westward within 
the low-level trade winds as it weakens and becomes vertically 
shallow. The latest NHC forecast track is largely an update of the 
previous one and remains close to the HCCA corrected consensus aid.

Blanca has a brief window today for some additional strengthening, 
although the vertical wind shear may already be increasing over the 
system. By tonight, increasing southwesterly or west-southwesterly 
shear should induce a weakening trend that will likely continue 
through late this week. As Blanca moves into an environment with 
cooler sea surface temperatures and drier mid-level air in 2-3 days, 
the cyclone is forecast to weaken to a depression by 72 hours and a 
remnant low by the end of the forecast period, if not sooner. Once 
again, the NHC intensity forecast captures the overall trend 
reflected by the HCCA and ICON consensus aids.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/0900Z 14.2N 109.6W   50 KT  60 MPH
 12H  01/1800Z 14.6N 110.5W   55 KT  65 MPH
 24H  02/0600Z 15.1N 111.5W   50 KT  60 MPH
 36H  02/1800Z 15.5N 112.3W   45 KT  50 MPH
 48H  03/0600Z 15.7N 112.8W   40 KT  45 MPH
 60H  03/1800Z 15.9N 113.5W   35 KT  40 MPH
 72H  04/0600Z 16.0N 114.4W   30 KT  35 MPH
 96H  05/0600Z 16.0N 116.4W   25 KT  30 MPH
120H  06/0600Z 16.1N 118.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Reinhart/Beven
 
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