ZCZC MIATCDEP2 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Blanca Discussion Number  10
NWS National Hurricane Center Miami FL       EP022021
900 PM MDT Tue Jun 01 2021
 
A cirrus canopy associated with a resurgence of deep convection 
is obscuring Blanca's center.  However, the cirrus has a 
sharp western edge in infrared satellite imagery, indicative of 
continued southwesterly shear.  Because Blanca's satellite 
appearance is a little better than it was earlier today, the 
initial intensity is being held at 45 kt, in best agreement with 
a Dvorak classification of T3.0 from TAFB.
 
A 2030 UTC AMSR microwave pass and recent visible images suggest 
that Blanca has turned slightly to the left and slowed down, with 
the initial motion now estimated to be 295/6 kt.  This slower 
motion is the result of a mid- to upper-level low which has 
developed near the northern Baja California peninsula and has 
dissolved the subtropical ridge.  With the steering flow 
essentially collapsing, Blanca is forecast to drift westward in the 
coming days, with its slowest forward speeds occurring from 24-48 
hours.  After 48 hours, there should be enough of a low-level ridge 
to help a weakening Blanca move a little faster toward the west 
within the trade wind flow.  Overall, the NHC track forecast favors 
a solution on the southern side of the guidance envelope, close to 
the previous forecast and the HFIP Corrected Consensus (HCCA).

Several environmental factors are likely to contribute to Blanca's 
weakening over the next few days.  (1) Moderate southwesterly 
vertical shear, caused by the aforementioned mid-/upper-level 
trough, is expected to gradually increase over the next 2 to 3 
days, (2) the upper-level environment is forecast to become more 
subsident after 24 hours, and (3) Blanca will be heading toward 
marginally warm waters of around 26 degrees Celsius.  Gradual 
weakening is therefore expected, and Blanca could become a tropical 
depression within 48 hours and a remnant low by day 4.  The 
intensity models are in good agreement on a gradual weakening 
trend, and the NHC official forecast closely follows the IVCN 
intensity consensus and the HCCA model.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/0300Z 14.9N 111.6W   45 KT  50 MPH
 12H  02/1200Z 15.1N 112.2W   40 KT  45 MPH
 24H  03/0000Z 15.3N 112.8W   40 KT  45 MPH
 36H  03/1200Z 15.5N 113.4W   35 KT  40 MPH
 48H  04/0000Z 15.6N 114.1W   30 KT  35 MPH
 60H  04/1200Z 15.6N 115.2W   30 KT  35 MPH
 72H  05/0000Z 15.6N 116.3W   25 KT  30 MPH
 96H  06/0000Z 15.7N 118.4W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  07/0000Z 16.0N 120.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 
$$
Forecaster Berg
 
NNNN