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Tropical Storm Blanca Discussion Number 11
NWS National Hurricane Center Miami FL EP022021
300 AM MDT Wed Jun 02 2021
Recent satellite imagery indicates southwesterly vertical wind shear
continues to impinge on the western side of Blanca's circulation.
The coldest cloud tops are displaced to the east of the estimated
center, and deep convection is becoming more limited in coverage.
GMI microwave data from 0450 UTC suggest the cyclone's low-level
circulation is losing some definition and may contain multiple
centers. Unfortunately, none of the overnight scatterometer passes
sampled the core of Blanca, although a recent ASCAT-A pass shows
several 30-32 kt wind vectors in the eastern semicircle over 60 n mi
from the center. The initial intensity is decreased to 40 kt with
this advisory, which falls between the subjective Dvorak estimates
from SAB (35 kt) and TAFB (45 kt) and is consistent with the latest
UW-CIMSS ADT current intensity estimate.
Environmental conditions along Blanca's forecast track should
maintain the current weakening trend through the forecast period.
This includes stronger vertical wind shear over the next few days
associated with a mid- to upper-level low near Baja California, in
addition to decreased oceanic heat content and a drier, more stable
environment aloft. The official NHC intensity forecast closely
follows the intensity consensus aid (IVCN), and Blanca is expected
to become a tropical depression by Thursday and a remnant low this
weekend.
The cyclone continues to turn more westward and slow down under
weakening steering currents, and its estimated motion is now an
uncertain 285/5 kt. A general westward motion is expected during the
next several days as the weakening cyclone is largely steered by the
low-level easterly trades. Based on a noticeable southward shift in
much of the guidance including the HFIP corrected consensus (HCCA),
the latest NHC track forecast is adjusted left of track from the
previous one and lies closer to the TVCE consensus aid.
FORECAST POSITIONS AND MAX WINDS
INIT 02/0900Z 15.0N 112.0W 40 KT 45 MPH
12H 02/1800Z 15.1N 112.5W 35 KT 40 MPH
24H 03/0600Z 15.3N 113.3W 35 KT 40 MPH
36H 03/1800Z 15.3N 114.0W 30 KT 35 MPH
48H 04/0600Z 15.3N 115.1W 30 KT 35 MPH
60H 04/1800Z 15.2N 116.2W 25 KT 30 MPH
72H 05/0600Z 15.1N 117.5W 25 KT 30 MPH
96H 06/0600Z 15.5N 119.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 07/0600Z 16.0N 121.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Reinhart/Beven
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