Eastern Pacific Basin Tropical Cyclones

Tropical Storm Sandra Forecast Discussion


000
WTPZ44 KNHC 081434
TCDEP4

Tropical Storm Sandra Discussion Number   5
NWS National Hurricane Center Miami FL       EP192021
700 AM PST Mon Nov 08 2021

Conventional satellite imagery and a 1206 UTC SSMIS microwave 
overpass indicate that Sandra's less-defined surface circulation 
remains sheared to the southwest of the warming cloud top 
convective mass.  The Dvorak satellite intensity estimates from 
TAFB and SAB are unchanged from the previous 6 hr estimates, and 
the initial intensity is held at 35 kt.

UW-CIMSS shear analysis and the statistical SHIPS models (ECMWF and
GFS) indicate that the 15-20 kt of southwesterly shear will persist
and increase in magnitude by Tuesday evening while the surrounding 
thermodynamic environment gradually becomes more stable.  Given 
these current and predicted inhibiting factors, Sandra is forecast 
to become a depression by this evening, and degenerate into a 
remnant low by Tuesday evening.  The NHC intensity forecast is an 
update of the previous one, and is based on the the NOAA HFIP 
corrected consensus model and agrees with the GFS and ECMWF global 
model solutions.

The initial motion is estimated to be west-northwestward, or 290/6 
kt.  A subtropical ridge located to the north of Sandra should 
steer the cyclone toward the west-northwest through this evening.  
Through the remainder of the forecast, the global models show the 
aforementioned low-to mid-level ridge building slightly toward the 
northwest of Sandra which should cause the cyclone to turn toward 
the west by early Tuesday.  The official track forecast follows 
suit and is once again adjusted a bit toward the left of the 
previous forecast and is nudged closer to the TCVE simple 
multi-model forecast.


FORECAST POSITIONS AND MAX WINDS

INIT  08/1500Z 14.6N 116.8W   35 KT  40 MPH
 12H  09/0000Z 15.0N 117.9W   30 KT  35 MPH
 24H  09/1200Z 15.1N 119.7W   30 KT  35 MPH
 36H  10/0000Z 14.7N 122.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 48H  10/1200Z 14.3N 125.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  11/0000Z...DISSIPATED

$$
Forecaster Roberts



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