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Post-Tropical Cyclone Blanca Forecast Discussion


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000
WTPZ42 KNHC 040833
TCDEP2

Post-Tropical Cyclone Blanca Discussion Number  19
NWS National Hurricane Center Miami FL       EP022021
200 AM PDT Fri Jun 04 2021

Blanca has been devoid of organized deep convection since midday 
yesterday, with the last convective burst near the center ceasing 
over 15 hours ago. Since that time there have been a few convective 
cells noted 120 to 150 n mi east-northeast of the center, but these 
have been short lived. This is a big change from this time 
yesterday, when a large burst of deep convection developed during 
the diurnal maximum close the center of the cyclone. This trend is 
indicative of the strong west-southwesterly shear and the dry and 
stable atmospheric environment taking their toll on the system. 
These hostile environmental factors are not expected to improve, 
while the forward path of the cyclone takes it over progressively 
cooler waters.  Therefore, it is anticipated that persistent deep 
convection will not redevelop near the center of the system, and 
Blanca is being designated as a remnant low. The low is expected to 
gradually spin down and is likely to dissipate within the next few 
days. The overnight ASCAT overpasses did not sample the center of 
the system, so a blend of the T/CI numbers of 1.0/2.0 from the most 
recent satellite intensity estimate from TAFB supports maintaining 
the advisory intensity at 25 kt.

Over the past 12 hours Blanca has been moving west-northwestward, or 
300/06 kt. A turn to the west is expected later this morning as the 
shallow system gets caught up in the flow around a low-level ridge 
to the north. This westward motion should continue until the system 
dissipates. The latest NHC track forecast is little changed from the 
previous one and is near the multi-model consensus.

This is the last NHC advisory on Blanca. For additional information
on the remnant low please see High Seas Forecasts issued by the
National Weather Service, under AWIPS header NFDHSFEPI, WMO header
FZPN02 KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php


FORECAST POSITIONS AND MAX WINDS

INIT  04/0900Z 16.3N 115.6W   25 KT  30 MPH...POST-TROPICAL
 12H  04/1800Z 16.4N 116.8W   25 KT  30 MPH...POST-TROP/REMNT LOW
 24H  05/0600Z 16.4N 118.3W   25 KT  30 MPH...POST-TROP/REMNT LOW
 36H  05/1800Z 16.4N 119.7W   20 KT  25 MPH...POST-TROP/REMNT LOW
 48H  06/0600Z 16.4N 121.1W   20 KT  25 MPH...POST-TROP/REMNT LOW
 60H  06/1800Z 16.4N 122.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  07/0600Z...DISSIPATED

$$
Forecaster Latto