Eastern Pacific Basin Tropical Cyclones

Hurricane Blas Forecast Discussion


000
WTPZ42 KNHC 152054
TCDEP2

Hurricane Blas Discussion Number   7
NWS National Hurricane Center Miami FL       EP022022
400 PM CDT Wed Jun 15 2022

The satellite presentation of Blas this afternoon remains quite 
healthy, with deep cold cloud tops below -80 C near the center and a 
well-defined curved band wrapping 3/4ths around the western side of 
the cyclone. A late arriving AMSR2 pass at 1854 UTC still showed a 
mid-level eye feature on 89-GHz, though it remains a bit open to 
the east on the 37-GHz channel. Subjective Dvorak estimates from 
1800 UTC were up to T4.5/77 kt from both TAFB and SAB, while the 
latest UW-CIMSS ADT estimate has been holding steady at T4.4/75 kt. 
These data support an initial intensity of 75 kt for this advisory.

Blas has maintained a general west-northwestward heading today,  
currently estimated at 290/5 kt. The track philosophy has also not 
changed much today, as a deep-layer ridge building westward to the 
north of Blas is expected to maintain the cyclone on its current 
heading with a bit of acceleration over the next couple of days. 
Afterwards, Blas is likely to become increasingly steered by the 
lower-level flow as it becomes vertically shallow, leading to a 
slowdown and bend in the track to the west and west-southwest at the 
end of the forecast period. There was a modest increase in forward 
motion from the guidance suite this cycle, so the track forecast was 
also nudged a bit faster, but is still very close to the previous 
forecast track and near the reliable consensus aids.

Blas has intensified 30-kt in the last 24 hours, which qualifies as 
rapid intensification. Whether of not this rate of intensification 
continues likely hinges on the impact of moderate (20-30 kt) 
easterly vertical wind shear which both the GFS and ECMWF suggest is 
already impinging on the cyclone. The latest intensity forecast 
still shows a peak of 85 kt in 24 h, but slows the rate of 
intensification relative to the prior advisory. This forecast is on 
the high side of the guidance envelope and is closest to the latest 
SHIPS and LGEM runs. After 36 h, sea-surface temperatures begin to 
rapidly decrease underneath Blas as it also moves towards an 
increasingly dry and stable environment, as seen by the widespread 
stratocumulus field to the northwest of the system on visible 
satellite. Weakening is forecast to commence by Friday, with the 
global model guidance now suggesting Blas could become a remnant low 
by the end of the forecast period as convection ceases.

While Blas is expected to remain off the coast of Mexico, its
associated swells are beginning to affect portions of the coast of
southwestern Mexico and are likely continue through the end
of the week.


FORECAST POSITIONS AND MAX WINDS

INIT  15/2100Z 15.1N 103.1W   75 KT  85 MPH
 12H  16/0600Z 15.5N 104.0W   80 KT  90 MPH
 24H  16/1800Z 16.1N 105.5W   85 KT 100 MPH
 36H  17/0600Z 16.7N 107.4W   80 KT  90 MPH
 48H  17/1800Z 17.4N 109.3W   75 KT  85 MPH
 60H  18/0600Z 18.0N 111.1W   65 KT  75 MPH
 72H  18/1800Z 18.3N 112.3W   55 KT  65 MPH
 96H  19/1800Z 18.8N 114.9W   35 KT  40 MPH
120H  20/1800Z 18.5N 116.6W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Papin



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