Eastern Pacific Basin Tropical Cyclones

Hurricane Blas Forecast Discussion


000
WTPZ42 KNHC 160835
TCDEP2

Hurricane Blas Discussion Number   9
NWS National Hurricane Center Miami FL       EP022022
400 AM CDT Thu Jun 16 2022

A GMI microwave overpass received just after the last advisory 
showed decay of the inner core structure of Blas, with the central 
deep convection occurring only in the southern semicircle.  In 
addition, the cloud pattern in infrared imagery now looks more like 
a shear pattern than a central dense overcast.  These changes are 
likely due to the effects of 15-25 kt of easterly shear currently 
analyzed over the cyclone.  Despite the convective decay, the 
intensity estimates from TAFB, SAB, and the CIMSS satellite 
consensus are unchanged since the last advisory.  Thus, the initial 
intensity remains a possibly generous 75 kt.

Little change in strength is likely during the next 6-12 h due to 
the shear.  The shear should diminish some between 12-24 h and 
allow Blas to strengthen a little more.  After that, the cyclone is 
forecast to move over decreasing sea surface temperatures, which 
should cause a gradual weakening for the remainder of the forecast 
period.  The new intensity forecast follows the overall trend of 
the guidance and has some minor adjustments from the previous 
advisory.

The microwave imagery indicated that the center was a little to the 
north of the previous advisory position, and the initial motion is 
a somewhat uncertain 300/5.  Blas should be steered west- 
northwestward with some increase in forward speed by the flow on the 
south side of a mid- to upper-level ridge.  As the cyclone weakens 
later in the forecast period, it is expected to turn west- 
southwestward following the lower-level tradewind flow. The new 
forecast track is a little to the north of, and faster than, the 
previous forecast track, and it lies near the various consensus 
models.

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  16/0900Z 15.8N 104.0W   75 KT  85 MPH
 12H  16/1800Z 16.2N 105.1W   75 KT  85 MPH
 24H  17/0600Z 17.0N 107.1W   80 KT  90 MPH
 36H  17/1800Z 17.8N 109.6W   75 KT  85 MPH
 48H  18/0600Z 18.2N 111.3W   65 KT  75 MPH
 60H  18/1800Z 18.6N 112.5W   55 KT  65 MPH
 72H  19/0600Z 18.9N 113.6W   45 KT  50 MPH
 96H  20/0600Z 19.0N 115.5W   35 KT  40 MPH
120H  21/0600Z 18.5N 117.0W   25 KT  30 MPH...POST-TROP/REMNT LOW

$$
Forecaster Beven



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