Eastern Pacific Basin Tropical Cyclones

Tropical Storm Blas Forecast Discussion


921 
WTPZ42 KNHC 180248
TCDEP2

Tropical Storm Blas Discussion Number  16
NWS National Hurricane Center Miami FL       EP022022
900 PM MDT Fri Jun 17 2022

Blas has fallen apart tonight.  The mid-level center of the cyclone 
has sheared off to the southwest, with no deep convection near the 
surface center, and a mostly-exposed low-level center was visible 
on the last few daylight satellite images.  Dvorak classifications 
are basically dropping as fast as the rules allow, and given the 
lack of any significant thunderstorm activity, the initial wind 
speed is set on the low end of the estimates to 60 kt.  

Continued weakening is anticipated due to Blas moving over cool 
waters, although the loss of strength could be tempered by 
decreasing wind shear as well.  The storm should produce a few more 
rounds of deep convection in the marginally unstable environment 
before eventually becoming a remnant low early next week.  Model 
guidance is in good agreement on this solution, and the only modest 
change to the forecast was lowering it in the near-term due to the 
initial intensity.  Additionally, the timing of Blas becoming a 
post-tropical cyclone was moved up by 12 h in this forecast cycle, 
and since most of the guidance indicate Blas should decay into a 
trough around 120 h, the NHC forecast does as well.

Blas has slowed considerably during the past several hours, 
probably due to the vortex decoupling, with an initial motion 
estimate of 290/6 kt.  A slow westward to west-northwestward motion 
is expected during the next several days due to the system 
weakening and becoming increasingly steered by the lighter 
low-level flow.  The latest NHC track forecast is basically an 
update of the previous one, shifted a bit to the north to come into 
better agreement with the model consensus aids.

While Blas is moving farther away from the coast of Mexico, its
associated swells are expected to continue to affect portions of the
coast of southwestern Mexico and the southern Baja California
peninsula for another day or two.  These conditions are likely to
cause dangerous surf and rip currents in those areas.


FORECAST POSITIONS AND MAX WINDS

INIT  18/0300Z 17.6N 110.2W   60 KT  70 MPH
 12H  18/1200Z 18.0N 111.3W   55 KT  65 MPH
 24H  19/0000Z 18.3N 112.5W   50 KT  60 MPH
 36H  19/1200Z 18.4N 113.4W   45 KT  50 MPH
 48H  20/0000Z 18.4N 114.2W   40 KT  45 MPH
 60H  20/1200Z 18.4N 115.2W   35 KT  40 MPH...POST-TROPICAL
 72H  21/0000Z 18.5N 116.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 96H  22/0000Z 19.0N 118.5W   25 KT  30 MPH...POST-TROP/REMNT LOW
120H  23/0000Z...DISSIPATED

$$
Forecaster Blake




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