Eastern Pacific Basin Tropical Cyclones

Tropical Storm Darby Forecast Discussion


000
WTPZ45 KNHC 100841
TCDEP5

Tropical Storm Darby Discussion Number   3
NWS National Hurricane Center Miami FL       EP052022
200 AM PDT Sun Jul 10 2022

Darby has changed little in structure tonight.  Microwave imagery 
from SSMIS at 0147 UTC revealed a small inner core with a primary 
band to the south of the center.  The storm continues to generate a 
well-defined upper-level outflow and some bursts of convection with 
-80 degrees C or colder cloud top temperatures near the center on 
geostationary satellite images.  The initial intensity remains at 40 
kt for this advisory based on a blend of subjective Dvorak estimates 
from SAB and TAFB.

Convective organization appears to have stalled in the past few 
hours, possibly due to some drier mid-level humidities, and as a 
result there has been no apparent change in intensity.  However, 
environmental conditions are expected to be conducive for 
strengthening in the next couple days and model guidance indicates 
Darby will intensify, possibly into a hurricane.  The system is 
predicted be over cooler ocean surface temperatures and entering a 
drier environment within 72 hours which should lead to weakening for 
the remainder of the forecast period.  The official NHC intensity 
prediction is above most of model guidance for the first couple of 
days and then is blended into the consensus for the rest of 
forecast.  

The tropical storm is moving westward at 13 kt and it is being 
steered by a deep-layer ridge to its north.  This motion is expected 
to continue at a slightly slower forward speed for the next couple 
of days.  In 3-4 days, Darby should reach a weakness in the ridge 
and turn west-northwestward to northwestward. The official NHC track 
forecast is a bit slower than the previous one, and it remains close 
to the TVCE and HCCA model consensus guidance.


FORECAST POSITIONS AND MAX WINDS

INIT  10/0900Z 14.3N 116.0W   40 KT  45 MPH
 12H  10/1800Z 14.4N 118.3W   45 KT  50 MPH
 24H  11/0600Z 14.3N 121.0W   55 KT  65 MPH
 36H  11/1800Z 14.3N 123.5W   65 KT  75 MPH
 48H  12/0600Z 14.6N 125.9W   75 KT  85 MPH
 60H  12/1800Z 14.9N 128.2W   75 KT  85 MPH
 72H  13/0600Z 15.4N 130.5W   70 KT  80 MPH
 96H  14/0600Z 16.9N 135.3W   60 KT  70 MPH
120H  15/0600Z 18.1N 139.8W   40 KT  45 MPH

$$
Forecaster Pasch/Bucci



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