Eastern Pacific Basin Tropical Cyclones

Tropical Storm Orlene Forecast Discussion


000
WTPZ41 KNHC 301436
TCDEP1

Tropical Storm Orlene Discussion Number   7
NWS National Hurricane Center Miami FL       EP162022
900 AM MDT Fri Sep 30 2022

Orlene has not changed much in organization during the past several 
hours, with satellite imagery showing a small central dense 
overcast with ragged outer convective banding. Interestingly, a 
recent SSMI/S overpass indicates that, despite analyses that the 
shear is 5 kt or less, the convection under the overcast is a bit 
asymmetric and mainly occurring to the southwest and south of the 
center.  Satellite intensity estimates are essentially unchanged 
since the previous advisory, so the initial intensity remains 50 kt.

Orlene is forecast to be in a moist, low-shear environment and over 
warm sea surface temperatures for the next 48 h.  These conducive 
conditions, combined with the small inner core, should allow steady 
to rapid strengthening once the core convection becomes more 
symmetric.  Based on this, the intensity forecast shows the system 
reaching a peak intensity of 85 kt in about 48 h.  After that time, 
the global models are in excellent agreement that the cyclone should 
encounter strong southwesterly shear that is likely to cause quick 
weakening.  The official forecast calls for a 60-kt intensity just 
before landfall, and this is near the upper edge of the intensity 
guidance.  However, there is still a chance that Orlene could be a 
hurricane at landfall if the shear is lighter than expected or the 
storm moves faster than currently forecast.

The initial motion is still northwestward or 320/4 kt.  Rawinsonde 
data shows a mid- to upper-level ridge over central Mexico to the 
northeast of Orlene, and a combination of rawinsonde data and water 
vapor imagery shows a developing mid- to upper-level trough over 
northwestern Mexico and the northern Baja California peninsula.  
Orlene should turn northward and north-northeastward between these 
features during the next couple of days, with this general motion 
continuing for the rest of the forecast period.  The new forecast 
track, which is similar to the previous forecast, calls for the 
system to pass west of Cabo Corrientes and near the Islas Marias in 
48-60 h and then make landfall on the mainland coast of Mexico just 
after 96 h.  This forecast is close to the consensus models, but 
slower than the GFS model. It should be noted that some of the 
ensemble guidance is forecasting the possibility that Orlene will 
get so strongly sheared that the northward motion will slow over 
the southern Gulf of California and keep the center offshore 
through 120 h.

Watches will likely be required for portions of the western coast 
of Mexico and the Islas Marias on the next advisory.

FORECAST POSITIONS AND MAX WINDS

INIT  30/1500Z 16.1N 107.1W   50 KT  60 MPH
 12H  01/0000Z 16.7N 107.3W   60 KT  70 MPH
 24H  01/1200Z 17.5N 107.3W   70 KT  80 MPH
 36H  02/0000Z 18.4N 107.2W   80 KT  90 MPH
 48H  02/1200Z 19.7N 107.0W   85 KT 100 MPH
 60H  03/0000Z 21.4N 106.6W   75 KT  85 MPH
 72H  03/1200Z 22.9N 106.4W   60 KT  70 MPH
 96H  04/1200Z 25.1N 106.0W   25 KT  30 MPH...INLAND
120H  05/1200Z...DISSIPATED

$$
Forecaster Beven



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