Eastern Pacific Basin Tropical Cyclones

Tropical Storm Orlene Forecast Discussion


990 
WTPZ41 KNHC 010311
TCDEP1

Tropical Storm Orlene Discussion Number   9
NWS National Hurricane Center Miami FL       EP162022
900 PM MDT Fri Sep 30 2022

Orlene had another burst of deep convection in the past few hours. 
Earlier microwave imagery from SSMI/S still showed a small inner 
core with a curved band to the south.  Subjective and objective 
satellite Dvorak classifications continue to range between 45 to 65 
kt.  Therefore, the initial intensity remains at 55 kt to represent 
a blend of these estimates.

The storm is embedded in an environment conducive for further 
intensification.  Global models suggest the vertical wind shear is 
low and the surrounding mid-level humidities are relatively moist 
and should remain this way for the next day or so.  These 
conditions, combined with warm sea surface temperatures, create the 
potential for steady to rapid intensification.  In fact, 
statistical guidance indicates there is a higher than average 
probability of rapid intensification in the upcoming 24 hours.  The 
official forecast still shows Orlene steadily strengthening to peak 
near 85 kt in 36 hours and little changes have been made since the 
previous advisory.  Beyond this period, the vertical wind shear is 
expected to increase and induce weakening until landfall.  It should 
be noted that the NHC intensity forecast is on the high end of the 
guidance to account for the possibility of rapid intensification.

The cyclone is moving along the periphery of a ridge over central 
Mexico.  In the next day, Orlene is expected to turn 
north-northeastward in the flow between the ridge and an upper-level 
trough over northwestern Mexico and the northern Baja California 
peninsula and continue this trajectory until landfall.  The latest 
NHC track prediction is slightly east of the previous track forecast 
and a little faster than the consensus model aids. This forecast 
favors the GFS track solution over the ECMWF.    

Based on the the forecast track and wind radii, the Government of 
Mexico has issued a Tropical Storm Warning and a Hurricane Watch for 
portions of mainland Mexico.  Additional watches and warnings will 
likely be required in the coming day.

Key Messages:

1. Hurricane conditions are possible in the Islas Marias on Sunday, 
where a hurricane watch has been issued.  Tropical storm conditions 
are expected within the tropical storm warning area from Playa 
Perula to San Blas within the next 36 h. Tropical storm conditions 
are possible over other portions of southwestern and west-central 
Mexico in the tropical storm watch area.

2. Heavy rainfall from Orlene is expected to lead to flash flooding,
as well as possible landslides in areas of mountainous terrain of
Southwest Mexico into Monday afternoon.


FORECAST POSITIONS AND MAX WINDS

INIT  01/0300Z 17.0N 107.2W   55 KT  65 MPH
 12H  01/1200Z 17.6N 107.2W   65 KT  75 MPH
 24H  02/0000Z 18.6N 107.1W   75 KT  85 MPH
 36H  02/1200Z 19.8N 106.8W   85 KT 100 MPH
 48H  03/0000Z 21.1N 106.5W   75 KT  85 MPH
 60H  03/1200Z 22.4N 106.3W   65 KT  75 MPH
 72H  04/0000Z 23.6N 106.0W   45 KT  50 MPH...INLAND
 96H  05/0000Z 25.5N 105.5W   25 KT  30 MPH...INLAND
120H  06/0000Z...DISSIPATED

$$
Forecaster Bucci




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