Eastern Pacific Basin Tropical Cyclones

Hurricane Orlene Forecast Discussion


000
WTPZ41 KNHC 022035
TCDEP1

Hurricane Orlene Discussion Number  17
NWS National Hurricane Center Miami FL       EP162022
300 PM MDT Sun Oct 02 2022

Although the satellite presentation of Orlene is not as impressive 
as it was overnight, the center is still embedded within an area of 
cloud top temperatures of -70 to -80 degrees Celsius.  The eye is 
also not as defined in conventional satellite imagery as earlier 
today, but an Air Force Force Reserve reconnaissance aircraft that 
made two passes through the center earlier this afternoon reported 
a closed 22 n-mi-wide eye on its final pass. The aircraft measured 
a peak 700-mb flight-level wind of 96 kt, and SFMR winds of 92 kt.  
Since the plane only made a couple passes through the eastern 
eyewall, the intensity is set at 100 kt, owing to some 
undersampling.

It has been difficult to determine if today's weakening was caused 
by an eyewall replacement cycle, the increase in southwesterly 
shear, or a combination of both.  Regardless, southwesterly 
vertical wind shear is forecast to increase during the next 12 to 
24 hours, which is expected to cause an additional reduction in 
wind speed, plus the entrainment of some drier mid-level air to the 
west of Orlene.  Orlene still is forecast to pass near or over the 
Islas Marias as a strong hurricane tonight, and reach the coast of 
mainland Mexico as a hurricane by on Monday. After landfall, rapid 
weakening is expected, and the low-level center should dissipate 
over the mountainous terrain of southwestern Mexico in 48-60 hours.

Satellite imagery and fixes from the aircraft show that Orlene is
still moving northward or 005/7 kt. The track forecast philosophy 
is unchanged from before.  Orlene should bend north-northeastward 
tonight as it is steered between a mid-level ridge to its east and 
a broad trough over northwestern Mexico.   The track guidance is in 
much better agreement this cycle, and the NHC forecast was only 
nudged slightly westward to be closer to the various consensus 
aids.

The updated track and wind radii forecast has necessitated the 
issuance of a Tropical Storm Warning along the coast of mainland 
Mexico to the northwest of the Hurricane Warning area.  No other 
changes were made to the existing wind warnings. 


Key Messages:

1. Hurricane conditions are expected in the Islas Marias tonight,
with tropical storm conditions beginning within the next few hours. 
A Hurricane Warning is in effect for a portion of west-central 
mainland Mexico, where hurricane conditions are expected on Monday 
with tropical storm conditions beginning late tonight. Preparations 
to protect life and property should be rushed to completion.

2. A dangerous storm surge is likely to cause coastal flooding in 
the Islas Marias and along the coast of mainland Mexico in the 
warning area in regions of onshore winds.

3. Heavy rainfall from Orlene is expected to lead to flash flooding, 
as well as possible landslides in areas of rugged terrain of 
southwest Mexico through Tuesday.


FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 20.4N 106.9W  100 KT 115 MPH
 12H  03/0600Z 21.4N 106.7W   90 KT 105 MPH
 24H  03/1800Z 22.4N 106.3W   80 KT  90 MPH
 36H  04/0600Z 23.3N 105.8W   45 KT  50 MPH...INLAND
 48H  04/1800Z 24.2N 105.3W   25 KT  30 MPH...INLAND
 60H  05/0600Z...DISSIPATED

$$
Forecaster Brown



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