WTPZ33 KNHC 310247
TCPEP3

BULLETIN
HURRICANE JIMENA ADVISORY NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132015
800 PM PDT SUN AUG 30 2015

…INTENSE HURRICANE JIMENA MOVING WEST-NORTHWESTWARD TOWARD THE
CENTRAL PACIFIC…
SUMMARY OF 800 PM PDT…0300 UTC…INFORMATION
———————————————-
LOCATION…15.0N 132.5W
ABOUT 1525 MI…2450 KM E OF HILO HAWAII
MAXIMUM SUSTAINED WINDS…150 MPH…240 KM/H
PRESENT MOVEMENT…WNW OR 290 DEGREES AT 16 MPH…26 KM/H
MINIMUM CENTRAL PRESSURE…936 MB…27.64 INCHES
WATCHES AND WARNINGS
——————–
There are no coastal watches or warnings in effect.
DISCUSSION AND 48-HOUR OUTLOOK
——————————
At 800 PM PDT (0300 UTC), the center of Hurricane Jimena was located
near latitude 15.0 North, longitude 132.5 West. Jimena is moving
toward the west-northwest near 16 mph (26 km/h), and this general
motion with a gradual decrease in forward speed is expected during
the next couple of days.

Maximum sustained winds are near 150 mph (240 km/h) with higher
gusts. Jimena is a category 4 hurricane on the Saffir-Simpson
Hurricane Wind Scale. Only slow weakening is forecast during the
next 48 hours.

Hurricane force winds extend outward up to 40 miles (65 km) from the
center and tropical storm force winds extend outward up to 140 miles
(220 km).

The estimated minimum central pressure is 936 mb (27.64 inches).
HAZARDS AFFECTING LAND
———————-
None.
NEXT ADVISORY
————-
Next complete advisory at 200 AM PDT.

$$
Forecaster Kimberlain



WTPZ43 KNHC 310249
TCDEP3

HURRICANE JIMENA DISCUSSION NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL EP132015
800 PM PDT SUN AUG 30 2015

Jimena’s cloud pattern has been in a remarkably steady state since
the last advisory. The hurricane continues to maintain a large
circular eye that has warmed slightly, surrounded by a nearly
uniform ring of deep convection. There is a faint asymmetry in the
convective distribution, suggestive of northerly or north-
northwesterly shear as diagnosed by the SHIPS model output.
Satellite classifications were T6.5/127 kt from TAFB and SAB, and
UW-CIMSS ADT values have held steady at 6.7/132 kt. A blend of
these data is used to set the initial intensity at 130 kt.

Even though large-scale atmospheric conditions are forecast to
remain relatively favorable around Jimena during the couple of days,
the intensity guidance indicates that Jimena should begin to weaken
soon. The weakening appears to largely be a function of slowly
decreasing SSTs along the cyclone’s path. Some westerly shear and a
larger drop-off in oceanic heat content later in the forecast period
suggest continued gradual weakening should occur, but neither the
atmosphere nor ocean should produce conditions hostile enough to
result in the cyclone’s rapid decline. The one caveat to the
intensity forecast is that Jimena, already exhibiting some
characteristics of an annular hurricane, could weaken more slowly
than forecast. The latest NHC intensity forecast is somewhat above
the multi-model consensus and is in best agreement with the HWRF
model that shows slower overall weakening.

Jimena’s heading has been a bit more westerly since the previous
advisory, but a longer-term average motion estimate is 290/14. A
longwave trough, extending southwestward from the U.S. west coast,
has eroded the subtropical ridge ridge between 140-150W. As Jimena
nears this weakness during the next few days, its forward speed
should gradually decrease on a slightly more poleward heading. In
the absence of much steering from days 3 to 5, Jimena should drift
northwestward. The latest NHC track forecast has hardly changed
from the previous one.
FORECAST POSITIONS AND MAX WINDS

INIT 31/0300Z 15.0N 132.5W 130 KT 150 MPH
12H 31/1200Z 15.4N 134.4W 125 KT 145 MPH
24H 01/0000Z 16.2N 136.8W 120 KT 140 MPH
36H 01/1200Z 16.8N 138.6W 115 KT 130 MPH
48H 02/0000Z 17.3N 140.0W 105 KT 120 MPH
72H 03/0000Z 18.3N 141.9W 90 KT 105 MPH
96H 04/0000Z 19.1N 143.0W 80 KT 90 MPH
120H 05/0000Z 20.2N 143.9W 70 KT 80 MPH

$$
Forecaster Kimberlain