Tropical Cyclone Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
WTPZ43 KNHC 281432

800 AM PDT FRI AUG 28 2015

Rapid intensification of Jimena continues this morning.  Microwave
data has shown an eye beneath the central dense overcast, and a
more definitive eye is just now becoming apparent in infrared
satellite imagery.  With subjective Dvorak estimates of T4.5/77 kt
from TAFB and SAB, and an objective estimate of T4.6/80 kt from
UW-CIMSS, Jimena`s initial intensity is raised to 80 kt.

Jimena is expected to remain in an environment of low shear and
over warm water for the duration of the forecast period.  Mid-level
moisture is high at the moment and is expected to only gradually
decrease during the next 2 to 3 days.  The SHIPS Rapid
Intensification Index (RII) is showing a 54 percent chance of a
30-kt increase in intensity during the next 24 hours.  Therefore, a
continuation of RI appears likely and is explicitly shown in the NHC
intensity forecast.  A peak intensity is expected in about 48 hours,
followed by gradual weakening through day 5 due to a slightly drier
environment and lower oceanic heat content values.  The updated NHC
intensity forecast is generally a blend of the previous forecast
with the latest SHIPS and LGEM guidance.  It should be noted that
once Jimena reaches its peak as a major hurricane, fluctuations in
intensity that deviate from the official forecast are likely due to
possible eyewall replacements.

Jimena appears to have slowed down a bit, and the initial motion is
270/10 kt.  The hurricane remains to the south of an anomalously
strong ridge that extends southwestward from the southwestern
United States, and this feature is expected to keep Jimena on a
westward course for the next 24 hours.  After that time, the ridge
is expected to weaken, which will allow Jimena to turn
west-northwestward through day 5.  The track guidance remains in
good agreement and very close to the previous forecast.  Therefore,
no significant changes are noted in the updated NHC track forecast.


INIT  28/1500Z 12.4N 122.0W   80 KT  90 MPH
 12H  29/0000Z 12.4N 123.6W   95 KT 110 MPH
 24H  29/1200Z 12.6N 125.5W  110 KT 125 MPH
 36H  30/0000Z 13.2N 127.3W  120 KT 140 MPH
 48H  30/1200Z 14.1N 129.2W  125 KT 145 MPH
 72H  31/1200Z 15.9N 133.9W  120 KT 140 MPH
 96H  01/1200Z 17.0N 138.0W  105 KT 120 MPH
120H  02/1200Z 17.5N 140.5W   90 KT 105 MPH

Forecaster Berg is the U.S. government's official web portal to all federal, state and local government web resources and services.