WTPA45 PHFO 300850
TCDCP5

HURRICANE MADELINE DISCUSSION NUMBER  15
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP142016
1100 PM HST MON AUG 29 2016
 
Madeline remains very well organized this evening, with an earlier
13 nm diameter eye now beginning to shrink. There is little or no
shear deformation present, with excellent outflow noted to the
north. Deep convection continues to completely encircle the eye,
with eyewall cloud top temperatures cooling a bit more to near -72
degrees Celsius. Subjective Dvorak satellite intensity estimates
are 6.0/115 kt from all three satellite analysis centers, while
UW-CIMSS provides an ADT of 5.5/102 kt. We will assign Madeline an
initial intensity of 115 kt for this advisory cycle, based on the
unanimous satellite center intensities. Hurricane hunters from the
53rd Weather Reconnaissance Squadron are slated to begin flying
investigative flights into Madeline Tuesday morning, which will
give us valuable information as to Madeline's actual intensity and
size.

Initial motion is 280/08 kt as the anticipated trend toward a more
westerly track appears to be taking hold. Track guidance remains
tightly packed through 36 hours, but begins to diverge noticeably
after that. Madeline is tracking along the southern flank of the
subtropical ridge, but an upper trough northwest of the main
Hawaiian Islands allowed this system to gain latitude over the past
few days. Global models show this upper trough will lift northward
through 48 hours, giving the ridge a larger steering role by
nudging Madeline westward and west southwestward through day 2.
Beyond 72 hours, the upper trough is forecast to begin digging
southward again, causing another track bend to the west northwest
on day 3 and beyond. Track guidance diverges beyond 36 hours as the
models handle the redigging upper trough differently. There are a
few models that take Madeline over southern portions of the Big
Island, notably GFDL and ECMWF. However other models, notably GFS
and FSSE, take Madeline noticeably farther south of the Big
Island. The forecast track for this advisory closely resembles the
last one, following TVCN consensus down the middle of the
guidance envelope.
 
Satellite loop suggests Madeline has likely reached peak intensity
and all guidance shows weakening through day 5 at various rates.
SHIPS, mainly citing SST potential, weakens Madeline very quickly to
a tropical storm by 72 hours. In contrast, the global models and
HWRF weaken madeline very gradually. Our forecast follows a middle
road, maintaining Madeline as a hurricane through day 4 along the
IVCN consensus path.
 
Users are reminded to not focus too closely on the deterministic
forecast track, and that hazards associated with hurricanes can
extend well away from the center.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/0900Z 19.1N 147.2W  115 KT 130 MPH
 12H  30/1800Z 19.2N 148.6W  110 KT 125 MPH
 24H  31/0600Z 19.1N 150.6W  100 KT 115 MPH
 36H  31/1800Z 18.7N 152.6W   90 KT 105 MPH
 48H  01/0600Z 18.5N 154.6W   80 KT  90 MPH
 72H  02/0600Z 18.4N 158.6W   70 KT  80 MPH
 96H  03/0600Z 18.9N 163.0W   65 KT  75 MPH
120H  04/0600Z 19.8N 168.1W   60 KT  70 MPH
 
$$
Forecaster Powell