WTPA45 PHFO 280910

TCDCP5



TROPICAL STORM MADELINE DISCUSSION NUMBER   7

NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI   EP142016

1100 PM HST SAT AUG 27 2016



The cloud pattern around Madeline has not become any better

organized over the past 12 hours and the amount of cold overcast

has decreased. Subjective Dvorak analyses from HFO and JTWC had

current intensities of 3.0, or 45 kt, while SAB had 3.5, or 55 kt.

I have kept the intensity at 50 kt, which may be generous.



The cyclone is tracking along the southwest edge of the subtropical

ridge. Aloft, a narrow ridge separates Madeline from a trough to

the northwest. The global models are in good agreement showing the

trough lifting out to the northeast in 3 days as a ridge builds

along 160W. As that ridge builds, Madeline should curve toward the

west, then toward the west southwest. The current track is very

slightly slower and farther south than the previous forecast.



Madeline is expected to be moving through an area with low vertical

wind shear over the next 2 days and sea surface temperatures, SST,

will remain warm. Conditions should be favorable for some

intensification during that period. After that, shear is expected

to increase and the environment is expected to become drier, so

weakening is expected. This forecast is very similar to the final

forecast from NHC, but the intensity has been kept a bit lower,

based on the current lack of strong organization on satellite

imagery.



The confidence in the track forecast decreases by day 3, so it is

too early to determine what impacts Madeline could have on the

Hawaiian Islands late in the forecast period.  It is important to

remind users that the average day 4 and 5 track forecast errors for

central Pacific tropical cyclones are around 185 and 250 miles,

respectively.





FORECAST POSITIONS AND MAX WINDS



INIT  28/0900Z 16.1N 140.6W   50 KT  60 MPH

 12H  28/1800Z 16.8N 141.6W   55 KT  65 MPH

 24H  29/0600Z 17.8N 143.0W   60 KT  70 MPH

 36H  29/1800Z 18.7N 144.5W   65 KT  75 MPH

 48H  30/0600Z 19.4N 146.3W   65 KT  75 MPH

 72H  31/0600Z 19.6N 150.3W   55 KT  65 MPH

 96H  01/0600Z 19.0N 154.5W   50 KT  60 MPH

120H  02/0600Z 18.5N 159.0W   40 KT  45 MPH



$$

Forecaster Donaldson