Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
1015 AM EDT Fri Sep 25 2015

Valid 00Z Sat Sep 26 2015 - 00Z Sat Oct 03 2015


--RESENT TO CORRECT GFS QPF--


...Tropical Depression Six-C Lurks to the Southeast...


If tropical depression Six-c follows the expected path, the Big
Island will be most vulnerable to torrential rainfall in the
coming days. Assuming the system curves off to the west tracking
south of Hawai'i, the next bifurcation in the forecast decision
tree will be if, when, and where the southern edge of the polar
jet buckles to the north of the state. The 00Z ECMWF digs a trough
along 155W late next week, with the 06Z GFS keeping the westerlies
zonal. Five-day QPF through 00Z October 1 is enormous for the Big
Island, with the 00Z ECMWF indicating 18.74" in the terrain and
the 06Z GFS a whopping 28.35".


Cisco