Prognostic Meteorological Discussion
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000
FXHW01 KWNH 301137
PMDHI

HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
736 AM EDT SUN AUG 30 2015

VALID 00Z MON AUG 31 2015 - 00Z MON SEP 07 2015

THE 30/00Z MODEL CYCLE OFFERED NO SURPRISES WITH THE CURRENT AND
NEAR-FUTURE FORECASTS FOR HAWAI`I AND THE CENTRAL PACIFIC. WILL
REFER YOU TO THE CENTRAL PACIFIC HURRICANE CENTER (CPHC) FOR THE
MOST RECENT AND PERTINENT WEATHER INFORMATION CONCERNING THE
SENSIBLE WEATHER ASSOCIATED AND HEADLINES WITH `KILO` AND
`IGNACIO`.

MEDIUM RANGE...
THE 30/00Z DETERMINISTIC GFS/ECMWF AND THEIR ENSEMBLES WERE IN
GOOD AGREEMENT UNTIL DAY 5 (4/12Z) WHEN MID-LATITUDE NORTH PACIFIC
FLOW BEGINS TO INTERACT WITH THE SUBTROPICS INVOF 160W LONGITUDE.

MUCH OF THE SPREAD IS RELATED TO THE NATURE AND SLOW, EASTWARD
MOVEMENT OF A STATIONARY BOUNDARY NEAR THE DATELINE AFTER DAY
5---AND TO WHAT EXTENT THE FLOW WILL/WILL NOT INCORPORATE SOME OF
`IGNACIO`, AND TURN IT NORTHWARD AND ALLOW IT TO CONTINUE
MIGRATING WESTWARD. BELIEVE THE MEDIUM RANGE SOLUTIONS HAVE
CORRECTLY ESTABLISHED THE LONGITUDE OF THE SLOW-MOVING BLOCK FROM
THE DATELINE EASTWARD TO 160W---BUT THE PRESENCE OF `KILO` AND
`IGNACIO` ARE PROVIDING SOME OF THE DIFFERENCES---AND IN A
FASHION---NOT MUCH DIFFERENT FROM THE GLOBAL GUIDANCE `MIGRATORY
STRUGGLES` OBSERVED WHEN GONI AND ATSANI WERE MIGRATING TOWARDS
THE MID-LATITUDE WESTERLIES. THESE `MIGRATORY STRUGGLES` DO NOT
PERTAIN TO A SURFACE PRESSURE FIELD DISCONNECT BETWEEN
SOLUTION---AS WAS OBSERVED WITH THE PREVIOUS TWIN-CYCLONE SCENARIO
IN THE WESTERN PACIFIC (GONI AND ATSANI).

AND THE DIFFERENCES ARE GENERATED IN THE CLEARLY FASTER
MID-LATITUDE GEFS/GFS SOLUTIONS. WOULD SUGGEST LEANING CLOSER TO
AN ECENS/ECMWF SOLUTION BEYOND DAY 5 TO ALLOW THE GLOBAL GUIDANCE
TO `RESET` THE DOWNSTREAM PATTERN BETWEEN 30N AND 45N LATITUDE
INVOF 160W.

VOJTESAK



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