Skip Navigation Links 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center



Follow the Weather Prediction Center on Facebook Follow the Weather Prediction Center on Twitter
NCEP Quarterly Newsletter
WPC Home
Analyses and Forecasts
   National High & Low
   WPC Discussions
   Surface Analysis
   Days ½-2½ CONUS
   Days 3-7 CONUS
   Days 4-8 Alaska
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/

Satellite and Radar Imagery
   Satellite Images
   National Radar
Product Archive
WPC Verification
   Medium Range
   Model Diagnostics
   Event Reviews
   Winter Weather
International Desks
Development and Training
WPC Overview
   About the WPC
   WPC History
   Other Sites
Meteorological Calculators
Contact Us
   About Our Site is the U.S. Government's official web portal to all federal, state, and local government web resources and services.
Hawaii Extended Forecast Discussion
(Latest Discussion - Issued 1214Z Apr 23, 2017)
Version Selection
Versions back from latest:  0   1   2   3   4   5   6   7   8   9   10   
Abbreviations and acronyms used in this product

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
814 AM EDT Sun Apr 23 2017

Valid 00Z Mon Apr 24 2017 - 00Z Mon May 01 2017

A surface ridge extending west-southwest from eastern Pacific high
pressure will maintain trades of at least moderate strength into
midweek, possibly weakening a bit into early Monday and then
becoming a little stronger Monday-Tuesday night.  Generally
windward focused shower activity should trend lighter early in the
week as precipitable water values decline to around an inch.  With
differences in specifics most guidance shows a modest increase in
moisture around midweek.

Broadly speaking the models and ensembles are gradually trending
toward a more common evolution for the amplifying upper trough
expected to reach the state by around Friday-Saturday.  This upper
trough will bring a surface front into the area and likely support
a period of more unsettled weather with potential for some locally
enhanced rainfall through the weekend.  Best guidance agreement
now exists into Thursday, through 00z of the 28th, with widening
spread of solutions thereafter.  Latest GFS runs have moderated
the more extreme aspects of forecasts from the past couple days
but may still be a little deep with a compact upper low that
closes off just north of 30N by Saturday and a little fast with
the part of the upper trough that crosses the state
Friday-Saturday.  The 00z GEFS mean agrees better with the 00z
ECMWF/ECMWF MEAN in keeping the axis of moisture along the front
somewhat westward of 00z/06z GFS runs, so would recommend those
solutions at this time.  Meanwhile the front will separate brisk
northeasterly winds over the northwestern islands from
southeasterly winds over the Big Island.