672  
FXHW01 KWNH 231235  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
835 AM EDT TUE OCT 23 2018  
 
VALID 00Z WED OCT 24 2018 - 00Z WED OCT 31 2018  
 
RECENT WATER VAPOR IMAGERY SHOWS DRY MID-LEVEL AIR STREAMING IN  
OVER HAWAII WHILE A PLUME OF DEEPER MOISTURE ASSOCIATED WITH  
EASTERLY WAVES SLOWLY MAKES ITS WAY TOWARD THE ISLANDS. NORTH OF  
THE ISLANDS IS AN ACTIVE MID-LATITUDE FLOW REGIME. A COLD FRONT IS  
FORECAST TO APPROACH THE NORTHERN ISLANDS BY EARLY FRIDAY MORNING  
BEFORE STALLING AND WASHING OUT OVER THE WEEKEND.  
 
TRADE WINDS ARE EXPECTED TO BE FLUCTUATE FROM 10-15 KTS TO  
20-25KTS AS THE WAVES PASS SOUTH OF THE ISLANDS. MOISTURE WILL  
ONCE AGAIN BEGIN TO SPREAD NORTH ACROSS PORTIONS OF HAWAII BY MID  
TO LATE WEEK INCREASING CHANCES FOR RAIN. GUIDANCE CONTINUES TO  
SUGGEST THAT THE BIG ISLAND WILL BE AFFECTED BY THE DEEPEST  
MOISTURE ASSOCIATED WITH THE WAVE BY LATE WEDNESDAY AS THE WAVE  
PASSES. LOCALLY HEAVY RAIN MAY BE POSSIBLE.  
 
THE GLOBAL MODELS AND THE ENSEMBLE MEANS ARE FAIRLY CLUSTERED WITH  
THE MODERATE AMPLITUDE TROUGH TRACKING THROUGH THE NORTH-CENTRAL  
PACIFIC AND THE TIMING OF THE COLD FRONT. AS THE MID-LATITUDE FLOW  
BECOMES MORE PROGRESSIVE, ENSEMBLES SHOW GENERAL AGREEMENT THAT A  
SECOND, SIMILAR TROUGH WILL AMPLIFY ACROSS THE NORTH CENTRAL  
PACIFIC BY SUN-MON; HOWEVER IS NOT AS CLUSTERED AS THE PRIOR  
TROUGH BUT SUGGESTS MORE POTENTIAL FOR ADDITIONAL SIGNIFICANT  
IMPACTS ON HAWAII JUST BEYOND THE END OF THE FORECAST PERIOD.  
 
CAMPBELL  
 

 
 
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