090  
FXHW01 KWNH 290748  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
347 AM EDT MON MAY 29 2023  
 
VALID 00Z TUE MAY 30 2023 - 00Z TUE JUN 06 2023  
 
EXPECT A TYPICAL TRADE PATTERN WITH WINDWARD/MOUNTAIN FOCUSED  
SHOWERS OVER THE NEXT SEVEN DAYS AS HIGH PRESSURE INITIALLY A  
LITTLE NORTH OF 40N LATITUDE GRADUALLY TRENDS WEAKER AS IT SETTLES  
ALONG 30N LATITUDE BY NEXT SUNDAY-MONDAY. WIND SPEEDS SHOULD  
INCREASE TOWARD MODERATE OR BRISK LEVELS BY MID-LATE WEEK AND THEN  
STABILIZE AS THE CLOSER PROXIMITY OF HIGH PRESSURE OFFSETS ITS  
WEAKENING TREND. GUIDANCE IS CONSISTENT IN SHOWING AN EAST-WEST  
WEAKNESS ALOFT OVER OR JUST NORTH OF THE STATE HELPING TO INCREASE  
MOISTURE/RAINFALL SOMEWHAT THROUGH MIDWEEK, AND ALLOWING FOR THE  
POSSIBILITY THAT A FEW SHOWERS COULD STRAY INTO LEEWARD LOCALES.  
 
FROM LATE WEEK INTO EARLY NEXT WEEK, GUIDANCE CONTINUES TO DIFFER  
SIGNIFICANTLY FOR HOW MUCH MOISTURE THERE WILL BE OVER THE  
ISLANDS, WITH SOME DEPENDENCE ON SUBTLE DETAILS (HAVING LOW  
PREDICTABILITY SEVERAL DAYS OUT IN TIME) OF A LINGERING WEAKNESS  
OVER/WEST-SOUTHWEST OF THE AREA. ALSO A COUPLE OF SHORTWAVES  
SHOULD PASS BY TO THE NORTH, AND THE FAR SOUTHERN PERIPHERY OF  
THESE FEATURES MAY HAVE SOME INFLUENCE. AS HAS BEEN THE CASE  
RECENTLY, THE 00Z ECMWF CONTINUES TO SHOW A PRONOUNCED DRIER TREND  
FRIDAY ONWARD VERSUS THE GFS THAT KEEPS RATHER HIGH PRECIPITABLE  
WATER VALUES OVER THE BIG ISLAND (WHILE OFFERING SOMEWHAT DRIER  
CONDITIONS FARTHER NORTHWEST). IN GENERAL THE GEFS AND ECMWF  
MEANS BOTH CONTINUE TO FAVOR A COMPROMISE APPROACH WHILE JUST  
MODERATELY TILTING TOWARD THE IDEAS OF THEIR RESPECTIVE PARENT  
MODELS. A COMPROMISE AMONG THESE MEANS LOOKS BEST FOR A SINGLE  
DETERMINISTIC FORECAST GIVEN THE CONTINUED SPREAD AND UNCERTAINTY  
FOR IMPORTANT DETAILS ALOFT.  
 
RAUSCH  
 

 
 
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