597  
FXHW01 KWNH 160759  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
208 AM EST THU JAN 16 2025  
 
VALID 00Z FRI JAN 17 2025 - 00Z FRI JAN 24 2025  
 
TODAY'S GUIDANCE CONTINUES TO SHOW GOOD AGREEMENT AND CONTINUITY  
INTO EARLY NEXT WEEK, FOLLOWED BY INCREASING DIVERGENCE FROM  
TUESDAY ONWARD. A FRONT PASSING THROUGH THE MAIN ISLANDS  
THURSDAY-FRIDAY WILL DISRUPT THE TRADES AND POSSIBLY BRING SOME  
POCKETS OF HEAVIER RAINFALL, THOUGH HIGHER TOTALS SHOULD REMAIN  
WELL TO THE NORTH. HIGH PRESSURE BEHIND THIS FRONT AND A WEAKER  
TRAILING FRONT TO THE NORTHWEST WILL LIKELY BRING MODERATE TO  
BRISK NORTHEASTERLY WINDS FOR THE WEEKEND INTO EARLY NEXT WEEK.  
GUIDANCE IS CONSISTENT IN SHOWING BELOW-CLIMATOLOGY PRECIPITABLE  
WATER VALUES BEHIND THE LATE-WEEK FRONT, KEEPING MOST SHOWERS  
FAIRLY LIGHT DURING THE WEEKEND AND FIRST PART OF NEXT WEEK.  
 
TODAY'S GUIDANCE SHOWS A SIMILAR DIVERGENCE FROM 24 HOURS AGO  
TUESDAY ONWARD WITH AN AMPLIFYING UPPER TROUGH AND LEADING COLD  
FRONT. AMONG THE STANDARD DYNAMICAL GUIDANCE, THE ECMWF/CMC AND  
THEIR ENSEMBLE MEANS ARE STILL SLOWER AND MORE AMPLIFIED WITH THE  
TROUGH VERSUS THE LATEST GFS RUNS. THE 00Z GEFS MEAN IS SOMEWHAT  
OF A COMPROMISE. AT THE SURFACE THIS MAKES THE DIFFERENCE BETWEEN  
A SLOWER/WETTER FRONTAL PASSAGE ON WEDNESDAY IN THE ECMWF CLUSTER  
VERSUS A FASTER/DRIER ONE IN THE GFS, ALONG WITH TRAILING HIGH  
PRESSURE RESTORING TRADE FLOW MORE QUICKLY. RECENT MACHINE  
LEARNING MODELS HAVE DISPLAYED TYPICAL SPREAD, BUT ON AVERAGE  
CONTINUE TO RECOMMEND A COMPROMISE SOLUTION (WHICH IS STILL  
PREFERRED) FOR THE UPPER TROUGH AND FRONTAL PROGRESSION. THE 00Z  
ECMWF RUN HAS TRENDED LIGHTER WITH ITS QPF ALONG THE FRONT VERSUS  
PREVIOUS RUNS, WHICH IS ONE STEP TOWARD A COMPROMISE EVEN IF ITS  
TIMING IS STILL RELATIVELY SLOW.  
 
RAUSCH  
 

 
 
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