371  
FXHW01 KWNH 210758  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 AM EST TUE NOV 21 2023  
 
VALID 00Z WED NOV 22 2023 - 00Z WED NOV 29 2023  
 
A STALLED FRONT AND MOISTURE BAND INITIALLY OVER THE STATE SHOULD  
DISSIPATE FAIRLY QUICKLY, LEADING TO A LIGHTER TREND FOR RECENT  
LOCALLY ENHANCED RAINFALL. GUIDANCE CONTINUES TO SHOW AN AREA OF  
ENHANCED MOISTURE JUST TO THE SOUTHEAST OF THE STATE BRUSHING AT  
LEAST THE BIG ISLAND AND PERHAPS TO SOME DEGREE THE REST OF THE  
STATE DURING TUESDAY-WEDNESDAY. THIS MOISTURE COULD STILL HELP TO  
ENHANCE RAINFALL TO SOME DEGREE. AMONG LATEST MODELS/MEANS, THE  
00Z ECMWF SHOWS SLIGHTLY HIGHER PRECIPITABLE WATER VALUES THAN  
MOST OTHER SOLUTIONS.  
 
EXPECT BRISK NORTHEASTERLY WINDS TO TRANSITION TO MODERATE TRADES  
THROUGH THURSDAY, FOLLOWED BY A SOUTHEASTERLY TREND AS A FRONT  
APPROACHES FROM THE WEST. OVER THE PAST DAY GUIDANCE HAS MADE A  
NOTABLE CHANGE IN THE CHARACTER OF THE SUPPORTING UPPER TROUGH BY  
THE WEEKEND, PULLING OFF ENERGY IN THE SOUTHERN PART OF THE TROUGH  
WHILE THE REST OF THE TROUGH PASSES BY JUST TO THE NORTH OF THE  
STATE. THIS LATTER PART OF THE TROUGH IS SOMEWHAT MORE AMPLIFIED  
IN THE GFS/GEFS THAN MOST OTHER SOLUTIONS, SO WOULD INITIALLY  
HEDGE AWAY A BIT FROM THE GFS IN PARTICULAR THAT ULTIMATELY HAS A  
NEARLY CLEAR FRONTAL PASSAGE BEFORE IT STALLS. ON THE OTHER HAND,  
THE 12Z ECMWF MEAN IS AMONG THE MAJORITY THAT BRINGS THE FRONT  
FARTHER SOUTH/SOUTHEAST THAN THE 00Z ECMWF. THIS CHANGE IN UPPER  
TROUGH DETAILS HAS REDUCED SOME OF THE RAINFALL TOTALS AS THE  
FRONT MOVES IN. BY NEXT TUESDAY THERE IS GENERAL AGREEMENT THAT  
UPSTREAM ENERGY SHOULD BEGIN TO DEVELOP ADDITIONAL TROUGHING JUST  
WEST OF THE STATE, LEADING TO THE POTENTIAL FOR INCREASING  
MOISTURE TO FOCUS ALONG THE STALLING FRONT. IT WILL LIKELY TAKE A  
WHILE TO RESOLVE THE DETAILS OF THIS EVOLUTION BUT THE PATTERN  
DOES AT LEAST SUGGEST THE POTENTIAL FOR INCREASING RAINFALL TOWARD  
NEXT TUESDAY.  
 
RAUSCH  
 
 
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