340  
FXHW01 KWNH 150749  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
348 AM EDT SAT APR 15 2023  
 
VALID 00Z SUN APR 16 2023 - 00Z SUN APR 23 2023  
 
MOST GUIDANCE AGREES FAIRLY WELL FOR THE GENERAL THEMES OF THE  
FORECAST THROUGH THE PERIOD, THOUGH A COUPLE DIFFERENCES ARISE FOR  
SPECIFICS NEXT WEEK. EXPECT MODERATE TRADES THIS WEEKEND WITH  
WINDWARD-FOCUSED SHOWERS TENDING TO BE IN THE LIGHT TO MODERATE  
SIDE OF THE SPECTRUM AS PRECIPITABLE WATER VALUES OVER NEAR OR A  
LITTLE BELOW CLIMATOLOGY. THEN CONSENSUS SHOWS GOOD CONTINUITY  
WITH A SYSTEM NORTHWEST OF THE ISLANDS PUSHING A FRONT TOWARD THE  
REGION EARLY NEXT WEEK, TURNING WINDS MORE SOUTHERLY. GUIDANCE IS  
SIMILAR IN DEPICTING THE POTENTIAL FOR THIS FRONT TO TAP A  
CONSIDERABLE AMOUNT OF TROPICAL MOISTURE (PWATS PERHAPS REACHING  
3+ STANDARD DEVIATIONS ABOVE NORMAL) WITH HEAVIEST RAINFALL LIKELY  
AFFECTING WESTERN AREAS ON TUESDAY AND CENTRAL LOCATIONS ON  
WEDNESDAY. RAIN SHOULD TREND LIGHTER OVER THE EASTERN HALF OF THE  
STATE LATER IN THE WEEK AS THE FRONT WEAKENS. MOST SOLUTIONS  
SUGGEST THE LINGERING MOISTURE BAND SHOULD RETURN BACK TO THE  
NORTHWEST BY FRIDAY-SATURDAY AS UPPER RIDGING BUILDS IN FROM THE  
EAST. AMONG THE 00Z GUIDANCE/12Z ECMWF MEAN, THE 00Z ECMWF IS A  
NOTABLE EXTREME IN BRINGING THE FRONT OR THE REMAINING SHEAR AXIS  
JUST EAST OF THE BIG ISLAND BY LATE IN THE WEEK. REMAINING MODELS  
AND MEANS SUGGEST THE FRONT SHOULD NOT REACH ANY FARTHER EAST THAN  
THE CENTRAL ISLANDS. BY THE END OF THE FORECAST NEXT SATURDAY,  
ONE OTHER DISCREPANCY ARISES INVOLVING THE RELATIVE STRENGTH OF  
RIDGE TO THE EAST AND AN UPPER TROUGH TO THE NORTHWEST AND ANOTHER  
FRONT THAT MAY APPROACH FROM THE NORTHWEST. THE 00Z GFS/GEFS MEAN  
LEAN TOWARD A STRONGER TROUGH/WEAKER RIDGE, BRINGING THE FRONT  
CLOSER TO THE AREA THAN OTHER SOLUTIONS. THE 00Z CMC/CMCENS AND  
12Z ECMWF MEAN MAKE UP THE STRONG RIDGE CLUSTER. SIMILAR  
DIFFERENCES WITH THE RIDGE PERSIST FROM YESTERDAY, SO A COMPROMISE  
APPEARS TO BE A REASONABLE APPROACH AT THIS TIME.  
 
RAUSCH  
 
 
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