137  
FXHW01 KWNH 180756  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
355 AM EDT WED OCT 18 2023  
 
VALID 00Z THU OCT 19 2023 - 00Z THU OCT 26 2023  
 
AFTER A PERIOD OF LIGHT TRADES AND LAND/SEA BREEZE INFLUENCE ON  
SHOWERS OVER SOME AREAS CONTINUING INTO WEDNESDAY, HIGH PRESSURE  
BEHIND A FRONT ARRIVING INTO THE NORTHWESTERN PART OF THE STATE  
THURSDAY-FRIDAY SHOULD BRING A BRIEF REBOUND IN TRADES AND  
WINDWARD RAINFALL FOCUS. THE FRONT'S MOISTURE BAND MAY SERVE TO  
ENHANCE TOTALS SOMEWHAT OVER THE NORTHWESTERN AND POSSIBLY CENTRAL  
ISLANDS LATE THIS WEEK. THIS AXIS OF MOISTURE SHOULD BEGIN TO  
DISSIPATE OR AT LEAST LIFT NORTHWARD DURING THE WEEKEND AS A  
STRONGER FRONT APPROACHES FROM THE NORTHWEST IN RESPONSE TO AN  
AMPLIFYING CENTRAL PACIFIC UPPER TROUGH. GUIDANCE STILL AGREES IN  
PRINCIPLE THAT THE SOUTHEASTERLY/SOUTHERLY FLOW AHEAD OF THE FRONT  
SHOULD DRAW UP ENHANCED MOISTURE FROM LOWER LATITUDES EARLY NEXT  
WEEK. CURRENT SPREAD FOR ALIGNMENT OF THE MOISTURE AXIS, WITH  
PRECIPITABLE WATER VALUES MOST LIKELY PEAKING AROUND TUESDAY,  
COVERS THE CENTRAL/EASTERN ISLANDS WITH THE 00Z GFS A BIT ON THE  
EASTERN SIDE OF THE ENVELOPE DUE TO EXTENDING THE UPPER TROUGH A  
LITTLE EASTWARD OF CONSENSUS. MEANWHILE THE 00Z ECMWF CONTINUES  
THE RECENT TENDENCY OF THAT MODEL TO BE SOMEWHAT DEEPER/SHARPER  
THAN MOST OTHER GUIDANCE WITH THE UPPER TROUGH EARLY IN THE WEEK,  
LEADING TO MUCH HEAVIER RAINFALL THAN WHAT OTHER MODELS ARE  
SHOWING. CURRENT PREFERENCE WOULD BE TO LEAN AWAY FROM THE ECMWF  
SPECIFICS UNTIL ONE OR MORE MODELS BEGIN TRENDING IN THAT  
DIRECTION, WHILE EXPECTING RAIN THAT COULD BE SOMEWHAT HEAVIER  
THAN OTHER MODELS AT LEAST ON A LOCALIZED BASIS. EVEN WITH THE  
DIFFERENCES ALOFT, THE LATEST MODELS AND MEANS ARE SIMILAR WITH  
BRINGING THE FRONT INTO THE MAIN ISLANDS DURING TUESDAY-WEDNESDAY.  
 
RAUSCH  
 

 
 
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