567  
FXHW01 KWNH 151229  
PMDHI  
 
HAWAII EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
729 AM EST THU FEB 15 2018  
 
VALID 00Z FRI FEB 16 2018 - 00Z FRI FEB 23 2018  
 
A SERIES OF VIGOROUS CLOSED UPPER LOWS WILL IMPACT HAWAII OVER THE  
NEXT WEEK, ACCORDING TO THE LATEST RELIABLE GLOBAL MODELS. THE  
RESULTANT FROM EACH FEATURE WILL BE MOIST UNSETTLED WEATHER WITH  
THE POTENTIAL FOR HEAVY TO EXCESSIVE RAINS. ALREADY A COMPACT  
CLOSED 500MB FEATURE IS LOCATED ABOUT 26N 161-162W AND KEEPING A  
MOIST PLUME OF TROPICAL MOISTURE WITH 1.50 INCH PRECIPITABLE WATER  
VALUES, ESPECIALLY NEAR THE BIG ISLAND AND MAUI. THIS FEATURE WILL  
BEGIN TO WEAKEN SLIGHTLY OVER THE NEXT DAY OR TWO, WHILE LIFTING  
NORTH AND GETTING CAUGHT UP IN THE WESTERLIES. HOWEVER, WITH THE  
BLOCKING LARGE SCALE PATTERN ACROSS THE MID-LATITUDES ACROSS THE  
PACIFIC, THE CONTINUOUS PLUME OF TROPICAL MOISTURE WILL REMAIN  
ESPECIALLY FOR THE EASTERN PORTION OF THE ISLANDS. THE NEXT SET OF  
UPPER DYNAMICS AND LOWERING UPPER HEIGHTS WILL ARRIVE ON SATURDAY  
INTO SUNDAY. THIS TIME, UPPER DYNAMICS WILL CLOSE OFF RIGHT OVER  
THE STATE, WHICH MAY HELP IN SHOVING THE TROPICAL MOISTURE SURGE  
EAST OF THE STATE BUT THE BIG ISLAND COULD STILL BE IMPACTED.  
ALSO, WITH THE LOW CLOSING OFF OVER THE STATE, EXPECT THE  
INCREASING CHANCES OF INSTABILITY SHOWERS/PERHAPS THUNDERSTORMS  
AND MAYBE EVEN SNOW FOR THE HIGHEST PEAKS OF THE BIG ISLAND. THIS  
LOW WILL BEGIN TO FILL AND WEAKEN ABOUT TUESDAY/WEDNESDAY BUT ONCE  
AGAIN, ANOTHER SET OF SHORT WAVE UPPER DYNAMICS DIG SOUTHEAST FROM  
THE CENTRAL PACIFIC AND CLOSE OFF NORTHWEST OF THE STATE. THIS MAY  
ALLOW THE PLUME OF TROPICAL MOISTURE TO RETROGRADE WESTWARD AND  
BEGIN TO ENCOMPASS THE ENTIRE STATE, JUST A LITTLE DIFFICULT TO  
PIN DOWN A WEEK OUT. ANOTHER ITEM, TOUGH TO PEG EXACTLY IF THESE  
FEATURES ARE TRUE KONA LOWS. BASED ON THE AVAILABLE GUIDANCE, THE  
MOST LIKELY LOW IS THE INITIAL ONE WHICH CONTAINS THE MOIST REGIME  
LOCKED IN ACROSS THE EASTERN PORTION OF THE STATE.  
 
MUSHER  
 

 
 
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