720
FXHW01 KWNH 220856
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
456 AM EDT TUE SEP 22 2026
VALID 00Z WED 23 SEP 2026 - 00Z WED 30 SEP 2026
..HEAVY RAIN AND FLOODING POTENTIAL WITH T.D. 15-E REMNANTS
ABOVE AVERAGE MOISTURE ALONG WITH BROAD, WEAK ENERGY ALOFT WILL
SUPPORT SCATTERED SHOWERS WHICH CONTAIN LOCALLY HEAVY
RAINFALL...ESPECIALLY IN WINDWARD/MAUKA AREAS UNDER MODERATE
TRADES WHICH STRENGTHEN TO STRONG TRADES DURING THE LATTER PART OF
THE WEEK.
CONVECTION WITH WHAT HAD BEEN TROPICAL DEPRESSION 15E CONTINUED TO
MOVE WEST-NORTHWESTWARD ACROSS THE PACIFIC AND WAS SEVERAL
HUNDRED MILES SOUTH OF THE HAWAIIAN ISLANDS AS OF LATE MONDAY
EVENING. THIS SYSTEM WILL BE INCREASING CHANCES OF ORGANIZED
SHOWERS AND THUNDERSTORMS AND ASSOCIATED FLOODING DURING THE NEXT
SEVERAL DAYS. THE AREAL EXTENT OF FLOODING AND ANY CONCERN FOR
WIND-RELATED HAZARD WILL DEPEND UPON THE AMOUNT OF
STRENGTHENING/REORGANIZATION OCCURS AS THE CONVECTION MOVES INTO
MORE FAVORABLE ENVIRONMENTAL CONDITIONS.
MULTIPLE DETERMINISTIC ECMWF RUNS AND THE EC ENSEMBLE SPREAD SOME
DEGREE OF HEAVY RAIN AND STRONG WINDS ACROSS MUCH OF THE STATE,
WHILE THE RECENT GFS RE-CURVES A CLOSED SURFACE LOW WESTWARD TO
THE SOUTH OF THE BIG ISLAND...LIMITING THE IMPACTS MAINLY TO THAT
ISLAND.
AS A RESULT...HEAVY TO EXCESSIVE RAINFALL IS POSSIBLE AND
FLOODING WILL BE A CONCERN, AT LEAST FOR THE BIG ISLAND BUT
POSSIBLY ACROSS OTHER ISLANDS AS WELL WHILE THE CONCERN FOR STRONG
WINDS LOOKS MORE CONFINED TO THE SOUTHERN ISLANDS. STAY TUNED FOR
FORECAST UPDATES ON THE DETAILS. THE HIGHER MOISTURE VALUES LOOK
TO CLEAR OUT NEXT WEEKEND AND EARLY NEXT WEEK.
BANN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page