709
FXHW01 KWNH 200841
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
441 AM EDT SAT JUN 20 2026
VALID 00Z SUN 21 JUN 2026 - 00Z SUN 28 JUN 2026
FORECAST REMAINS ON TRACK AS AN UPPER-LEVEL TROUGH LOCATED TO THE
NORTH OF THE ISLANDS START OF THE PERIOD AND A SURFACE FRONT
POSITIONED WELL TO THE NORTHWEST. THIS WILL COMBINE TO DISRUPT
THE TYPICAL TRADE WIND INVERSION, RESULTING IN LIGHT SURFACE WINDS
ACROSS THE REGION UNTIL EARLY NEXT WEEK. AS THE INITIAL UPPER
TROUGH CONTINUES TO BE POSITIONED TO THE NORTH OF THE STATE, THE
SURFACE BOUNDARY IS EXPECTED TO REMAIN IN PLACE AND DRIFT CLOSER
TO THE ISLANDS AS SHORTWAVE ENERGY MOVING THROUGH THE WESTERLIES
PROVIDES UPPER- LEVEL SUPPORT TO AMPLIFY ANOTHER TROUGH NORTH-
NORTHEAST OF THE STATE BY TUESDAY. THIS CONFIGURATION MAY FAVOR A
SHIFT TO A MORE NORTHEASTERLY FLOW OVER THE ISLANDS EARLY NEXT
WEEK. BY THE LATTER HALF OF THE FORECAST PERIOD, THE
AFOREMENTIONED TROUGH MAY CUT OFF AND SINK SOUTHWARD AS THE
SUBTROPICAL JET ALSO LIFTS NORTH. THIS MAY LEAD TO ADDITIONAL RAIN
CHANCES BY LATE WEEK, AS HIGHLIGHTED BY THE ECMWF EFI QPF
VARIABLE WITH SOME LOW VALUES FOR THE BIG ISLAND AND MAUI FOR
WEDNESDAY INTO THURSDAY.
SNELL
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