066
FXHW01 KWNH 210854
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
454 AM EDT SUN JUN 21 2026
VALID 00Z MON 22 JUN 2026 - 00Z MON 29 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 FOR THE NEXT DAY OR SO. 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 THIS
WEEK. BY WEDNESDAY THROUGH THE REMAINDER OF THE FORECAST PERIOD,
THE AFOREMENTIONED TROUGH IS EXPECTED TO BECOME CUT OFF AND SINK
SOUTHWARD AS THE SUBTROPICAL JET ALSO LIFTS NORTH. THIS MAY LEAD
TO ADDITIONAL RAIN CHANCES THROUGH LATE WEEK, AS HIGHLIGHTED BY
THE ECMWF EFI QPF VARIABLE WITH SOME LOW VALUES (0.5-0.7) FOR
WEDNESDAY INTO THURSDAY. ADDITIONALLY, AN INCREASE TOWARDS MORE
TYPICAL TRADE WINDS CAN BE EXPECTED AS WELL.
SNELL
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