596
FXHW01 KWNH 180751
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
351 AM EDT MON MAY 18 2026
VALID 00Z TUE 19 MAY 2026 - 00Z TUE 26 MAY 2026
EARLY IN THE FORECAST PERIOD, THE BROAD AND RELATIVELY FLAT
MID/UPPER LEVEL TROUGH WILL LINGER, MAINTAINING MODEST MID- LEVEL
INSTABILITY. THIS COMBINED WITH THE SLIGHTLY VEERED
(SOUTHEASTERLY) LOW-LEVEL FLOW WILL MAINTAIN HIGHER PWAT VALUES
(1.5 TO 2.0") THROUGH EARLY WED. AS A RESULT POPS WILL REMAIN
ELEVATED (GENERALLY 50-70%) TUE THROUGH EARLY WED ACROSS
WINDWARD SLOPES. LATER WED AFTERNOON, DIURNAL ACTIVITY WILL
BECOME MORE INFREQUENT AND ISOLATED AS HIGH PRESSURE BUILDS IN
FROM THE NORTH AND SURFACE WINDS BACK TOWARDS THE MORE TYPICAL
E-NE TRADE WIND PATTERN.
THE STABLE AND PERSISTENT E-NE TRADES WILL REMAIN LOCKED IN THU
THROUGH EARLY NEXT WEEK, AS THE BROAD 1032+ MB SURFACE HIGH
CENTERED WELL N-NE OF THE ISLANDS WILL MAINTAIN MODERATE TO
LOCALLY STRONG TRADES (15-25 MPH WITH HIGHER GUSTS). DEEP-
TROPOSPHERIC STABILITY AND SEASONABLY DRIER AIRMASS (PWAT VALUES
NEAR 1.0-1.2") WILL PERSIST AS WELL, MAINTAINING POPS NEAR
CLIMATOLOGICAL NORMS WITH THE HIGHLY-PREDICTABLE SPATIAL AND
DIURNAL DISTRIBUTION OF FAST-MOVING TRADE SHOWERS. POPS WILL RANGE
FROM 30-50% OVER WINDWARD SLOPES AND GENERALLY LESS THAN 15%
ACROSS LEEWARD AREAS.
HURLEY
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