754
FXHW01 KWNH 160718
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 AM EDT SAT MAY 16 2026
VALID 00Z SUN 17 MAY 2026 - 00Z SUN 24 MAY 2026
THROUGH MONDAY, AS THE CLOSED MID-LEVEL LOW OPENS AND DRIFTS
FARTHER AWAY FROM THE STATE, THE THREAT/COVERAGE OF CONVECTION
WILL DECREASE. WHILE THE INSTABILITY DECREASES OVER THE WEEKEND,
LOW-LEVEL MOISTURE WILL INCREASE FROM THE SOUTHEAST WITH PWAT
VALUES APPROACHING 1.5-1.7+ INCHES. THIS MOISTURE SURGE IS
ASSOCIATED WITH A TROPICAL PLUME RIDING THE PERIPHERY OF A
STRENGTHENING RIDGE TO THE E-NE. PERIODS OF HEAVY RAIN WILL BE
POSSIBLE THROUGH THIS WEEKEND, WITH SOME ENHANCED SHOWERS
POSSIBLE ELSEWHERE ACROSS THE STATE. THE FLOW WILL REMAIN LIGHT-
MODERATE SOUTHEASTERLY THROUGH SUNDAY, WHICH MAY LEAD TO SOME
LEEWARD ENHANCEMENT AND LOCALIZED SEA-BREEZE CONVECTION OVER THE
SMALLER ISLANDS WHERE TERRAIN- INDUCED CONVERGENCE IS MAXIMIZED.
BY MONDAY, THE MOISTURE PLUME BEGINS TO SHIFT WESTWARD, AND THE
AIRMASS WILL SLOWLY START TO STABILIZE AS THE ULL LOSES ITS
INFLUENCE.
DURING THE MEDIUM RANGE (TUESDAY-SATURDAY), AS THE SURFACE HIGH TO
THE NORTH STRENGTHENS AND MIGRATES EASTWARD, THE PRESSURE GRADIENT
ACROSS THE CENTRAL PACIFIC WILL TIGHTEN. THIS WILL RESULT IN
MODERATE TO BREEZY EAST-NORTHEAST TRADES (15-25 MPH) TUESDAY AND
WEDNESDAY, AS PWAT VALUES DROP BACK TO 1.1-1.2" BY WED. THIS WILL
SHIFT THE RAINFALL DISTRIBUTION BACK TO THE CLASSIC WINDWARD AND
MAUKA FOCUS. BY NEXT WEEKEND, PWATS WILL DECREASE TO AROUND 1.0",
WHICH WOULD BE 1 TO 1.5 STANDARD DEVIATIONS BELOW NORMAL.
HURLEY
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