487
FXHW01 KWNH 260710
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
310 AM EDT THU MAR 26 2026
VALID 00Z FRI 27 MAR 2026 - 00Z FRI 03 APR 2026
A BROAD UPPER-LEVEL TROUGH POSITIONED NORTHEAST OF THE HAWAIIAN
ISLANDS WILL GRADUALLY PULL AWAY AS A NEW UPPER-LEVEL TROUGH AND
ASSOCIATED CLOSED LOW OVER THE CENTRAL PACIFIC DIGS SOUTHEASTWARD
NORTH OF THE STATE BY THE END OF THE WEEK. THIS EVOLUTION WILL
MAINTAIN BELOW-NORMAL HEIGHTS OVER THE REGION THROUGH THIS
WEEKEND. HOWEVER, THE STRONGEST FORCING AND ENERGY ASSOCIATED WITH
THESE RELOADING HEIGHT FALLS ARE FORECAST TO REMAIN NORTH AND
EVENTUALLY NORTHEAST OF THE ISLANDS. CONSEQUENTLY, SURFACE LOW
PRESSURE EAST OF HAWAII NEAR 150W IS EXPECTED TO STAY WELL AWAY
FROM THE REGION. THERE IS STRONG MODEL AGREEMENT REGARDING THE
MASS FIELDS OVER THE NEXT 5 DAYS, PARTICULARLY CONCERNING THE
DEVELOPMENT AND PERSISTENCE OF A DEEP LAYER RIDGE BETWEEN 160W
AND 175W. THIS PATTERN WILL ALLOW FOR A SURFACE RIDGE TO SETTLE
SOUTH OVER THE ISLANDS THROUGH THE WEEKEND AND INTO NEXT WEEK.
NORTHEASTERLY TRADE WINDS WILL TEND TO VEER BY EARLY NEXT WEEK AS
THE SURFACE RIDGE NORTH OF THE ISLANDS SHIFTS FARTHER EASTWARD.
THE ATMOSPHERE REMAINS RELATIVELY STABLE WITH THE TRADE WIND
INVERSION LIKELY TO HOLD BETWEEN 5000 AND 7000 FEET WHICH WILL
TEND TO CAP THE VERTICAL GROWTH OF CLOUDS. WHILE THE MULTI-MODEL
CONSENSUS PRECLUDES ANY ORGANIZED THREAT OF HEAVY RAINFALL OVER
THE NEXT 7 DAYS, SCATTERED SHOWERS WILL REMAIN POSSIBLE FOR
WINDWARD SLOPES THROUGH THE PERIOD. THE GREATEST POTENTIAL FOR
THESE SHOWERS WILL BE OVER THE WINDWARD SLOPES OF THE BIG ISLAND
AS SHALLOW MOISTURE REMAINS EMBEDDED IN THE TRADE FLOW. LEEWARD
LOCATIONS SHOULD REMAIN MOSTLY DRY UNDER THIS REGIME, WITH ONLY
MINIMAL TRADE SHOWERS DRIFTING OVER THE TERRAIN DURING THE
OVERNIGHT HOURS.
ORRISON
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