354
FXHW01 KWNH 030753
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
253 AM EST SAT JAN 3 2026
VALID 00Z SUN 04 JAN 2026 - 00Z SUN 11 JAN 2026
OVERALL SYNOPTIC PATTERN WILL MAINTAIN AT LEAST A SHORT PERIOD OF
PERSISTENCE HEADING INTO SATURDAY WITH PREVAILING EASTERLIES
PROVIDING SOME ENHANCED SHOWER ACTIVITY WITHIN THE EASTERN
PERIPHERY OF MAUI AND THE BIG ISLAND. HIGH PRESSURE TO THE NORTH
WILL BECOME LESS OF A FACTOR SATURDAY EVENING AS THE UPPER PATTERN
ACROSS THE PACIFIC BECOMES MORE AMPLIFIED WITH A MID-LEVEL
DISTURBANCE FORECAST TO EMERGE ON THE SOUTHERN FLANK OF THE RIDGE
AND BEGIN TO CLOSE OFF AS IT MIGRATES TO THE NORTHWEST OF HAWAII.
BY SUNDAY, INFLUENCE FROM THE DEVELOPING CLOSED UPPER DISTURBANCE
TO THE NORTHWEST OF THE ISLANDS WILL BECOME APPARENT WITH
WEAKENING TRADES AND SIGNIFICANT UPTICK IN REGIONAL MOISTURE AS
THE SHIFTING PATTERN INITIATES A MORE ROBUST MID-LEVEL FLUX AS
EVIDENT BY THE SURGE IN MOISTURE BETWEEN 700-500MB IN THE GLOBAL
DETERMINISTIC OUTPUT(S). THIS WILL ALLOW FOR SIGNIFICANTLY
GREATER COVERAGE IN RAINFALL POTENTIAL WITH THE WESTERN HALF OF
THE ISLAND CHAIN BECOMING THE MOST SUSCEPTIBLE TO HEAVIER PRECIP
GIVEN THEIR PROXIMITY TO THE APPROACHING UPPER DISTURBANCE. LESS
SPREAD EXISTS WITHIN DETERMINISTIC GUIDANCE, BUT THERE IS STILL
SOME MOVEMENT IN THE HEIGHT FIELDS AS MODELS TRY TO DISCERN THE
LONGITUDINAL SHIFT AS THE ULL TRACKS CLOSER TO HAWAII'S LATITUDE.
REGARDLESS OF THE TRACK OF THE DISTURBANCE, PROSPECTS FOR HEAVY
RAINFALL ACROSS THE WESTERN ISLANDS AND THE SOUTHERN COASTS OF
MAUI/BIG ISLAND ARE MUCH HIGHER THAN THE PREVIOUS SEVERAL DAYS.
THIS PATTERN WILL LIKELY LINGER INTO MID- WEEK BEFORE THE UPPER
FEATURE BREAKS DOWN AND WE GET A BIT OF RELAXATION INTO THE SECOND
HALF OF THE PERIOD.
KLEEBAUER
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