936
FXHW01 KWNH 020743
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 AM EST FRI JAN 2 2026
VALID 00Z SAT 03 JAN 2026 - 00Z SAT 10 JAN 2026
GENERAL PERSISTENCE IN THE FORECAST OVER THE NEXT 24-48 HRS WITH
PREVAILING EASTERLY TRADES STEMMING FROM THE SOUTHERN FLANK OF A
BROAD SURFACE RIDGE SITUATED WELL TO THE NORTH OF THE ISLAND
CHAIN. CONSISTENT EASTERLIES WILL AID IN SCATTERED ENHANCED
RAINFALL PROSPECTS WITHIN THE WINDWARD (EASTERN) SIDE OF THE
ISLANDS WITH GUIDANCE COMING INTO BETTER ALIGNMENT WITH THE
GREATEST PROSPECTS THROUGH MAUI AND THE BIG ISLAND, ESPECIALLY THE
EAST SIDE OF THE BIG ISLAND NEAR HILO. PWAT ANOMALIES BETWEEN
1-1.5 STANDARD DEVIATIONS ABOVE NORMAL WILL BE COINCIDENT WITH
RELATIVELY BETTER QPF OUTPUTS AS CUSTOMARY WITH A GENERAL 1-2",
LOCALLY HIGHER IN THE IMPACTED AREAS. THIS PATTERN WILL BE
CONSISTENT THROUGH SATURDAY BEFORE WE FINALLY SEE A SHIFT IN THE
SYNOPTIC PATTERN.
BY SUNDAY, INFLUENCE FROM A DEVELOPING CLOSED UPPER DISTURBANCE TO
THE NORTHWEST OF THE ISLAND CHAIN WILL BECOME APPARENT WITH
WEAKENING TRADES AND SIGNIFICANT UPTICK IN REGIONAL MOISTURE AS
THE SHIFTING PATTERN INITIATES A MORE ROBUST MID-LEVEL FLUX,
ESPECIALLY WHEN ASSESSING POINT SOUNDINGS FROM BOTH THE EC AND GFS
COMBOS, DICTATING A SURGE IN MOISTURE BETWEEN 700-500MB. 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. THERE'S STILL A BIT OF UNCERTAINTY
ON THE EXACT TRAJECTORY OF THE CLOSED ULL, BUT THE 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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