163
FXHW01 KWNH 250834
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
334 AM EST THU DEC 25 2025
VALID 00Z FRI 26 DEC 2025 - 00Z FRI 02 JAN 2026
AN UPPER-LEVEL RIDGE CENTERED OVER THE ISLANDS WILL MAINTAIN
STABLE CONDITIONS AT THE START OF THE PERIOD, WHILE A ROBUST
SURFACE HIGH TO THE NORTH CONTINUES TO DRIVE THE SYNOPTIC PATTERN.
SIMULTANEOUSLY, THE SURFACE HIGH WILL MIGRATE EAST, ALLOWING THE
PRESSURE GRADIENT TO RELAX AND SURFACE WINDS TO VEER TO A MORE
SOUTHEASTERLY DIRECTION. THIS TRANSITION WILL INTRODUCE A
RELATIVELY DRIER AIRMASS FROM THE EAST THAT WILL REMAIN IN PLACE
INTO THE WEEKEND.
THE PATTERN IS EXPECTED TO TRANSITION OVER THE WEEKEND AS THE
UPPER RIDGE SHIFTS EASTWARD, AND BY MONDAY, AN UPPER-LEVEL TROUGH
IS FORECAST TO MOVE ACROSS THE CENTRAL PACIFIC NORTH OF THE
STATE. THIS FEATURE WILL PUSH A COLD FRONT TOWARD THE WESTERN
ISLANDS. WHILE MODEL GUIDANCE REMAINS UNCERTAIN REGARDING THE
PRECISE TIMING OF THIS BOUNDARY, THE GENERAL CONSENSUS FAVORS THE
FRONT STALLING AND WEAKENING IN THE VICINITY OF THE WESTERN
ISLANDS DURING THE FIRST HALF OF THE WEEK. AHEAD OF THIS FEATURE,
THE GLOBAL GUIDANCE SHOWS AN UPTICK IN PWATS, LIKELY APPROACHING
OR EXCEEDING 1.5+ INCHES, AS ML CAPES LIKELY REACH 250-500+ J/KG.
THIS WILL BRING AN INCREASED RISK FOR SHOWERS DURING THE EARLY
PART OF NEXT WEEK, FOLLOWED BY A RETURN TO MORE STANDARD
NORTHEASTERLY TRADES AS HIGH PRESSURE AND A DRIER REGIME BUILD
BACK ACROSS THE ISLANDS TO START OFF THE NEW YEAR.
HURLEY
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