859
FXHW01 KWNH 040802
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
302 AM EST WED FEB 4 2026
VALID 00Z THU 05 FEB 2026 - 00Z THU 12 FEB 2026
...POTENT WINTER SYSTEM TO IMPACT THE ISLANDS THIS WEEKEND WITH
HEAVY RAINFALL AND GALE FORCE TRADE WINDS...
THE FORECAST PERIOD BEGINS WITH A BRIEF LULL IN ACTIVITY, AS A
TRANSIENT, LOW-AMPLITUDE RIDGE TRAVERSES THE CENTRAL PACIFIC,
PROVIDING A SHORT WINDOW OF STABLE CONDITIONS AND LIGHT WINDS ON
THURSDAY. HOWEVER, AS EXPECTED THE UPPER LEVEL PATTERN IS
EXPECTED TO AMPLIFY SIGNIFICANTLY BY FRIDAY AS A DEEP LONGWAVE
TROUGH DIGS TOWARD THE ISLANDS FROM THE NORTHWEST. AS THIS OCCURS,
A COLD FRONT WILL MOVE INTO THE WESTERN ISLANDS LATE FRI INTO
SAT. THE TIGHTENING PRESSURE GRADIENT BETWEEN THIS FRONT AND THE
STRONG HIGH BUILDING TO THE NORTH WILL LEAD TO STRONG, POTENTIALLY
GALE- FORCE TRADE WINDS. AS NOTED THE PAST COUPLE OF DAYS, THE
INTERACTION BETWEEN THE DIGGING UPPER TROUGH AND THE SURFACE
BOUNDARY WILL LEAD TO AN EXTENDED PERIOD OF KONA-LIKE CONDITIONS
WITH DEEPENING MOISTURE, PWATS INCREASING TO AOA 1.75 INCHES, AND
THUS MORE FREQUENT SHOWERS AND THUNDERSTORMS WITH BOUTS OF HEAVY
RAINFALL BEFORE STRONG EASTERLY TRADES STABILIZE THE PATTERN EARLY
NEXT WEEK.
IN TERMS OF THE GUIDANCE, THE LATEST OPERATIONAL GLOBAL MODELS
ARE IN REASONABLE AGREEMENT INTO EARLY NEXT WEEK. THIS LEADS TO
INCREASED FORECAST CONFIDENCE OF A RATHER UNSETTLED, WET FORECAST
WITH THE COLD POOL ALOFT (-15C AT 500 MB) AND A STALLED SURFACE
FRONT, PARTICULARLY OVER THE WESTERN AND CENTRAL ISLANDS IN TERMS
OF COVERAGE/FREQUENCY AND AMOUNTS WITH THE SHOWERS AND
THUNDERSTORMS.
HURLEY
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