527
FXHW01 KWNH 200815
PMDHI
HAWAII EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
415 AM EDT THU AUG 20 2026
VALID 00Z FRI 21 AUG 2026 - 00Z FRI 28 AUG 2026
A WEAK WAVE OF LOW PRESSURE MOVING NORTH OF THE ISLANDS THURSDAY
AND FRIDAY SHOULD DISRUPT THE TRADES AND SLIGHTLY INCREASE
INSTABILITY OVER THE AREA. STILL LOOKING AT SCATTERED SHOWER
ACTIVITY, BUT MAY BE MORE SEA BREEZE AND TERRAIN INDUCED COMPARED
TO THE TYPICAL WINDWARD TRADE SHOWERS.
BY THE WEEKEND, THE FOCUS WILL SHIFT TO WHAT IS LIKELY TO BECOME
A TROPICAL CYCLONE APPROACHING FROM THE SOUTHEAST. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH A BROAD AREA OF LOW PRESSURE
CENTERED WELL EAST-SOUTHEAST OF THE ISLANDS CONTINUE TO BECOME
BETTER ORGANIZED AND WITH ENVIRONMENTAL CONDITIONS APPEARING
FAVORABLE, TROPICAL CYCLONE DEVELOPMENT APPEARS VERY LIKELY WITHIN
THE NEXT DAY. THE MAJORITY OF THE ENSEMBLE GUIDANCE CONTINUE TO
TRACK THE SYSTEM SOUTH OF THE ISLANDS THIS WEEKEND INTO EARLY NEXT
WEEK. HOWEVER, EVEN WITH A SOUTHERLY TRACK, STRONG EASTERLY FLOW
AND DEEPER MOISTURE NORTH OF THE SYSTEM ARE LIKELY TO BRING HEAVY
RAINS TO PARTS OF THE ISLANDS, WITH THE BIG ISLAND MOST LIKELY TO
SEE HEAVY TOTALS. THIS RAINFALL MAY PRODUCE SIGNIFICANT IMPACTS,
INCLUDING FLOODING AND MUDSLIDES, ESPECIALLY IN AREAS RECENTLY
IMPACTED BY LALA.
A RETURN TO MORE TYPICAL EASTERLY TRADES IS EXPECTED AS THE SYSTEM
IS LIKELY TO MOVE SOUTHWEST OF THE ISLANDS BY THE MIDDLE PART OF
THE WEEK.
PEREIRA
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