FXHW01 KWNH 200717

PMDHI 



Hawaii Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

317 AM EDT Fri Mar 20 2026



Valid 00Z Sat 21 Mar 2026 - 00Z Sat 28 Mar 2026



...Prolonged wet pattern to continue into Monday across Hawai'i...



The guidance agrees on upper level troughing waxing and waning

over Hawai'i during the next week, though the degree of troughing

late next week remains an open question -- the 00z GFS may be a

too emphatic/too far south with an upper level low at that time 

range. 



The attendant front of a nearby surface low sweeps from west to 

east across the main islands from today into Monday as the parent 

cyclone escapes into the northeast Pacific. This system continues 

to disrupt trades in the short term and brings periods of 

heavy/excessive rainfall which supports the risk of life- 

threatening flash flooding and landslides over ground saturated by

recent prolific rains. As surface ridging builds from Tuesday 

onward to the north and northeast, rain chances/amounts fade as 

trade winds return.



Roth