####018001903####
FXHW01 KWNH 090756

PMDHI 



Hawaii Extended Forecast Discussion

NWS Weather Prediction Center College Park MD

355 AM EDT Tue Apr 09 2024



Valid 00Z Wed Apr 10 2024 - 00Z Wed Apr 17 2024



Continue to expect weakening trades to turn southeasterly by

Wednesday as a deep-layer low closes off northwest of the main

islands with a front/convergence axis extending south from the

surface low.  The upper low should achieve its most southern

latitude around early Friday and then lift northeastward,

ultimately being replaced by another upper low near 40N.  The

upper trough axis anchored by these lows should begin to drift

eastward by Sunday-Tuesday, pushing the surface front eastward

into the western and possibly central main islands during the

first half of next week.  The overall pattern will support a

northward surge of moisture, likely bringing precipitable water

values to 1.5 inches or higher for multiple days after midweek. 

Dynamical guidance and ECMWF-initialized machine learning models

still suggest that the system's trailing surface boundary will

focus an axis of potentially heavy rainfall over or just west of

Kauai and vicinity from Thursday onward.  Effects over the western

islands continue to be sensitive to exact longitude of the heavy

rain axis, with no clear clustering/trending yet to emerge within

the overall guidance envelope.  There is reasonable agreement

toward gradual eastward progression of the surface feature and

supporting upper trough by Sunday into the early part of the next

work week, which would spread rainfall over more of the western

half of the islands and perhaps eventually bring some drier air

into the far western islands.  There is typical spread for how

much eastward progress there is, with an intermediate solution

providing a reasonable starting point.



Rausch



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