Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
425 AM EDT Tue Mar 31 2020

Valid 00Z Wed Apr 01 2020 - 00Z Wed Apr 08 2020

...Heavy rain potential late this week into next week...

Relaxing pressure gradient will ease trades over the next couple
of days with precipitable water values ranging from 1.2 to 1.6
inches, favoring windward/mauka showers. By late Wed into Thu,
troughing south of the Aleutians will dig southward between along
170W to near 33-35N by 12Z Sun, which was a bit farther west than
24 hrs ago. The 00Z GFS/ECMWF/Canadian/UKMET all cluster close
together with the ensemble means showing a near -4 sigma
standardized height anomaly (500mb). This will increase the chance
of drawing deeper tropical moisture across at least part of the
region late this week but especially into next week as a cold
front approaches then likely stalls just to the northwest of the
area. By next Mon-Tue, the 00Z ECMWF/Canadian were a bit quicker
to bring the upper low back east to start to rejoin the westerly
flow while the GFS was slower by about 24 hrs. This may drag the
front toward or into Kauai by then but the ECMWF was actually on
the faster side of all the ensembles. Prefer a middle ground for
now given the uncertainty in the pattern.


Fracasso