Maui on Friday what am I looking at PPK?
Mahalo
Honolulu, HI
Weather Forecast Office
Area Forecast Discussion for Hawaii
Weather.gov > Honolulu, HI > Hawaii > Area Forecast Discussion
Issued: Feb 12, 2019 3:53 AM HST
Synopsis
The northerly winds will be shifting to the north-northeast today then northeast tonight as the surface low lifts out further away from the islands and a strong surface high builds in far to the north of the islands. A wet trade pattern is likely for the islands between tonight and Thursday as a band interact with another cold upper level disturbance. There is a high degree of uncertainty for the upcoming weekend weather, but we are looking at a drier trade wind regime, although the trades will still be breezy.
Discussion
The culprit of yesterday's weather, a strong surface low, is now located some 740 miles NE of Maui, heading NE toward California. A strong high pressure cell of 1036mb, currently far NNW of Kauai, will be moving southeastward in the next 48 hours, then eastward after 48 hours. This will result in the winds shifting to the NNE today, then to the NE tonight, and hold through Friday. A trough is forecast to form some 750 miles NE of Maui over the weekend, thus maintaining the NE trade winds over the weekend. The NE trades will be strengthening through tonight across the smaller islands, then reaching the Big Island Wednesday night. There is some hint of the trades trending slightly lower over the weekend, but that remains to be seen.
While it is pretty much back to normal at the lower elevations, it remains windy at the top of the Big Island summits. The High Wind Warning remains in effect for the Big Island summits through 6 pm HST this afternoon. Currently, speeds are down from earlier in the evening but still estimated in the low end warning range of around 50 mph.
In the way of showers, we currently have an area of scattered showers moving through the islands from the north and northwest. These showers should ease off later this morning. A band of enhanced showers has becoming noticeable on satellite in the past couple of hours, located 350 miles N of Oahu. It is moving south at 20 mph, making the arrival time of early this evening for Kauai, and the rest of the smaller islands overnight tonight, and the Big Island Wednesday morning. Models have this band stalled over the islands through Thursday. As noted, the showers looks enhanced, so locally heavy showers is a good possibility at this time. These showers will be supported by a cold pool of air at the higher levels. So as the upper disturbance drops down on the islands on Wednesday, the freezing level is expected to lower from the current 12k feet to as low as 9k feet Wednesday afternoon and evening. Some wintery weather is expected, especially for the Big Island summits, and may be Haleakala on Maui. I won't rule out a slight chance of a thunderstorm for Maui and the Big Island, but we will see. We will be keeping a close tab on this developing situation.
The weekend forecast will be challenging as well. The ECMWF and GFS differs, with the EC developing a surface low over the island chain between Friday night and Saturday, while the GFS has a surface trough some 700 miles east of the Big Island. We are siding with the GFS at this point, but this subject to change. More to come.
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