Last Updated on Saturday, 07 December 2013 07:21
Winds Statewide in a glance ...just go HERE(this link is also the 4th drop down under weather)
Dec 07, 2013 4:00 AM HST
Winds will veer out of the southeast today, leading to another round of sea breezes with afternoon clouds and interior showers. Deep moisture will move up from the south late tonight and will affect mainly the Big Island Sunday and Monday. The rest of the state can expect a dominant land and sea breeze pattern producing afternoon clouds and showers, though there will be a chance of passing showers moving up from the south at any time. Expect increasing humidity and volcanic haze statewide. Trade winds will rebuild Tuesday and Wednesday.
DiscussionModerate trades in place now will rapidly veer out of the southeast today as a strong front moving well northwest of the state pushes a surface ridge down toward the islands. Modest windward shower activity this morning will give way to a convective pattern this afternoon as sea breezes develop. Expect afternoon clouds and a chance of showers for interior and mauka areas. Midlevel ridging will continue to produce stable conditions over the smaller islands with some weakening over and south of the Big Island. The overnight soundings show this trend already underway with the inversion up near 9000 ft at Hilo. As a result, there could be a few heavier showers on the Big Island slopes this afternoon.
An increase in clouds and showers is expected mainly over the Big Island on Sunday and Monday. An upper level low currently centered 800 miles south of Oahu is enhancing showers and thunderstorms along the ITCZ about 375 miles south of the Big Island. The combination an amplifying ridge at the surface and aloft along 140°W and deep troughing northwest of the state will cause deep moisture to be drawn northward over the eastern end of the island chain as early as late tonight. Midlevel ridging will be eroded with 500 mb temps dropping as low as -9C, probably not cold and unstable enough for heavy showers and thunderstorms. The Big Island can expect layered clouds with showers focused on southeast slopes.
Across the western end of the state, expect gentle south to southeast winds to bring spotty showers, increased humidity, and volcanic haze up from the south. Daytime sea breezes will also produce afternoon clouds and a chance of showers over interior and mauka sections.
Trade winds will make a return on Tuesday as the front to the north weakens and lifts out and the layered moisture near the Big Island dissipates. A following high passing about 800 miles north of the islands will drive the return of the trades, and building ridging aloft will produce increasingly stable conditions. Thus, a return to a typical windward and mauka shower pattern is expected.
In the long range, the latest runs of the GFS and and ECMWF are backing off on predictions of a return to southeasterly flow on Thursday. The current forecast still calls for the southeasterly winds to redevelop, but we have trended back to trade winds by Friday.