Strong trades tonight and Tuesday will ease during late week eventually veering to southeasterly. A band of showers will focus showers primarily windward and mauka tonight.
Longwave ridging centers over the islands through late this week in maintenance of a rather transient period of trade wind weather. A brief period of strong trades anchored along the lead edge of building high pressure will sweep through the area tonight through Tuesday bringing with it a convergent band of showers. This band is seen on afternoon visible imagery immediately offshore and approaching the islands from the east and is poised to arrive late this evening. Solid presentation on satellite suggests a high coverage of showers some of which be ushered leeward at times by strengthening trades within a weakly stable boundary layer.
Progression of mid-latitude troughing across the N Central Pacific then ushers governing high pressure east causing trades to weaken through midweek then veer to SE this weekend. The gradient over the western end of the state further weakens as attendant surface pressure falls spread eastward potentially favoring a couple days of a land/sea breeze pattern over the smaller islands early next week.
Modeling suggests the Pacific jet will once again nose into the lower latitudes in the introducing potential for low pressure west of the islands and a potentially more active pattern reemerging by mid/late next week.
.AVIATION,
Breezy trade winds continue across Hawaii into Tuesday. AIRMET Tango for tempo moderate turbulence downwind of terrain on all islands below 8000 feet will likely continue through then.
Increasing showers late tonight as an old boundary embedded in the trade wind flow brings MVFR ceilings and visibility to most windward areas. AIRMET Sierra has been posted for tempo mountain obscurations above 2500 feet this afternoon, with other islands expected to be included in AIRMET Sierra tonight. Brief mountain obscurations may also occur as clouds and showers pass to leeward sides of the smaller islands at times. Expect improving conditions to VFR Tuesday morning.
Breezy trade winds continue across Hawaii into Tuesday. AIRMET Tango for tempo moderate turbulence downwind of terrain on all islands below 8000 feet will likely continue through then.
Increasing showers late tonight as an old boundary embedded in the trade wind flow brings MVFR ceilings and visibility to most windward areas. AIRMET Sierra has been posted for tempo mountain obscurations above 2500 feet this afternoon, with other islands expected to be included in AIRMET Sierra tonight. Brief mountain obscurations may also occur as clouds and showers pass to leeward sides of the smaller islands at times. Expect improving conditions to VFR Tuesday morning.
Fresh to strong easterly trade winds will prevail through Tuesday night. Trades have held in the moderate to locally strong range today as robust high pressure far north-northwest of the islands drifted eastward and broad area of low pressure northwest of Kauai remained nearly stationary. Trade winds will increase overnight as a band of moisture moves over the area from the northeast, with widespread fresh to strong winds holding through Tuesday night. A Small Craft Advisory (SCA) remains in effect for the typically windy waters around Big Island and Maui and will expand to most waters tonight as winds and seas increase. The high will weaken as it passes north of Hawaii on Wednesday, and the low to the northwest will lift northward, leading a gradual decline in trade winds locally. Winds may decline further and shift out of the southeast late Friday and Saturday as the low redevelops and pushes a surface ridge toward Kauai.
A small north swell will continue to gradually decline into Wednesday. A moderate, medium period north-northeast (010-030 degrees) swell will arrive late Wednesday and peak Thursday and Friday. Surf along north facing shores could approach the High Surf Advisory level during the peak, with the largest swells favoring the eastern end of the island chain, and a Marine Weather Statement may be needed for harbor surges at Kahului and Hilo. The north swell will decline over the weekend as a small northwest swell arrives.
For east facing shores, wrapping north swell will produce small surf across exposed coastlines tonight, while building trade winds lead to an increase in short period trade wind energy. Breezy trades will produce rough conditions above seasonal average Tuesday and Wednesday. Short period trade wind swell will decline by Christmas, but wrapping northerly swell will affect exposed eastern shores into Friday. Surf along south facing shores will remain very small through the week.
Small Craft Advisory from 6 PM this evening to 6 PM HST Tuesday for Kauai Northwest Waters-Kauai Windward Waters-Kauai Leeward Waters-Kauai Channel-Oahu Windward Waters-Oahu Leeward Waters- Kaiwi Channel-Maui County Windward Waters-Maui County Leeward Waters.
Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.
