textproduct: Honolulu

SYNOPSIS

A high pressure system far to the northeast of the state will keep trade wind weather in the forecast through much of this week. We are closely monitoring an area for potential tropical cyclone development roughly 1100 miles east-southeast of the Hawaiian Islands. Based on the latest Tropical Weather Outlook from the National Hurricane Center, further development is expected by the middle of this week. The long range Hawaii forecast could change dramatically if this system moves towards the islands.

DISCUSSION

A high pressure system far to the northeast of the state will keep trade wind weather conditions blowing through much of this week. A weak easterly wave (low level trough) moving through the islands continues to produce some unsettled clouds drifting in on the trade winds. This low level trough will continue to enhance showers, as it drifts from east to west across the state, favoring the windward mountain areas tonight before passing west of the island chain. Drier weather trends with brief passing showers are forecast from Wednesday through Friday.

We are closely monitoring a large area of disorganized convection for potential tropical cyclone development roughly 1100 miles east-southeast of the Hawaiian Islands. Based on the latest Tropical Weather Outlook from the National Hurricane Center issued at 2 AM HST, environmental conditions are conducive for further development of this system into a tropical cyclone by the middle of this week. The long range Hawaii forecast for this upcoming weekend could change dramatically if this system develops and then moves towards the islands. Stay tuned for the latest updates on this developing tropical cyclone from the National Hurricane Center online at www.hurricanes.gov and your favorite local media outlets.

AVIATION

Fresh trades expected for the next several days. Low cigs and SHRA expected over windward and mauka locations. IFR/MVFR conds possible in heavier SHRA, otherwise VFR should prevail.

AIRMET Sierra is in effect for mtn obsc for windward areas of all islands due to a steady stream of showers carrying in with the trades.

AIRMET Tango is in effect for mod turb lee of terrain due to wind speeds.

MARINE

High pressure to the far northeast will remain nearly stationary through midweek as moderate to locally strong trade winds persist through Wednesday. The Small Craft Advisory (SCA) has been extended through Tuesday afternoon for the windier waters and channels around Maui County and the Big Island. Borderline conditions will likely continue through at least Wednesday, which may prompt further extensions of the SCA. Later in the week, the focus will shift to the deep tropics southeast of the state. Latest guidance from the National Hurricane Center has a high chance in 7 days for a tropical cyclone to form southeast of the islands. Depending on the track, it will have differing effects on local winds, seas and weather as early as Thursday. Northeasterly winds appear likely to strengthen as the cyclone approaches during the latter half of the week, but impacts will be highly track-dependent and there is significant forecast uncertainty at this time.

Surf along south facing shores will remain near the August average today as overlapping south swells impact the islands. Surf builds slowly through the week. A moderate, long period south swell is expected to arrive late Tuesday, fill in Wednesday, and remain elevated through Friday. Surf may approach advisory levels at the peak of the swell.

Surf along east facing shores will continue to remain moderate and rough due to moderate to locally strong trade winds. Later in the week, the track of a developing tropical cyclone will dictate the potential for a swell from the southeast to east. Aside from wrapping trade wind energy, surf along north-facing shores will remain flat to tiny through the week.

Due to a combination of peak monthly high tides and water levels running higher than predicted in a few locations, a Coastal Flood Statement is in effect for minor coastal flooding around the afternoon high tide through at least Tuesday. Tides will be decreasing on Wednesday, but coastal flooding may continue to be possible around high tide for locations where water levels are running highest.

FIRE WEATHER

Fire weather conditions this week will remain just below critical thresholds this week due to the lack of stronger wind speeds. Minimum humidity levels will briefly reach criteria each day over the driest leeward areas and the lower sustained wind speeds will be the limiting factor. Temperature inversion heights near Maui and the Big Island will range from 5,500 to 6,500 feet elevation today.

HFO WATCHES/WARNINGS/ADVISORIES

Small Craft Advisory until 6 PM HST Tuesday for Maalaea Bay- Pailolo Channel-Alenuihaha Channel-Big Island Leeward Waters-Big Island Southeast Waters.