Warnings
None

Cloud Cover and Precipitation Forecast
The summit will remain dry and stable through the night. Banding high clouds dropping down from the north will likely result in extensive cloud cover particularly during the latter half of the night.

Summary of Key Meteorological Variables
Summit temperatures will be near 3 C this afternoon and -1 C for the night. Winds will be from the north at 5-15 mph, with seeing likely around 0.8-0.9 arcseconds. Precipitable water is expected to be in the 1.25-1.75 mm range for the first half of the night and 1.5-2 mm range for the second half.

Discussion
The tradewind inversion will continue to cap the fairly limited supply of low-level moisture near 8 thousand feet and keep the summit-level air mass quite stable and likely free of extensive fog throughout most of the forecast period. However, there is a chance that humidity will increase toward 60-80% and perhaps short-lived fog and/or light precipitation as a band of mid/upper-level moisture sweeps through the area tomorrow night. The air mass is expected to dry out on Thursday, which should help drop humidity and the risk for fog/precipitation thereafter. Extensive afternoon clouds are possible through Thursday, but should taper for the weekend.

A band of high clouds dropping down from the north is expected to rapidly sweep through the Big Island primarily during the latter half of tonight. While these clouds should slip southeastward tomorrow afternoon, broken mid-level clouds will likely move through the area for that night. These clouds should also drop southeastward and breakdown on Thursday, leaving isolated to scattered mid/high clouds primarily along the northeastern skies for the remainder of the forecast period.

Precipitable water is expected to linger near 1.5-2 mm for tonight, then increase to 3-4+ mm for the remainder of the forecast period.

Lingering mesoscale turbulence aloft will likely result in poor/variable seeing for much of tonight. Although this turbulence is slated to shift eastward tomorrow morning, more mid-level turbulence and moisture dropping down from the north will probably allow the poor/variable seeing to continue for that night. Seeing is slated to gradually improve as this moisture/turbulence tapers over the next couple of nights. In fact, there is a good chance for good/excellent seeing for much of the weekend.

Although the mid-level ridge is expected to sag southward as a westerly trough passes far to the north over the next several days, the ridge is not slated to drop south of the Big Island at any time. Consequently, it will continue to promote strong large-scale subsidence in the region and maintain the tradewind inversion near 8 thousand feet well into next week. Unfortunately, this passing trough will still send the mid and upper portion of a dissipating cold front through the Islands over the next two nights. The latter half is expected to precede the former by sending broken high clouds through the area for tonight. Although these clouds should rapidly shift eastward late tomorrow morning, the mid-level portion is slated to arrive late tomorrow afternoon in the form of scattered to broken mid-level clouds and moisture. This moisture/clouds may increase humidity toward 60-80%, and could result in short-lived fog and precipitation for that night. The atmosphere is slated to gradually dry out as a deep mid/upper-level ridge fills in from the west starting Thursday morning, which should lead to more normal-like conditions for the weekend. While this ridge is not expected to sit directly over the state (but rather to the north), it will eventually promote deep northerly flow near the Big Island, which should result in good/excellent seeing for that time as well.

Astronomical Observing Quality Guidance
Seeing/CN² Images are not available today. Sorry for the inconvenience.