Warnings
Blizzard-like conditions.

Cloud Cover and Precipitation Forecast
Moderate to heavy snow, ice, thick clouds, extensive fog, and thunderstorms will plaque the summit tonight.

Summary of Key Meteorological Variables
Summit temperatures will be near -4 C tonight and -6 C tomorrow morning. Precipitable water is expected to > 10 mm for the night. Summit winds will exceed 50 mph, with shear near 10 to 20 mph.

Discussion
The atmosphere near the summit is expected to be saturated and unstable for the next 24 hours. As a result, moderate to heavy snow, extensive fog, thunderstorms and ice are all penciled in for tonight and possibly into noon tomorrow. The inversion is still projected to briefly build in at 6-8 thousand feet while summit-level humidity plummets toward 20% for Saturday night and possibly Sunday night. While this would normal call for dry and stable conditions, I still say there is a reasonable chance for periodic fog and ice on those nights due to the close proximity of wet/unstable conditions (although Sunday night will likely be slightly drier). Minor instability is expected to build in aloft while more mid/low-level moisture moves in from the southeast during the early part of next week. Thus, the odds on fog and precipitation will increase slightly for Monday and Tuesday night.

Thick clouds will block all of the sky for tonight, with most of these clouds drifting east of the Big Island after noon tomorrow. Thus, only residual summit/mid-level clouds will likely linger in the area for Saturday night. These clouds should be very minimal and short-lived as strong winds will tend to tear them apart. However, another patch of post-frontal scattered mid/upper-level clouds are expected to build in just west and/or over the summit for Sunday night. In addition to this, some mid/low-level clouds may start to move in from the east for Sunday and Monday night. These two features may increase cloud cover slightly for those nights. More high clouds are expected to become more organized to the southwest and possibly move over the summit next week Tuesday and especially Wednesday night.

Precipitable water is expected to increase to more than 10 mm for tonight then rapidly decline toward 1-2 mm for Saturday night. Again, there is still a bit of uncertainty for Saturday night's forecast, in which case PW could be much more than the given value. PW is projected to increase to 2-3 mm for Sunday, 4-6 for Monday night, and then drop toward 3-4 mm for Tuesday night.

Observing won't be possible tonight (due to the blizzard-like conditions) and probably tomorrow night (due to the winds and the possibility for fog). Nonetheless, expect bad/lousy seeing due to wind shake and slight instability/turbulence aloft for Saturday night. Improving conditions (i.e. drop in winds) and weak to moderate shear/turbulence in the free atmosphere will likely make for average seeing for the following three nights.

A relatively strong cold front will continue to march southeastward and through the Island chain during the next 24 hours. While the front is still located just west or over Kauai at the moment, strong/deep convection ahead of the front is beginning to move through the Island of Maui. These thunderstorms are expected to remain quite intense as it crosses over the Big Island tonight. As a result, blizzard-like conditions, with moderate to heavy snow (probably down toward 11 thousand feet), ice, extensive fog, poor visibility, and high winds are all penciled in for tonight. The front is slated to drift barely east of the Big Island as its' parent low catches up with it and briefly stalls over or just north of the Islands tomorrow afternoon/evening. While this would normally call for dry/stable air at the summit as the front passes, the close proximity of the low will help to keep the atmosphere near the Big Island somewhat unstable (and possibly saturated), making fog and/or isolated thunderstorms a possibility for Saturday night (and maybe Sunday night). It probably won't matter, because the strong southwesterly winds will likely make observing very difficult, if not impossible, on Saturday night. Conditions could improve slightly as the low lifts off toward the north (which will help to decrease the winds and stabilize the environment) and a brief slot of dry air moves over the summit for Sunday night. However, another blast of cold air/instability is slated to build aloft during the early half of next week. At the same time, tonight's passing front will begin to retrograde westward (back with the strengthen trades) and over the Islands. Thus, the moist/unstable conditions may return during the early part of next week. While precipitation should be very minimal with the return of the front and upper-level instability, fog and possibly isolated thunderstorms could be an issue for next week. In sum, tonight and likely tomorrow night will be worthless; there is a chance for observing during the following 3 nights, but periodic fog could still be a problem.

Astronomical Observing Quality Guidance
Vertical Profiles from MM5 (vertical coordinate is pressure in mb):

Tonight's (Friday Night) Collage	NOT AVAILABLE
Thursday Night's Collage (available after 0800 HST on Thursday)	Seeing Cn2
Friday Night's Collage (available after 0800 HST on Friday)	Seeing Cn2