|Mauna Kea Observatories Forecast|
5 PM HST Wednesday 06 November (0300 UTC Thursday 7 November) 2013
Fog, ice and high humidity
|Cloud Cover and Fog/Precipitation Forecast|
There is a moderate/high risk for fog, ice and high humidity throughout the night; precipitation is unlikely. Broken mid/upper-level clouds will continue to fill in from the southwest contributing to extensive cloud cover for tonight.
Summary of Key Meteorological Variables|
Summit temperatures will be near -0.5 C this evening and -1 C tomorrow morning. Winds will be from the SW at 15-30 mph, with seeing around 0.8-0.9 arcseconds. Precipitable water is expected to be in the 3-4 mm range for the night.
The tradewind inversion will remain weak/elevated near 12-13 thousand feet probably through tomorrow afternoon, then will fall apart again as the entire atmosphere turns moist and unstable probably through the weekend. Consequently, there is a moderate to high risk for fog, ice and high humidity throughout most of the forecast period. There is also a chance for convection in the area, flurries and perhaps brief periods of heavier snowfall/rain, mainly after Thursday night. Extensive daytime clouds are expected throughout the forecast period.
Broken mid/upper-level clouds will continue to fill in from the SW, contributing to extensive cloud cover for tonight. More widespread thicker clouds will drift in from the south and merge with these clouds starting early tomorrow morning and will continue to stream through the area probably into Monday afternoon. This will likely result inovercast skies with very brief/occasional clearings for the remainder of the forecast period.
Precipitable water will likely linger in the 3-4 mm range for tonight, then increase to 4+ mm for the remainder of theforecast period.
Boundary layer turbulence, upper-level turbulence, instability and/or wet conditions will contribute to poor/bad seeingthrough the next 5 nights.
No change since the morning forecast...A developing low to the north of the Islands will continue to drop southward over the next 12-24 hours, then wobble westward before its lower and upper half separates (the latter flattening out and shifting eastward) over the weekend. Unfortunately, this low will allow minor instability to persist in the area during its tenure and is expected to drag lots of moisture/clouds back over or just north the state by late tomorrow afternoon and into Friday. Initially, the instability will keep the inversion weak/elevated just below summit-level, but as the moisture fills into the area it will help erode the inversion further perhaps resulting in a saturated air mass for Thursday and especially Friday night. There is a slight possibility that the air mass will try to stabilize as the lowloses its upper-level support late Saturday. But its lower half will still linger to the NW of the Big Island and keepmoisture in the area until new stronger/sharper troughs digs in to the NNE late Sunday. This new trough and its associated front is expected to reinforce the instability in the area and squash all the moisture that the current lowdragged northward back through the Islands (in a more organized state) late Sunday night. Models indicated that this moisture will eventually stall out over/near the Big Island early Monday, which will allow the environment to remain quite wet well into the middle part of next week. Regardless, there is a moderate/high risk for fog, ice andhigh humidity throughout the forecast period (particularly after tonight). Convection, flurries and perhaps brief periods of heavy snow are also possible, especially for Friday and late Sunday. Lots of thick clouds are also slated to spread into the area starting late tonight, blanketing skies probably for the remainder of the forecast period. All in all, it looks like the wet/unstable conditions will continue, may even take a turn for the worse as we head into the weekend and could persist well into the middle part of next week.
WRF Astronomical Observing Quality Guidance|
Cloud Cover and Precipitable Water Analyses
MK CN² Profiles
5 Day Forecast Summary (Graphical Trend)|
Cover (%)||Height (km)||Probability (%)
|Wed Nov 06 - 8 PM
60 / 15||-0.5||SW/15-30||
|Thu Nov 07 - 2 AM||
70-90||8-10||50 / 10||
4-10||75 / 25||3||
75 / 40||-0.5||SW/10-20||
|Fri Nov 08 - 2 AM||
80-100||4-10||90 / 60||
4-10||95 / 75||3||
95 / 60||0||W/5-15||
|Sat Nov 09 - 2 AM||
80-100||4-10||95 / 60||
4-10||95 / 60||2||
Sun Nov 10 - 2 AM||80-100||4-10||
75 / 40||-1.5||WNW/10-20||
80-100||4-10||90 / 50||
|Mon Nov 11 - 2 AM||80-100||
4-10||95 / 75||-2||
95 / 75||0||E/5-15||
|Rise and Set times for the Sun and Moon|