Current Conditions
Temp-0.0 C
RH65 %
WindW 13 mph
Mauna Kea Observatories Forecast
4 PM HST Wednesday 21 March (0200 UTC Thursday 22 March) 2018
Chances for fog
Cloud Cover and Fog/Precipitation Forecast
High scattered clouds overhead will continue to stream over from the West, moving eastward, through this evening and tonight. Light precipitation is possible, but not very likely.
Summary of Key Meteorological Variables
Summit temperatures will be near 0.5 C this evening and -0.5 C tonight. Winds will be from the NW at 15-25 mph. Precipitable water is expected to still exceed 4 mm, and observing conditions will continue to be poor.
The airmasses will continue to be quite wet throughout. Although they might dry out a little a times, particularly tomorrow during the daytime, the large moisture supply from the mid/low level could pop up at anytime at the summit through Friday. The environment will be completely saturated by late Friday and into the weekend as a short wave trough will advect even more moisture over the area, destabilizing the atmosphere and likely resulting in frozen precipitation and possibly thunderstorms then. The airmasses will quickly dry out on Monday as the front passes through the State. Daytimes clouds are very likely throughout.

High clouds overhead will continue to stream over from the West, moving eastward, through today, tonight and tomorrow. They might thin and open up some tomorrow during the daytime but will start thicking again during the evening hours and they will close up the sky completely by Friday and through the weekend. A mostly clear sky is expected from Monday and onward.

Precipitable water will continue to exceed 4 mm throughout the forecast period.

Observing conditions will remain rather poor to unoperable as clouds continue to cross the sky and moisture will continue to remain elevated. Shear aloft is also contributing negatively to the current observing conditions.

Not much is changed since the morning forecast... The current weather scenario continues to be dominated by the strong high pressure system north of the State and the upper level trough/low NW of the islands' chain. This latter is advecting deep moisture and high clouds through the summit skies and will continue to do so through Thursday and Friday. These conditions will degrade further starting on Friday and through the weekend as a short wave trough approaches the State from the NW. Moisture will increase even more and the so will instability. Thunderstorms along the summit slopes will be likely and precipitation migh fall at the summit in the form of frozen rain/flurries/snow. Conditions will therefore be unoperable then as adverse weather (fog, precipitation, and sustained surface winds) will plague the summit. Conditions are expected to largely improve on Monday as the system quickly moves eastward and away from the Big Island.
WRF Astronomical Observing Quality Guidance
Cloud Cover and Precipitable Water Analyses
MK CN² Profiles
5 Day Forecast Summary (Graphical Trend)
HST Cloud Fog/Precip Temp Wind Seeing PW
Cover (%) Height (km) Probability (%) (Celcius) (Dir/MPH) (Arcseconds) (mm)
Wed Mar 21 - 8 PM50-704-780 / 100.5NW/25-400.6-16-10
Thu Mar 22 - 2 AM50-705.5-740 / 0-0.5WNW/15-250.55-0.956-10
2 PM30-504-770 / 104W/10-20NaN10-14
8 PM30-505-740 / 0-0.5W/10-200.65-1.058-12
Fri Mar 23 - 2 AM40-605-730 / 0-1.5W/10-200.6-18-12
2 PM60-804-780 / 303.5WSW/15-25NaN8-12
8 PM80-1004-890 / 40-1.5WSW/20-351-1.412-16
Sat Mar 24 - 2 AM80-1004-8100 / 90-1.5WSW/20-351-1.412-16
2 PM80-1004-9100 / 90-0.5SW/30-45NaN12-16
Sun Mar 25 - 2 AM80-1004-9100 / 90-3W/30-451.3-1.712-16
2 PM80-1004-9100 / 90-1WSW/15-25NaN10-12
Mon Mar 26 - 2 AM40-604-780 / 30-2.5SW/20-351.3-1.76-10
2 PM0-20Clear20 / 02WSW/15-25NaN3.5-4.5
Rise and Set times for the Sun and Moon
Night (HST) Sun Set Twilight End Twilight Beg Sun Rise Moon Rise Moon Set Illumination (%) RA DEC
Wed Mar 21 - Thu Mar 22 18:42 19:47 5:11 6:15 N/A 22:58 25 4 02.7 15 30
Thu Mar 22 - Fri Mar 23 18:42 19:47 5:10 6:14 N/A 23:58 35 4 59.7 18 06
Fri Mar 23 - Sat Mar 24 18:43 19:47 5:09 6:13 N/A 0:59 47 5 58.9 19 38
Sat Mar 24 - Sun Mar 25 18:43 19:47 5:08 6:13 N/A 1:57 58 6 59.3 19 56
Sun Mar 25 - Mon Mar 26 18:43 19:48 5:07 6:12 N/A 2:54 69 7 59.9 18 55
Forecast Issued by: Tiziana Cherubini
Next update at 10 AM HST (2000 UTC) Thursday 22 March 2018.
Additional Information
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