Current Conditions
Temp8.7 C
RH47 %
WindNW 8 mph
RoadOpen
Mauna Kea Observatories Forecast
10 AM HST (2000 UTC) Monday 10 March 2014
Warning(s)
Chance for moisture
Increasing winds
Cloud Cover and Fog/Precipitation Forecast
There is a small/moderate risk for periodic fog, ice, high humidity and/or summit-level clouds throughout the night; precipitation is not expected.
Summary of Key Meteorological Variables
Summit temperatures will be near 4 C this afternoon, -3 C this evening and -4.5 C tomorrow morning. Winds will be from the NW at 10-20 mph for today, increasing to 20-35 mph by the end of the night. Precipitable water is expected to be in the 3-4 mm range, with seeing around 0.8-0.9 arcseconds.
Discussion
Patches of mid-level moisture and minor instability is expected to linger in the area, perhaps allowing for periods of fog, ice and/or high humidity through the night. This moisture/instability is slated to shift out of the area, while the inversion rebuilds through tomorrow, ensuring the summit remains dry and stable for the remainder of the forecast period. Some afternoon clouds are possible over the next 2 days, but will become minimal and short-lived thereafter.

There is a possibility for patches of summit-level clouds in the area for tonight, but these clouds will shift eastward leaving predominately clear skies for the following 4 nights.

Precipitable water is expected to linger in the 3-4 mm range for tonight, but will slip toward 1 mm or less for the following 4 nights.

Upper-level turbulence and minor boundary layer turbulence will contribute to poor seeing for tonight. Summit-level winds are slated to dramatically increase through tomorrow, likely resulting in awful seeing for Tuesday, Wednesdsay and probably Thursday night. While there is a possibility that winds will subside a bit, perhaps allowing seeing to improve early Friday evening, winds may pick back up again as that night progresses.

Although a new deep ridge is slated to fill from the west over the next 24-36 hours, patches of mid/level moisture and minor instability along its western edge will continue to pass through the area and may allow for periods of fog, ice, high humidity and/or summit-level clouds mainly over the next 24 hours. The bulk of the moisture is slated to shift well east of the Big Island late tomorrow morning, but a tight wind gradient is set to build in over the summit beginning late tonight, which will increase summit-level winds over the following 24 hours. Stiff northerly winds will likely top 50 mph, with gusts upwards of 75 mph are likely for the second half of tomorrow night and all of Wednesday night. Winds are expected to subside as the ridge settles back in to the north of the state and weakens a bit in response a large trough brewing to the northwest starting late Thursday afternoon. The trough is not expected to affect the stability of the atmosphere, but instead will squash the ridge back over the state late in the week. Unfortunately, that may tighten the wind gradient again, allowing winds to pick back up over the weekend.
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)
Mon Mar 10 - 2 PM40-604-560 / 54NW/10-20NaN3-6
8 PM0-20Clear40 / 0-3NW/15-300.6-13-4
Tue Mar 11 - 2 AM0-20Clear20 / 0-4.5NW/20-350.6-1.13-4
2 PM20-404-4.525 / 00NNW/25-40NaN2-4
8 PM0-5Clear0 / 0-4N/35-501-21.5-2
Wed Mar 12 - 2 AM0-5Clear0 / 0-4NNE/40-601-31-1.5
2 PM0-20Clear0 / 02NNE/40-60NaN0.8-1.2
8 PM0-5Clear0 / 0-2NE/40-601-30.8-1
Thu Mar 13 - 2 AM0-5Clear0 / 0-2NE/40-601-30.8-1
2 PM0-20Clear0 / 05ENE/30-45NaN0.8-1.2
Fri Mar 14 - 2 AM0-5Clear0 / 00ENE/25-400.8-1.60.8-1
2 PM0-20Clear0 / 06NNE/15-30NaN1-2
Sat Mar 15 - 2 AM0-5Clear0 / 00NNE/15-300.5-11-2
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
Mon Mar 10 - Tue Mar 11 18:39 19:43 5:20 6:25 N/A 3:17 75 7 29.0 16 26
Tue Mar 11 - Wed Mar 12 18:39 19:43 5:20 6:24 N/A 3:58 83 8 17.6 14 08
Wed Mar 12 - Thu Mar 13 18:40 19:44 5:19 6:23 N/A 4:38 90 9 05.4 11 13
Thu Mar 13 - Fri Mar 14 18:40 19:44 5:18 6:22 N/A 5:16 95 9 52.7 7 47
Fri Mar 14 - Sat Mar 15 18:40 19:44 5:17 6:21 17:02 5:54 98 10 39.8 3 57
Forecast Issued by: Ryan Lyman
Next update at 5 PM HST Monday 10 March (0300 UTC Tuesday 11 March) 2014.
Additional Information
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This message is also available at the MKWC road conditions page.
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