Maunakea Observatories Forecast
5 PM HST Thursday 12 March (0300 UTC Friday 13 March) 2026
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Warning(s)
Fog, ice and snow
Moderate/strong winds
Cloud Cover and Fog/Precipitation Forecast
Extensive fog, ice, clouds and snow are expected to plague the summit through the night.
Summary of Key Meteorological Variables
Summit temperatures will be near -3 C this evening and -4 C tomorrow morning. Winds will be from the SW at 35-50 mph for today, easing a bit for the morning hours. Seeing and PW are expected to exceed 1 arcsecond and 4 mm, respectively, through the night.
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Discussion
The atmosphere near the Big Island will remain saturated and unstable, allowing extensive fog, ice and snow to plague the summit through the next 5 nights. Periods of heavy snow and large drifting are also possible at virtually anytime, particularly over much of the weekend. Extensive daytime clouds are expected throughout the forecast period.
Broken to overcast thick clouds will continue to build in in from the west and SW, blanketing summit skies through the next 5 nights.
Precipitable water is expected to exceed 4 mm throughout the forecast period.
Strong free atmospheric turbulence, as steady influx of deep moisture and eventually boundary layer turbulence will contribute to bad seeing through the next 5 nights.
No change since the morning forecast...A large-scale trough and reflective surface low will remain quasi-stationary to the NW of the state for another 12-18 hours, then will gradually shift eastward before lifting off to the NE later next week. Initially, low-level convergence and widespread instability along the SE flank of the low will allow for deep clouds/convection to develop in the area, resulting in extensive fog, ice, clouds and snow at the summit for tonight. The low is expected to gain access to a steady stream of widespread deep tropical moisture as a short-wave trough digs in from the NW and injects fresh upper-level instability (both dynamically and thermodynamically) early tomorrow morning. This stream of moisture is expected to flow over much of the state, even as the low departs to the NE over the early/middle part of next week, contributing to an extended period of inoperable conditions. In addition, the injection of fresh instability, will allow the low to further deepen and significantly tighten the wind gradient in the area over much of the forecast period, particularly over the weekend. This will result in a rather dramatic increase in summit-level winds, where gusts could touch 100 mph on Saturday. These winds, combined with the potential for heavy snow, could translate to blizzard-like conditions and large drifting between early Friday morning and late Sunday night. Long-term projections suggest that the air mass will begin to dry as the moisture finally lifts off toward the NE and east maybe around next week Wednesday/Thursday.
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5 Day Forecast Summary (Graphical Trend)
| HST |
Cloud |
Fog/Precip |
Temp |
Wind |
Seeing |
PW |
| Cover (%) |
Height (km) |
Probability (%) |
(Celsius) |
(Dir/MPH) |
(Arcseconds) |
(mm) |
| Thu Mar 12 - 8 PM | 80-100 | 4-9 | 100 / 90 | -3 | SW/35-50 | 1-3 | 10-15 |
| Fri Mar 13 - 2 AM | 80-100 | 4-9 | 100 / 95 | -4 | SW/25-40 | 1-3 | 10-15 |
| 2 PM | 80-100 | 4-10 | 100 / 95 | 0 | SW/35-50 | NaN | 10-15 |
| 8 PM | 80-100 | 4-10 | 100 / 95 | -3 | SW/50-70 | 1-3 | 10-15 |
| Sat Mar 14 - 2 AM | 80-100 | 4-10 | 100 / 95 | -3 | SW/60-80 | 1-3 | 10-15 |
| 2 PM | 80-100 | 4-10 | 100 / 90 | 1 | SW/60-80 | NaN | 10-15 |
| 8 PM | 80-100 | 4-10 | 100 / 90 | -2 | WSW/50-70 | 1-3 | 10-15 |
| Sun Mar 15 - 2 AM | 80-100 | 4-10 | 100 / 95 | -2.5 | SW/40-60 | 1-3 | 10-15 |
| 2 PM | 80-100 | 4-10 | 100 / 95 | 1.5 | WSW/35-50 | NaN | 10-15 |
| Mon Mar 16 - 2 AM | 80-100 | 4-10 | 100 / 95 | -1.5 | WSW/30-45 | 1-3 | 10-15 |
| 2 PM | 80-100 | 4-10 | 100 / 95 | 1.5 | WSW/25-40 | NaN | 10-15 |
| Tue Mar 17 - 2 AM | 80-100 | 4-10 | 95 / 90 | -1.5 | WSW/20-35 | 1-3 | 10-15 |
| 2 PM | 80-100 | 4-10 | 95 / 90 | 2 | W/15-30 | NaN | 10-15 |
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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 |
| Fri Mar 13 - Sat Mar 14 |
18:40 |
19:44 |
5:18 |
6:22 |
3:28 |
N/A |
22 |
20 03.1 |
-24 10 |
| Sat Mar 14 - Sun Mar 15 |
18:40 |
19:44 |
5:17 |
6:21 |
4:10 |
N/A |
14 |
20 54.2 |
-20 18 |
| Sun Mar 15 - Mon Mar 16 |
18:40 |
19:45 |
5:16 |
6:20 |
4:50 |
N/A |
8 |
21 43.7 |
-15 25 |
| Mon Mar 16 - Tue Mar 17 |
18:41 |
19:45 |
5:15 |
6:19 |
5:27 |
16:52 |
3 |
22 32.1 |
-9 45 |
| Tue Mar 17 - Wed Mar 18 |
18:41 |
19:45 |
5:14 |
6:19 |
6:03 |
17:48 |
1 |
23 20.1 |
-3 31 |
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Forecast Issued by: Ryan Lyman
Next update at 10 AM HST (2000 UTC) Friday 13 March 2026.
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Additional Information
For public road conditions and snow report message please call (808) 935-6268.
This message is also available at the MKWC road conditions page.
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