Maunakea Observatories Forecast
5 PM HST Friday 10 April (0300 UTC Saturday 11 April) 2026
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Warning(s)
Fog/ice, chances for precipitation/snowModerately strong wind through the night
Cloud Cover and Fog/Precipitation Forecast
Fog/CC and high humidity continue to plague the summit tonight. Precipitation, also in the form of ice/snow is possible during the evening hours.
Summary of Key Meteorological Variables
Summit temperatures will be near 0.5/0 C this evening and through the night. Winds will be from the WNW at 30-45 mph for this evening, decreasing to 25-35 mph during the second half of the night. 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 quite saturated and unstable, allowing extensive fog, high humidity, ice and periods of precipitation, also in the form of light flurries, to plague the summit over much of the next 5 nights. A brief drying trend is possible from later tonight into Saturday evening. Worsening conditions (heavy snow and deep cloud cover) are expected from Sunday through the end of the forecast period.
Broken to overcast thick clouds will continue to stream in the area from the SW throughout most of this forecast period. There is a chance for a brief clearing as clouds pass more to the southern skies for tonight and saturday, but more thick widespread clouds will build back in from the SW afterward, resulting in mostly overcast skies for the following 3 nights. A clearing trend is projected for the middle of the coming week.
Precipitable water is expected to exceed 4 mm throughout the forecast period.
A saturated/unstable air mass, combined with moderate to strong winds at the surface, as well as periods of strong free atmospheric turbulence, will contribute to bad seeing throughout the forecast period.
Not changes since the morning forecast... The current weather scenario is dominated by yet another upper level low to the WNW of the State. This system is projected to remain quasy stationary/steady before shifting off to the east around the early to middle part of next week. Deep widespread moisture/clouds will continue to pour in from the SW, resulting in a saturated air mass and inoperable summit conditions through most of this forecast period. A bout of precipitation, perhaps in the form of snow, is possible during the evening hours of tonight. There is a chance that the deep moisture advected over by this system will slide off to the southern half of the Big Island later tonight, perhaps opening up skies a bit for early tomorrow morning and part of Saturday. However, the environment is saturated enough to result in periods of fog, ice and high humidity at the summit regardless. In addition, the low will draw another band of widespread/thick moisture/clouds in from the SW and over the Big Island area by Sunday. This band will likely remain quasi-stationary before dissipating and/or lifting northward with the low around the middle part of next week. There is also a possibility for another influx of fresh instability and/or upper-level diffluence with the passing of another Short Wave Trough around Sunday night. This could result in another flare-up in convection, heavy snow/rain at the summit and perhaps blizzard-like conditions around that time.
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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) |
| Fri Apr 10 - 8 PM | 60-80 | 4-9 | 100 / 80 | 0.5 | WNW/30-45 | 1.5-3.5 | 10-14 |
| Sat Apr 11 - 2 AM | 50-70 | 4-7 | 90 / 70 | 0.5 | WNW/25-40 | 1-2 | 8-12 |
| 2 PM | 60-80 | 4-7 | 80 / 60 | 4 | W/20-30 | NaN | 10-14 |
| 8 PM | 70-90 | 4-8 | 70 / 50 | 0.5 | W/15-25 | 1-2 | 8-12 |
| Sun Apr 12 - 2 AM | 80-100 | 4-10 | 80 / 60 | 0.5 | SSW/10-10 | 1-2 | 8-12 |
| 2 PM | 80-100 | 4-10 | 80 / 60 | 5 | SSW/10-10 | NaN | 10-14 |
| 8 PM | 80-100 | 4-10 | 100 / 80 | 1 | SW/20-30 | NaN | 10-14 |
| Mon Apr 13 - 2 AM | 80-100 | 4-10 | 100 / 90 | 0.5 | SW/20-30 | NaN | 10-14 |
| 2 PM | 80-100 | 4-10 | 100 / 90 | 4 | WSW/15-25 | NaN | 10-14 |
| Tue Apr 14 - 2 AM | 80-100 | 4-10 | 100 / 80 | 0.5 | WSW/20-30 | NaN | 10-14 |
| 2 PM | 80-100 | 4-10 | 100 / 60 | 3 | SW/15-25 | NaN | 10-14 |
| Wed Apr 15 - 2 AM | 80-100 | 4-10 | 100 / 60 | 0.5 | WSW/15-25 | NaN | 10-14 |
| 2 PM | 80-100 | 4-10 | 100 / 50 | 4.5 | WSW/15-25 | NaN | 10-14 |
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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 |
| Sat Apr 11 - Sun Apr 12 |
18:48 |
19:54 |
4:51 |
5:57 |
2:43 |
N/A |
28 |
21 25.9 |
-17 23 |
| Sun Apr 12 - Mon Apr 13 |
18:48 |
19:54 |
4:50 |
5:56 |
3:21 |
N/A |
20 |
22 14.1 |
-12 05 |
| Mon Apr 13 - Tue Apr 14 |
18:49 |
19:55 |
4:49 |
5:56 |
3:57 |
N/A |
12 |
23 01.7 |
-6 06 |
| Tue Apr 14 - Wed Apr 15 |
18:49 |
19:55 |
4:48 |
5:55 |
4:34 |
N/A |
6 |
23 49.9 |
0 18 |
| Wed Apr 15 - Thu Apr 16 |
18:49 |
19:56 |
4:48 |
5:54 |
5:12 |
17:26 |
2 |
0 39.5 |
6 51 |
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Forecast Issued by: Tiziana Cherubini
Next update at 10 AM HST (2000 UTC) Monday 13 April 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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