Current Conditions
Temp-2.7 C
RH99 %
WindENE 14 mph
RoadClosed
Maunakea Observatories Forecast
5 PM HST Tuesday 30 November (0300 UTC Wednesday 1 December) 2021
Warning(s)
Extensive periods of Fog, ice, snow/flurries.
Cloud Cover and Fog/Precipitation Forecast
Wintery weather will continue at the summit with mostly overcast skies and intermittent frozen precipitation.
Summary of Key Meteorological Variables
Summit temperatures will be near -4C this evening and -3.5C tonight. Winds will be predominantly from the ESE, starting the evening off at 15 to 25 mph, decreasing as the night progresses. PW will exceed the 4 mm threshold throughout the night. Overall unoperable conditions.
Discussion
The airmasses over and around the summit are saturated. The tradewind inversion is expected to remain absent throughout this forecast period, therefore extensive periods of fog and ice are very likely at anytime. There are also chances for thunderstomrs to develop along the eastern slopes of Maunakea through today/tomorrow. While instability is expected to decrease some as Wednesday progresses and through Thursday, a greater instability will interest the area from Friday and throughout the weekend.

Cloud cover is expected to remain elevated throughout most of this forecast period. Patches of blue skies are possible intermittently from now through Wendsday/Thursday, while summit skies will be completely overcast afterward.

Precipitable water will exceed the 4 mm threshold throughout the next 5 nights.

Unoperable conditions due to extensive cloud cover and saturated air masses will characterize the next five nights. Strong surface winds will also become an issue over the weekend.

No changes since the morning forecast... The current weather scenario is dominated by the upper level low now placed just a tad south of the Big Island. This system and its associated cold pool of air, will stall in the area for the next 24/36 hours, and will continue to provide instability and support pockets of thunderstorms, mostly along the eastern side of the island and along the eastern slopes of the mountains. Therefore extensive periods of fog, ice and frozen precipitation are very likely throughout the next couple of days. This system is expected to wander off toward the northeast by Wednesday pushed eastward by a very deep upper level trough which is expected to approach the area on Thursday. This system and the associated surface front will stall over the area from Friday and through the weekend. Because of the lingering moisture from the previous system and the strenght of this second one, which is expected to develop in a very strong upper level low, chances are that conditions will worsen with thunderstorm/snowfall/ice. Surface gradients are also projected to strenghten then and surface winds to increase above warning level particularly on Saturday night. Overall unoperable conditions will characterize this forecasting period.
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 (%) (Celsius) (Dir/MPH) (Arcseconds) (mm)
Tue Nov 30 - 8 PM80-1003.5-7100 / 80-4ESE/15-251.3-1.76-10
Wed Dec 01 - 2 AM80-1003.5-7100 / 90-3.5ESE/25-351.8-2.28-12
2 PM70-903.5-790 / 70-0.5SE/15-25NaN8-12
8 PM70-904-780 / 60-2.5SSW/10-201.3-1.78-12
Thu Dec 02 - 2 AM70-904-890 / 60-4SSW/5-150.8-1.26-10
2 PM60-804-880 / 600WSW/5-15NaN6-10
8 PM60-803.5-890 / 70-2WSW/5-150.8-1.28-12
Fri Dec 03 - 2 AM70-903.5-890 / 70-3W/10-200.8-1.26-10
2 PM80-1003.5-8100 / 80-0.5W/20-30NaN4-8
Sat Dec 04 - 2 AM80-1003-8100 / 90-5SW/35-451.5-2.58-12
2 PM80-1003-8100 / 90-2SW/50-70NaN8-12
Sun Dec 05 - 2 AM80-1003-8100 / 90-6SW/50-701.5-2.58-12
2 PM80-1003-8100 / 90-2SSW/35-45NaN8-12
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
Tue Nov 30 - Wed Dec 01 17:51 18:59 5:23 6:31 3:44 N/A 12 13 53.6 -8 35
Wed Dec 01 - Thu Dec 02 17:51 18:59 5:23 6:32 4:48 N/A 5 14 48.1 -14 27
Thu Dec 02 - Fri Dec 03 17:51 19:00 5:24 6:32 5:55 16:42 1 15 46.5 -19 34
Fri Dec 03 - Sat Dec 04 17:52 19:00 5:24 6:33 7:04 17:35 0 16 48.9 -23 29
Sat Dec 04 - Sun Dec 05 17:52 19:00 5:25 6:33 N/A 18:35 2 17 54.3 -25 47
Forecast Issued by: Tiziana Cherubini
Next update at 10 AM HST (2000 UTC) Wednesday 1 December 2021.
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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