Current Conditions
Temp-1.0 C
RH99 %
WindWSW 33 mph
Mauna Kea Observatories Forecast
4 PM HST Tuesday 20 March (0200 UTC Wednesday 21 March) 2018
Chances for fog/ice
Sustained/Strong winds
Cloud Cover and Fog/Precipitation Forecast
High clouds overhead will continue to break down and thin through this afternoon and evening while moving eastward. Nonetheless more high clouds will be approaching from the West during the second half of tonight. Summit level clouds might linger in the afternoon, evening and result in fog during the first part of the night.
Summary of Key Meteorological Variables
Summit temperatures will be near -3.5 C this evening and -2.5 C tonight. Winds will be from the NW at 30-45 mph. Precipitable water is expected to still exceed 4 mm, and observing conditions will continue to be poor.
The airmasses continue to be nearly saturated at and above summit level. They are expected to dry out some in the mid/summit levels late tonight. Nevertheless, in spite of the overall slightly drying trend, blobs of moisture will be passing by through Thursday and the airmasses are expected to be completely saturated by early Friday and into the weekend. Daytime clouds will be extensive throughout.

High clouds from the West will be breaking down some through today but more high clouds are expected to approach the area from the West during the second half of tonight. Although they might break and thin some through Wednesday and Thursday, will then ticken and get more organized from Friday and onward when they will close up the summit sky.

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

Observing conditions will remain poor to inoperable as winds at the summit remain sustained/strong, moisture continue to plague the area and shear aloft also increase.

Not much is changed since the morning forecast... While the high pressure far North of the Hawaiian Islands shifts southeastward through this week, the surface gradients are rather strong and as a result the wind at the summit will remain sustained, at times strong, through today, possibly tapering some from later tonight and through Wednesday. The airmasses being quite moist will dry out a little today and on/off through Wednesday, but deep moisture is expected to be advected over the area by a short wave trough approaching the State from the West on Friday. The resulting front will cross the islands through the weekend bringing more moisture and likely unoperable conditions at the summit then. The model project the front to move eastward and away at the beginning of the coming week dragging the bulk of the moisture out of the islands' chain.
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)
Tue Mar 20 - 8 PM30-506-7.580 / 20-3.5NW/35-501-1.44-8
Wed Mar 21 - 2 AM60-806-7.530 / 0-2.5NW/30-451-1.44-8
2 PM60-804-780 / 03NW/25-35NaN4-8
8 PM60-804-740 / 5-1.5NW/20-350.8-1.26-10
Thu Mar 22 - 2 AM40-606-7.540 / 0-1.5WNW/15-250.8-1.26-10
2 PM20-404-770 / 04WSW/15-25NaN6-10
8 PM20-405-7.560 / 10-1W/15-250.7-1.110-14
Fri Mar 23 - 2 AM30-504-760 / 20-0.5W/20-350.6-110-14
2 PM60-804-8100 / 902W/15-25NaN10-14
Sat Mar 24 - 2 AM80-1004-8100 / 90-1.5WSW/20-351.3-1.712-16
2 PM80-1004-8100 / 90-0.5WSW/25-40NaN14-18
Sun Mar 25 - 2 AM80-1004-8100 / 90-2.5W/15-251.3-1.712-18
2 PM30-505-760 / 20-0.5W/15-25NaN4-8
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 Mar 20 - Wed Mar 21 18:42 19:46 5:12 6:16 N/A 21:59 16 3 07.9 12 03
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
Forecast Issued by: Tiziana Cherubini
Next update at 10 AM HST (2000 UTC) Wednesday 21 March 2018.
Additional Information
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