Current Conditions
Temp-1.1 C
RH84 %
WindNW 30 mph
RoadOpen
Mauna Kea Observatories Forecast
10 AM HST (2000 UTC) Monday 22 December 2014
Warning(s)
Strong winds.Precipitation in the form of ice/snow/flurries
Cloud Cover and Fog/Precipitation Forecast
The summit skies will close up throughout today. High chances are for fog and precipitation in the form of ice/snow/flurries.
Summary of Key Meteorological Variables
The summit temperature will be near 3 C this afternoon, -2.5 C this evening and -4.5 C tonight. Winds will be from the WSW at 35 to 50 mph, with possible stronger gusts. Precipitable water will exceed the 4 mm threshold. Observing conditions will be overall unoperable.
Discussion
The tradewind inversion is already weaking and lifting. It is expected to vanish throughout today. This will allow the mid and low level moisture to reach the summit from this afternoon. Expect fog and precipitation in the form of ice, snow and flurries tonight and possibly tomorrow. The atmosphere will remain unstable throughout most of this forecast period, with signs of the tradewind rebuilding starting on Friday.

Mid-high clouds will start approaching the summit today. As the inversion lifts and vanishes low-mid clouds will also raise to the summit level throughout this afternoon night. The summit skies will be therefore occluded tonight and through the next two nights. They might start open up a bit on Thursday and through Friday.

Precipitable water will exceed the 4 mm threshold tonight throught Wednesday nigth. It will range between 2 and 3 mm on Thursday and linger close to 2 mm on Friday.

Observing conditions will be unoperable/very poor throughout the forecast period.

A weakening cold front is moving through the island chain today, advecting low-mid clouds toward the Big Island. Meanwhile and upper level trough is approaching the State from the NW. This trough is projected to stall west of the Hawaiian Islands and develop into a mid level low which is expected to rapidly advect sub-tropical moisture and clouds over the Big Island from this afternoon and through Wednesday. Atmospheric instability will rapidly increase while winds at the summit will pick up and quickly reach warning levels. Fog is very likely and precipitation in the form of ice/snow/flurries is also likely for tonight and possibly tomorrow. Overall observing conditions will be very poor/unoperable at least through Wednesday nigth. While weather conditions will improve from Christmas day and onward, the atmosphere will take its time to regain dry and stable conditions.
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 Dec 22 - 2 PM10-307-830 / 03SSW/15-25NaN3-5
8 PM50-704-670 / 30-2.5SW/25-401-1.44-6
Tue Dec 23 - 2 AM80-1003.5-690 / 70-4.5WSW/35-501.3-1.76-12
2 PM80-1003.5-690 / 70-2.5S/40-55NaN6-12
8 PM80-1003.5-690 / 70-4S/40-550.8-1.26-12
Wed Dec 24 - 2 AM80-1004-680 / 50-5.5S/45-601-1.44-6
2 PM70-904-680 / 50-1.5SSW/40-55NaN2.5-3.5
8 PM50-704-670 / 40-2SW/40-501.3-1.73.5-4.5
Thu Dec 25 - 2 AM30-505-740 / 10-4SW/30-401.3-1.74-6
2 PM30-505-740 / 103W/30-40NaN4-6
Fri Dec 26 - 2 AM10-307-810 / 01WNW/25-350.8-1.22-3
2 PM10-307-810 / 0-1.5WSW/25-35NaN1.5-2.5
Sat Dec 27 - 2 AM10-306-830 / 00WNW/30-400.8-1.21.5-2.5
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 Dec 22 - Tue Dec 23 17:58 19:07 5:34 6:43 N/A 19:08 3 19 20.7 -17 06
Tue Dec 23 - Wed Dec 24 17:59 19:08 5:35 6:44 N/A 20:10 7 20 19.7 -14 41
Wed Dec 24 - Thu Dec 25 17:59 19:08 5:35 6:44 N/A 21:12 15 21 17.5 -11 20
Thu Dec 25 - Fri Dec 26 18:00 19:09 5:36 6:45 N/A 22:13 24 22 13.5 -7 20
Fri Dec 26 - Sat Dec 27 18:01 19:09 5:36 6:45 N/A 23:13 34 23 08.1 -2 57
Forecast Issued by: Tiziana Cherubini
Next update at 5 PM HST Monday 22 December (0300 UTC Tuesday 23 December) 2014.
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.
NWS Hawaiian Islands Synoptic Discussion and Guidance
Honolulu National Weather Service Data and Products