Current Conditions
Temp-2.0 C
RH99 %
WindSW 2 mph
RoadOpen (4x4)
Mauna Kea Observatories Forecast
5 PM HST Friday 27 March (0300 UTC Saturday 28 March) 2020
Warning(s)
Fog, ice and high humidity
Chance for flurries/tstorms
Cloud Cover and Fog/Precipitation Forecast
Extensive fog, ice, high humidity, broken clouds and/or light flurries are expected to plague the summit through the night.
Summary of Key Meteorological Variables
Summit temperatures will be near -4 C this evening and -5 C tomorrow morning. Winds will be from the SW at 10-20 mph for today and 5-15 mph for the night. Seeing and precipitable water are expected to exceed 1 arcsecond and 4 mm, respectively, through the night.
Discussion
The air mass near the Big Island is expected to turn saturated and unstable, allowing high humidity, extensive fog and ice to plague the summit throughout most of the forecast period. There is a high risk for flurries, and there is a chance for isolated convection in the area and perhaps brief periods of heavy snow at the summit at virtually anytime, but particularly near sunrise/sunset. Extensive daytime clouds are expected throughout the forecast period.

Broken to overcast thick clouds will continue to fill in from the south, contributing to extensive cloud cover, if not overcast skies through the next 5 nights.

Precipitable water is expected to exceed 4 mm throughout the forecast period.

A fairly saturated/unstable air mass, combined with instability and even periods of upper-level turbulence will contribute to bad seeing through the next 5 nights.

No change since the morning forecast...A relatively deep mid/upper-level low embedded in a strong/well-defined tropical upper-tropospheric trough (TUTT) will continue to take shape to the NW, destabilize the air mass and draw moisture in from the south, while also enhancing the incoming low-level cloud field over the next 2 days. This will allow the atmosphere to turn quite saturating, contributing to extensive fog, ice and high humidity at the summit over the next 2 nights. Isolated convection, flurries and perhaps brief periods of moderate/heavy snow are also possible at virtually anytime, but particularly near sunset/sunrise. While the low is set to weaken as the weekend progresses, widespread instability associated with the TUTT combined with lots of moisture left in the area will remain an issue until another embedded new short-wave trough/low fills in from the west around Tuesday. Consequently, there is a very good chance that the inoperable/wet conditions will persist well into the middle-part of next week.
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)
Fri Mar 27 - 8 PM70-904-8.5100 / 90-4SW/5-151-26-10
Sat Mar 28 - 2 AM80-1004-8100 / 65-5SW/5-151-26-10
2 PM80-1004-9100 / 75-2SW/5-15NaN6-10
8 PM60-804-8100 / 90-4W/5-151-26-10
Sun Mar 29 - 2 AM60-804-8100 / 90-4.5WSW/10-201-26-10
2 PM70-904-995 / 75-2W/15-30NaN6-10
8 PM40-604.5-890 / 40-4WNW/10-200.8-1.64-8
Mon Mar 30 - 2 AM60-804.5-1090 / 40-4W/10-200.8-1.64-8
2 PM80-1004-1090 / 500W/10-20NaN6-10
Tue Mar 31 - 2 AM80-1005-1090 / 40-3W/15-300.8-1.66-10
2 PM80-1004-1090 / 60-1W/15-30NaN6-10
Wed Apr 01 - 2 AM60-805-890 / 65-4WNW/10-200.7-1.36-10
2 PM80-1004-890 / 75-1NNW/5-15NaN6-10
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 Mar 28 - Sun Mar 29 18:44 19:49 5:04 6:09 N/A 22:38 21 4 07.8 18 12
Sun Mar 29 - Mon Mar 30 18:44 19:49 5:03 6:08 N/A 23:32 29 4 58.6 20 58
Mon Mar 30 - Tue Mar 31 18:45 19:50 5:02 6:07 N/A 0:27 39 5 52.3 22 47
Tue Mar 31 - Wed Apr 01 18:45 19:50 5:01 6:06 N/A 1:22 49 6 48.5 23 28
Wed Apr 01 - Thu Apr 02 18:45 19:50 5:00 6:05 N/A 2:17 60 7 46.6 22 49
Forecast Issued by: Ryan Lyman
Next update at 10 AM HST (2000 UTC) Monday 30 March 2020.
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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