Current Conditions
Temp-2.9 C
RH91 %
WindSE 3 mph
RoadClosed
Mauna Kea Observatories Forecast
5 PM HST Monday 02 March (0300 UTC Tuesday 3 March) 2015
Warning(s)
Chance for fog/ice, high humidity and flurries
Cloud Cover and Fog/Precipitation Forecast
There is a chance for periods of fog, ice and high humidity through the night; flurries are also possible mainly for this evening. Broken mid/upper-level clouds will continue to linger along the southern/eastern skies, and may occasionally drift over the summit area during the night.
Summary of Key Meteorological Variables
Summit temperatures will be near -3.5 C for the night. Winds will be light and from the west, with seeing around 0.6-0.7 arcseconds. Precipitable water is expected to be in the 3-4 mm range for the night.
Discussion
Although the mid-level air mass is set to dry out overnight, the inversion will remain rather weak/indistinct, which may allow for more periods of fog, ice and high humidity during that time. There is also a possibility for another round of afternoon convection and flurries, the latter of which may spill into to the early evening hours. More moisture is expected to fill into the area through tomorrow afternoon, which will help (re)saturate the entire air mass and increase the odds on more fog, ice, high humidity and snow at the summit probably for the remainder of the week. There is a (greater) chance for convection and periods of heavy snow particularly for Wednesday/Thursday and again over the weekend. Extensive daytime clouds are likely through the week.

Broken mid/upper-level clouds will continue to linger along the southern/eastern skies, and will occasionally drift over the summit area during the night. The southern clouds are slated to spill northward through tomorrow, and will blanket summit skies probably for the remainder of the forecast period.

There is a fairly good chance that precipitable water will drop toward 3 mm overnight, but is expected to increase back to 6-8+ mm for the remainder of the forecast period.

There is possibility that seeing will dip toward 0.6 arcseconds as minimal turbulence persists in the free atmosphere for tonight. However, an influx of more moisture, instability and eventually turbulence will contribute to poor/bad seeing and/or inoperable conditions for the following 4 nights.

Little change since the mroning forecast...The atmosphere near the Big Island is expected to briefly dry out as the bulk of the moisture and clouds linger off toward to the south and east for tonight. However, there is still a possibility for periods of fog, ice, high humidity and flurries particularly for this evening. Lightning may also be visible along the eastern skies through the night. Unfortunately, the clouds/moisture to the south is set to reorganize and shift back over the Big Island as a new short-wave trough digs into the north through tomorrow, with a second one following suit later in the week. This will likely resaturate the air mass and allow widespread instability to persist in the area probably for the remainder of the week. Consequently, there is a very good chance for extensive cloud cover/fog, ice, high humidity and flurries during that time. There is also a possibility for widespread convection and periods of heavy snow at the summit, especially around Wednesday and again over the weekend. Winds are slated to increase to 30+ mph beginning late Wednesday night, and may contribute to large drifts during the second half of the week. All in all, expect, at best, less than marginal conditions/skies for tonight, and inoperable conditions/skies probably for the remainder of the 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)
Mon Mar 02 - 8 PM50-705-975 / 40-3.5W/5-150.5-0.83-4
Tue Mar 03 - 2 AM30-505-840 / 20-3.5W/5-150.5-0.73-4
2 PM60-804-880 / 601W/5-15NaN4-8
8 PM80-1004-995 / 75-2.5NNW/0-100.8-1.66-10
Wed Mar 04 - 2 AM80-1004-10100 / 95-3SW/0-101-28-12
2 PM80-1004-10100 / 95-1SSW/0-10NaN8-12
8 PM80-1004-10100 / 95-3WSW/5-151-38-12
Thu Mar 05 - 2 AM80-1004-8100 / 95-3WSW/20-351-38-12
2 PM80-1004-1095 / 90-2WSW/40-60NaN6-10
Fri Mar 06 - 2 AM80-1004-1090 / 75-4W/40-601-26-10
2 PM80-1004-1095 / 75-1W/40-60NaN6-10
Sat Mar 07 - 2 AM80-1004-1095 / 90-3W/40-601-28-12
2 PM80-1004-1095 / 900W/40-60NaN8-12
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
Mon Mar 02 - Tue Mar 03 18:36 19:41 5:27 6:31 N/A 5:26 95 9 12.3 11 34
Tue Mar 03 - Wed Mar 04 18:37 19:41 5:26 6:30 16:59 6:05 98 9 59.4 8 24
Wed Mar 04 - Thu Mar 05 18:37 19:41 5:25 6:30 17:48 6:42 100 10 45.7 4 54
Thu Mar 05 - Fri Mar 06 18:37 19:42 5:25 6:29 18:36 7:19 100 11 31.5 1 11
Fri Mar 06 - Sat Mar 07 18:38 19:42 5:24 6:28 19:24 N/A 97 12 17.2 -2 36
Forecast Issued by: Ryan Lyman
Next update at 10 AM HST (2000 UTC) Tuesday 3 March 2015.
Additional Information
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This message is also available at the MKWC road conditions page.
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