MKWC archive forecast page
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Please select a year and month and links of all available forecasts for that period will be given in the 'Select Forecast' menu.
Selection: 2009
11
Nov 09 2009 (afternoon)



Mauna Kea Forecast

Latest Forecast for Mauna Kea Observatories
5 PM HST Monday 09 November (0300 UTC Tuesday 10 November) 2009

Warnings
Fog and high humidity

Cloud Cover and Precipitation Forecast
There is a moderate risk for fog, high humidity and perhaps light rain through the night. Broken to overcast thick clouds will continue to linger overhead during the night.

Summary of Key Meteorological Variables
Summit temperatures will be near 1 C this evening and 0 C tomorrow morning. Winds will be from the WSW at 10-20 mph for the night. Precipitable water is expected to exceed 4 mm, while seeing will likely be around 0.8-1 arcsecond.

Graphical Summary

Discussion
The tradewind inversion will continue to break down as instability builds in from the NW and deep moisture gathers in the area over the next 24 hours. This will eventually lead to a saturated atmosphere after tonight and probably into the weekend. Nevertheless, there is a moderate to high risk for fog, high humidity and perhaps ice throughout the forecast period (particularly after tonight). Thunderstorms and light snow are also possible after tomorrow afternoon and especially around Wednesday/Thursday. Extensive afternoon clouds are likely throughout the forecast period.

Although the high clouds over and to the west of the summit are expected to shift eastward through the night, broken thick mid-level clouds will continue to gather in the area during this time. These clouds are expected to linger as deeper clouds develop over and to the north of the Big Island probably for the remainder of the forecast period. Nevertheless, this will likely lead to extensive cloud cover for the next 5 nights.

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

Strong shear/turbulence in the free atmosphere combined with building instability and moisture will likely result in seeing near 0.8-1 arcsecond for tonight. Seeing will likely exceed 1 arcsecond as this instability/moisture lingers in the area, resulting in a saturated atmosphere probably for the remainder of the forecast period.

Minimal change since the morning forecast....An already battered mid-level ridge will continue to fall apart as an upper-level trough developing to the northwest digs toward the Islands over the next 24-36 hours. This building instability combined with moisture gathering in the area will likely lead to a fairly saturated atmosphere as early as mid-day tomorrow. In fact, there is a strong possibility that high humidity, fog and obviously clouds will be an issue for tonight. Conditions may only grow worse once this passing trough deposits a rather deep mid/upper-level low over Kauai around Wednesday. This could lead to widespread instability and lots of moisture in the region, perhaps allowing deep convection to develop in the area and light snow to fall at the summit on Wednesday and Thursday. Although this low is expected to gradually fall apart as the week progresses, it is also slated to stick around and keep the atmosphere fairly moist well into the weekend. At any rate, cloud skies and poor/wet conditions will likely plague the summit throughout the forecast period.

Astronomical Observing Quality Guidance
05 pm HST Monday 09 November (03 UTC Tuesday 10 November)CN2
08 pm HST Monday 09 November (06 UTC Tuesday 10 November)CN2
11 pm HST Monday 09 November (09 UTC Tuesday 10 November)CN2
02 am HST Tuesday 10 November (12 UTC Tuesday 10 November)CN2
05 am HST Tuesday 10 November (15 UTC Tuesday 10 November)CN2
08 am HST Tuesday 10 November (18 UTC Tuesday 10 November)CN2
Latest WRF CN2 Profiles Animation | Collage


5-day Forecast
Summary

Graphical Trend
08 pm HST
Mon 09 Nov
02 am HST
Tue 10 Nov
02 pm HST
Tue 10 Nov
08 pm HST
Tue 10 Nov
02 am HST
Wed 11 Nov
02 pm HST
Wed 11 Nov
08 pm HST
Wed 11 Nov
02 am HST
Thu 12 Nov
02 pm HST
Thu 12 Nov
02 am HST
Fri 13 Nov
02 pm HST
Fri 13 Nov
02 am HST
Sat 14 Nov
02 pm HST
Sat 14 Nov
06 UTC
Tue 10 Nov
12 UTC
Tue 10 Nov
00 UTC
Wed 11 Nov
06 UTC
Wed 11 Nov
12 UTC
Wed 11 Nov
00 UTC
Thu 12 Nov
06 UTC
Thu 12 Nov
12 UTC
Thu 12 Nov
00 UTC
Fri 13 Nov
12 UTC
Fri 13 Nov
00 UTC
Sat 14 Nov
12 UTC
Sat 14 Nov
00 UTC
Sun 15 Nov
Cloud Cover (%) 80 to 100 70 to 90 70 to 90 60 to 80 70 to 90 80 to 100 80 to 100 80 to 100 80 to 100 80 to 100 80 to 100 80 to 100 80 to 100
Cloud Height (km) above sea level 6-10 6-9 4-8 4-8 4-9 4-10 4-10 4-10 4-10 4-10 4-10 4-8 4-7
Chance for Fog/Precip (%) 50/10 75/25 90/50 90/60 90/75 90/75 90/75 90/75 90/75 90/60 90/50 75/50 75/50
PW (mm, summit upward) 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8 4 to 8
Mean Seeing (arcsecs) 0.8 ± 0.3 1.0 ± 0.3 N/A 1.2 ± 0.4 1.5 ± 0.5 N/A 1.5 ± 0.5 1.4 ± 0.5 N/A 1.3 ± 0.5 N/A 1.2 ± 0.5 N/A
Summit Temp (°C) 1 0 2 -1 -2 1 -3 -2 2 -0.5 2 -1 2
Wind Dir/Speed (mph)
    Summit (615 hPa)
    19,000 ft (500 hPa)
    24,500 ft (400 hPa)
    31,000 ft (300 hPa)
    35,000 ft (250 hPa)
    40,000 ft (200 hPa)
    46,000 ft (150 hPa)
    54,000 ft (100 hPa)

WSW/5 to 15

WSW/5 to 15

WNW/10 to 20

WNW/10 to 20

W/10 to 20

SW/10 to 20

SSW/10 to 20

SSW/15 to 30

SSW/15 to 30

SSW/15 to 30

SSW/10 to 20

WSW/10 to 20

SSW/10 to 20


 Rise and Set times for the Sun and Moon
Night (HST)
Sun Set
Twilight End
Twilight Beg
Sun Rise
Moon Rise
Moon Set
Illum (%)
RA
Dec
Mon.Nov.09/Tue.Nov.10
17:53
19:00
5:12
6:19
0:39
N/A
41
10 00.1
9 07
Tue.Nov.10/Wed.Nov.11
17:53
18:59
5:13
6:19
1:37
N/A
30
10 50.7
3 13
Wed.Nov.11/Thu.Nov.12
17:53
18:59
5:13
6:20
2:34
N/A
20
11 40.2
-2 45
Thu.Nov.12/Fri.Nov.13
17:52
18:59
5:14
6:20
3:30
N/A
12
12 29.4
-8 30
Fri.Nov.13/Sat.Nov.14
17:52
18:59
5:14
6:21
4:27
N/A
6
13 19.4
-13 47


Forecast issued by: Ryan Lyman
Contact Us - (808) 932-2323
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Next update at 10 AM HST (2000 UTC) Tuesday 10 November 2009.
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This page was last modified on: Tue, Jun 23 2015 - 2320 UTC
Send comments to: Ryan Lyman