Ladyandtramp.com: NWS Digital Forecast Cloud Cover Plot

NWS Digital Forecast Cloud Cover Plot

Amateur astronomers pay attention to the sky and how clear it is. Years ago, we all waited until the evening news to look at the 15 second glance at the satellite image to decide if we should drive out to dark skies to view the stars or not. Today, not only can you get satellite images online in 80 zillion different ways, but you can now also get forecasts for sky cover.

This uses Experimental NWS digital forecast data for sky cover for a 5x5km "grid" of space. Use at your own risk (or fun). Subject to change at any time. Generally, NWS updates the data every hour, but different forecast offices around the county update as often as every three hours or as little as twice a day.

Click on the link above each plot to see these data plotted in a different way. These data are updated 35 minutes past the hour. These CSC like displays are made with apologies to Clear Sky Clock creator Attilla Danko! You are welcome to make comments to bbunge@ladyandtramp.com.

Laurel Highland Star Cruise

Cloud Cover 64 90 87 84 76 91 91 86 89 79 82 87 87 76 70 69 57 50 50 87 91 92 70 72 76 56 47 55 52 54 58 48 45 53 49
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Tuckahoe State Park (MD)

Cloud Cover 56 65 74 72 70 73 75 86 96 85 75 69 67 56 44 41 37 39 41 32 50 59 70 78 81 76 70 58 47 49 51 49 51 50 60
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Bowie, MD

Cloud Cover 48 62 75 70 65 75 100 100 86 86 67 67 53 32 24 41 35 30 42 68 55 55 77 79 82 76 70 52 60 60 44 42 39 50 61
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
CM Crockett Park, VA

Cloud Cover 44 60 76 70 65 84 100 100 81 81 60 70 49 27 21 36 35 24 38 68 55 55 77 73 68 66 63 48 60 60 42 43 44 56 67
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Spruce Knob (Gatewood)

Cloud Cover 51 69 88 76 65 87 100 100 90 90 71 100 67 56 58 28 30 59 62 68 81 81 96 90 85 79 72 52 60 60 67 71 74 81 87
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Spruce Knob (TMI)

Cloud Cover 51 70 89 77 65 87 100 100 100 100 74 100 70 62 64 30 32 69 69 68 81 81 97 91 85 80 73 52 60 60 67 71 75 82 88
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Cherry Springs State Park (PA)

Cloud Cover 91 93 73 66 59 76 93 95 97 93 89 81 73 80 86 78 70 67 64 80 72 76 80 86 92 86 79 66 52 46 40 44 47 57 71
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Sky Meadows State Park (VA)

Cloud Cover 49 63 78 71 65 84 100 100 80 80 64 81 62 38 31 40 38 30 42 68 51 51 64 67 68 67 66 49 60 60 54 45 36 42 48
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Southern Park (MD)

Cloud Cover 41 54 67 66 65 74 100 92 87 87 67 59 42 21 18 39 33 24 38 68 56 56 82 83 83 76 68 52 60 60 45 39 32 42 53
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Oregon Star Party

Cloud Cover 6 6 2 2 2 2 12 12 12 12 12 12 12 12 44 44 44 44 45 45 68 68 62 62 55 55 55 55 58 58 59 59 62 62 48
Hour (Eastern) 11 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 23 05 11 17 23 05 11 17 23 05 11 17 23 05 11 17 18
Day Sat Sun Mon Tue Wed Thu Fri
Pasco, WA

Cloud Cover 3 3 3 3 3 3 21 21 21 21 28 28 28 28 36 36 36 36 58 58 56 56 43 43 41 41 41 41 36 36 45 45 38 38 34
Hour (Eastern) 11 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 23 05 11 17 23 05 11 17 23 05 11 17 23 05 11 17 18
Day Sat Sun Mon Tue Wed Thu Fri
Greenbank Radio Observatory (WV)

Cloud Cover 52 75 83 84 86 81 77 80 86 79 83 85 67 56 46 48 49 41 32 59 89 95 95 90 81 77 63 60 60 54 54 60 68 70 65
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri
Coinjock, NC

Cloud Cover 15 20 11 16 21 36 50 60 70 77 83 74 64 36 21 21 20 22 25 39 57 56 72 70 70 59 50 53 42 49 59 53 51 59 69
Hour (Eastern) 14 17 20 23 02 05 08 11 14 17 20 23 02 05 08 11 14 17 20 02 08 14 20 02 08 14 20 02 08 14 20 02 08 14 20 18
Day Sat Sun Mon Tue Wed Thu Fri

Clear Overcast

This data is retrieved from NWS using their National Digital Forecast Database via a XML web service

There are differences between this data and the Clear Sky Clock (CSC). Where CSC goes out about 48 hours, this forecasts out seven days, keeping in mind that forecasts are less accurate the farther out they are. The CSC data is specifically designed for astronomical purposes, the NWS data isn't. The CSC data is a computer model. These are forecasts generated by a human who might be using model, other data and experience as input. NWS forecasters are forecasting percentage of cloud cover. Thin clouds or haze can quickly add up and as a result, it's rare to see percentages less then 15. My personally experience is percentages less then 30 percent are usually good enough for most casual astronomical observing.

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bbunge@ladyandtramp.com

status

Cloud Cover	64	90	87	84	76	91	91	86	89	79	82	87	87	76	70	69	57	50	50	87	91	92	70	72	76	56	47	55	52	54	58	48	45	53	49
Hour (Eastern)	14	17	20	23	02	05	08	11	14	17	20	23	02	05	08	11	14	17	20	02	08	14	20	02	08	14	20	02	08	14	20	02	08	14	20	18
Day	Sat				Sun								Mon								Tue				Wed				Thu				Fri