Station Overview Station Location
Station Number MD-MG-18 Latitude 39.092094
Station Name Colesville 1.7 W Longitude -77.038549
County Montgomery Elevation (ft) 361



Month 30 Yr Avg by PRISM Total Prcp Sum Days Covered By All Observations Daily Prcp Sum Daily Observation Count Multiday Prcp Sum Days Covered by Multiday Observations Multiday Observation Count Days With Prcp Days With Trace Total Snowfall Days With Snowfall Days With Snow On Ground
Oct 09 3.51 5.64 28 5.16 22 0.48 6 1 11 3 0.0 0 0
Nov 09 3.54 5.40 31 2.43 22 2.97 9 3 10 1 0.0 0 0
Dec 09 3.25 7.51 30 7.51 30 0.00 0 0 13 0 26.4 5 12
Jan 10 3.00 2.16 29 1.54 26 0.62 3 1 8 2 8.8 2 7
Feb 10 2.85 3.92 24 3.92 24 0.00 0 0 8 2 44.3 7 24
March 10 3.82 3.79 30 3.79 30 0.00 0 0 15 0 0.0 0 4
April 10 3.39 2.42 29 2.28 21 0.14 8 1 5 1 0.0 0 0
May 10 4.25 3.87 21 2.23 19 1.64 2 1 8 2 0.0 0 0
June 10 3.96 2.07 28 1.02 20 1.05 8 2 6 2 0.0 0 0
July 10 4.02 6.03 33 4.12 23 1.91 10 3 5 1 0.0 0 0
Aug 10 3.21 7.37 27 7.33 25 0.04 2 1 11 3 0.0 0 0
Sept 10 4.05 3.50 17 2.69 13 0.81 4 1 6 0 0.0 0 0
Water Year Totals: 42.85" 53.68" 327 days 44.02" 275 9.66" 52 days 14 106 days 17 days 79.5" 14 days 47 days



Days in Water Year Cell Color Key
        Daily Observation with Prcp         Missing Day
        Multiday Observation         Daily/Multiday Observation Conflict

Day of Year Daily Prcp Multiday Prcp
10/1/2009 T
10/2/2009
10/3/2009 0.04
10/4/2009 0.00
10/5/2009 0.00
10/6/2009 0.00
10/7/2009 0.04
10/8/2009 0.00
10/9/2009 T
10/10/2009 0.02
10/11/2009 0.01
10/12/2009 0.00
10/13/2009 0.00
10/14/2009
10/15/2009 0.15
10/16/2009 0.87
10/17/2009 0.85
10/18/2009 1.45
10/19/2009 T
10/20/2009 0.00
10/21/2009
10/22/2009
10/23/2009
10/24/2009 **
10/25/2009 **
10/26/2009 0.48
10/27/2009 0.58
10/28/2009 1.14
10/29/2009 0.01
10/30/2009 0.00 **
10/31/2009 **
11/1/2009 **
11/2/2009 0.61
11/3/2009 0.00
11/4/2009 0.00
11/5/2009 0.00
11/6/2009 0.03
11/7/2009 0.00
11/8/2009 0.00
11/9/2009 0.00
11/10/2009 0.00
11/11/2009 0.13
11/12/2009 1.07
11/13/2009 0.21
11/14/2009 0.37
11/15/2009 0.01
11/16/2009 0.00
11/17/2009 0.00
11/18/2009 0.00
11/19/2009 0.01
11/20/2009 **
11/21/2009 **
11/22/2009 **
11/23/2009 **
11/24/2009 1.74
11/25/2009 0.15
11/26/2009 0.10
11/27/2009 0.35
11/28/2009 T
11/29/2009
11/30/2009 0.00
12/1/2009 0.30
12/2/2009 0.00
12/3/2009 0.80
12/4/2009 0.00
12/5/2009 0.02
12/6/2009 0.74
12/7/2009 0.00
12/8/2009 0.00
12/9/2009 1.61
12/10/2009 0.01
12/11/2009 0.00
12/12/2009
12/13/2009 0.03
12/14/2009 0.73
12/15/2009 0.00
12/16/2009 0.00
12/17/2009 0.00
12/18/2009 0.00
12/19/2009 0.68
12/20/2009 1.10
12/21/2009 0.00
12/22/2009 0.00
12/23/2009 0.00
12/24/2009 0.00
12/25/2009 0.00
12/26/2009 1.19
12/27/2009 0.07
12/28/2009 0.00
12/29/2009 0.00
12/30/2009 0.00
12/31/2009 0.23
Day of YearDaily PrcpMultiday Prcp
1/1/2010 0.21
1/2/2010 0.00
1/3/2010 0.00
1/4/2010 0.00
1/5/2010 0.00
1/6/2010 0.00
1/7/2010 0.00
1/8/2010 0.12
1/9/2010 0.00
1/10/2010 0.00
1/11/2010 0.00
1/12/2010 0.00
1/13/2010 0.00
1/14/2010
1/15/2010 0.00
1/16/2010 0.00
1/17/2010 **
1/18/2010 **
1/19/2010 0.62
1/20/2010 0.04
1/21/2010 0.00
1/22/2010 0.13
1/23/2010 T
1/24/2010 T
1/25/2010 0.52
1/26/2010 0.14
1/27/2010 0.02
1/28/2010 0.00
1/29/2010 0.00
1/30/2010
1/31/2010 0.36
2/1/2010 0.00
2/2/2010 0.00
2/3/2010 0.37
2/4/2010 0.00
2/5/2010
2/6/2010 1.75
2/7/2010 0.48
2/8/2010 0.00
2/9/2010 0.00
2/10/2010 0.63
2/11/2010 0.47
2/12/2010 0.00
2/13/2010 0.00
2/14/2010 0.00
2/15/2010 0.00
2/16/2010 0.03
2/17/2010 0.00
2/18/2010 T
2/19/2010 0.00
2/20/2010 0.00
2/21/2010 0.00
2/22/2010 0.00
2/23/2010 0.15
2/24/2010
2/25/2010 0.04
2/26/2010 T
2/27/2010
2/28/2010
3/1/2010 0.00
3/2/2010 0.00
3/3/2010 0.08
3/4/2010 0.01
3/5/2010
3/6/2010 0.00
3/7/2010 0.00
3/8/2010 0.00
3/9/2010 0.00
3/10/2010 0.00
3/11/2010 0.00
3/12/2010 0.57
3/13/2010 0.51
3/14/2010 1.00
3/15/2010 0.07
3/16/2010 0.05
3/17/2010 0.00
3/18/2010 0.00
3/19/2010 0.00
3/20/2010 0.00
3/21/2010 0.00
3/22/2010 0.03
3/23/2010 0.37
3/24/2010 0.01
3/25/2010 0.00
3/26/2010 0.28
3/27/2010 0.11
3/28/2010 0.00
3/29/2010 0.64
3/30/2010 0.03
3/31/2010 0.03
Day of YearDaily PrcpMultiday Prcp
4/1/2010 0.00
4/2/2010 0.00
4/3/2010 0.00
4/4/2010 0.00
4/5/2010 0.00
4/6/2010 T
4/7/2010 0.00
4/8/2010 0.00
4/9/2010 0.72
4/10/2010 0.00
4/11/2010 0.00
4/12/2010 0.00
4/13/2010 **
4/14/2010 **
4/15/2010 **
4/16/2010 **
4/17/2010 **
4/18/2010 **
4/19/2010 **
4/20/2010 0.14
4/21/2010 0.00
4/22/2010 0.27
4/23/2010 0.00
4/24/2010
4/25/2010 0.13
4/26/2010 1.00
4/27/2010 0.16
4/28/2010 0.00
4/29/2010 0.00
4/30/2010 0.00
5/1/2010
5/2/2010
5/3/2010 0.49
5/4/2010 0.03
5/5/2010
5/6/2010
5/7/2010
5/8/2010
5/9/2010
5/10/2010
5/11/2010 0.00
5/12/2010 0.17
5/13/2010 0.92
5/14/2010 0.00
5/15/2010
5/16/2010
5/17/2010 0.04
5/18/2010 0.41
5/19/2010 0.01
5/20/2010 0.00
5/21/2010 0.00
5/22/2010 0.00
5/23/2010 **
5/24/2010 1.64
5/25/2010 T
5/26/2010 0.00
5/27/2010 0.00
5/28/2010 0.16
5/29/2010 T
5/30/2010 0.00
5/31/2010 0.00
6/1/2010 0.00
6/2/2010 T
6/3/2010
6/4/2010 0.04
6/5/2010 **
6/6/2010 **
6/7/2010 **
6/8/2010 0.36
6/9/2010 0.00
6/10/2010 0.19
6/11/2010 0.00
6/12/2010
6/13/2010 T
6/14/2010 0.02
6/15/2010 0.28
6/16/2010 0.00
6/17/2010 0.16
6/18/2010 0.00
6/19/2010 0.00
6/20/2010 0.00
6/21/2010 0.00
6/22/2010 0.00
6/23/2010 0.33
6/24/2010 0.00
6/25/2010 0.00
6/26/2010 0.00
6/27/2010 **
6/28/2010 **
6/29/2010 **
6/30/2010 0.69
Day of YearDaily PrcpMultiday Prcp
7/1/2010 0.00
7/2/2010 0.00
7/3/2010 0.00
7/4/2010 0.00
7/5/2010 0.00
7/6/2010 0.00
7/7/2010 0.00
7/8/2010 0.00
7/9/2010 0.00 **
7/10/2010 **
7/11/2010 0.59
7/12/2010 0.00
7/13/2010 0.84
7/14/2010 1.49
7/15/2010 0.22
7/16/2010 **
7/17/2010 **
7/18/2010 **
7/19/2010 **
7/20/2010 0.73
7/21/2010 0.00
7/22/2010 T
7/23/2010 0.00
7/24/2010
7/25/2010 0.00
7/26/2010 0.97
7/27/2010 0.00
7/28/2010 0.00
7/29/2010 0.00
7/30/2010 0.60
7/31/2010 0.00
8/1/2010 **
8/2/2010 0.04
8/3/2010 T
8/4/2010 0.96
8/5/2010 T
8/6/2010 0.03
8/7/2010 0.00
8/8/2010 0.00
8/9/2010 0.00
8/10/2010 0.00
8/11/2010 0.00
8/12/2010 2.07
8/13/2010 0.98
8/14/2010 0.06
8/15/2010
8/16/2010 0.40
8/17/2010 0.00
8/18/2010 1.77
8/19/2010 0.76
8/20/2010 0.00
8/21/2010
8/22/2010 0.01
8/23/2010 0.15
8/24/2010 0.14
8/25/2010 T
8/26/2010 0.00
8/27/2010 0.00
8/28/2010
8/29/2010 0.00
8/30/2010 0.00
8/31/2010
9/1/2010 0.00
9/2/2010
9/3/2010
9/4/2010
9/5/2010
9/6/2010
9/7/2010
9/8/2010 0.00
9/9/2010
9/10/2010 0.00
9/11/2010 **
9/12/2010 **
9/13/2010 **
9/14/2010 0.81
9/15/2010 0.00
9/16/2010 0.00
9/17/2010 0.23
9/18/2010
9/19/2010
9/20/2010
9/21/2010
9/22/2010
9/23/2010 0.02
9/24/2010 0.00
9/25/2010
9/26/2010 0.00
9/27/2010 0.33
9/28/2010 0.31
9/29/2010 0.02
9/30/2010 1.78



Observation Date Observation Time Precipitation Snowfall Snowfall SWE Snow Depth Snow SWE Notes
10/1/2009 7:00 AM T M M M M
10/3/2009 7:00 AM 0.04 M M M M RW Last night around 8PM (.02) 10/2 and again early am 10/3
10/4/2009 7:00 AM 0.00 0.0 M M M
10/5/2009 7:00 AM 0.00 0.0 M M M
10/6/2009 7:00 AM 0.00 0.0 M M M
10/7/2009 7:00 AM 0.04 M M M M AM showers before obs time 10/7.
10/8/2009 7:00 AM 0.00 0.0 M M M
10/9/2009 7:00 AM T M M M M Rain shower around 10PM last night (10/8)
10/10/2009 8:00 AM 0.02 M M M M Early AM shower.
10/11/2009 7:00 AM 0.01 M M M M Rain from yesterday 10/10 10-12AM
10/12/2009 7:00 AM 0.00 0.0 M M M
10/13/2009 7:00 AM 0.00 0.0 M M M
10/15/2009 7:00 AM 0.15 M M M M Light rain at obs time. .13 by 11PM last night, .02 additional overnight.
10/16/2009 7:00 AM 0.87 M M M M
10/17/2009 7:30 AM 0.85 0.0 M M M Continuous light rain for 24hrs, .38 by 7AM-Mid 10/16. .47 Mid-7:30AM 10/17. Yesterdays max temp only 42 F.
10/18/2009 7:00 AM 1.45 0.0 M M M Continuous rain finally ends sometime in the Early AM. Subtotals: .69 7:30 AM-5:30 PM 10/17, .32 5:30PM-Mid 10/17, .44 12:01-7AM 10/18. 24-h total 1.45. Continuous rain and drizzle was observed since Wednesday afternoon(10/14); 85 hours, totaling 3.32.
10/19/2009 7:00 AM T 0.0 M M M First Frost. 10/19. Rain from yesterday morning.
10/20/2009 7:00 AM 0.00 0.0 M M M
10/27/2009 7:20 AM 0.58 0.0 M 0.0 M Rain began early AM (before 4:30AM) 10/27. Light rain at obs time.
10/28/2009 7:00 AM 1.14 0.0 M 0.0 M .29 7A-10PM 10/27 .85 10PM-7AM.
10/29/2009 7:00 AM 0.01 0.0 M 0.0 M Rain from yesterday morning just after 7AM (10/28)
10/30/2009 7:00 AM 0.00 0.0 M 0.0 M
11/3/2009 7:00 AM 0.00 0.0 M M M
11/4/2009 7:00 AM 0.00 0.0 M 0.0 M
11/5/2009 7:00 AM 0.00 0.0 M M M
11/6/2009 7:00 AM 0.03 0.0 M 0.0 M RW last evening (11/5) around 5-7 PM.
11/7/2009 7:00 AM 0.00 0.0 M M M
11/8/2009 7:00 AM 0.00 0.0 M M M
11/9/2009 7:00 AM 0.00 0.0 M M M
11/10/2009 7:00 AM 0.00 0.0 M 0.0 M
11/11/2009 8:00 AM 0.13 0.0 M 0.0 M Light rain at obs time
11/12/2009 7:00 AM 1.07 0.0 M 0.0 M Continuous rain since yesterdays obs time... .67 8A-10:30 PM 11/11. .40 10:30PM - 8AM.
11/13/2009 7:00 AM 0.21 0.0 M 0.0 M
11/14/2009 7:00 AM 0.37 0.0 M 0.0 M
11/15/2009 7:00 AM 0.01 0.0 M 0.0 M
11/16/2009 7:00 AM 0.00 0.0 M 0.0 M
11/17/2009 7:00 AM 0.00 0.0 M 0.0 M
11/18/2009 7:00 AM 0.00 0.0 M 0.0 M
11/19/2009 7:00 AM 0.01 0.0 M 0.0 M Drizzle at obs time.
11/25/2009 7:00 AM 0.15 0.0 M 0.0 M 24-hr drizzle
11/26/2009 7:00 AM 0.10 0.0 M 0.0 M
11/27/2009 7:00 AM 0.35 0.0 M 0.0 M Rain last night around 9PM.
11/28/2009 7:00 AM T 0.0 M 0.0 M
11/30/2009 7:00 AM 0.00 0.0 M 0.0 M
12/1/2009 7:00 AM 0.30 0.0 M 0.0 M
12/2/2009 7:00 AM 0.00 0.0 M 0.0 M
12/3/2009 7:00 AM 0.80 0.0 M 0.0 M
12/4/2009 7:00 AM 0.00 0.0 M 0.0 M
12/5/2009 7:00 AM 0.02 0.0 M 0.0 M Light rain at obs time
12/6/2009 7:00 AM 0.74 3.5 M 2.5 M Rain changed to snow by about 10:AM Dec. 5. Heavy wet snow continued to about 4PM, then light snow showers with some snow grains to 8PM.
12/7/2009 7:00 AM 0.00 0.0 M 2.0 M
12/8/2009 7:00 AM 0.00 0.0 M 2.0 M Saturday's heavy wet snow turns to ice and refuses to melt.
12/9/2009 7:15 AM 1.61 0.1 M T M Precip began as sleet last night around 8PM-9PM, changed to rain. .34 by midnight. Northwest branch river at Bonifant Road is outside of its banks. Drizzle at obs time.
12/10/2009 7:00 AM 0.01 0.0 M 0.0 M Rain ends around 9AM 12/9. Clearing afterwards. All snow cover gone by evening as temps reach 52.
12/11/2009 7:00 AM 0.00 0.0 M 0.0 M
12/13/2009 7:30 AM 0.03 0.0 M 0.0 M Rain freezes on some cold ground surfaces but not on vegetation or autos.
12/14/2009 7:00 AM 0.73 0.0 M 0.0 M Rain from obs time yesterday (12/13) to about 4 PM. 12/13. Year-to-date Precip total (Jan 1 - Dec 14) exceeds 50 inches with this event.
12/15/2009 7:00 AM 0.00 0.0 M 0.0 M
12/16/2009 7:00 AM 0.00 0.0 M 0.0 M
12/17/2009 7:00 AM 0.00 0.0 M 0.0 M
12/18/2009 7:00 AM 0.00 0.0 M 0.0 M
12/19/2009 7:00 AM 0.68 7.0 0.68 7.0 0.68 Snow began around 9:30 PM 12/18. Moderate to heavy snow at obs time. Snow drifting and somewhat difficult to measure. Measurements between 17 and 19 cm, with higher amounts well away from trees (but on the lawn) Precip from core sample. Seems reasonably close to 10-to 1. Gauge catch is unreliable and low due to wind, 7AM guage catch readings: .34 for around 11 cm. - 12 to 1.
12/20/2009 7:30 AM 1.10 14.7 M 18.5 M Storm total 21.7 inches, 1.78 liquid = 12 to 1 ratio. Precip estimate from the snow/liquid ratio taken from of the full 12 inch rain gauge. .90/12.0 and applied to the 14.7 measurement. Snow measured taken from the total accumulation from 2 snow boards, one placed at 7AM and at another placed at 2PM without clearing the first. Both gave consistent results. Storm sub totals: .5 inches at 11:30 12/17, 7.0 7 AM 12/19, 14.0 2PM 12/19, 18. at 4 PM, 21.5 inches at 9PM (Second snow board cleared) 21.7 by 11PM. Highest snow depth 20 inches when snow became light at around 9 PM. Snow ended around 11 PM.
12/21/2009 7:00 AM 0.00 0.0 M 15.0 M
12/22/2009 7:00 AM 0.00 0.0 M 14.0 M
12/23/2009 7:00 AM 0.00 0.0 M 11.0 M
12/24/2009 7:00 AM 0.00 0.0 M 10.5 M
12/25/2009 9:00 AM 0.00 0.0 M 10.0 M
12/26/2009 7:30 AM 1.19 0.0 M 3.0 M Rain holds off until temps rise above freezing on Christmas day. .43 by 11 PM 12/25. .76 overnight.
12/27/2009 7:00 AM 0.07 0.0 M T M
12/28/2009 7:00 AM 0.00 0.0 M T M
12/29/2009 7:00 AM 0.00 0.0 M T M
12/30/2009 7:00 AM 0.00 0.0 M T M
12/31/2009 7:00 AM 0.23 1.1 M 1.0 M Precip began in the early AM 12/31 as sleet and freezing rain, forming a hard lower layer of snow cover, followed by an inch or so of a mix of soft and grainy snow. Melted Gauge catch .23.
1/1/2010 7:00 AM 0.21 T M 0.5 M Some snow yesterday morning, no further accumulation. A little sleet mixed with rain at one point last night. Calendar year 2009 finishes with 53.51 inches total.
1/2/2010 7:00 AM 0.00 0.0 M T M
1/3/2010 7:00 AM 0.00 0.0 M T M
1/4/2010 7:00 AM 0.00 0.0 M T M
1/5/2010 7:00 AM 0.00 0.0 M T M
1/6/2010 7:00 AM 0.00 0.0 M T M
1/7/2010 7:00 AM 0.00 0.0 M T M
1/8/2010 7:00 AM 0.12 2.2 M 2.0 M Snow began 9:PM 1/7. .8 Inch by 1AM, 2.2 inches of fluff total. Precip from melted gauge catch.
1/9/2010 7:00 AM 0.00 0.0 M 1.0 M
1/10/2010 7:00 AM 0.00 0.0 M 0.5 M
1/11/2010 7:00 AM 0.00 0.0 M 0.5 M
1/12/2010 7:00 AM 0.00 0.0 M 0.5 M
1/13/2010 7:00 AM 0.00 0.0 M T M
1/15/2010 7:00 AM 0.00 0.0 M T M
1/16/2010 7:00 AM 0.00 0.0 M 0.0 M
1/20/2010 7:00 AM 0.04 T M T M Sleet overnight. Debated whether new snow was .1 inch or trace since measurement was about .05. Because sleet melted on many surfaces, I went with trace.
1/21/2010 7:00 AM 0.00 0.0 M 0.0 M
1/22/2010 7:00 AM 0.13 T M 0.0 M Precip began as sleet about 9PM last night, changed to a cold rain.
1/23/2010 7:00 AM T 0.0 M 0.0 M
1/24/2010 8:00 AM T 0.0 M 0.0 M
1/25/2010 7:00 AM 0.52 0.0 M 0.0 M
1/26/2010 7:00 AM 0.14 0.0 M 0.0 M
1/27/2010 7:00 AM 0.02 T M 0.0 M Showers Snow mixed with rain around 3PM.
1/28/2010 7:00 AM 0.00 0.0 M 0.0 M
1/29/2010 7:00 AM 0.00 0.0 M 0.0 M
1/31/2010 7:00 AM 0.36 6.6 M 6.0 M Precip-to-snow ratio estimated from melted gauge snowfall catch. 19-to 1.
2/1/2010 7:00 AM 0.00 0.0 M 4.5 M
2/2/2010 7:00 AM 0.00 0.0 M 3.0 M
2/3/2010 7:00 AM 0.37 5.2 M 7.0 M Snow began around 7PM. 3.2 by 11:30 PM 2/2, 2.0 additional by 7AM. Precip estimated by gauge catch ratio from the 11:30 obs applied to the storm total. The gauge catch after midnight seemed too low.
2/4/2010 7:00 AM 0.00 0.0 M 3.0 M
2/6/2010 7:00 AM 1.75 22.0 M 24.0 M Snowing at obs time. Drifting... snow boards weren't of much use. Measurement an average of new snow (existing snow cover had an icy top that could be felt). Precip estimated from melted ratio of full 12-inch gauge applied to total. Power out from 4AM-2PM. Snow from yesterday and last night had the consistency of flour. Current snow more fluffy.
2/7/2010 7:00 AM 0.48 7.0 M 27.0 M Precip from core sample on new snow. 29 inches total in storm. Snow finally ended about 4PM 2/6.
2/8/2010 7:00 AM 0.00 0.0 M 24.0 M
2/9/2010 7:00 AM 0.00 0.0 M 23.0 M
2/10/2010 7:00 AM 0.63 4.3 M 25.0 M Snow began 4: PM 2/9. 2.5 inches by 11 PM. Change to sleet and some freezing rain around Midnight (2/9-2/10). ,3 inch sleet layer, then an additional 1.5 inches of snow by obs time of 7AM.
2/11/2010 7:00 AM 0.47 5.3 M 27.0 M Blowing snow... Snowfall difficult to measure. An average of 6.8 inches of snow above the sleet layer was observed. 1.5 inches of that amount was reported for yesterday's obs. Precip from core on snowboard and gauge catch. Storm total - 9.6 Month total so far: 43.8 - season total 79.0 inches.
2/12/2010 7:00 AM 0.00 0.0 M 25.0 M
2/13/2010 7:00 AM 0.00 0.0 M 22.5 M
2/14/2010 7:00 AM 0.00 0.0 M 21.0 M
2/15/2010 7:00 AM 0.00 0.0 M 20.0 M
2/16/2010 7:00 AM 0.03 0.4 M 20.0 M
2/17/2010 7:00 AM 0.00 0.0 M 19.0 M
2/18/2010 7:00 AM T T M 18.0 M Revised report. A few snow flakes were observed on 2/17 just after observation time.
2/19/2010 7:00 AM 0.00 0.0 M 16.0 M
2/20/2010 7:00 AM 0.00 0.0 M 14.0 M
2/21/2010 7:00 AM 0.00 0.0 M 13.0 M
2/22/2010 7:00 AM 0.00 0.0 M 12.0 M
2/23/2010 7:00 AM 0.15 0.0 M 10.0 M
2/25/2010 7:00 AM 0.04 0.1 M 7.0 M Rain changing to snow and possibly sleet sometime between midnight and dawn.
2/26/2010 7:00 AM T T M 6.0 M Occasional very light snow flurries for the last 24 hrs.
3/1/2010 7:00 AM 0.00 0.0 M 4.0 M
3/2/2010 7:00 AM 0.00 0.0 M 3.0 M
3/3/2010 7:00 AM 0.08 T M 2.0 M Rain and snow mixed. There was enough wet snow to accumulate on cars at 10:PM, but in general, snow melted as it fell. My snow board, resting on top of snow cover, did not accumulate snow, so new snow=Trace.
3/4/2010 7:00 AM 0.01 M M 1.0 M Snow cover difficult to measure. 50% cover with area covered between 1 and 6 inches. The area selected in previous days as having "average" snow still has about an inch.
3/6/2010 7:00 AM 0.00 0.0 M T M
3/7/2010 7:00 AM 0.00 0.0 M T M
3/8/2010 7:00 AM 0.00 0.0 M 0.0 M
3/9/2010 7:00 AM 0.00 0.0 M 0.0 M
3/10/2010 7:00 AM 0.00 0.0 M 0.0 M
3/11/2010 7:00 AM 0.00 0.0 M 0.0 M
3/12/2010 7:00 AM 0.57 0.0 M 0.0 M
3/13/2010 7:00 AM 0.51 0.0 M 0.0 M wind but not much rain
3/14/2010 7:30 AM 1.00 0.0 M 0.0 M 1.00 - no rounding... Switch to daylight time.
3/15/2010 7:00 AM 0.07 0.0 M 0.0 M
3/16/2010 7:00 AM 0.05 0.0 M 0.0 M
3/17/2010 7:00 AM 0.00 0.0 M 0.0 M
3/18/2010 7:00 AM 0.00 0.0 M 0.0 M
3/19/2010 7:00 AM 0.00 0.0 M 0.0 M
3/20/2010 7:00 AM 0.00 0.0 M 0.0 M
3/21/2010 7:00 AM 0.00 0.0 M 0.0 M
3/22/2010 7:00 AM 0.03 0.0 M 0.0 M
3/23/2010 7:00 AM 0.37 0.0 M 0.0 M
3/24/2010 7:00 AM 0.01 0.0 M 0.0 M
3/25/2010 7:00 AM 0.00 0.0 M 0.0 M
3/26/2010 7:00 AM 0.28 0.0 M 0.0 M
3/27/2010 7:00 AM 0.11 0.0 M 0.0 M
3/28/2010 7:00 AM 0.00 0.0 M 0.0 M
3/29/2010 7:00 AM 0.64 0.0 M 0.0 M
3/30/2010 7:00 AM 0.03 0.0 M 0.0 M
3/31/2010 7:00 AM 0.03 0.0 M 0.0 M
4/1/2010 7:00 AM 0.00 0.0 M 0.0 M
4/2/2010 7:00 AM 0.00 0.0 M 0.0 M
4/3/2010 7:00 AM 0.00 0.0 M 0.0 M
4/4/2010 7:00 AM 0.00 0.0 M 0.0 M
4/5/2010 7:00 AM 0.00 0.0 M 0.0 M
4/6/2010 7:00 AM T 0.0 M 0.0 M A few drops of rain just prior to obs time at 7AM.
4/7/2010 7:00 AM 0.00 0.0 M 0.0 M
4/8/2010 7:00 AM 0.00 0.0 M 0.0 M
4/9/2010 7:00 AM 0.72 0.0 M 0.0 M Precip begins around 7:30 PM 4/8 as thundershowers until about 10 PM.. just rain after that
4/10/2010 7:00 AM 0.00 0.0 M 0.0 M
4/11/2010 7:00 AM 0.00 0.0 M 0.0 M
4/12/2010 7:00 AM 0.00 0.0 M 0.0 M
4/21/2010 7:00 AM 0.00 0.0 M 0.0 M
4/22/2010 7:00 AM 0.27 0.0 M 0.0 M
4/23/2010 7:00 AM 0.00 0.0 M 0.0 M
4/25/2010 7:30 AM 0.13 0.0 M 0.0 M
4/26/2010 7:00 AM 1.00 0.0 M 0.0 M Thunderstorms 9:30-Midnight. Pea Size hail 10:54 PM.
4/27/2010 7:00 AM 0.16 0.0 M 0.0 M
4/28/2010 7:00 AM 0.00 0.0 M 0.0 M Light Frost in frost-prone locations.
4/29/2010 7:00 AM 0.00 0.0 M 0.0 M
4/30/2010 7:00 AM 0.00 0.0 M 0.0 M 2009-2010 Seasonal snowfall total =80.1 inches. Snowfall is rarely if ever observed in the DC area from May-Sept, so the New Snow and total snow will be default NA until Oct 1.
5/3/2010 7:00 AM 0.49 M M M M
5/4/2010 7:00 AM 0.03 M M M M
5/11/2010 7:00 AM 0.00 0.0 M M M
5/12/2010 7:00 AM 0.17 M M M M
5/13/2010 7:00 AM 0.92 M M M M TRW around 6 PM. Drizzle overnight.
5/14/2010 7:00 AM 0.00 0.0 M M M
5/17/2010 8:00 AM 0.04 M M M M
5/18/2010 8:00 AM 0.41 M M M M
5/19/2010 7:00 AM 0.01 M M M M
5/20/2010 7:00 AM 0.00 0.0 M M M
5/21/2010 7:00 AM 0.00 0.0 M M M
5/22/2010 7:00 AM 0.00 0.0 M M M
5/25/2010 7:00 AM T M M M M
5/26/2010 7:00 AM 0.00 0.0 M M M
5/27/2010 7:00 AM 0.00 0.0 M M M
5/28/2010 7:00 AM 0.16 M M M M Thunder showers 11PM 5/27 to 3AM 5/28.
5/29/2010 7:00 AM T M M M M
5/30/2010 7:00 AM 0.00 0.0 M M M
5/31/2010 7:00 AM 0.00 0.0 M M M
6/1/2010 7:00 AM 0.00 0.0 M M M
6/2/2010 7:00 AM T M M M M Trace precip in RW- around 11PM 6/1. Possible shower around 2PM --- trace amounts at most.
6/4/2010 7:00 AM 0.04 M M M M
6/9/2010 7:00 AM 0.00 0.0 M M M
6/10/2010 7:00 AM 0.19 M M M M Rain showers off and on yesterday (June 9 .17) with an additional .02 inch of precip sometime overnight.
6/11/2010 7:00 AM 0.00 0.0 M M M
6/13/2010 7:00 AM T M M M M
6/14/2010 7:00 AM 0.02 M M M M Rain shower around 9AM 6/13.
6/15/2010 7:00 AM 0.28 M M M M Heavy rainshower around 7:30 PM no thunder
6/16/2010 7:00 AM 0.00 0.0 M M M
6/17/2010 7:00 AM 0.16 M M M M
6/18/2010 7:00 AM 0.00 0.0 M M M
6/19/2010 7:00 AM 0.00 0.0 M M M
6/20/2010 7:00 AM 0.00 0.0 M M M
6/21/2010 7:00 AM 0.00 0.0 M M M
6/22/2010 7:00 AM 0.00 0.0 M M M
6/23/2010 7:00 AM 0.33 M M M M
6/24/2010 7:00 AM 0.00 0.0 M M M
6/25/2010 7:00 AM 0.00 0.0 M M M
6/26/2010 7:00 AM 0.00 0.0 M M M
7/1/2010 7:00 AM 0.00 0.0 M M M
7/2/2010 7:00 AM 0.00 0.0 M M M
7/3/2010 7:00 AM 0.00 0.0 M M M
7/4/2010 7:00 AM 0.00 0.0 M M M
7/5/2010 7:00 AM 0.00 0.0 M M M
7/6/2010 7:00 AM 0.00 0.0 M M M
7/7/2010 7:00 AM 0.00 0.0 M M M 100 degrees F for a max (7/6). Second hottest day since records began at this location in 1991. (Hottest 101 F July 6, 1999)
7/8/2010 7:00 AM 0.00 0.0 M M M Max temp 7/7 = 100 F
7/9/2010 7:00 AM 0.00 0.0 M M M
7/12/2010 7:00 AM 0.00 0.0 M M M
7/13/2010 7:00 AM 0.84 M M M M Trw in late afternoon 7/12 (.07) and another around 10PM
7/14/2010 7:15 AM 1.49 M M M M Trw 7/13 8PM-10PM and again 11:PM- 1AM. Light rain at observation time.
7/15/2010 7:00 AM 0.22 M M M M Rain yesterday morning (7/14) - noon
7/21/2010 7:00 AM 0.00 0.0 M M M
7/22/2010 7:00 AM T M M M M A few rain drops at 8 AM yesterday morning (7/21)
7/23/2010 7:00 AM 0.00 0.0 M M M
7/25/2010 7:00 AM 0.00 0.0 M M M
7/26/2010 7:00 AM 0.97 M M M M TRW+ 4PM 7/25 .97 in about 20 minutes. Damaging winds.
7/27/2010 7:00 AM 0.00 0.0 M M M
7/28/2010 7:00 AM 0.00 0.0 M M M
7/29/2010 7:00 AM 0.00 0.0 M M M
7/30/2010 7:00 AM 0.60 M M M M
7/31/2010 7:00 AM 0.00 0.0 M M M
8/3/2010 7:00 AM T M M M M
8/4/2010 7:00 AM 0.96 M M M M Thunderstorms in the early AM 8/4
8/5/2010 7:00 AM T M M M M
8/6/2010 7:00 AM 0.03 M M M M
8/7/2010 7:00 AM 0.00 0.0 M M M
8/8/2010 7:00 AM 0.00 0.0 M M M
8/9/2010 7:00 AM 0.00 0.0 M M M
8/10/2010 7:00 AM 0.00 0.0 M M M
8/11/2010 7:00 AM 0.00 0.0 M M M
8/12/2010 8:10 AM 2.07 M M M M Heavy thunderstorm at obs time (7:AM) Rain began at 6:55, continued to just after 8AM. 2.07 inches in just one hour Numerous close (near direct) lightning strikes. Moderate wind.
8/13/2010 7:00 AM 0.98 M M M M Rain showers off and on yesterday and last night. TRW's yesterday evening (.25). Rain Mid-7A = .73. Big totals from yesterday morning's showers on yesterdays obs (which ended at 8AM.) 2-day total 3.05 inches.
8/14/2010 7:00 AM 0.06 M M M M Rain from yesterday morning 7-9 AM
8/16/2010 7:00 AM 0.40 M M M M Rain showers 9AM-3PM yesterday (8/15)
8/17/2010 7:00 AM 0.00 0.0 M M M
8/18/2010 7:30 AM 1.77 M M M M Rain Midnight to 7:30 AM obs time. Drizzle at obs time
8/19/2010 7:00 AM 0.76 M M M M Rain showers yesterday (8/18), especially in the morning around 8AM
8/20/2010 7:00 AM 0.00 0.0 M M M
8/22/2010 7:00 AM 0.01 M M M M
8/23/2010 7:00 AM 0.15 M M M M
8/24/2010 7:30 AM 0.14 M M M M
8/25/2010 7:00 AM T M M M M
8/26/2010 7:00 AM 0.00 0.0 M M M
8/27/2010 7:00 AM 0.00 0.0 M M M
8/29/2010 7:00 AM 0.00 0.0 M M M
8/30/2010 7:00 AM 0.00 0.0 M M M
9/1/2010 7:00 AM 0.00 0.0 M M M
9/8/2010 7:00 AM 0.00 0.0 M M M
9/10/2010 7:00 AM 0.00 0.0 M M M
9/15/2010 7:00 AM 0.00 0.0 M M M
9/16/2010 7:00 AM 0.00 0.0 M M M
9/17/2010 7:00 AM 0.23 0.0 M 0.0 M
9/23/2010 7:00 AM 0.02 0.0 M 0.0 M
9/24/2010 7:00 AM 0.00 0.0 M 0.0 M
9/26/2010 7:00 AM 0.00 0.0 M 0.0 M
9/27/2010 7:30 AM 0.33 0.0 M 0.0 M .07 in morning rain yesterday (9/26) 8 - 11 AM. .26 in the early AM 9/27. Light rain at obs time.
9/28/2010 7:00 AM 0.31 0.0 M 0.0 M
9/29/2010 7:00 AM 0.02 0.0 M 0.0 M Rain yesterday (9/28) morning, within a few hours of the obs time.
9/30/2010 7:20 AM 1.78 0.0 M 0.0 M



Start Date End Date & Time Duration in Days Precipitation Snow Depth Snow Depth SWE Notes
10/24/2009 10/26/2009 7:00 AM 3 0.48 M M
10/30/2009 11/02/2009 12:00 AM 4 0.62 M M
10/31/2009 11/02/2009 7:00 AM 3 0.61 M M
11/20/2009 11/24/2009 8:00 AM 5 1.74 M M
1/17/2010 1/19/2010 7:00 AM 3 0.62 0.0 M
4/13/2010 4/20/2010 7:00 AM 8 0.14 0.0 M
5/23/2010 5/24/2010 7:00 AM 2 1.64 M M
6/5/2010 6/08/2010 7:00 AM 4 0.36 M M
6/27/2010 6/30/2010 7:00 AM 4 0.69 M M
7/9/2010 7/11/2010 7:00 AM 3 0.59 M M
7/10/2010 7/11/2010 7:00 AM 2 0.59 M M Rain split obs time on the 10th... Got out late, no point in reporting amount except for 2-day total.
7/16/2010 7/20/2010 7:00 AM 5 0.73 M M
8/1/2010 8/02/2010 7:00 AM 2 0.04 M M
9/11/2010 9/14/2010 7:00 AM 4 0.81 M M



Observation Date Observation Time Notes Largest Stone Size Average Stone Size Smallest Stone Size Stone Consistency Duration Minutes Durration Accuracy Damage Timing More Rain than Hail Hail Started Largest Hail Started Angle of Impact Number of Stones on Pad Distance Between Stones on Pad Depth of Stones on Ground
4/25/2010 10:54 PM 1/4" Pea Size Rice Rice Hard 3 2min no damage Continuous True After rain Same time as smaller hail vertical