Station Overview Station Location
Station Number MD-MG-62 Latitude 39.08527
Station Name Rockville 1.8 W Longitude -77.1873
County Montgomery Elevation (ft) 422



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 3.41 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Nov 09 3.57 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Dec 09 3.09 1.63 2 1.63 2 0.00 0 0 2 0 21.0 2 2
Jan 10 2.89 2.09 20 2.09 20 0.00 0 0 10 0 10.2 4 8
Feb 10 2.72 4.27 6 4.27 6 0.00 0 0 6 0 48.4 6 6
March 10 3.70 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
April 10 3.28 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
May 10 4.20 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
June 10 3.77 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
July 10 3.87 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Aug 10 3.18 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Sept 10 3.99 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Water Year Totals: 41.67" 7.99" 28 days 7.99" 28 0.00" 0 days 0 18 days 0 days 79.6" 12 days 16 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
10/2/2009
10/3/2009
10/4/2009
10/5/2009
10/6/2009
10/7/2009
10/8/2009
10/9/2009
10/10/2009
10/11/2009
10/12/2009
10/13/2009
10/14/2009
10/15/2009
10/16/2009
10/17/2009
10/18/2009
10/19/2009
10/20/2009
10/21/2009
10/22/2009
10/23/2009
10/24/2009
10/25/2009
10/26/2009
10/27/2009
10/28/2009
10/29/2009
10/30/2009
10/31/2009
11/1/2009
11/2/2009
11/3/2009
11/4/2009
11/5/2009
11/6/2009
11/7/2009
11/8/2009
11/9/2009
11/10/2009
11/11/2009
11/12/2009
11/13/2009
11/14/2009
11/15/2009
11/16/2009
11/17/2009
11/18/2009
11/19/2009
11/20/2009
11/21/2009
11/22/2009
11/23/2009
11/24/2009
11/25/2009
11/26/2009
11/27/2009
11/28/2009
11/29/2009
11/30/2009
12/1/2009
12/2/2009
12/3/2009
12/4/2009
12/5/2009
12/6/2009
12/7/2009
12/8/2009
12/9/2009
12/10/2009
12/11/2009
12/12/2009
12/13/2009
12/14/2009
12/15/2009
12/16/2009
12/17/2009
12/18/2009
12/19/2009 0.59
12/20/2009 1.04
12/21/2009
12/22/2009
12/23/2009
12/24/2009
12/25/2009
12/26/2009
12/27/2009
12/28/2009
12/29/2009
12/30/2009
12/31/2009
Day of YearDaily PrcpMultiday Prcp
1/1/2010 0.44
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 0.11
1/9/2010 0.00
1/10/2010 0.00
1/11/2010 0.00
1/12/2010 0.00
1/13/2010
1/14/2010
1/15/2010
1/16/2010
1/17/2010
1/18/2010 0.69
1/19/2010
1/20/2010
1/21/2010 0.05
1/22/2010 0.13
1/23/2010 0.07
1/24/2010
1/25/2010 0.22
1/26/2010 0.02
1/27/2010 0.02
1/28/2010
1/29/2010
1/30/2010
1/31/2010 0.34
2/1/2010
2/2/2010
2/3/2010 0.30
2/4/2010
2/5/2010
2/6/2010 2.34
2/7/2010 0.51
2/8/2010
2/9/2010
2/10/2010 0.50
2/11/2010 0.59
2/12/2010
2/13/2010
2/14/2010
2/15/2010
2/16/2010 0.03
2/17/2010
2/18/2010
2/19/2010
2/20/2010
2/21/2010
2/22/2010
2/23/2010
2/24/2010
2/25/2010
2/26/2010
2/27/2010
2/28/2010
3/1/2010
3/2/2010
3/3/2010
3/4/2010
3/5/2010
3/6/2010
3/7/2010
3/8/2010
3/9/2010
3/10/2010
3/11/2010
3/12/2010
3/13/2010
3/14/2010
3/15/2010
3/16/2010
3/17/2010
3/18/2010
3/19/2010
3/20/2010
3/21/2010
3/22/2010
3/23/2010
3/24/2010
3/25/2010
3/26/2010
3/27/2010
3/28/2010
3/29/2010
3/30/2010
3/31/2010
Day of YearDaily PrcpMultiday Prcp
4/1/2010
4/2/2010
4/3/2010
4/4/2010
4/5/2010
4/6/2010
4/7/2010
4/8/2010
4/9/2010
4/10/2010
4/11/2010
4/12/2010
4/13/2010
4/14/2010
4/15/2010
4/16/2010
4/17/2010
4/18/2010
4/19/2010
4/20/2010
4/21/2010
4/22/2010
4/23/2010
4/24/2010
4/25/2010
4/26/2010
4/27/2010
4/28/2010
4/29/2010
4/30/2010
5/1/2010
5/2/2010
5/3/2010
5/4/2010
5/5/2010
5/6/2010
5/7/2010
5/8/2010
5/9/2010
5/10/2010
5/11/2010
5/12/2010
5/13/2010
5/14/2010
5/15/2010
5/16/2010
5/17/2010
5/18/2010
5/19/2010
5/20/2010
5/21/2010
5/22/2010
5/23/2010
5/24/2010
5/25/2010
5/26/2010
5/27/2010
5/28/2010
5/29/2010
5/30/2010
5/31/2010
6/1/2010
6/2/2010
6/3/2010
6/4/2010
6/5/2010
6/6/2010
6/7/2010
6/8/2010
6/9/2010
6/10/2010
6/11/2010
6/12/2010
6/13/2010
6/14/2010
6/15/2010
6/16/2010
6/17/2010
6/18/2010
6/19/2010
6/20/2010
6/21/2010
6/22/2010
6/23/2010
6/24/2010
6/25/2010
6/26/2010
6/27/2010
6/28/2010
6/29/2010
6/30/2010
Day of YearDaily PrcpMultiday Prcp
7/1/2010
7/2/2010
7/3/2010
7/4/2010
7/5/2010
7/6/2010
7/7/2010
7/8/2010
7/9/2010
7/10/2010
7/11/2010
7/12/2010
7/13/2010
7/14/2010
7/15/2010
7/16/2010
7/17/2010
7/18/2010
7/19/2010
7/20/2010
7/21/2010
7/22/2010
7/23/2010
7/24/2010
7/25/2010
7/26/2010
7/27/2010
7/28/2010
7/29/2010
7/30/2010
7/31/2010
8/1/2010
8/2/2010
8/3/2010
8/4/2010
8/5/2010
8/6/2010
8/7/2010
8/8/2010
8/9/2010
8/10/2010
8/11/2010
8/12/2010
8/13/2010
8/14/2010
8/15/2010
8/16/2010
8/17/2010
8/18/2010
8/19/2010
8/20/2010
8/21/2010
8/22/2010
8/23/2010
8/24/2010
8/25/2010
8/26/2010
8/27/2010
8/28/2010
8/29/2010
8/30/2010
8/31/2010
9/1/2010
9/2/2010
9/3/2010
9/4/2010
9/5/2010
9/6/2010
9/7/2010
9/8/2010
9/9/2010
9/10/2010
9/11/2010
9/12/2010
9/13/2010
9/14/2010
9/15/2010
9/16/2010
9/17/2010
9/18/2010
9/19/2010
9/20/2010
9/21/2010
9/22/2010
9/23/2010
9/24/2010
9/25/2010
9/26/2010
9/27/2010
9/28/2010
9/29/2010
9/30/2010



Observation Date Observation Time Precipitation Snowfall Snowfall SWE Snow Depth Snow SWE Notes
12/19/2009 7:00 AM 0.59 7.8 M 7.0 M [Details forthcoming as of 2010/01/13]
12/20/2009 7:00 AM 1.04 13.2 M 16.5 M Greatest December Snowfall in Rockville, MD since early 1800s. Snow ended 1140P...then ZL--/ZL- 230-315A, no glazing seen. [Additional details forthcoming as of 2010/01/13].
1/1/2010 12:00 AM 0.44 1.3 M 1.0 M On 31st: -FZRA/-PL B~320A...to -SN/SN predawn before ending ~700A...then stray drop/-SP/PL- 1200P-400P, --RA to -RA 400P-late evening.
1/2/2010 7:00 AM 0.00 0.0 M 0.5 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 0.11 2.7 0.11 2.5 M On 7th: S- B~930P, continuing thru mdnt. 12:1 SLR.....On 8th: Snow E~430A, but not before an impressive period of S with huge fluffy flakes, 200-415A. 29:1 SLR.....Storm Total SLR 25:1.
1/9/2010 7:00 AM 0.00 0.0 M 1.5 M
1/10/2010 7:00 AM 0.00 0.0 M 1.0 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
1/18/2010 6:00 AM 0.69 0.0 M 0.0 M On 17th: -RA/ocnl RA 630A-1030P
1/21/2010 12:00 AM 0.05 T M M M On 20th: -RA/-DZ 300-715A, including period of -PL 530-545A. Note "New Snowfall" total is only sleet
1/22/2010 12:00 AM 0.13 T M M M On 21st: -RA w/ocnl -PL/(and maybe some -SN?) 745P-Obs.
1/23/2010 12:00 AM 0.07 T M M M On 22nd: -RA/(ocnl mixing with -PL?) Mdnt-200P. Note: "New snowfall" is sleet and only sleet.
1/25/2010 12:00 AM 0.22 0.0 M 0.0 M On 24th: -SH RA's/-RA 830-1130A, 430-900P...then -RA/(RA?) 900P-Obs
1/26/2010 12:00 AM 0.02 0.0 M 0.0 M On 25th: -RA Mdnt-1030A...then --SH RA's 400-1100P
1/27/2010 7:00 AM 0.02 0.1 M 0.0 M On 26th: Couple snow pellet showers ~300-400PM, then occ. RW-/sprinkles into early evening.
1/31/2010 7:00 AM 0.34 6.1 M 4.5 M On 30th: -SN/SN 915A-500P, keyed on by SN 1000-1100A & 300-400P...then -SN/--SN 500-1115P. Mixed w/snow pellets at onset. SLR 18:1...||...Further Notes: great dendrites 115P-end...915A-100P (0.16", 2.3", 14:1 SLR), then 100-11115P (0.18", 3.8", 21:1 SLR).
2/3/2010 7:00 AM 0.30 5.4 M 6.0 M On 2nd: A few flakes 500-505P, then S- B~530P. At onset snow melted as it fell, but began sticking to pavement 600-645PM, but measured 0.2" on car top at 600P. Slowly increasing in intensity to period of S 930-1150P.....On 3rd: S- until a good burst of S right before ending ~500A.....**TO NOTE**: Liquid precipitation on 2nd is estimated as a chunk of snow fell off top of gauge.
2/6/2010 7:00 AM 2.34 22.5 M 21.0 M On 5th: Few flakes 1028-1045AM, then continuous S- from 1045A on...Small, wet flakes with visibility dropping around 1140A...Snow lighter in intensity at 100P, but increasing again at 115P...Thin, patchy shades of slush appear on pavement 120-200PM...Period of S/occ. S+ (visibility < 1/4 mile) from some great dendrites 240-425P...Back to S- after 425P, with smaller/wetter flakes/maybe some snow pellets? ...Temp finally =32.0 deg at 430P...[From 1030A-600P: estimated 1.9" (240-425P), at ~15:1 ratio and 1.1"/hr ..summed with..another 1.9" at ~8:1 ratio otherwise.]...S/occ. S+ 600-900P...S+ 900P-Mdnt...Lightning to west @ 1040P, thunder possibly.......On 6th: S/S+ Mdnt-600A...Lightning & Thunder @ 1210A. Large pine tree branches snap off from weight of snow ~130A...S-/S 600-OBS...Wind Data: not as windy at 300A...light winds 430-OBS.....9.6:1 SLR.
2/7/2010 7:00 AM 0.51 6.7 M 22.0 M S-/S OBS-900A...S+/S 900A-1200P...S-/occ. S 1200P-500P.....Wind data: light winds OBS-800A...near calm 900-1000A. 13:1 SLR, but 10.2:1 SLR for entire storm.....Greatest snowfall on record at site since Jan 1772.
2/10/2010 7:00 AM 0.50 4.7 M 24.0 M
2/11/2010 7:00 AM 0.59 8.8 M 29.0 M
2/16/2010 7:00 AM 0.03 0.3 M 18.0 M S- 215-430P. Snow melted as it fell, with 0.3" coming from snow cover. Patchy glaze in evening. SLR ~10:1



Start Date End Date & Time Duration in Days Precipitation Snow Depth Snow Depth SWE Notes



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