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 10 3.41 0.00 0 0.00 0 0.00 0 0 0 0 0.0 0 0
Nov 10 3.57 0.14 1 0.14 1 0.00 0 0 1 0 0.0 0 0
Dec 10 3.09 0.22 6 0.22 6 0.00 0 0 5 1 2.1 5 1
Jan 11 2.89 2.00 27 2.00 27 0.00 0 0 11 5 12.3 9 12
Feb 11 2.72 2.02 26 2.02 26 0.00 0 0 11 1 1.2 2 9
March 11 3.70 6.01 14 6.01 14 0.00 0 0 12 2 0.2 1 0
April 11 3.28 5.12 22 5.12 22 0.00 0 0 15 6 0.0 0 0
May 11 4.20 2.42 27 2.42 27 0.00 0 0 15 4 0.0 0 0
June 11 3.77 0.93 25 0.93 25 0.00 0 0 8 5 0.0 0 0
July 11 3.87 4.57 22 4.57 22 0.00 0 0 9 0 0.0 0 0
Aug 11 3.18 5.53 25 5.53 25 0.00 0 0 10 3 0.0 0 0
Sept 11 3.99 9.91 27 9.91 27 0.00 0 0 14 5 0.0 0 0
Water Year Totals: 41.67" 38.87" 222 days 38.87" 222 0.00" 0 days 0 111 days 32 days 15.8" 17 days 22 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
10/1/2010
10/2/2010
10/3/2010
10/4/2010
10/5/2010
10/6/2010
10/7/2010
10/8/2010
10/9/2010
10/10/2010
10/11/2010
10/12/2010
10/13/2010
10/14/2010
10/15/2010
10/16/2010
10/17/2010
10/18/2010
10/19/2010
10/20/2010
10/21/2010
10/22/2010
10/23/2010
10/24/2010
10/25/2010
10/26/2010
10/27/2010
10/28/2010
10/29/2010
10/30/2010
10/31/2010
11/1/2010
11/2/2010
11/3/2010
11/4/2010
11/5/2010
11/6/2010
11/7/2010
11/8/2010
11/9/2010
11/10/2010
11/11/2010
11/12/2010
11/13/2010
11/14/2010
11/15/2010
11/16/2010
11/17/2010
11/18/2010
11/19/2010
11/20/2010
11/21/2010
11/22/2010
11/23/2010
11/24/2010
11/25/2010
11/26/2010 0.14
11/27/2010
11/28/2010
11/29/2010
11/30/2010
12/1/2010
12/2/2010
12/3/2010
12/4/2010 T
12/5/2010
12/6/2010
12/7/2010
12/8/2010
12/9/2010
12/10/2010
12/11/2010 0.02
12/12/2010
12/13/2010 0.01
12/14/2010 0.02
12/15/2010
12/16/2010
12/17/2010 0.16
12/18/2010
12/19/2010
12/20/2010
12/21/2010
12/22/2010
12/23/2010
12/24/2010
12/25/2010
12/26/2010
12/27/2010 0.01
12/28/2010
12/29/2010
12/30/2010
12/31/2010
Day of YearDaily PrcpMultiday Prcp
1/1/2011
1/2/2011 0.05
1/3/2011 T
1/4/2011
1/5/2011
1/6/2011
1/7/2011 0.01
1/8/2011 0.01
1/9/2011 0.04
1/10/2011 0.00
1/11/2011 0.00
1/12/2011 0.19
1/13/2011 T
1/14/2011 T
1/15/2011 0.00
1/16/2011 0.00
1/17/2011 0.00
1/18/2011 0.48
1/19/2011 0.02
1/20/2011 0.00
1/21/2011 0.03
1/22/2011 0.00
1/23/2011 0.00
1/24/2011 0.00
1/25/2011 0.00
1/26/2011 0.18
1/27/2011 0.95
1/28/2011 T
1/29/2011 0.04
1/30/2011 T
1/31/2011 0.00
2/1/2011 0.01
2/2/2011 0.86
2/3/2011 0.01
2/4/2011 0.00
2/5/2011 0.09
2/6/2011 0.13
2/7/2011 0.00
2/8/2011 0.01
2/9/2011 0.00
2/10/2011 T
2/11/2011 0.00
2/12/2011 0.00
2/13/2011 0.00
2/14/2011 0.00
2/15/2011 0.00
2/16/2011 0.00
2/17/2011 0.00
2/18/2011 0.00
2/19/2011 0.00
2/20/2011
2/21/2011 0.01
2/22/2011 0.36
2/23/2011 0.00
2/24/2011 0.00
2/25/2011 0.29
2/26/2011 0.01
2/27/2011
2/28/2011 0.24
3/1/2011 0.32
3/2/2011
3/3/2011
3/4/2011
3/5/2011
3/6/2011 0.12
3/7/2011 2.48
3/8/2011
3/9/2011
3/10/2011 0.45
3/11/2011 1.36
3/12/2011
3/13/2011
3/14/2011
3/15/2011
3/16/2011 0.35
3/17/2011
3/18/2011
3/19/2011
3/20/2011
3/21/2011 0.15
3/22/2011 0.19
3/23/2011 0.02
3/24/2011 0.34
3/25/2011 0.03
3/26/2011
3/27/2011 T
3/28/2011 T
3/29/2011
3/30/2011
3/31/2011 0.20
Day of YearDaily PrcpMultiday Prcp
4/1/2011 0.15
4/2/2011 T
4/3/2011 0.13
4/4/2011 T
4/5/2011 0.24
4/6/2011 0.08
4/7/2011 0.00
4/8/2011 0.01
4/9/2011 0.45
4/10/2011 T
4/11/2011
4/12/2011 T
4/13/2011 1.08
4/14/2011
4/15/2011
4/16/2011 T
4/17/2011 1.45
4/18/2011
4/19/2011 T
4/20/2011 0.05
4/21/2011
4/22/2011
4/23/2011 0.45
4/24/2011 0.05
4/25/2011 0.02
4/26/2011
4/27/2011 0.01
4/28/2011 0.64
4/29/2011 0.31
4/30/2011
5/1/2011 0.00
5/2/2011 0.04
5/3/2011 0.00
5/4/2011 0.33
5/5/2011 0.23
5/6/2011 0.00
5/7/2011 0.01
5/8/2011 T
5/9/2011 0.00
5/10/2011
5/11/2011 0.00
5/12/2011 0.00
5/13/2011 T
5/14/2011 0.01
5/15/2011 0.69
5/16/2011 0.07
5/17/2011 0.06
5/18/2011 0.29
5/19/2011 0.13
5/20/2011 0.04
5/21/2011 T
5/22/2011 0.00
5/23/2011 0.20
5/24/2011 0.09
5/25/2011 T
5/26/2011 0.00
5/27/2011
5/28/2011 0.18
5/29/2011 0.05
5/30/2011
5/31/2011
6/1/2011
6/2/2011 0.00
6/3/2011
6/4/2011
6/5/2011 T
6/6/2011 0.00
6/7/2011
6/8/2011 0.00
6/9/2011
6/10/2011 T
6/11/2011 0.00
6/12/2011 0.00
6/13/2011 T
6/14/2011 0.00
6/15/2011 0.01
6/16/2011 0.00
6/17/2011 0.05
6/18/2011 0.13
6/19/2011 T
6/20/2011 0.28
6/21/2011 0.05
6/22/2011 0.17
6/23/2011 0.00
6/24/2011 T
6/25/2011 0.00
6/26/2011 0.00
6/27/2011 0.02
6/28/2011 0.00
6/29/2011 0.22
6/30/2011 0.00
Day of YearDaily PrcpMultiday Prcp
7/1/2011
7/2/2011
7/3/2011 1.77
7/4/2011 0.11
7/5/2011 0.01
7/6/2011 0.00
7/7/2011 0.03
7/8/2011 0.00
7/9/2011 1.44
7/10/2011 0.00
7/11/2011
7/12/2011 0.53
7/13/2011 0.00
7/14/2011 0.22
7/15/2011 0.00
7/16/2011 0.00
7/17/2011
7/18/2011
7/19/2011 0.00
7/20/2011 0.02
7/21/2011 0.00
7/22/2011 0.00
7/23/2011 0.00
7/24/2011 0.00
7/25/2011 0.00
7/26/2011 0.44
7/27/2011
7/28/2011
7/29/2011 0.00
7/30/2011
7/31/2011
8/1/2011 0.00
8/2/2011 0.00
8/3/2011 0.00
8/4/2011 0.13
8/5/2011 T
8/6/2011
8/7/2011 0.26
8/8/2011 0.41
8/9/2011 0.00
8/10/2011 T
8/11/2011 0.00
8/12/2011
8/13/2011 0.00
8/14/2011 0.11
8/15/2011 2.04
8/16/2011 0.00
8/17/2011 0.00
8/18/2011 0.00
8/19/2011 0.35
8/20/2011 0.00
8/21/2011 0.00
8/22/2011 0.03
8/23/2011 0.00
8/24/2011
8/25/2011
8/26/2011 0.12
8/27/2011
8/28/2011 1.97
8/29/2011 0.11
8/30/2011 T
8/31/2011
9/1/2011 0.00
9/2/2011 0.07
9/3/2011 0.00
9/4/2011 0.04
9/5/2011 0.00
9/6/2011 1.69
9/7/2011 0.99
9/8/2011 2.63
9/9/2011 3.41
9/10/2011 0.23
9/11/2011 0.00
9/12/2011 0.28
9/13/2011 0.00
9/14/2011
9/15/2011 0.07
9/16/2011 0.08
9/17/2011 0.00
9/18/2011 T
9/19/2011 0.00
9/20/2011 T
9/21/2011 0.17
9/22/2011 0.07
9/23/2011 0.00
9/24/2011
9/25/2011 0.01
9/26/2011
9/27/2011 T
9/28/2011 T
9/29/2011 0.17
9/30/2011 T



Observation Date Observation Time Precipitation Snowfall Snowfall SWE Snow Depth Snow SWE Notes
11/26/2010 12:00 AM 0.14 T M 0.0 M On 25th: -PL/-RA 300-330A (at 41-40°F)...then -RA/--RA >330A.
12/4/2010 7:00 AM T T M 0.0 M Few flakes of snow ~300P
12/11/2010 7:00 AM 0.02 0.1 M T M S- 1030A-1205P, while temps meander from 30 to 29 to 30. SLR ~8:1
12/13/2010 7:00 AM 0.01 0.1 M 0.0 M S-/S-- 230A-dawn, all sublimating
12/14/2010 7:00 AM 0.02 0.3 M T M Rogue band of lake-effect snow from Superior-Huron-Erie connection set up in a very thin NNW to SSE direction along I-270 corridor. SW-/SW-- 1030P-420A, but long tapering-off period before 420A. SLR ~15:1.
12/17/2010 7:00 AM 0.16 1.5 0.16 1.0 M Temperature: Local Max=23F at onset of snow, Local Min=21 between 1200P and 100P EST. Snow Ratio: Overall=9.4:1 Snow Intensity: SN- 950A-720P, although OCNL SN-/SN 1210P-100P. Snowfall Data (6-Hour): 950A-1159A=0.5"...1200P-559P=1.0"...600P-720P=Trace Additional Notes: Generally small flakes...except for (comparatively larger) small dendrites ~1200P-100P and ~205-240P...and very small flakes 300-405P.
12/27/2010 7:00 AM 0.01 0.1 M 0.0 M
1/2/2011 10:00 AM 0.05 0.0 M 0.0 M On 1st: few drops during day & evening, dampness on ground from condensation. On 2nd: DL-/RA- 335-1000A. Temperature peaked at 57 shortly after midnight.
1/3/2011 10:00 AM T 0.0 M 0.0 M On 2nd: Sprinkles 200-300P
1/7/2011 7:00 AM 0.01 0.1 M T M On 7th: SH SN- ~500-540A. Both liquid & frozen precip amounts rounded up to 0.01" & 0.1", respectively.
1/8/2011 7:00 AM 0.01 0.2 M T M SH SN- 1205-230A (~0.012" liquid, ~0.16" frozen) ... then SN-- 320-420A (T liquid, T frozen) ... then few flakes/S-- 420A-OBS (T liquid, T frozen).
1/9/2011 7:00 AM 0.04 0.4 M T M On 8th: -SH SN/(SH SN?) 0700-0815A. Fine flakes, SLR ~10:1. "Storm" Totals: 0.05" liquid, 0.5" frozen, SLR ~11:1, all snow falling on 8th between 1205A & 815A.
1/10/2011 7:00 AM 0.00 0.0 M T M
1/11/2011 7:00 AM 0.00 0.0 M T M
1/12/2011 7:00 AM 0.19 2.1 M 2.0 M All on 11th: Afternoon SH SN-s: 101-132P...210-215P...227-235P...335-345P. Then, early evening wintry mix: OCNL FZDL-/SN- 400-500P...(continuous) ZL-/ZR-/(few PE-/SN-) 500-515P...FZRA-/(few PE-/SN-) 515-530P...PE-/SN-/FZRA- 530-630P. Finally, evening snow: SN- 630-640P...SN/SN- (large dendrites) 640P-720P...SG-/SN-/(FZRA-?) 720-815P...SN- 815-1005P...SN- tapering to SN-- 1005-1030P...S-- E~1050P. Total Frozen Precip = 2.2". Overall SLR ~15:1, although likely 15-20:1 during times of large flakes (640-720P...902-925P...940-1030P). Contact for hourly Obs/Accumulations.
1/13/2011 7:00 AM T T M 1.5 M SW--/briefly SW- ~615-630P; the small flurry came down I-270 corridor from NNW per tail of yesterday's storm's short wave
1/14/2011 7:00 AM T T M 1.0 M Snow flurry ~~530-600A, yielding the appearance of thin crystal-like frost on car tops/newspaper bag.
1/15/2011 7:00 AM 0.00 0.0 M 0.5 M Most surfaces bare of snow
1/16/2011 7:00 AM 0.00 0.0 M T M Most surfaces bare of snow.
1/17/2011 7:00 AM 0.00 0.0 M T M
1/18/2011 7:00 AM 0.48 0.8 M 1.0 M On 17th: 0.18" LIQ, 1.0" FRZ (0.8" snow/snow pellets, 0.2" sleet): SN-/SP- 645-930P...FZDL-/PE-/GS- 930-1020P...SN-/S/SP 1020-1055P...PL-/ZR-/GS-/S- 1055P-1159P. 0.8" Snow depth at 1100P packed down by sleet, total frozen depth at 1159P = 0.8"...On 18th: 0.30" LIQ MDNT-259A, 0.06" LIQ 300-515A, T sleet: ZR-/little IP- MDNT-130A...ZR- 130-230A...ZR-/ZL- 230-430A...ZL- 430-515A.
1/19/2011 7:00 AM 0.02 0.0 M 0.5 M OCNL -DZ/-RA ~1130PM on 18th thru 700A OBS on 19th. Temps creeping slowly from just above 32 to 33 during this duration. New ice accumulating on elevated wood, mainly liquid on other surfaces. Dense fog evening of 18th thru OBS.
1/20/2011 7:00 AM 0.00 0.0 M T M On 19th: Light fog and mist clearing ~930A
1/21/2011 7:00 AM 0.03 0.2 M T M On 20th: Few small flakes 1110-1115P ... On 21st: SN- 1205-225A, including wet, small flakes 200-225A, w/RA- possibly mixing in 200-215A...then SN-- 240-330A...finally a few flakes at 1050A. Pre-dawn snow melting on most paved surfaces, as T=35 at 1200A, T=32.5 at 330A (local min), then T=33.5 at 430A (local max).
1/22/2011 7:00 AM 0.00 0.0 M T M
1/23/2011 7:00 AM 0.00 0.0 M T M
1/24/2011 7:00 AM 0.00 0.0 M T M 24th: Overnight Min = 10, coldest so far this winter.
1/25/2011 7:00 AM 0.00 0.0 M T M
1/26/2011 7:00 AM 0.18 1.3 M 1.0 M All precipitation fell during the 26th......'1.3"' is total frozen, only snow = 1.2". SN-/SP-/SG-/SN 225-440A...FZDZ-/SN-/FZRA-/PE-/SG- 440A-Obs. Heaviest Precip (320-355A) featured large dendrites. Temps fell from 35 at precip's onset to near 32 at Obs, but snow began sticking around 34. Therefore RA and DZ listed as "FZ", with most rain presumably sticking as ice on new snow, despite liquid drops evident on elevated raingage.
1/27/2011 7:00 AM 0.95 6.8 M 6.0 M All precipitation fell during the 26th......'6.8"' is total Frozen, while only snow = 6.4"...||...0cnl ZR-/RA- Obs-101A...SN-/RA- 1010-1020A...OCNL -DZ 1020A-300P...RA- 300-310P...Changeover RA-TO-PL 310-319P... PL 320-357P, w/few snow flakes 340-357P...Changeover PL-TO-SN 357-404P...SN-/SG- 405-420P...SN 420-430P...SN/+SN 430-750P...SN 750-840P...-SN 840-1020P...Ocnl -SN 1020-1115P...||...Thunder ~330P & ~405-410P...||...Pre-Snow Totals (Obs-404P): 0.24" LIQ, 0.3" FRZ (PL)...Snow Totals (405-1115P): 0.71" LIQ, 6.5" FRZ, ~9:1 SLR.
1/28/2011 7:00 AM T T M 5.5 M On 28th: Snow flurry 455-510A, dropping scattered, non-continuous flakes on car windshield
1/29/2011 7:00 AM 0.04 0.4 M 5.5 M S- 930A-215P, with "heaviest" rate 1000A-1230P. Snow melted as it fell, observation taken from top of pre-existing snowpack.
1/30/2011 7:00 AM T T M 5.0 M Second clipper in two days brings flurries/S--/Ocnl S- ~1000A-100P. Liquid Total = 0.0045"
1/31/2011 7:00 AM 0.00 0.0 M 4.5 M
2/1/2011 7:00 AM 0.01 T M 4.0 M On 31st (0.01 LIQ, T FRZ): Few flakes 645-650P...-SG B~715P, becoming -SN (small-medium flakes), E~845P...||...On 1st: --FZDZ 150A-Obs (T), leaving a patchy ultra-thin glaze.
2/2/2011 7:00 AM 0.86 0.0 M 3.5 M On 1st: FZDZ-- Obs-about 900A (T), thin glaze developed, so thin in some places it was only in the cracks of pavement and surface was not slick...glaze melting off during ~1000-1130A as Temps 31->32 under brightening overcast...then -RA 945P-Mdnt (0.15")...||...On 2nd: RA/-RA Mdnt-330A...then RW-/R- 425-645A...finally L-/R-- 645A-Obs. (0.71" on 2nd).
2/3/2011 7:00 AM 0.01 0.0 M 2.5 M -DZ/--RA Obs-900A
2/4/2011 7:00 AM 0.00 0.0 M 2.5 M
2/5/2011 7:00 AM 0.09 0.0 M 2.0 M -RA 115-330A...then -DZ 545A-Obs
2/6/2011 7:00 AM 0.13 0.0 M 1.5 M 0.13" from -DZ/(Ocnl -RA?) Obs-420P...then T from -RA 650-710P. -FG/Ocnl FG Obs-early evening.
2/7/2011 7:00 AM 0.00 0.0 M 0.5 M
2/8/2011 7:00 AM 0.01 0.0 M T M Did not see it, but assume -SH RA ~245-315A...||...Snow pack is completely gone in large tracks, 0.75-1.25" in other large (shaded) tracks. 0.5" may be best reading, but nearest observation site average is ~0.2"
2/9/2011 7:00 AM 0.00 0.0 M T M
2/10/2011 7:00 AM T 0.1 M T M Liq = 0.004", Frz = 0.05"...||...-SN/--SN 540-745P...--SN ~845-900P...-SN 1010-1115P...--SN 1115-1205P. Thin dusting evident at 700P, sublimating away before dawn.
2/11/2011 7:00 AM 0.00 0.0 M T M
2/12/2011 7:00 AM 0.00 0.0 M T M
2/13/2011 7:00 AM 0.00 0.0 M T M
2/14/2011 7:00 AM 0.00 0.0 M T M
2/15/2011 7:00 AM 0.00 0.0 M T M
2/16/2011 7:00 AM 0.00 0.0 M T M
2/17/2011 7:00 AM 0.00 0.0 M T M Small remnant snow/ice patch took a big hit yesterday, I doubt it will survive to 700A tomorrow...
2/18/2011 7:00 AM 0.00 0.0 M T M Only a very small patch of snow/ice in swail in shaded backyard. Max = 71 during day on 17th.
2/19/2011 7:00 AM 0.00 0.0 M T M
2/21/2011 7:00 AM 0.01 0.0 M 0.0 M On 20th: -RA/--RA 730-830P
2/22/2011 7:00 AM 0.36 1.1 M 1.0 M
2/23/2011 7:00 AM 0.00 0.0 M 0.5 M
2/24/2011 7:00 AM 0.00 0.0 M T M
2/25/2011 8:00 AM 0.29 0.0 M 0.0 M
2/26/2011 7:00 AM 0.01 0.0 M 0.0 M On 25th: OCNL -RA until ~100P
2/28/2011 7:00 AM 0.24 0.0 M 0.0 M -RA/RA 1205-200A LT
3/1/2011 7:00 AM 0.32 0.0 M 0.0 M
3/6/2011 7:00 AM 0.12 0.0 M 0.0 M
3/7/2011 6:00 AM 2.48 0.2 M T M Storm Total 2.60" (2.55" rain, 0.05" snow). -RA to --SN at ~1045PM. Becoming -SN/SN ~1130PM-1245AM, with big wet flakes. -SN E ~200AM. Temps holding at 33 during & after snow. Snow melted as it fell, but 0.2" accumulated on car tops.
3/10/2011 7:00 AM 0.45 0.0 M 0.0 M On 9th, 0.06" total: Sprinkle ~700PM LT, then -RA ~900PM LT thru MDNT LT...||...On 10th, 0.39" total: steady -RA MDNT LT thru Obs.
3/11/2011 7:00 AM 1.36 0.0 M 0.0 M 0.88" Obs-700PM LT, 0.44" 700PM LT-1200AM LT, 0.04" 1200AM LT-Obs...||...Generally steady -RA until early afternoon, then --RA/Ocnl -RA, until weak squall line brings -RA/ocnl RA 722-740PM LT. Then Ocnl -RA/-DZ until E~300AM LT.
3/16/2011 7:00 AM 0.35 0.0 M 0.0 M 0.10" 1730LT-0000LT...0.22" 0000LT-100LT...0.03" 100LT-300LT. Sprinkle 1730-1740LT.
3/21/2011 7:00 AM 0.15 T M T M Sprinkles/--RA B ~late evening on 20th. Pea-sized hail with +RA 632-635LT. Rain quickly becoming -RA 635LT-Obs. See hail report for more details.
3/22/2011 7:00 AM 0.19 0.0 M 0.0 M Rain of varying intensity from observation time, ending by 845A.
3/23/2011 7:00 AM 0.02 0.0 M 0.0 M Sprinkle 2010-2020LT, then --RA/-DZ late evening-Obs.
3/24/2011 7:00 AM 0.34 0.0 M 0.0 M
3/25/2011 7:00 AM 0.03 0.0 M 0.0 M
3/27/2011 7:00 AM T T M T M Ocnl few flakes 100-500LT, then --SN 500LT-Obs
3/28/2011 7:00 AM T T M M M
3/31/2011 7:00 AM 0.20 T M T M
4/1/2011 7:00 AM 0.15 0.0 M 0.0 M -RA ending predawn
4/2/2011 7:00 AM T 0.0 M 0.0 M Sprinkle or two 1445-1630LT
4/3/2011 7:00 AM 0.13 T M 0.0 M 1/8-1/4" A 1417-1423LT, followed immediately by +SH RA and then -SH RA. See separate Hail Report for further details.
4/4/2011 7:00 AM T 0.0 M 0.0 M OCNL -SH RA/--SH RA after 2000LT, with T&L after 2138LT.
4/5/2011 7:00 AM 0.24 0.0 M 0.0 M Rainfall amount is estimated: 0.32" was observed at 1150LT on 5th...Sprinkle on 4th at 1305LT. Record (1985-2011) Max Daily Temp on 5th of 84 degrees. Old record for date: 79 in 1989.
4/6/2011 7:00 AM 0.08 0.0 M 0.0 M
4/7/2011 7:00 AM 0.00 0.0 M 0.0 M Possible yet unlikely sprinkle on 6th at 1520LT.
4/8/2011 7:00 AM 0.01 0.0 M 0.0 M
4/9/2011 7:00 AM 0.45 0.0 M 0.0 M --RA B~ 1245LT, soon becoming -RA, continuing until ~2045LT. OCNL RA/-RA 1100-1400LT, RA 1730-1800LT. OCNL -DZ/--RA >2045LT.
4/10/2011 7:00 AM T 0.0 M 0.0 M
4/12/2011 7:00 AM T 0.0 M 0.0 M Sprinkle ~0045LT
4/13/2011 8:00 AM 1.08 0.0 M 0.0 M
4/16/2011 7:00 AM T 0.0 0.00 M M
4/17/2011 7:00 AM 1.45 0.0 M 0.0 M 0.34" 700-1700LT...0.56" 1700-1900LT...0.55" 1900-2240LT.
4/19/2011 7:00 AM T 0.0 M 0.0 M Sprinkle 0658LT-Obs
4/20/2011 7:00 AM 0.05 0.0 M 0.0 M Sprinkle E~700LT...OCNL --RA/sprinkles 900-1600LT, last being 1545-1600LT. Also -TSHRA ~945LT, brief SH RA 1400-1401LT, & -SH RA ~1430LT.
4/23/2011 7:00 AM 0.45 0.0 M 0.0 M Rainfall amount includes that which fell after -RA B~130LT on the 22nd...0.42" ending 0100LT on 23rd.
4/24/2011 7:00 AM 0.05 0.0 M 0.0 M -RA/-DZ overnight (0.03")...-SH RA 1210-1240LT (0.01")...-SH RA 2220-2240LT (0.01")
4/25/2011 7:00 AM 0.02 0.0 M 0.0 M -TSH RA 1610-1630LT (Trace)...Sprinkle/--SH RA 2345-0005LT...-SH RA 210-230LT (0.015")...||...1610-1630LT storm appeared to be rather violent (Tornado Warning) with significant rain falling just a few miles to north...Considerable lightning in evening to south before 2345-0005LT sprinkle.
4/27/2011 7:00 AM 0.01 0.0 M 0.0 M Pre-dawn rain on 27th
4/28/2011 7:00 AM 0.64 0.0 M 0.0 M -TSH RA 1825-1905LT, but +TSH RA 1845-1900LT (0.43")...then --TSH RA 2235-2315LT, becoming -TSH RA 2315-2355LT, with strong gusts (0.16")...-TSHRA ~430LT-OBS (0.05")
4/29/2011 7:00 AM 0.31 0.0 M 0.0 M
5/1/2011 7:00 AM 0.00 0.0 M M M
5/2/2011 7:00 AM 0.04 0.0 M 0.0 M On 1st: Sprinkle just before noon...then OCNL --RA/-RA 1300-1630LT, becoming continuous 1630-1800LT.
5/3/2011 7:00 AM 0.00 0.0 M M M
5/4/2011 7:00 AM 0.33 0.0 M 0.0 M On 3rd: Sprinkles amid and after breezy fro pa ~2105LT...giving way to steadier rain...On 4th: 0.11" by 100LT; OCNL -RA overnight, continuing thru OBS.
5/5/2011 7:00 AM 0.23 0.0 M 0.0 M On 4th: -RA/OCNL RA OBS-1045LT...then sprinkles 1515-1520LT & 1700-1705LT.
5/6/2011 7:00 AM 0.00 0.0 M M M
5/7/2011 7:00 AM 0.01 0.0 M 0.0 M Precipitation Total = 0.007". Sprinkles 1858-1923LT...TRW- 1923-1933LT...(T?)R-/R-- 1937-1945LT.
5/8/2011 7:00 AM T 0.0 M 0.0 M On 7th: Possible few drops in afternoon but likely not...On 8th: --DZ 100-130LT
5/9/2011 7:00 AM 0.00 0.0 M M M
5/11/2011 7:00 AM 0.00 0.0 M M M
5/12/2011 7:00 AM 0.00 0.0 M M M
5/13/2011 7:00 AM T 0.0 M 0.0 M On 13th: Several, mainly brief periods of L--/mist B~600LT
5/14/2011 7:00 AM 0.01 0.0 M 0.0 M Several, mainly brief periods of mist/--DZ during the 24-HR period. No measurable rain before 100LT on 14th.
5/15/2011 7:00 AM 0.69 0.0 M 0.0 M OCNL --DZ/-DZ during day. -DZ B~1915LT, slowly becoming -RA 2000-2100LT, then TSHRA, tapering off around 0000LT.
5/16/2011 7:00 AM 0.07 0.0 M 0.0 M TSHRA/-TSHRA ~1800-1900LT
5/17/2011 7:00 AM 0.06 0.0 M 0.0 M On 16th: Sprinkles/few drops at 1520LT, 1540LT, 1815-1825LT, 1843-1900LT...On 17th: Sprinkles/-DZ/--RA 130-300LT
5/18/2011 7:00 AM 0.29 0.0 M 0.0 M On 17th: Sprinkles 1200-1230LT, 1530LT On 18th: Sprinkle 100LT before a couple small, yet locally potent -SHRA/SHRA 130-300LT
5/19/2011 7:00 AM 0.13 0.0 M 0.0 M On 18th: 0.07" during day, 0.06" in evening
5/20/2011 7:00 AM 0.04 0.0 M 0.0 M On 19th: Sprinkle ~1130LT, -TSHRA's 1900-1905LT (~0.01") and 2130-2200LT (~0.03").
5/21/2011 7:00 AM T 0.0 M 0.0 M On 20th: Sprinkles 1300-1500LT
5/22/2011 7:00 AM 0.00 0.0 M M M
5/23/2011 7:00 AM 0.20 0.0 M 0.0 M TSHRA 310-345LT
5/24/2011 7:00 AM 0.09 0.0 M 0.0 M On 23rd: --SH RA 1730-1740LT (T), then SH RA 1830-1843LT (0.09").
5/25/2011 7:00 AM T 0.0 M 0.0 M On 24th: Sprinkle 750-805A, then --TSHRA/sprinkle 1538-1603LT, 1607-1615LT.
5/26/2011 7:00 AM 0.00 0.0 M M M
5/28/2011 7:00 AM 0.18 0.0 M 0.0 M TSHRA's 1955-2015LT and 2050-2100LT.
5/29/2011 7:00 AM 0.05 0.0 M 0.0 M -SH RA 2020-2041LT
6/2/2011 7:00 AM 0.00 0.0 M M M
6/5/2011 7:00 AM T 0.0 M 0.0 M On 4th: Sprinkles at 1600LT & 1730LT...On 5th: Pre-dawn Sprinkles
6/6/2011 7:00 AM 0.00 0.0 M M M
6/8/2011 7:00 AM 0.00 0.0 M 0.0 M
6/10/2011 7:00 AM T 0.0 M 0.0 M --TSHRA brings only a few drops at ~1915LT and ~1945-1950LT ... -TSHRA/--TSHRA 2050-2100LT.
6/11/2011 7:00 AM 0.00 0.0 M 0.0 M
6/12/2011 7:00 AM 0.00 0.0 M 0.0 M
6/13/2011 5:42 AM T 0.0 M 0.0 M 12th: --TSHRA from impressive long-lived line of storms that collapsed just before reaching us...brings TSprinkle 1630LT and then enough to wet exposed ground 1640-1649LT.
6/14/2011 7:00 AM 0.00 0.0 M 0.0 M
6/15/2011 7:00 AM 0.01 0.0 M 0.0 M On 14th: -SH RA around 1800LT
6/16/2011 7:00 AM 0.00 0.0 M 0.0 M
6/17/2011 7:00 AM 0.05 0.0 M 0.0 M On 16th: -SH RA ~700-800LT (0.02") ... -SH RA 1855-1930LT (T) ... OCNL -SH RA/--SH RA w/few claps of thunder 2130-0050LT.
6/18/2011 7:00 AM 0.13 0.0 M 0.0 M On 17th: TSHRA- 1613-1620LT (0.01"), TSprinkle 2000-2005LT (T), TSHRA-/TSHRA-- 2025-2030LT (0.01") ... On 18th: -SHRA/SHRA 335-~415LT (0.11").
6/19/2011 7:00 AM T 0.0 M 0.0 M 18th: Sprinkle 2045-2115LT
6/20/2011 7:00 AM 0.28 0.0 M 0.0 M -RA 145LT-OBS. Finally a gentle soaking rain. We could use 5 times as much but we'll take it.
6/21/2011 7:00 AM 0.05 0.0 M 0.0 M
6/22/2011 7:00 AM 0.17 0.0 M 0.0 M On 21st: TSHRA 2045-2115LT (briefly heavy 2055-2107LT), continuing as -TSHRA until 2145LT (0.17"). According to radar was very near bullseye for this small cell.
6/23/2011 7:00 AM 0.00 0.0 M 0.0 M
6/24/2011 7:00 AM T 0.0 M 0.0 M On 23th: Sprinkles ~900LT and ~1200-1300LT
6/25/2011 7:00 AM 0.00 0.0 M 0.0 M
6/26/2011 7:00 AM 0.00 0.0 M 0.0 M
6/27/2011 7:00 AM 0.02 0.0 M 0.0 M On 26th: Sprinkles 1700-1800LT...few drops 2000-2030LT...-DZ ~2330LT (All totalling T)......On 27th: --RA B~120LT, E~ prior to Obs (All totalling 0.02").
6/28/2011 7:00 AM 0.00 0.0 M 0.0 M
6/29/2011 7:00 AM 0.22 0.0 M 0.0 M On 28th: -TSHRA 1910-1945LT, except for +TSHRA 1920-1930LT. Much L&T 1900-1930LT.
6/30/2011 7:00 AM 0.00 0.0 M 0.0 M
7/3/2011 7:00 AM 1.77 0.0 M 0.0 M TSHRA/OCNL +TSHRA 320-435LT (0.71")...then mainly heavy TSHRA 435-540LT (1.04"). Considerable L&T during both storms, with one bolt very close to home at 500LT. A small, quick popcorn -SHRA with a lone L&T bolt 540-555LT (0.01"), followed by a final heavy sprinkle/SHRA 615-617LT (0.01")....Flooding was noted as "Minor (typical)" but these storms brought the most impressive localized flooding/puddles so far this convective season; however high-lying ground/turf was free of standing water/mud/puddles, indicating how dry it has been.
7/4/2011 7:00 AM 0.11 0.0 M 0.0 M -TSHRA/TSHRA 1746-1830LT, then tapering to sprinkles, E~1850LT.
7/5/2011 7:00 AM 0.01 0.0 M 0.0 M On 4th: Sprinkle/-DZ at 2000LT, then -SHRA/--SHRA 2013-~2100LT.
7/6/2011 7:00 AM 0.00 0.0 M 0.0 M
7/7/2011 7:00 AM 0.03 0.0 M 0.0 M On 6th: -DZ 915-~1000LT
7/8/2011 7:00 AM 0.00 0.0 M 0.0 M Thunder from early evening storms just to north
7/9/2011 7:00 AM 1.44 0.0 M 0.0 M Few drops ~215P...TSHRA #1 (0.96"): 1502-1610LT; TSHRA/SHRA #2 (0.48"): 1610-1715LT...:...-TSHRA 1502-1515LT, TSHRA 1515-1525LT, +TSHRA 1525-1545LT, TSHRA 1545-1600LT, -TSHRA 1600-1610LT, TSHRA/SHRA 1610-1625, SHRA/OCNL +SHRA 1625-1700LT, -SHRA 1700-1715LT.
7/10/2011 7:00 AM 0.00 0.0 M 0.0 M
7/12/2011 7:00 AM 0.53 0.0 M 0.0 M On 11th: TSHRA 2010-2045LT, +TSHRA/OCNL TSHRA ~2014-2027LT. Storm preceded by very dark sky and mammatus clouds directly overhead.
7/13/2011 7:00 AM 0.00 0.0 M 0.0 M
7/14/2011 7:00 AM 0.22 0.0 M 0.0 M TSprinkle 1400LT, becoming TSHRA (briefly +TSHRA 1500-1501), E~1525LT.
7/15/2011 7:00 AM 0.00 0.0 M 0.0 M
7/16/2011 7:00 AM 0.00 0.0 M 0.0 M
7/19/2011 7:00 AM 0.00 0.0 M 0.0 M
7/20/2011 7:00 AM 0.02 0.0 M 0.0 M -SHRA 1652-1715LT
7/21/2011 7:00 AM 0.00 0.0 M 0.0 M
7/22/2011 7:00 AM 0.00 0.0 M 0.0 M
7/23/2011 7:00 AM 0.00 0.0 M 0.0 M
7/24/2011 7:00 AM 0.00 0.0 M 0.0 M
7/25/2011 7:00 AM 0.00 0.0 M 0.0 M
7/26/2011 7:00 AM 0.44 0.0 M 0.0 M
7/29/2011 7:00 AM 0.00 0.0 M 0.0 M
8/1/2011 7:00 AM 0.00 0.0 M M M
8/2/2011 7:00 AM 0.00 0.0 M M M
8/3/2011 7:00 AM 0.00 0.0 M M M
8/4/2011 7:00 AM 0.13 0.0 M 0.0 M
8/5/2011 7:00 AM T 0.0 M 0.0 M Fog/Mist lasting an hour or two after 8/4/2011 Obs, likely a drizzle drop or two reaching the ground.
8/7/2011 7:00 AM 0.26 0.0 M 0.0 M Few brief popcorn SHRA's mid-afternoon to early evening (0.06"+)...then steady -RA/(OCNL RA?) 2000-2130LT...sprinkles from shower passing to north, E~0015LT.
8/8/2011 7:00 AM 0.41 0.0 M 0.0 M -SHRA 1515-1557LT (0.39"), except SHRA 1530-1545LT. Lone clap of thunder ~1540LT. Light ground fog in nearby low-lying park towards end of shower. Temperature dropped from ~90 to 83 during shower, dewpoints oppresively high following shower. Further sprinkles/-SH RA later in afternoon/early evening (0.02").
8/9/2011 7:00 AM 0.00 0.0 M M M
8/10/2011 7:00 AM T M M M M Sprinkle ~1100LT, lasting only a minute or so.
8/11/2011 7:00 AM 0.00 0.0 M M M
8/13/2011 7:00 AM 0.00 0.0 M M M
8/14/2011 7:00 AM 0.11 0.0 M 0.0 M --SHRA 925-945LT, next Sprinkle 1015-1030LT (both totaling 0.02"); then -TSHRA ~1325-1345LT. Quite humid following TSHRA.
8/15/2011 7:00 AM 2.04 0.0 M 0.0 M On 14th: TSHRA 2135-2205LT, but ++TSHRA 2142-2155LT...On 15th: Few drops of drizzle 630-700LT?
8/16/2011 7:00 AM 0.00 0.0 M M M
8/17/2011 7:00 AM 0.00 0.0 M M M
8/18/2011 7:00 AM 0.00 0.0 M M M
8/19/2011 7:00 AM 0.35 0.0 M 0.0 M Sprinkle ~1015LT ... then numerous -TSHRA's off and on ~1400-100LT
8/20/2011 7:00 AM 0.00 0.0 M M M
8/21/2011 7:00 AM 0.00 0.0 M M M
8/22/2011 7:00 AM 0.03 0.0 M 0.0 M -TSHRA's early PM and ~1600LT, bring significant rain just East & South of station.
8/23/2011 7:00 AM 0.00 0.0 M 0.0 M
8/26/2011 7:00 AM 0.12 0.0 M 0.0 M
8/28/2011 9:30 AM 1.97 0.0 M 0.0 M Rainfall ending at 800AM EST is estimate as observation was delayed until 930AM EST. OCNL -RA 1135-~1500LT, then continuous, slow-soaking -RA/OCNL RA. 0.30" total at ~1700LT, 0.90" total at 2300LT, 1.46" total at 100LT. Damaging gusts (at least for Oak leaves and mainly small branches) B~115LT. Thunder ~130LT. Much minor tree damage.
8/29/2011 7:00 AM 0.11 0.0 M 0.0 M Rainfall is estimated for 700-930LT on 28th
8/30/2011 7:00 AM T 0.0 M 0.0 M Few drops 1717-1742LT ... Brief sprinkle at 1900LT ... Brief drops ~1930LT.
9/1/2011 7:00 AM 0.00 0.0 M 0.0 M
9/2/2011 8:00 AM 0.07 0.0 M 0.0 M -TSHRA 140-200LT, with a Tsprinkle from the western edge of the storm's northern (2nd) lobe, ~220-230LT.
9/3/2011 7:00 AM 0.00 0.0 M 0.0 M
9/4/2011 8:45 AM 0.04 0.0 M 0.0 M Thunder B~1000LT, -TSHRA B~1008LT.
9/5/2011 7:00 AM 0.00 0.0 M 0.0 M
9/6/2011 8:00 AM 1.69 0.0 M 0.0 M -SHRA 1525-1600LT (0.02") ... then -RA/-DZ B~1900LT, +RA 2138-2153LT (likely with cold fropa as temperatures drop quickly thru 60s), RA/+RA 1117-~1130LT (1.44" ~1900-0100LT) ... (0.23" 0100LT-OBS)
9/7/2011 8:00 AM 0.99 0.0 M 0.0 M Spotty -RA OBS-900LT (0.01") ... then RA 900-1500LT (0.60", most falling 1400-1500LT) ... next RA/-RA 1500-0100LT (0.28") ... finally -RA 0100-0800LT (0.10").
9/8/2011 8:00 AM 2.63 0.0 M 0.0 M TSHRA-/TSHRA 1100-1500LT (0.78") ... then OCNL -RA ~1550-1900LT, RA/-RA/+RA 1900-2250LT (1.07") ... (T?)-RA/RA 2250LT-0100LT (0.24") ... 0100-0800LT (0.54").
9/9/2011 8:00 AM 3.41 0.0 M 0.0 M ~10-year Flash Flooding across Watts Branch, Seneca and Dry Seneca Creek watersheds. In early evening on 8th following key arteries were impassible: River Road, Glen Road, Turkey Foot Road, and Seneca Road. Flash flood washed out north side of Montevideo Road at Dry Seneca Creek (39.094, -77.347) although old bridge remains standing. As for Rockville 1.8W: GREATEST SINGLE-DAY RAINFALL since 9/30/2010's 4.40", GREATEST 4-DAY TOTAL (8.77") since 6/25-28/2006, (excluding June 2006, GREATEST SINCE ELOISE's ~9.3" over 4-days in Sept 1975). RA/+RA OBS-1410LT (1.81") ... OCNL RA/-RA/+RA 1410-1850LT (1.29"), including continuous Thunder yet little rain 1500-1600LT as torrential rains fall immediately to west ... OCNL -RA/-DZ 1850-0100LT (0.06") ... and of course more steady rain 0100LT-OBS (~0.25").
9/10/2011 7:00 AM 0.23 0.0 M 0.0 M
9/11/2011 7:00 AM 0.00 0.0 M 0.0 M
9/12/2011 7:00 AM 0.28 0.0 M 0.0 M
9/13/2011 7:00 AM 0.00 0.0 M 0.0 M
9/15/2011 8:00 AM 0.07 0.0 M 0.0 M
9/16/2011 8:00 AM 0.08 0.0 M 0.0 M
9/17/2011 7:00 AM 0.00 0.0 M 0.0 M
9/18/2011 8:00 AM T 0.0 M 0.0 M
9/19/2011 7:00 AM 0.00 0.0 M 0.0 M
9/20/2011 7:00 AM T 0.0 M 0.0 M
9/21/2011 7:00 AM 0.17 0.0 M 0.0 M
9/22/2011 7:00 AM 0.07 0.0 M 0.0 M
9/23/2011 7:00 AM 0.00 0.0 M 0.0 M
9/25/2011 7:00 AM 0.01 0.0 M 0.0 M
9/27/2011 7:00 AM T 0.0 M 0.0 M
9/28/2011 7:00 AM T 0.0 M 0.0 M Estimated precipitation.
9/29/2011 7:00 AM 0.17 0.0 M 0.0 M
9/30/2011 7:00 AM T 0.0 M 0.0 M On 29th: Sprinkle at 1230LT.



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
3/21/2011 6:32 AM Brief strong convective cell. -RA started at 632A, and hail began within a minute thereafter, a few stones at first, but quickly becoming very numerous. Rain intensity quickly increased with hailstones. Nearly all stones were 0.15-0.25" in diameter. Hail ended at 635A as +RA became -RA/RA. Hail was numerous enough to leave a very thin slush on pavement (~0.02"?). Temperatures dropped (slightly?) to 41 by end of hailstorm. At time of report many hailstones still visible and intact on ground, but not pavement. No noticeable damage, but if leaves were out then minor leaf damage may have occurred. 1/4" Pea Size 1/4" Pea Size Rice Hard|White Ice 3 1min no damage Continuous True Same time as rain After smaller hail 10-20 0.02
4/2/2011 2:17 PM Main hail precipitation 1417-1421LT. Second lighter period of smaller, softer hail 1423LT. --SH RA/-SH RA B~1424LT, continuing thru time of this report. T=44 at time of report. 1/4" Pea Size Rice Rice Mixed|Clear Ice|White Ice 6 1min no damage Intermittent False Before rain Before smaller hail 10-20 0
7/3/2011 8:00 PM NOT AT REGISTERED LOCATION. Hail occurred at southern parts of Brigantine Island, NJ. Lat/Long of 2 locations on island observing hail are: 39.390889, -74.396732 39.382323, -74.406226 1/4" Pea Size 1/4" Pea Size Rice Soft|White Ice 8 2min no damage Continuous True After rain Same time as smaller hail 10-20