BLUE HILL METEOROLOGICAL OBSERVATORY 
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 4, 2012
ALL TIMES ARE IN EASTERN STANDARD TIME

MORNING RAIN SHOWERS & DRIZZLE BRING 0.01 INCH OF RAINFALL;
LACK OF SUNSHINE CONTINUES

Occasional light rain showers and intermittent drizzle that began
early this morning and ended by early afternoon brought only 0.01 inch
of precipitation to the summit.

Temperatures are a few degrees warmer than yesterday, but with a cool
afternoon high only in the mid 50s, the average temperature for the day
is likely to fall just short of the normal value.  Consequently, today
will most likely extend our cool streak to 8 days.

Low stratus clouds have settled on the summit at times today, reducing
visibility to near zero.  However, the clouds have lifted briefly on a
couple of occasions, allowing for visibility to improve to near 10 miles.
Sunshine has evaded the summit once again, with no sunshine being
observed since April 30.

April rankings and stats below:

BHO Warmest April Corrected Mean Temp, 1885-2012 (deg F)
1) 51.5 in 2010
2) 51.0 in 1976
3) 49.9 in 2012
4) 49.4 in 1945
5) 49.0 in 1994
 
BHO Sunniest April, 1885-2012 (hours)
1) 266.8 in 1899 (69%)
2) 259.7 in 1968 (67%)
3) 256.7 in 1977 (66%)
4) 253.8 in 1927 (65%)
5) 249.7 in 2012 (64%)

BHO Warmest January-April Corrected Mean Temp, 1885-2012 (deg F)
1) 39.7 in 2012
2) 38.3 in 2002
3) 37.9 in 1998
4) 37.2 in 2010
5) 36.9 in 1990

BHO Driest January-April, 1885-2012 (inches)
1)  9.19 in 1985
2)  9.61 in 2012
3) 10.41 in 1927
4) 10.74 in 1941
5) 10.89 in 1892

BHO Slowest Wind Speed January-April, 1885-2012 (mph)
1) 13.1 in 2012
2) 13.2 in 2005
3) 13.6 in 2001
4) 13.7 in 2008
5) 13.8 in 1995
   13.8 in 2010

Also, April 2012 has been the only April on record to have no
maximum temperature under 50 degrees.

APRIL 2012 PRELIMINARY STATS
TEMPERATURE:
Average Max Temp:  61.8F [+6.1F]
Average Min Temp:  40.1F [+2.4F]
Mean Temp:  51.0F [+4.3F]
24-hr. Corr Mean Temp:  49.9F
Max Temp:  89F on 16th
Min Temp:  31F on  3rd, 6th, 28th
Total heating degree day units (month):    429   [-133]
Total heating degree day units (season): 4,714 [-1,312] *start July 1
Total cooling degree day units (month):     11     [+8]
Total cooling degree day units (season):    15    [+11] *start Jan 1
PRECIPITATION:
Total precipitation:  3.52 ins. [-1.03 ins.]
Greatest 24-hr precipitation:  3.09 ins. on 22nd-23rd
Total snowfall:  Trace [-3.1 ins.]
WIND:
Avg wind speed: 12.8 MPH
Avg corrected wind speed:  13.2 MPH
Prevailing wind direction: NW [18%]
Peak gust:  50 MPH NE on 22nd
Peak fastest mile: 37 MPH NE on 22nd, 23rd
SUNSHINE:
Total Campbell-Stokes card minutes: 14,982 of possible 23,250, or 64%
Total astronomical minutes:         15,458 of possible 24,094, or 64% 

Today's observations:
 
7 A.M.
Weather: Sky obscured by dense fog, stratus drifting over summit,
light rain shower continued from previous hour and ended at unknown time
Temperature: 49F, Dew point: 49F, Wind: S at 11 kts,
Sea-level pressure: 30.01 inches Hg, falling then more slowly 
Visibility: 1/16 mile, dense fog
24-hour precip: 0.04 inch
6-hour precip: 0.01
6-hour min. temp: 47F
BHO SA 1155 W3 X 1/16F 161/49/49/1711/001/ STRA DRFTNG OVR SMT RW-CTD
EUKN/ 8//// 56024 MANUAL 60001 MANUAL 70004 ASOS 70003 10049 20047

10 A.M. 
Weather: Broken stratus, overcast stratus, thin fog/haze all quadrants
Temperature: 52F, Dew Point: 52F; Wind: S at 12 kts
Sea-level pressure: 29.99 inches Hg, falling then more slowly  
Visibility: 10 miles, increasing past hour, thin fog/haze all quadrants
3-hour precip: Trace 
BHO SA 1455 E2 BKN 4 OVC 10 156/52/52/1912/999/ THN FG/HZ ALQDS VSBY
INCRSNG PST HR/ 8/6// 56005 MANUAL 6000/
 
1 P.M.  
Weather: Sky obscured by fog, stratus occasionally drifting over
summit, light drizzle continued from previous hour and ended at unknown
time, precipitation very light
Temperature: 54F, Dew Point: 53F; Wind: SSW at 9 kts
Wind: Direction gradually veering (clockwise)
Sea-level pressure: 29.96 inches Hg, falling then more slowly  
Visibility: 2 miles, increasing, fog
6-hour precip: Trace 
6-hour max. temp: 54F
BHO SA 1755 W4 X 2F 147/54/53/2109/996/ STRA OCNLY DRFTNG OVR SMT
VSBY INCRSNG WND GRDLY VEERING L-CTD EUKN PCPN VRY LGT/ 8//// 56014
MANUAL 6000/ 10054 20049

WEATHER SUMMARY FOR THURSDAY, MAY 3 

TEMPERATURE (DEGREES F)
MAX.....51    NORMAL.....63
MIN.....44    NORMAL.....44
MEAN....48    NORMAL.....53
 
DEPARTURE FROM 30-YEAR NORMAL.......................-5
TOTAL DEPARTURE FOR THE MONTH......................-19 [-6.5 deg.]

HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY..............17   DEPARTURE..........+4
TOTAL HEATING UNITS FOR THE MONTH..............55   DEPARTURE.........+16 
TOTAL HEATING UNITS FOR THE SEASON...........4769   DEPARTURE.......-1296
TOTAL HEATING UNITS LAST SEASON TO DATE......5920   DIFFERENCE......-1151

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............14 SSE AT 11:45 P.M.
                   AERO..................16 SSE AT 11:45 P.M.
                   ASOS..................15 S   AT 11:54 P.M.
                   DAVIS.................12 ESE AT  2:35 A.M. RMY N/A
THE FASTEST MILE FOR YESTERDAY...........10 S   AT 11:54 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE............10 S   AT 11:57 P.M.
DAVIS MAXIMUM 2-MINUTE AVERAGE............8 E   AT  6:25 P.M.
AVERAGE WIND SPEED AND DIRECTION........4.2 ESE
                   ASOS.................3.9
                   DAVIS................3.9 ESE [118 deg.]
* last of several occurrences....
 
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.04   DEPARTURE..........-0.09
                         ASOS..............0.03
TOTAL PRECIPITATION FOR THE MONTH..........0.79   DEPARTURE..........+0.42
                         ASOS..............0.77
TOTAL PRECIPITATION FOR THE YEAR..........10.40   DEPARTURE..........-8.52
                         ASOS.............10.51
	
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0    DEPARTURE...........0.0
TOTAL SNOWFALL FOR THE MONTH................0.0    DEPARTURE..........-0.1
TOTAL SNOWFALL FOR THE SEASON..............24.2    DEPARTURE.........-35.9

PRELIMINARY CLIMATE SUMMARY FOR APRIL & MAY 2012 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust when significant
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
4/1  50/34/42/+1/0.14/0.0/360/47    20 SSW AERO 20 MPH SSW RMY N/A
4/2  51/35/43/+2/0.04/T/353/46      35 NNW AERO 33 MPH NNW RMY 35
4/3  57/31/44/+2/0.00/0.0/724/94    36 NW  AERO 37 MPH NW  RMY 40
4/4  62/38/50/+8/T/0.0/688/89       40 NW  AERO 39 MPH NW  RMY 43
4/5  51/33/42/-1/0.00/0.0/660/85    29 NW  AERO 27 MPH NW  RMY 30
4/6  51/31/41/-2/0.00/0.0/623/80    26 NNW AERO 26 MPH NNW RMY 28
4/7  54/32/43/0/0.00/0.0/305/39     31 NW  AERO 32 MPH NW  RMY 32
4/8  51/37/44/0/0.00/0.0/086/11     32 NW  AERO 31 MPH NW  RMY 33
4/9  57/43/50/+6/T/0.0/323/41       44 W   AERO 42 MPH W   RMY 44
4/10 61/40/51/+6/0.00/0.0/600/76    32 W   AERO 31 MPH W   RMY 34 
4/11 57/40/49/+4/0.00/0.0/397/50    21 NE  AERO 20 MPH NE  RMY 22
4/12 54/39/47/+2/0.16/0.0/127/16    25 NNW AERO 24 MPH NNW RMY 28
4/13 63/36/50/+4/0.00/0.0/782/98    24 W   AERO 23 MPH W   RMY 25
4/14 70/44/57/+11/0.00/0.0/617/77   25 SSW AERO 27 MPH SSW RMY 28
4/15 75/52/64/+17/T/0.0/426/53      23 W   AERO 23 MPH W   RMY 25
4/16 89/57/73/+26/0.01/0.0/678/84   28 SSW AERO 30 MPH SSW RMY 32
4/17 83/53/68/+21/0.00/0.0/777/96   28 W   AERO 28 MPH W   RMY 32 
4/18 61/45/53/+5/0.00/0.0/487/60    27 NNW AERO 27 MPH NNW RMY N/A
4/19 70/44/57/+9/0.00/0.0/676/83    23 S   AERO 22 MPH S   RMY 25
4/20 75/46/61/+12/0.00/0.0/768/94   30 S   AERO 31 MPH S   RMY 33
4/21 75/51/63/+14/T/0.0/508/62      32 S   AERO 37 MPH SSW RMY 38
4/22 59/41/50/+1/1.16/0.0/000/00    50 NE  AERO 51 MPH NE  RMY 52
4/23 61/42/52/+2/1.99/0.0/000/00    46 NE  AERO 47 MPH NE  RMY 48
4/24 57/43/50/0/0.00/0.0/737/89     37 SSW AERO 42 MPH S   MMY N/A 
4/25 61/41/51/+1/T/0.0/548/66       32 W   AERO 33 MPH W   RMY 32
4/26 66/36/51/0/0.01/0.0/417/50     29 SSW AERO 31 MPH SSW RMY N/A
4/27 56/36/46/-5/0.01/0.0/568/68    39 W   AERO 41 MPH W   RMY 42
4/28 58/31/45/-7/0.00/0.0/821/98    30 WNW AERO 35 MPH WNW RMY 31
4/29 58/36/47/-5/0.00/0.0/807/96    38 NW  AERO 42 MPH NW  RMY 42
4/30 61/35/48/-4/0.00/0.0/641/76    23 S   AERO 25 MPH S   RMY 26

5/1  47/42/45/-8/0.65/0.0/000/00    33 SE  AERO 36 MPH SE  RMY 37 
5/2  50/43/47/-6/0.05/0.0/000/00    16 ENE AERO 16 MPH ENE RMY 17
5/3  51/44/48/-5/0.08/0.0/000/00    14 SSE AERO 16 MPH SSE RMY N/A

5/4  our morning low temp: 47F; the normal low is now 44F

DAILY RECORDS FOR MAY 2012
None so far.

DAILY RECORDS FOR APRIL 2012
4/16 - NEW DAILY RECORD HIGH MAXIMUM TEMP OF 89F;
surpasses the previous record of 87F in 1896.
4/23 - NEW DAILY RECORD PRECIPITATION OF 1.99 INCHES;
surpasses the previous record of 1.51 inches in 1998. 

DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):

RECORDS FOR MAY 4
HIGH 90F IN 2001
LOW 27F IN 1911 (RECORD FOR MAY)
PRECIP 1.92 INCHES IN 1893
SNOWFALL 0.1 INCHES IN 1920
PEAK GUST 60 MPH NW IN 1966

RECORDS FOR MAY 5
HIGH 92F IN 1949
LOW 30F IN 1891
PRECIP 2.74 INCHES IN 1922
SNOWFALL 3.0 INCHES IN 1917
PEAK GUST 58 MPH S IN 1966 & 58e MPH SW IN 1976

TODAY'S REPORT PREPARED BY: Sean Fankhauser