BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS 02186
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
 
DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY MAY 3, 2010 
ALL TIMES ARE IN EASTERN STANDARD TIME
 
A VERY WARM START TO MAY
THE WEEKEND TWO-DAY AVERAGE
WAS 19 DEGREES ABOVE THE 30-YEAR NORMAL
RECORD HIGH MINIMUM TEMPERATURE EQUALED MAY 1ST
 
Our temperatures reached the 80's on both
weekend days with 81 degrees on Saturday
followed by 87 degrees Sunday. The average
temperature for both days combined was 19 degrees
on the plus side of normal. Saturday's minimum
temperature of 58 degrees equaled the record
high minimum for the date which was set in 2001. 
 
April 2010 finished as the warmest on record
with a corrected mean temperature of 51.5, which
is 0.5 degree higher than the previous warmest
April in 1976.  It also had the warmest average
minimum on record and the 2nd warmest average
maximum.

The year to date (Jan-Apr) ranks third warmest
on record. The month tied for the warmest monthly
minimum temperature with 31 on the 28th, and it
had the earliest 90+ temperature on record with
90 on the 7th.  
 
Warmest April Corrected Mean Temperature (deg F)
 
1) 51.5 in 2010
2) 51.0 in 1976
3) 49.4 in 1945
4) 49.0 in 1994
5) 48.9 in 2005
   48.9 in 2009
 
Warmest Jan-Apr Corrected Mean Temperature (deg F)
 
1) 38.3 in 2002
2) 37.9 in 1998
3) 37.2 in 2010
4) 36.9 in 1990
5) 36.8 in 2006
 
Warmest April Average Maximum Temperature (deg F)
 
1) 62.4 in 1976
2) 62.2 in 2010
3) 61.2 in 1945
4) 60.4 in 1941
5) 60.3 in 1991
 
Warmest April Average Minimum Temperature (deg F)
 
1) 41.8 in 2010
2) 41.5 in 1945
3) 40.5 in 1910
4) 40.4 in 1976
5) 39.7 in 1998
 
Warmest April Monthly Minimum Temperature (deg F)
 
1) 31 in 1951
   31 in 1986
   31 in 1998
   31 in 2010
5) 30 in 1901
   30 in 1902
   30 in 1945
   30 in 1988
   30 in 1991
   30 in 1994
 
Earliest 90+ degree temperature
 
1) 90 on 7 April 2010
2) 93 on 17 April 2002
3) 92 on 18 April 1976
4) 94 on 19 April 1976
 

THE APRIL 2010 STATS
 
[Temp. deg. F]
Average maximum temperature:  62.2F
Average minimum temperature:  41.8F
Mean temperature: 52.0 {5.7]
Maximum temperature:  90F on April 7
Minimum temperature:  31F on April 28
Total heating degree day units: 386 [-176]
Heating season: 5482 [-544]
Cooling degree day units: 3 [0]
Precipitation:  2.45 inches (1.87 below normal)
Greatest in 24 hours: 1.12 ins. on 9th
Snowfall:  Trace (3.1 inches below normal)
Prevailing wind:  12.3 mph West
Peak Gust:  55 mph WNW on April 29
Sunshine: Astronomical: 234.4 hrs.
14065/24094 mins: = 58%
Sunshine: Campbell-Stokes card, 226.2 hrs.
13570/23250 mins. = 58%
Long-term average sunshine for April: 49%
 
Today's observations:
 
7 A.M.
Weather: Obscurement with dense fog, light rain,
visibility lowered rapidly as low clouds enveloped
the summit just before observation 
Temperature: 68F, Dew point: 68F, Wind: S at 13 kts
Sea-level pressure: 29.66 inches Hg, steady
Visibility: 1/4 variable 1/8 to 1 mile, stratus
drifting over the summit 
6-hour minimum temp: 68F
6-hourly precip: 0.04 in.
24-hourly precip: 0.04 in.
BHO SA 1155 W2 X 1/4VR-F 045/68/68/1913/966/
STRA DRFTG OVR SMT VSBY LWRD RPDLY VSBY 1/8V1/
8//// 56009 ASOS 60003 MANUAL 6004/ ASOS 70003
MANUAL 70004 10072 20068
 
10 A.M.
Weather: Overcast altostratus, altocumulus,
few stratocumulus distant SE-S
Temperature: 71F, Dew point: 65F, Wind: SW at 15G22 kts,
Wind: Direction variable S-WSW
Sea-level pressure: 29.63 inches Hg, falling
Visibility: 30 miles, light distant haze
3-hour precip: trace  
BHO SA 1455 E130 OVC 30 034/71/65/2215G22/963/
FEW SC DSNT SE-S FEW LWR AC DSNT LGT DSNT WND 19V25/
8/57/ 56011 MANUAL 6000/
 
1 P.M.
Weather: Scattered altocumulus, altocumulus of a chaotic
sky, scattered dense ci, thin overcast cirrus, and breaks
in the overcast.  An altocumulus layer was receding to the
northeast and east 
Temperature: 77F, Dew point: 65F, Wind: SSW at 17G24 kts,
Wind: Peak wind from southwest at 28 kts @ 12:23 p.m.,
Wind: Direction variable S-WSW
Sea-level pressure: 29.59 inches Hg, falling
Visibility: 30 miles, distant haze
6-hourly max. temp: 77F
6-hourly precip: trace
BHO SA 1755 150 SCT 180 SCT 220 SCT 250 –BKN 300 –OVC 30
020/77/65/2117G24/959/ SC ALQDS AC LYR NE-E RCDNG AC CHAOTIC
FEW ACSL PTCHS DENS CI BINOVC DSNT HZ PK WND 2328/23
WND 17V25/ 8/592 56014 MANUAL 6000/ 10077 20068 
 
WEATHER SUMMARY FOR SUNDAY, MAY 2
 
TEMPERATURE (DEGREES F)
MAX.....87     NORMAL.....62
MIN.....56     NORMAL.....43
MEAN....72     NORMAL.....52
 
DEPARTURE FROM 30-YEAR AVERAGE...............+20
TOTAL DEPARTURE FOR THE MONTH................+38 [+18.8 DEGREES/DAY]
 
HEATING DEGREE DAYS
TOTAL HEATING UNITS FOR YESTERDAY.............0    DEPARTURE.......-13
TOTAL HEATING UNITS FOR THE MONTH.............0    DEPARTURE.......-26
TOTAL HEATING UNITS FOR THE SEASON.........5482    DEPARTURE......-570
TOTAL HEATING UNITS LAST SEASON TO DATE....5907    DIFFERENCE.....-425
 
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY.............29 SSW AT 11:55 A.M.  
                   AEROVANE..............28 SSW AT 11:55 A.M.  *    
                   ASOS..................29 S   AT 11:59 A.M.     
                   DAVIS.................31 SSW AT 11:55 A.M.        
THE FASTEST MILE FOR YESTERDAY...........23 SSW AT 11:57 A.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE............23 SSW AT 11:56 A.M.      
MAXIMUM 2-MINUTE DAVIS AVERAGE...........24 SSW AT 11:56 A.M.           
AVERAGE WIND SPEED AND DIRECTION........12.5 S
                   ASOS.................12.6
                   DAVIS................11.2 S [190 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..........0.04  DEPARTURE......-0.22
                         ASOS..............0.03
TOTAL PRECIPITATION FOR THE YEAR..........30.40  DEPARTURE.....+12.19
                         ASOS.............30.48
 
SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE......-0.1
TOTAL SNOWFALL FOR THE MONTH................0.0  DEPARTURE......-0.1
TOTAL SNOWFALL FOR THE SEASON..............64.4  DEPARTURE......+4.3
 
PRELIMINARY CLIMATE SUMMARY FOR APRIL-MAY 2010 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
TSTM: Thunderstorm day (thunder heard some time during day)
....: Data not yet available, records not finalized
 
4/1  59/43/51/+10/T/0/359/47        24 NNW   AERO 30 MPH NNW
4/2  67/46/57/+15/0.00/0/728/95     21 SSE
4/3  75/45/60/+18/0.00/0/731/95     26 SSE
4/4  76/45/61/+19/0.00/0/617/80     27 W     AERO 29 MPH W 
4/5  72/53/63/+20/0.00/0/635/82     37 SSE   AERO 40 MPH SSE
4/6  68/50/59/+16/T/0/202/26        23 W    
4/7  90/45/68/+25/0.00/0/578/74     36 WSW   AERO 41 MPH WSW
4/8  65/45/55/+11/0.00/0/611/78     31 ENE
4/9  56/37/47/+3/1.12/0/000/00      35 W     AERO 39 MPH W
4/10 56/37/47/+3/0.00/0/663/84      45 W     AERO 52 MPH W
4/11 69/47/58/+13/0.00/0/506/64     36 W     AERO 40 MPH W
4/12 61/43/52/+7/0.00/0/635/80      31 W     AERO 33 MPH W
4/13 56/39/48/+3/0.00/0/613/77      23 S     
4/14 65/37/51/+5/0.00/0/760/95      28 WNW   AERO 32 MPH WNW
4/15 60/40/50/+4/0.00/0/739/92      30 NE
4/16 43/34/39/-7/0.50/T/000/00      26 E
4/17 41/36/39/-8/0.14/T/000/00      27 ENE 
4/18 49/37/43/-4/0.07/0/032/04      29 WNW
4/19 58/35/47/0/0.00/0/667/82       30 WNW   AERO 32 MPH WNW
4/20 68/43/56/+8/T/0/694/85         26 WNW   AERO 28 MPH WNW
4/21 71/49/60/+11/0.00/0/590/72     30 S     AERO 31 MPH SSE
4/22 70/46/58/+7/0.08/0/444/54      31 SE                    
4/23 62/44/53/+4/0.01/0/494/60      24 NE
4/24 67/43/55/+6/0/0/769/93         31 SSE  
4/25 60/47/54/+4/0/0/041/05         28 SSW
4/26 56/44/50/0/0.18/0/175/21       18 NE    AERO 22 MPH NNE
4/27 47/33/40/-10/0.23/0/000/00     27 W
4/28 46/31/39/-12/0.12/T/228/27 *   41 WNW   AERO 45 MPH WNW
4/29 59/38/49/-2/0.00/0/773/92      55 WNW   AERO 63 MPH WNW
4/30 74/42/58/+6/0.00/0/783/93      39 W     AERO 41 MPH W
 
* sunshine corrected from 000/00 as was reported on May 1......
 
5/1  81/58/70/+18/0.00/0.0/.../..   29 SE
5/2  87/56/72/+20/0.00/0.0/.../..   29 SSW
 
5/3  our morning low temp: 68F; the normal low is now 43F
 
NEW DAILY RECORDS FOR MAY 2010
5/1 - minimum temp. of 58F equals record high
      minimum for the date set in 2001
 
NEW DAILY RECORDS FOR APRIL 2010
4/4 - new record high maximum temperature of 76F;
surpasses 71F in 1950.
4/5 - new record high minimum temperature of 53F;
surpasses 52F in 1981
4/7 - new record high maximum temperature of 90F;
surpasses 86F in 1929
4/29 - new record peak wind gust of 55 MPH WNW;
surpasses 54 MPH WSW in 1981
 
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
 
RECORDS FOR MAY 3
HIGH 92F IN 2001
LOW 31F IN 1888
PRECIP 2.25 INS IN 1900
SNOWFALL TRACE IN 1908, 1985
PEAK GUST 71 MPH W IN 2002
 
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
 
TODAY'S REPORT PREPARED BY: Robert Skilling/Mike Iacono