Wednesday, May 5, 2021

BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA

WEDNESDAY, MAY 5, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0434E
SUNSET:  1848E

CHILLY WITH VERY LIGHT RAIN….

Today we experienced more rainfall with an overnight total
of 0.32 inches and an additional 0.02 inches between the
7 and 1 P.M. observations. Visibility was a half mile at
best due to fog, with an average visibility of an 1/8th
mile. Wind was dead calm this morning with a very light
northeasterly breeze through the rest of the day.

The high so far today is 48F, this is 15 degrees below the
normal high of 63F. The low since midnight is 44F, which
is a degree below the daily normal low of 44F.

Today’s Observations:

7 A.M.
Weather: Light rain
Temperature: 45F; Dew Point: 45F; Relative Humidity: 100%
Wind: Calm
Sea-level pressure: 29.79 in Hg, falling then rising
Visibility: 1/2th mile, fog
6-hr Max temp: 45F
6-hr Min temp: 44F
24-hr Precip: 0.32 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 X W3 1/2R-F 089/45/45/0000/979/ R-CTD WND CALM/ 8////
51009 70032 10045 20044

10 A.M.
Weather: Fog
Temperature: 47F; Dew Point: 47F; Relative Humidity: 100%
Wind: NE @ 5 kts, light and variable
Sea-level pressure: 29.75 in Hg; falling steadily
Visibility: 1/16th mile, fog
3-hr Precip: 0.01 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 X W3 1/16F 075/47/47/0405/975/ WND L/V/ 8////
6001/ 58014

1 P.M.
Weather: Very light rain
Temperature: 46F, Dew point: 46F; Relative Humidity: 100%
Wind: NNE @ 7 kts
Sea-level pressure: 29.70 in Hg; falling steadily
Visibility: 1/16th miles, fog
6-hr Max temp: 48F
6-hr Min temp: 45F
6-hr Precip: 0.02 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 X W2 1/16R-F 058/46/46/0207/970/ R-CTD PCPN VRY
LGT/ 8//// 6002/ 58017 10048 20045

SUMMARY FOR TUESDAY, MAY 4, 2021

TEMPERATURE (DEGREES F)
MAX…….50     NORMAL…..63
MIN…….44     NORMAL…..44
MEAN……47     NORMAL…..54

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….. -7
TOTAL DEPARTURE FOR THE MONTH…………………+4 [+0.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………18  DEPARTURE…….+7
TOTAL HEATING UNITS FOR THE MONTH……………43  DEPARTURE…….-6
TOTAL HEATING UNITS FOR THE SEASON…………5384  DEPARTURE…..-699
TOTAL HEATING UNITS LAST SEASON TO DATE…….5543  DEPARTURE…..-159

COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0  DEPARTURE……. 0
TOTAL COOLING UNITS FOR THE MONTH…………… 0  DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE SEASON………….. 0  DEPARTURE…….-3
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2  DEPARTURE…….-2

PEAK WIND GUST (MPH):
                     420C/Official…………..36 NNE @ 10:30 A.M.
                     AEROVANE (south tower)…..32 NNE @  9:57 A.M.
                     ASOS…………………..36 NE  @ 10:37 A.M.
                     DAVIS #1……………….33 NE  @ 10:35 A.M.
                     DAVIS #2 (south tower)…..34 NNE @ 10:35 A.M.
                     RMY……………………37     @ 10:34 A.M.
                     VECTOR…………………37     @ 10:35 A.M.
                     MERLIN…………………34

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………23 NNE @ 12:02 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….22 NE  @ 12:13 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………23 NE  @ 12:12 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………23 NE  @  8:59 A.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..22 ENE @  8:56 A.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..22     @  8:56 A.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL……11.2 NNE [268 total miles]                     ASOS…………………11.3
                     DAVIS #1……………..11.4 ENE
                     DAVIS #2……………..11.5 NE
                     RMY………………….10.8 E
                     VECTOR……………….11.1

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.32  DEPARTURE….+0.20
                             ASOS………….0.32
TOTAL PRECIPITATION FOR THE MONTH………….1.15  DEPARTURE….+0.66
                             ASOS………….1.11
TOTAL PRECIPITATION FOR THE YEAR………….16.21  DEPARTURE….-2.83
                              ASOS………..16.39

PRELIMINARY CLIMATE SUMMARY FOR APRIL CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system gust
RMY:  R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

04/01   56/30/43/+2/0.89/T/000/00        44 NW   AERO 51 NW   RMY 49
04/02   37/24/31/-10/0.00/0.0/614/80     28 NW   AERO 32 NNW  RMY 30
04/03   48/23/36/-6/0.00/0.0/755/98      24 NW   AERO 25 NW   RMY 26
04/04   58/33/46/+4/0.00/0.0/734/95      38 NNW  AERO 41 NNW  RMY 41
04/05   57/41/49/+6/T/T/031/04           41 NNW  AERO 48 NNW  RMY 50
04/06   61/40/51/+8/0.00/0.0/412/53      26 NNW  AERO 25 NNW  RMY 31
04/07   57/41/49/+6/0.00/0.0/391/50      23 ENE  AERO 21 ENE  RMY 22
04/08   59/43/51/+7/0.00/0.0/745/95      22 ENE  AERO 22 ENE  RMY 24
04/09   69/42/56/+12/0.00/0.0/707/90     24 S    AERO  M   M  RMY 26
04/10   75/43/59/+14/0.00/0.0/576/73     26 SSW  AERO 28 SSW  RMY 30
04/11   53/40/47/+2/T/0.0/000/00         33 ENE  AERO 33 ENE  RMY 34
04/12   46/37/42/-3/0.05/0.0/000/00      36 ENE  AERO 37 ENE  RMY 41
04/13   56/37/47/+1/T/0.0/415/52         31 NE   AERO 30 NE   RMY 33
04/14   56/42/49/+3/0.00/0.0/729/91      22 ESE  AERO 23 ESE  RMY 22
04/15   51/37/44/-3/0.30/0.0/016/02      26 ESE  AERO 25 ESE  RMY 28
04/16   39/31/35/-12/2.22/3.6/000/00     48 NNW  AERO 58 NNW  RMY 58
04/17   45/34/40/-7/0.07/T/040/05        27 NNW  AERO 30 NNW  RMY 29
04/18   60/38/49/+1/0.00/0.0/666/82      28 NW   AERO 28 NW   RMY 31
04/19   66/44/55/+7/T/0.0/…/..         22 SSW  AERO 25 SSW  RMY 28
04/20   72/45/59/+10/0.00/0.0/…/..     38 SW   AERO 37 WSW  RMY 40
04/21   68/32/50/+1/0.48/*T/…/..       45 S    AERO 51 S    RMY 51 TSTM
04/22   44/28/36/-13/T/T/…/..          54 W    AERO 55 W    RMY 59
04/23   58/32/45/-5/0.00/0.0/…/..      47 W    AERO 48 W    RMY 52
04/24   70/44/57/+7/0.00/0.0/…/..      33 WNW  AERO 37 WNW  RMY 55
04/25   54/44/49/-1/0.20/0.0/…/..      23 NNE  AERO 20 SSW  RMY 24
04/26   55/40/48/-3/0.00/0.0/…/..      39 NW   AERO 40 NW   RMY 43
04/27   67/38/53/+2/T/0.0/…/..         26 W    AERO 28 WNW  RMY 28
04/28   63/46/55/+3/0.18/0.0/…/..      18 ENE  AERO 21 WNW  RMY 20
04/29   54/44/48/-4/0.42/0.0/…/..      18 ENE  AERO 20 NNE  RMY 19
04/30   62/41/52/0/0.08/0.0/…/..       58 WNW  AERO 60 WNW  RMY 65

*Trace of frozen on 04/21 was hail, 1/8″ diameter, this does not
count as snowfall.

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/PEAK GUST/AERO/RMY GUST
AERO: Aerovane wind recording system gust
RMY:  R.M. Young wind gust recording system
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
M:    Missing data

05/01   62/38/50/-3/0.06/0.0/…/..       31 WNW  AERO 35 WNW  RMY 40
05/02   76/48/62/+9/0.01/0.0/…/..       41 SW   AERO 41 SW   RMY 46
05/03   67/48/58/+5/0.07/0.0/…/..       21 E    AERO 20 E    RMY 20
05/04   50/44/47/-7/…./0.0/…/..       36 NNE  AERO 32 NNE  RMY 37

05/05 The low since midnight is 44F, the daily normal low is 45F

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

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

RECORDS FOR MAY 6
HIGH 90F IN 1930
LOW 29F IN 1891
PRECIP 1.04 INCHES IN 1890
SNOWFALL TRACE IN 1917, 1952, 1996
PEAK GUST 65 MPH SSE IN 1989

TODAY’S REPORT PREPARED BY: Benjamin Turner