Saturday, May 1, 2021

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

SATURDAY, MAY 1, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0439E
SUNSET:  1844E

SKIES BEGIN TO CLEAR AS VISIBILITY AND WIND SPEED
INCREASES….

Today started off mostly on the cloudy side following
some light rainfall overnight. That event left 0.12 ins.
in the gauge by the 7 A.M. There was a very light rain
shower that passed through between 7-8 A.M. that left
only a trace.

Since then, cloud cover has decreased significantly,
and we are seeing an average visibility of 80 miles.
This is accompanied by a stiff northwesterly wind
with frequent gusts above 20 mph. The max gust so far
today is 36 mph around 11 A.M.  

The high so far today is 60F, this is 2 degrees below the
normal high of 62F. The low since midnight is 38F, which
is 5 degrees below the daily normal low of 43F.

Today’s Observations:

7 A.M.
Weather: Scattered stratocumulus, broken cirrostratus,
few stratocumulus
Temperature: 42F; Dew Point: 37F; Relative Humidity: 81%
Wind: WNW at 11G22 kts
Sea-level pressure: 29.70 in Hg, rising, then more rapidly
Visibility: 75 miles
6-hr Max temp: 42F
6-hr Min temp: 38F
24-hr Precip: 0.12 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 80 SCT 220 BKN 75 059/42/37/3011G22/970/ 8/856
51042 70012 10042 20038

10 A.M.
Weather: Few cumulus and altocumulus
Temperature: 52F; Dew Point: 45F; Relative Humidity: 55%
Wind: WNW @ 18G24 kts
Peak Wind: 35 MPH (30 kts) WNW @ 9:11 AM
Sea-level pressure: 29.75 in Hg; rising steadily
Visibility: 80 miles
3-hr Precip: Trace
3-hr Snow: 0.00 ins.
BHO SA 1455 CLR 80 075/52/45/2918G24/975/ FEW CU/AC ALQDS
PK WND 3130/11/ 8/170 600// 51016

1 P.M.
Weather: Scattered cumulus and cirrostratus
Temperature: 60F, Dew point: 35F; Relative Humidity: 39%
Wind: WNW @ 15G25 kts
Sea-level pressure: 29.76 in Hg; rising steadily
Visibility: 80 miles
6-hr Max temp: 60F
6-hr Min temp: 42F
6-hr Precip: Trace
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 50 SCT 250 SCT 80 080/60/35/2915G25/976/ 8/106
600// 51005 10060 20042


SUMMARY FOR FRIDAY, APRIL 30, 2021

TEMPERATURE (DEGREES F)
MAX…….62     NORMAL…..61
MIN…….41     NORMAL…..43
MEAN……52     NORMAL…..52

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL…….  0
TOTAL DEPARTURE FOR THE MONTH……………….+29 [+0.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………13  DEPARTURE…..+/-0
TOTAL HEATING UNITS FOR THE MONTH…………..519  DEPARTURE……-32
TOTAL HEATING UNITS FOR THE SEASON…………5341  DEPARTURE…..-694
TOTAL HEATING UNITS LAST SEASON TO DATE…….5521  DEPARTURE…..-180

PEAK WIND GUST (MPH):
                     420C/Official…………..58 WNW @  4:13 P.M.
                     AEROVANE (south tower)…..60 WNW @  3:56 P.M.
                     ASOS…………………..57 W   @  4:18 P.M.
                     DAVIS #1……………….62 WNW @  4:19 P.M.
                     DAVIS #2 (south tower)…..58 WNW @  3:03 P.M.
                     RMY……………………65     @  4:18 P.M.
                     VECTOR…………………67     @  4:18 P.M.
                     MERLIN…………………61

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………44 W   @  3:58 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….41 W   @  3:58 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………46 W   @  3:58 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………41 W   @  5:27 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..38 WNW @  3:25 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..41     @  3:24 P.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL……22.0 WNW [529 total miles]                     ASOS…………………20.3
                     DAVIS #1……………..22.1 WNW
                     DAVIS #2……………..22.3 WNW
                     RMY………………….19.4 WNW
                     VECTOR……………….20.8


PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.12  DEPARTURE….-0.01
                             ASOS………….0.11
TOTAL PRECIPITATION FOR THE MONTH………….4.89  DEPARTURE….+0.33
                             ASOS………….4.77
TOTAL PRECIPITATION FOR THE YEAR………….15.12  DEPARTURE….-3.49
                              ASOS………..15.33


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/…./…/…/..      18 ENE  AERO 21 WNW  RMY 20
04/29   54/44/48/-4/…./…/…/..      18 ENE  AERO 20 NNE  RMY 19
04/30   62/41/52/0/…./…/…/..       58 WNW  AERO 60 WNW  RMY 65

05/01 The low since midnight is 38F, the daily normal low is 43F

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

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

RECORDS FOR MAY 1
HIGH 87F IN 1899
LOW 29F IN 1978
PRECIP 2.53 INCHES IN 1921
SNOWFALL TRACE IN 1905,1917,1921,1995,2016
PEAK GUST 57 MPH NW IN 1974

RECORDS FOR MAY 2
HIGH 92F IN 2001
LOW 29F IN 1903
PRECIP 1.36 INCHES IN 2006
SNOWFALL TRACE IN 1920, 1941
PEAK GUST 58 MPH S IN 1983

TODAY’S REPORT PREPARED BY: Benjamin Turner