Friday, April 30, 2021

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

FRIDAY, APRIL 30, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0440E
SUNSET:  1843E

DRIER & BRIGHTER, BUT WIND BEGINS TO RIP…

We picked up some beneficial rainfall yesterday into the overnight
hours. Our standard gauge clocked in 0.44 inches for the total,
though our annual deficit remains in the hole…just shy of -3.50 inches.
Blue Hill missed out on the main action, however, as a band of heavy
rain trained across the northern tier of MA. Some towns reported
over 3 inches of rain…impressive!

The storm system responsible for that rainfall is long gone, yet
its center continues to deepen rapidly. This has created an increasing
pressure gradient resulting in escalating wind gusts. Peak gust
through 7AM was just 22 MPH, but we are now seeing gusts into the low
50 MPH range.

Cold air advection in the wake of the storm is leading to diurnal
instability. Mostly cloudy skies are the main feature today keeping the
sunshine rather limited.

The high so far today is 62F, this is 1 degree above the
normal high of 61F. The low since midnight is 45F, which
is 2 degrees above the daily normal low of 43F.

Today’s Observations:

7 A.M.
Weather: Scattered Stratus Fractus, Broken Stratocumulus,
Broken Altocumulus & Altostratus (few stratus fractus
occasionally drifting over summit)
Temperature: 49F; Dew Point: 49F; Relative Humidity: 100%
Wind: W at 10 kts
Sea-level pressure: 29.28 in Hg, rising, then falling
Visibility: 50 miles (thin fog)
6-hr Max temp: 49F
6-hr Min temp: 45F
24-hr Precip: 0.44 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 10 SCT 30 BKN 130 BKN 50 914/49/49/2610/928/
FEW STFRA OCCLY DRFTG OVR SMT THN F ALQDS/ 8/570 58008
70044 10049 20045

10 A.M.
Weather: Broken Cumulus
Temperature: 58F; Dew Point: 45F; Relative Humidity: 62%
Wind: W @ 21G38 kts
Peak Wind: 45 MPH (39 kts) WNW @ 8:58 AM
Sea-level pressure: 29.23 in Hg; rising, then falling
Visibility: 75 miles
3-hr Precip: 0.00 ins.
3-hr Snow: 0.00 ins.
BHO SA 1455 40 BKN 75 909/58/45/2821G38/923/ PK WND 2939/1358/
8/100 58005

1 P.M.
Weather: Broken Cumulus
Temperature: 59F, Dew point: 42F; Relative Humidity: 53%
Wind: W @ 26G38 kts
Peak Wind: 50 MPH (43 kts) W @ 11:53 AM
Sea-level pressure: 29.25 in Hg; falling, then rising
Visibility: 65 miles, hazy
6-hr Max temp: 62F
6-hr Min temp: 49F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 40 BKN 65 905/59/42/27026G38/925/ HAZY
PK WND 2743/1653/ 8/100 55004 10062 20049

SUMMARY FOR THURSDAY, APRIL 29, 2021

TEMPERATURE (DEGREES F)
MAX…….54     NORMAL…..61
MIN…….44     NORMAL…..43
MEAN……48     NORMAL…..52

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. -4
TOTAL DEPARTURE FOR THE MONTH……………….+29 [+0.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………17  DEPARTURE…….-4
TOTAL HEATING UNITS FOR THE MONTH…………..506  DEPARTURE……-32
TOTAL HEATING UNITS FOR THE SEASON…………5328  DEPARTURE…..-694
TOTAL HEATING UNITS LAST SEASON TO DATE…….5503  DEPARTURE…..-175

PEAK WIND GUST (MPH):
                     420C/Official…………..18 ENE @  6:24 P.M.
                     AEROVANE (south tower)…..20 ENE @ 10:29 P.M.
                     ASOS…………………..19 NNE @ 10:30 P.M.
                     DAVIS #1……………….18 ENE @  6:23 P.M.
                     DAVIS #2 (south tower)…..20  NE @ 10:29 P.M.
                     RMY……………………19     @  6:23 P.M.
                     VECTOR…………………20     @  6:24 P.M.
                     MERLIN…………………22

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 ENE @  6:25 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 ENE @  6:27 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………15 ENE @  6:26 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………15 ENE @  6:26 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..14 E   @  6:24 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..14     @  6:24 P.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL…….6.4 ENE [153 total miles]                     ASOS………………….6.9
                     DAVIS #1………………7.0 ENE
                     DAVIS #2………………7.0 ENE
                     RMY…………………..6.8 E
                     VECTOR………………..7.0

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.44  DEPARTURE….+0.31
                             ASOS………….0.42
TOTAL PRECIPITATION FOR THE MONTH………….4.83  DEPARTURE….+0.40
                             ASOS………….4.71
TOTAL PRECIPITATION FOR THE YEAR………….15.00  DEPARTURE….-3.42
                              ASOS………..15.22

SNOWFALL (INCHES) THROUGH THIS MORNING (EST):
TOTAL SNOWFALL 24 HOURS ENDING 7 A.M………..0.0  DEPARTURE…+/-0.0
TOTAL SNOWFALL FOR THE MONTH ………………3.6  DEPARTURE…..+0.6
TOTAL SNOWFALL FOR THE SEASON……………..76.2  DEPARTURE….+14.0

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 The low since midnight is 45F, 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 APRIL 30
HIGH 86 IN 1942
LOW 30 IN 1931
PRECIP 1.41 IN 1991
SNOWFALL 0.3 IN. IN 1909
PEAK GUST 64e MPH NW IN 1978

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

TODAY’S REPORT PREPARED BY: Andrew Swanson