Tuesday, May 18, 2021

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

TUESDAY, MAY 18, 2021
ALL TIMES ARE IN EASTERN STANDARD TIME
SUNRISE: 0420E
SUNSET:  1902E

FIRST 80 DEGREE DAY OF THE SEASON OBSERVED HERE AT BLUE HILL…

The day has seen variable amounts of cloud cover, but
enough sun to drive temperatures into the low 80s early
this afternoon. A brief rain shower was observed after the
1 P.M. observation, but only a trace fell.

BHO Mean Date of the First 80 deg F: May 7th
BHO Earliest Date of the First 80 deg F: March 15th, 1990
BHO Latest Date of the First 80 deg F: June 19th, 1917
These data were prepared by our Chief Scientist, Mike Iacono.

The wind has become gusty as we moved into the early afternoon
with gusts mainly between 25-30 mph.

The high so far today is 81F, which is 14 degrees
above the normal high of 67F. The low since midnight
is 54F, which is 6 degrees above the daily normal low
of 48F.

Today’s Observations:

7 A.M.
Weather: Broken cirrostratus, thin broken cirrus,
few altocumulus/castellanus SSE-S and WNW-N
Temperature: 62F; Dew Point: 45F; Relative Humidity: 53%
Wind: W at 10 kts
Sea-level pressure: 30.26 in. Hg; rising, then more slowly
Visibility: 60 miles
6-hr Max temp: 62F
6-hr Min temp: 54F
24-hr Precip: 0.00 ins.
24-hr Snow: 0.0 ins.
Snow Depth: 0.0 ins.
BHO SA 1155 E200 BKN 250 -BKN 60 246/62/45/2810/026/
FEW AC/ACC SSE-S AND WNW-N THN K LYR ALNG HRZN NE-E/
8/087 51008 10062 20054

10 A.M.
Weather: Thin broken cirrus, few cumulus all quadrants,
few altocumulus castellanus distant SSE-S, few cirrostratus
distant WSW and distant N-SE
Temperature: 77F; Dew Point: 41F; Relative Humidity: 27%
Wind: W @ 12G20 kts
Sea-level pressure: 30.24 in Hg; rising, then falling
Visibility: 40 miles, hazy
3-hr Precip: 0.00 ins.
3-hr Snow: 0.0 ins.
BHO SA 1455 250 -BKN 40 239/77/41/2812G20/024/ FEW CU ALQDS
FEW ACC DSNT SSE-S FEW CS DSNT WSW AND DSNT N-SE HAZY/ 8/186 58005

1 P.M.
Weather: Broken cumulus, broken altocumulus, thin broken cirrus
Temperature: 81F, Dew point: 42F; Relative Humidity: 25%
Wind: WNW @ 10G20 kts
Sea-level pressure: 30.18 in Hg; falling, then more rapidly
Visibility: 30 miles, hazy
6-hr Max temp: 81F
6-hr Min temp: 62F
6-hr Precip: 0.00 ins.
6-hr Snow: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E60 BKN 85 BKN 250 -BKN 30 220/81/42/2910G20/018/
HAZY/ 8/261/ 58019 10081 20062

SUMMARY FOR MONDAY, MAY 17, 2021

TEMPERATURE (DEGREES F)
MAX…….77     NORMAL…..67
MIN…….52     NORMAL…..48
MEAN……65     NORMAL…..57

DEPARTURE FROM 30-YEAR (1981-2010) NORMAL……. +8
TOTAL DEPARTURE FOR THE MONTH……………….+10 [+0.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL THRU JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………… 0  DEPARTURE…….-8
TOTAL HEATING UNITS FOR THE MONTH…………..159  DEPARTURE……-18
TOTAL HEATING UNITS FOR THE SEASON…………5500  DEPARTURE…..-712
TOTAL HEATING UNITS LAST SEASON TO DATE…….5713  DEPARTURE…..-228

COOLING DEGREE DAYS (SEASON JAN THRU DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………… 0  DEPARTURE…….-1
TOTAL COOLING UNITS FOR THE MONTH…………… 1  DEPARTURE…….-6
TOTAL COOLING UNITS FOR THE SEASON………….. 1  DEPARTURE…….-8
TOTAL COOLING UNITS LAST SEASON TO DATE……… 2  DEPARTURE…….-1

PEAK WIND GUST (MPH):
                     420C/Official…………..20 SSW  @  5:24 P.M.
                     AEROVANE (south tower)…..21 SSW  @  5:41 P.M.
                     ASOS…………………..20 SSW  @  5:14 P.M.
                     DAVIS #1……………….20 SSW  @  5:31 P.M.
                     DAVIS #2 (south tower)…..20 S    @  4:59 P.M.
                     RMY……………………21      @  5:07 P.M.
                     VECTOR…………………22      @  5:07 P.M.
                     MERLIN…………………19

FASTEST MILE:
CONTACTING ANEMOMETER/OFFICIAL………………14 SSW @   5:30 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….15 SW  @   5:28 P.M.
MAXIMUM 2-MINUTE DAVIS #1 AVERAGE……………14 SW  @   5:26 P.M.
MAXIMUM 2-MINUTE DAVIS #2 AVERAGE……………16 SSW @   5:32 P.M.
MAXIMUM 2-MINUTE RMY AVERAGE………………..15 SW  @   5:24 P.M.
MAXIMUM 2-MINUTE VECTOR AVERAGE……………..15     @   5:24 P.M.

AVERAGE WIND SPEED AND DIRECTION:
                     CONTACTING/OFFICIAL…… 7.6 WSW [183 total miles]                     ASOS………………… 8.0
                     DAVIS #1…………….. 7.9 W
                     DAVIS #2…………….. 8.1 W
                     RMY…………………. 7.5 W
                     VECTOR………………. 8.0

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST):
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…….0.00  DEPARTURE….-0.13
                             ASOS………….0.00
TOTAL PRECIPITATION FOR THE MONTH………….1.80  DEPARTURE….-0.29
                             ASOS………….1.74
TOTAL PRECIPITATION FOR THE YEAR………….16.86  DEPARTURE….-3.78
                              ASOS………..17.02

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/0.0/619/76         22 SSW  AERO 25 SSW  RMY 28
04/20   72/45/59/+10/0.00/0.0/564/69     38 SW   AERO 37 WSW  RMY 40
04/21   68/32/50/+1/0.48/*T/435/53       45 S    AERO 51 S    RMY 51 TSTM
04/22   44/28/36/-13/T/T/658/80          54 W    AERO 55 W    RMY 59
04/23   58/32/45/-5/0.00/0.0/817/99      47 W    AERO 48 W    RMY 52
04/24   70/44/57/+7/0.00/0.0/753/91      33 WNW  AERO 37 WNW  RMY 55
04/25   54/44/49/-1/0.20/0.0/017/02      23 NNE  AERO 20 SSW  RMY 24
04/26   55/40/48/-3/0.00/0.0/825/99      39 NW   AERO 40 NW   RMY 43
04/27   67/38/53/+2/T/0.0/359/43         26 W    AERO 28 WNW  RMY 28
04/28   63/46/55/+3/0.18/0.0/352/42      18 ENE  AERO 21 WNW  RMY 20
04/29   54/44/48/-4/0.42/0.0/008/01      18 ENE  AERO 20 NNE  RMY 19
04/30   62/41/52/0/0.08/0.0/666/79       58 WNW  AERO 60 WNW  RMY 65

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/-3/0.06/0.0/659/78       31 WNW  AERO 35 WNW  RMY 40
05/02   76/48/62/+9/0.01/0.0/220/26       41 SW   AERO 41 SW   RMY 46
05/03   67/48/58/+5/0.07/0.0/400/47       21 E    AERO 20 E    RMY 20
05/04   50/44/47/-7/0.78/0.0/000/00       36 NNE  AERO 32 NNE  RMY 37
05/05   48/44/46/-8/0.45/0.0/000/00       18 ESE  AERO 14 ESE  RMY 17
05/06   64/45/55/+1/0.00/0.0/780/91       33 NW   AERO 38 NNW  RMY 39
05/07   61/43/52/-3/0.00/0.0/516/60       28 ESE  AERO 22 ESE  RMY 26
05/08   54/40/47/-8/0.00/0.0/069/08       24 SSW  AERO 23 SSW  RMY 25
05/09   66/42/54/-1/T/0.0/579/67          30 SW   AERO 29 SW   RMY 34
05/10   60/45/53/-2/0.39/0.0/…/..       21 W    AERO 20 W    RMY 20
05/11   63/45/54/-2/0.00/0.0/…/..       38 WNW  AERO 41 WNW  RMY 41
05/12   65/41/53/-3/0.00/0.0/…/..       28 NW   AERO M  M    RMY 31
05/13   69/45/57/+1/0.00/0.0/…/..       22 WNW  AERO 21 WNW  RMY 21
05/14   76/49/63/+8/0.00/0.0/…/..       23 WNW  AERO 23 WNW  RMY 25
05/15   75/55/65/+8/0.01/0.0/…/..       24 SSE  AERO 26 SSE  RMY 26
05/16   78/54/66/+9/0.01/0.0/…/..       36 W    AERO 37 W    RMY 42
05/17   77/52/65/+8/0.00/0.0/…/..       20 SSW  AERO 21 SSW  RMY 21

05/18 The low since midnight is 54F, the daily normal low is 48F
 

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

RECORDS FOR MAY 18
HIGH 96F IN 2017(RECORD FOR MAY)
LOW 35F IN 2002
PRECIP 1.93 INS IN 2007
SNOW TRACE IN 2002 (Ice pellets)
PEAK GUST 64 MPH SSW IN 2000

RECORDS FOR MAY 19
HIGH 91F IN 1962
LOW 34F IN 2002
PRECIP 1.54 INCHES IN 1900
PEAK GUST 58 MPH NW IN 1964

TODAY’S REPORT PREPARED BY: Matt Douglas