Friday, May 19, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, MAY 19, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

TEMPERATURES STILL POSSIBLY RECORD BREAKING BEFORE COLD FRONT APPROACHES

Temperatures had risen to 89F by 1:00PM. We could potentially beat the
record of 91 set back in 1962. Yesterday we broke a few temperature records
the high of 96F was both the high maximum temperature for the day and also
for the month of May. The previous warmest day in May was 94F set back in
2010. Yesterday’s minimum of 69F broke the previous record of 61F set in
1943. An overnight thunderstorm reached Great Blue Hill just before midnight
and left 0.01 inches of precipitation.

Hazy conditions continued today. Visibility decreased throughout the
day and was only 20 miles during the 10AM and 1PM observations. Winds
were gusting up to 35 MPH and were out of the southwest.

The average maximum temperature of 56.8F for the first 15 days of
May 2017 ranks as the sixth coldest since 1885.  However, ranking
the maximum temperature over the first 15 days of May shows that
the reading of 65F this month (on May 2, May 4, and May 6) is the
coldest on record.

BHO Coldest 1st-15th May Average Maximum Temperature, deg F (1885-2017)

1) 48.6 in 1917
2) 55.3 in 1885
3) 56.0 in 1962
4) 56.1 in 1921
5) 56.5 in 1954
6) 56.8 in 2017
7) 56.9 in 1920
8) 57.0 in 1907

BHO Coldest 1st-15th May Maximum Temperature, deg F (1885-2017):

1) 65 in 2017
2) 66 in 1917
3) 68 in 1962
68 in 1967
5) 69 in 1966
6) 70 in 1898
70 in 1928

Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus ENE-SSE, few cirrus all directions
Temperature: 73F; Dew Point: 63F; Wind: WSW at 11G18 kts
Sea-level pressure: 29.84 ins. Hg, rising then more slowly
Visibility: 50 miles, distant haze in all directions
6-hr Max temp: 73F
6-hr Min temp: 67F
24-hr precip: 0.01 in.
BHO SA 1155 CLR 50 105/73/63/2511G18/984/ FEW AC ENE-SSE
FEW CI ALQDS DSNT HZ ALQDS/ 8/041 51014 MANUAL 70001 ASOS 70001 10073 20067

10 A.M.
Weather: Clear, few cumulus NW-NNW
Temperature: 84F; Dew Point: 61F; Wind: W at 9G18 kts
Sea-level pressure: 29.82 ins. Hg, rising then falling
Visibility: 20 miles, hazy
BHO SA 1455 CLR 20 099/84/61/2609G18/982/ FEW CU NW-NNW HAZY/ 8/100 58006

1 P.M.
Weather: Scattered cumulus
Temperature: 89F; Dew Point: 57F; Wind: W at 18G30 kts
Sea-level pressure: 29.80 ins. Hg, falling, then more slowly
Visibility: 40 miles, Hazy
6-hr Max temp: 89F
6-hr Min temp: 73F
BHO SA 1755 65 SCT 20 090/89/57/2618G30/980/ HAZY PK WND 2630/52/
8/200 58009 10089 20073

SUMMARY FOR THURSDAY, MAY 18, 2017

TEMPERATURE (DEGREES F)
MAX…..96   NORMAL…..67
MIN…..69   NORMAL…..48
MEAN….83   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………+25
TOTAL DEPARTURE FOR THE MONTH……………………-17 [-1.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE………-25
TOTAL HEATING UNITS FOR THE MONTH………….220   DEPARTURE………+35
TOTAL HEATING UNITS FOR THE SEASON………..5553   DEPARTURE……..-667
TOTAL HEATING UNITS LAST SEASON TO DATE……5209   DIFFERENCE…….+344

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..18   DEPARTURE……….+9
TOTAL COOLING UNITS FOR THE MONTH…………..28   DEPARTURE………+21
TOTAL COOLING UNITS FOR THE SEASON………….48   DEPARTURE………+39
TOTAL COOLING UNITS LAST SEASON TO DATE……..21   DIFFERENCE……..+44

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….39 WNW AT 11:23 P.M.
AERO……………………41 WNW AT 11:23 P.M.
ASOS……………………43 WNW AT 11:25 P.M.
DAVIS…………………..38 SW  AT 07:43 P.M. RMY 42
FASTEST MILE FOR YESTERDAY…………………30 WNW AT 11:23 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………29 WNW AT 11:26 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..29 WSW AT 11:25 P.M.
AVERAGE WIND SPEED AND DIRECTION………….15.2 WSW
ASOS………………….14.4
DAVIS…………………13.4 WSW [248 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.01  DEPARTURE……-0.12
ASOS…………..0.01
TOTAL PRECIPITATION FOR THE MONTH……….3.16  DEPARTURE……+0.95
ASOS…………..3.23
TOTAL PRECIPITATION FOR THE YEAR……….23.97  DEPARTURE……+3.21
ASOS……………N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR MAY CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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

5/1  50/43/47/-6/T/034/04                  21 N   AERO 18 N   RMY 22
5/2  65/42/54/+1/0.26/136/16               41 W   AERO 44 W   RMY 43
5/3  52/42/53/0/0.00/595/70                37 WNW*AERO 39 WNW RMY 40
5/4  65/40/53/-1/0.00/724/85               23 S   AERO 23 S   RMY 24
5/5  51/44/48/-6/0.73/000/00               28 E   AERO 28 E   RMY N/A
5/6  65/50/58/+4/0.23/094/11               46 SSE AERO 48 SSE RMY 49
5/7  63/47/55/0/T/670/78                   35 S   AERO 38 S   RMY 39
5/8  54/38/46/-9/T/224/26                  29 WSW AERO 29 WSW RMY 32
5/9  53/36/45/-10/T/251/29                 20 ESE AERO 17 ESE RMY 19
5/10 57/42/50/-5/0.00/225/26               17 NNE AERO 16 NW  RMY N/A
5/11 58/45/52/-4/0.00/443/51               23 NE* AERO 23 NE  RMY 23
5/12 57/41/49/-7/0.01/…/..               21 NE  AERO 20 NE  RMY 19
5/13 57/41/49/-7/0.19/…/..               24 ENE AERO 24 E   RMY N/A
5/14 47/43/45/-12/1.49/…/..              33 NNE AERO 36 N   RMY 36
5/15 58/43/51/-6/0.24/…/..               36 NNW AERO 40 NNW RMY 41
5/16 79/51/65/+8/0.00/…/..               26 WNW AREO 26 WNW RMY 29
5/17 90/60/75/+18/T/…/..                 32 SSE AERO 33 SW* RMY 34
5/18 96/69/83/+25/0.01/…/..              39 WNW AERO 41 WNW RMY 42 TSTM

5/19 Low temp since midnight is 67F; normal low is now 48F

DAILY RECORDS FOR MAY

5/17/17: DAILY RECORD MAXIMUM TEMPERATURE OF 90F,
BREAKS PREVIOUS RECORD OF 88F SET IN 1974
AND TIED IN 1977

5/17/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 60F,
TIES PREVIOUS RECORD SET IN 1932

5/18/17: DAILY RECORD MAXIMUM TEMPERATURE OF 96F,
BREAKS PREVIOUS RECORD OF 88F SET IN 1906
AND TIED IN 1936 AND 1986

5/18/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 69F,
BREAKS PREVIOUS RECORD OF 61 SET IN 1943

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

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

RECORDS FOR MAY 20
HIGH 91F IN 1975,1996
LOW 37F IN 1948, 2002
PRECIP 1.65 INCHES IN 1969
PEAK GUST 57 MPH S IN 1963, WNW IN 1982

TODAY’S REPORT PREPARED BY: Nick Rousseau and Kaitlin Geagan