Wednesday, May 17, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
WEDNESDAY, MAY 17, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

NEW MAX. TEMP. RECORD FOR TODAY, SOUTH WINDS BRING
HAZY CONDITIONS AND DIMINISHING VISIBILITY

Extremely warm temperatures continued today and were
higher than originally forecast.  Temps. had reached
89F at Great Blue Hill by 1:00PM EST which breaks the
previous record of 88F set in 1974 and tied in 1977.
Dew points were on the rise into the upper 50s by the
afternoon.  Along with warmth and humidity, southerly
winds also brought hazy conditions.  Visibility dropped
from 70 miles to 40 miles as the day progressed.

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: Scattered altocumulus, thin smoke layer along horizon NNW-NNE
Temperature: 66F; Dew Point: 49F; Wind: SSW at 6 kts,
Wind speed: Light
Sea-level pressure: 30.00 ins. Hg, rising, then more quickly
Visibility: 70 miles
6-hr Max temp: 66F
6-hr Min temp: 60F
24-hr precip: Trace.
BHO SA 1155 84 SCT 70 159/66/49/2106/000/
THN K LYR ALG HRZN NNW-NNE WND LGT/ 8/030 53008 10066 20060

10 A.M.
Weather: Scattered altostratus
Temperature: 78F; Dew Point: 47F; Wind: SSW at 10G18 kts
Sea-level pressure: 29.95 ins. Hg, falling, then more quickly
Visibility: 40 miles, distant haze in all directions
BHO SA 1455 65 SCT 40 142/78/47/2110G18/995/ DSNT HZ ALQDS/ 8/010 58017

1 P.M.
Weather: Few cumulus in all directions, scattered cirrostratus
Temperature: 88F; Dew Point: 56F; Wind: SW at 12G23 kts
Sea-level pressure: 29.87 ins. Hg, falling steadily
Visibility: 40 miles, hazy
6-hr Max temp: 89F
6-hr Min temp: 66F
BHO SA 1755 250 SCT 40 115/88/56/2312G23/987/ FEW CU ALQDS HAZY/
8/105 58027 10089 20066

SUMMARY FOR TUESDAY, MAY 16, 2017

TEMPERATURE (DEGREES F)
MAX…..79   NORMAL…..66
MIN…..51   NORMAL…..48
MEAN….65   NORMAL…..57

DEPARTURE FROM 30-YEAR NORMAL…………………….+8
TOTAL DEPARTURE FOR THE MONTH……………………-60 [-4.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………0   DEPARTURE……….-9
TOTAL HEATING UNITS FOR THE MONTH………….220   DEPARTURE………+51
TOTAL HEATING UNITS FOR THE SEASON………..5553   DEPARTURE……..-650
TOTAL HEATING UNITS LAST SEASON TO DATE……5193   DIFFERENCE…….+360

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….26 WNW AT 3:32 P.M.
AERO……………………26 WNW AT 3:31 P.M.
ASOS……………………28 WNW AT 3:32 P.M.
DAVIS…………………..25  W  AT 3:31 P.M. RMY 29
FASTEST MILE FOR YESTERDAY…………………20 WNW AT 3:31 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………20 WNW AT 3:51 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..19  W  AT 3:33 P.M.
AVERAGE WIND SPEED AND DIRECTION………….13.2 WNW
ASOS………………….12.7
DAVIS…………………11.7 WNW [296 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…TRACE  DEPARTURE……-0.12
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….3.15  DEPARTURE……+1.20
ASOS…………..3.22
TOTAL PRECIPITATION FOR THE YEAR……….23.96  DEPARTURE……+3.46
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 Low temp since midnight is 60F; normal low is now 48F

DAILY RECORDS FOR MAY

5/17/17: DAILY RECORD MAXIMUM TEMPERATURE OF 89F (through 13E),
BREAKS PREVIOUS RECORD OF 88F SET IN 1974
AND TIED IN 1977

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

RECORDS FOR MAY 17
HIGH 88F IN 1974, 1977
LOW 34F IN 1956, 1957
PRECIP 2.07 INS IN 1916
PEAK GUST 52 MPH SW IN 1967, W IN 1974

RECORDS FOR MAY 18
HIGH 88F IN 1906, 1936, 1986
LOW 35F IN 2002
PRECIP 1.93 INS IN 2007
SNOW TRACE IN 2002 (Ice pellets)
PEAK GUST 64 MPH SSW IN 2000

TODAY’S REPORT PREPARED BY: Nick Rousseau and Cecilia Borries-Strigle