Sunday, May 21, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, MAY 21, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

COOLER TEMPERATURES CONTINUE

Temperatures have been slightly below normal today, dropping
to a morning low of 45F and warming to a max. of 66F by 1:00PM
EST.  Light northeast winds slightly increased in the afternoon
with gusts up to 18 MPH.  Skies remained mostly cloudy with
altocumulus for much of the morning and early afternoon. Dew
points in the mid 30s and 40s made for a very pleasant spring day.

The high temperature of 96F on the 18th was not only a record
for the date and for the month of May, it was also the highest
temperature of 95F or more so early in the year, breaking the
previous occurrence of 95F or more, which was 98F on June 3,
1919.  The cumulative temperature departure over the last four
days of +66 degrees has nearly erased all of the negative
temperature departure accumulated over the first 15 days of
the month.

Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, scattered cirrus
Temperature: 55F; Dew Point: 43F; Wind: NE at 5 kts,
Wind speed: Light
Sea-level pressure: 30.39 ins. Hg, rising, then more quickly
Visibility: 70 miles, distant fog in all directions
6-hr Max temp: 55F
6-hr Min temp: 45F
24-hr precip: 0.00 in.
BHO SA 1155 200 SCT 250 SCT 70 292/55/43/0505/039/ DSNT FG ALQDS
WND LGT/ 8/031 53012 10055 20045

10 A.M.
Weather: Few cumulus SE-W, broken altocumulus
Temperature: 62F; Dew Point: 42F; Wind: NE at 7 kts
Sea-level pressure: 30.40 ins. Hg, steady then rising
Visibility: 70 miles
BHO SA 1455 E200 BKN 70 295/62/42/0407/040/ FEW CU SE-W/ 8/130 50003

1 P.M.
Weather: Broken altocumulus
Temperature: 64F; Dew Point: 33F; Wind: NE at 10G14 kts
Sea-level pressure: 30.34 ins. Hg, falling, then more quickly
Visibility: 70 miles
6-hr Max temp: 66F
6-hr Min temp: 54F
BHO SA 1755 E200 BKN 70 275/64/33/0510G14/034/ 8/030 58020 10066 20054

SUMMARY FOR SATURDAY, MAY 20, 2017

TEMPERATURE (DEGREES F)
MAX…..67   NORMAL…..68
MIN…..49   NORMAL…..49
MEAN….58   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………..0
TOTAL DEPARTURE FOR THE MONTH…………………….-2 [-0.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………7   DEPARTURE………..0
TOTAL HEATING UNITS FOR THE MONTH………….227   DEPARTURE………+27
TOTAL HEATING UNITS FOR THE SEASON………..5560   DEPARTURE……..-675
TOTAL HEATING UNITS LAST SEASON TO DATE……5221   DIFFERENCE…….+339

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….23 NE  AT 7:35 A.M.
AERO……………………22 NE  AT 7:37 A.M. *
ASOS……………………24 E   AT 7:37 A.M.
DAVIS…………………..20 NE  AT 7:55 A.M. RMY 21
FASTEST MILE FOR YESTERDAY…………………15 ENE AT 7:58 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………17 ENE AT 8:25 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..15 ENE AT 9:18 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..8.8 NE
ASOS…………………..9.0
DAVIS………………….7.3 ENE [055 deg.]

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……….3.16  DEPARTURE……+0.68
ASOS…………..3.23
TOTAL PRECIPITATION FOR THE YEAR……….23.97  DEPARTURE……+2.94
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 89/56/73/+15/T/…/..                 35 W   AERO 33 W   RMY 37
5/20 67/49/58/0/0.00/…/..                23 NE  AERO 22 NE  RMY 21

5/21 Low temp since midnight is 45F; normal low is now 49F

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;
BREAKS PREVIOUS MONTHLY RECORD OF 94F SET ON
MAY 26, 2010

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

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

RECORDS FOR MAY 21
HIGH 92F IN 1921
LOW 35F IN 1907
PRECIP 1.61 INS IN 1954
PEAK GUST 74 MPH WSW IN 2006

RECORDS FOR MAY 22
HIGH 93F IN 1911
LOW 35F IN 1907
PRECIP 3.75 INCHES IN 1920
PEAK GUST 49e MPH SSW IN 1947

TODAY’S REPORT PREPARED BY: Cecilia Borries-Strigle