Thursday, July 20, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, JULY 20, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

CONTINUED HEAT AND POOR VISIBILITY, BUT DRIER AIR

Yesterday a maximum of 90F was reached around 3:30 P.M. EST.
Temperatures only dropped down to 70F overnight. Yesterday’s
average temperature of 80F was 8F above normal. A maximum of
90F was reached by the 1:00 P.M. observation. The air was
slightly drier than yesterday, with the dew point at 66F at
1:00 P.M. compared to 70F yesterday at the same time.
Visibility remained poor, at only 25-30 miles. Dense cirrus
covered much of the sky throughout the day. By the afternoon,
there was a layer of broken cumulus with a moderate vertical
extent. There was also a layer of scattered altocumulus.
Winds increased throughout the day out of the west. The peak
gust so far has been 22 MPH at 12:35 P.M. Pressure was rising
early in the morning, but it began falling a few hours before
noon. Pressure continued to fall faster as the day went on.

Today’s Observations:

7 A.M.
Weather: Scattered cirrus
Temperature: 76F; Dew Point: 65F; Wind: WNW at 7 kts
Sea-level pressure: 29.98 ins. Hg, rising, then more quickly
Visibility: 25 miles, hazy
6-hr Max temp: 76F
6-hr Min temp: 70F
24-hr precip: 0.00 in.
BHO SA 1155 250 SCT 25 153/76/65/2907/998/ HAZY/ 8/002 53006
10076 20070

10 A.M.
Weather: Few altocumulus in all directions, broken cirrus
Temperature: 83F; Dew Point: 67F; Wind: WSW at 6 kts
Sea-level pressure: 29.96 ins. Hg, falling, then more quickly
Visibility: 30 miles, hazy
BHO SA 1455 E250 BKN 30 146/83/67/2506/996/ FEW AC ALQDS HAZY/
8/002 57007

1 P.M.
Weather: Broken cumulus, broken altocumulus, broken cirrus
Temperature: 88F; Dew Point: 66F; Wind: W at 9G14 kts
Sea-level pressure: 29.91 ins. Hg, falling, then more quickly
Visibility: 30 miles, hazy
6-hr Max temp: 90F
6-hr Min temp: 76F
BHO SA 1755 E50 BKN 140 BKN 250 BKN 35 128/88/66/2609G14/991/
HAZY/ 8/232 58018 10090 20076

SUMMARY FOR WEDNESDAY, JULY 19, 2017

TEMPERATURE (DEGREES F)
MAX…..90   NORMAL…..81
MIN…..70   NORMAL…..63
MEAN….80   NORMAL…..72

DEPARTURE FROM 30-YEAR NORMAL…………………….+8
TOTAL DEPARTURE FOR THE MONTH……………………+23 [+1.4 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..15   DEPARTURE……….+7
TOTAL COOLING UNITS FOR THE MONTH………….155   DEPARTURE………+25
TOTAL COOLING UNITS FOR THE SEASON…………356   DEPARTURE………+97
TOTAL COOLING UNITS LAST SEASON TO DATE…….317   DEPARTURE………+39

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….22 SW  AT 2:42 P.M.
AERO……………………22 SW  AT 2:50 P.M.*
ASOS……………………22 WSW AT 2:55 P.M.
DAVIS…………………..22 WSW AT 1:27 P.M. RMY 22
FASTEST MILE FOR YESTERDAY…………………15 SW  AT 2:54 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………17 SW  AT 2:55 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..15 SW  AT 2:55 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..9.1 SW
ASOS…………………..9.4
DAVIS………………….7.5 WSW [247 DEG.] *last of multiple occurrences

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……….1.58  DEPARTURE……-0.75
ASOS…………..1.55
TOTAL PRECIPITATION FOR THE YEAR……….32.95  DEPARTURE……+3.65
ASOS……………N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR JULY 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

7/1  85/67/76/+6/T/439/48                  35 S   AERO 37 S   RMY 38
7/2  87/69/78/+8/T/785/86                  25 W*  AERO 28 W*  RMY 27
7/3  85/67/76/+5/0.00/894/98               28 W*  AERO 29 W   RMY 30
7/4  84/62/73/+2/0.00/783/86               17 W   AERO 17 W   RMY 18
7/5  82/62/72/+1/0.00/855/94               20 S   AERO 20 ENE RMY 20
7/6  82/60/71/+0/0.00/664/73               21 SSW AERO 22 SSW RMY 21
7/7  71/60/66/-5/0.63/000/00               28 ENE AERO 28 ENE RMY 27
7/8  84/61/73/+1/0.15/463/51               30 SW* AERO 32 SSW RMY 33 TSTM
7/9  81/60/71/-1/0.00/897/99               26 W   AERO 26 W   RMY 26
7/10 85/63/74/+2/T/751/83                  25 SW  AERO 25 S   RMY 26
7/11 82/66/74/+2/0.25/253/28               24 S   AERO 24 S   RMY N/A
7/12 85/68/77/+5/0.43/325/36               23 NE  AERO 22 NE  RMY 23 TSTM
7/13 68/55/62/-10/0.03/000/00              28 NNE AERO 28 NE  RMY 29
7/14 63/56/60/-12/0.02/…/..              15 E   AERO 14 E   RMY 14
7/15 80/60/70/-2/0.00/…/..               18 S   AERO 16 S   RMY 18
7/16 87/64/76/+4/0.00/…/..               18 SSE AERO 16 E   RMY 17
7/17 84/68/76/+4/0.00/…/..               25 S   AERO 25 S*  RMY 25
7/18 85/68/77/+5/0.07/…/..               23 S   AERO 23 S   RMY 23
7/19 90/70/80/+8/0.00/…/..               22 SW  AERO 22 SW* RMY 22

7/20 Low temp since midnight is 70F; normal low is now 63F

DAILY RECORDS FOR JULY

None so far.

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

RECORDS FOR JULY 20
HIGH 99F IN 1991
LOW 47F IN 1890
PRECIP 1.64 INS IN 1938
WIND 56e MPH SSW IN 1943

RECORDS FOR JULY 21
HIGH 100F IN 1977 [RECORD FOR MONTH] LOW 48F IN 1890
PRECIP 2.09 INS IN 1938
PEAK GUST 60e MPH WNW IN 1977

TODAY’S REPORT PREPARED BY: Lizzy Suzedell