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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, SEPTEMBER 22, 2018 
ALL TIMES ARE IN EASTERN STANDARD TIME

PARTLY TO MOSTLY CLOUDY TODAY WITH DRIER AIR ARRIVING...

As the day began, the dew point was still in the low to middle
60s. Following a rain shower between 1 and 2 AM EST that
brought 0.07 inches of precipitation, the wind began veering
from south to west to NNW during the day and drier air began
moving into the area. Bt 7 AM the dew point had dropped to 
53F, and by 1 PM it was down into the upper 40s. The peak gust
for the day of 37 mph from the SW occurred at 1:22 AM EST during
the rainfall early today. Since then, a mostly mid-level cloud 
cover has filled part of the sky all day with a few lower and 
higher clouds. The visibility has responded to the drying air, 
rising from near 50 miles at 7 AM to nearly 80 miles at the 
1 PM observation. 

Today's Observations:

7 A.M.
Weather: Scattered stratocumulus castellanus NE and ESE-SE,
scattered altocumulus, scattered cirrus, few cirrocumulus
overhead 
Temperature: 64F; Dew Point: 53F; Wind: W at 22G29 kts 
Wind: Peak gust 29 kts, W at 6:55 AM 
Sea-level pressure: 29.98 ins. Hg, rising, then more slowly        
Visibility: 50 miles, visibility increasing
6-hr Max temp: 68F
6-hr Min temp: 64F
24-hr Precip: 0.07 ins.   
BHO SA 1155 25 SCT 130 SCT 25 SCT 50 151/64/53/2822G28/998/ 
SCCAS NE AND ESE-S FEW CC OVHD VSBY INCR PK WND 2829/55/ 8/241 
51030 6007/ 70007 10068 20064

10 A.M.
Weather: Broken altocumulus, broken cirrus, few cumulus and
stratocumulus in all directions
Temperature: 67F; Dew Point: 52F; Wind: NW at 14G20 kts  
Sea-level pressure: 30.08 ins. Hg, rising, then more slowly
Visibility: 75 miles 
3-hr Precip: 0.00 ins.
BHO SA 1455 E130 BKN 250 BKN 75 187/67/52/3214G20/008/ 
FEW CU/SC ALQDS/ 8/131 51036

1 P.M.
Weather: Scattered altocumulus, broken cirrus, few cumulus 
distant S-SW
Temperature: 67F; Dew Point: 47F; Wind: NNW at 8 kts
Sea-level pressure: 30.12 ins. Hg, rising steadily     
Visibility: 75 miles 
6-hr Max temp: 70F
6-hr Min temp: 64F 
6-hr Precip: 0.00 ins.
BHO SA 1755 E130 BKN 250 BKN 75 201/67/47/3408/012/ FEW CU 
DSNT S-SW/ 8/131 52014 10070 20064

  
SUMMARY FOR FRIDAY, SEPTEMBER 21, 2018 

TEMPERATURE (DEGREES F)
MAX.....70   NORMAL.....70
MIN.....55   NORMAL.....53
MEAN....63   NORMAL.....61

DEPARTURE FROM 30-YEAR NORMAL.......................+2
TOTAL DEPARTURE FOR THE MONTH......................+76 [+3.4 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............2   DEPARTURE.........-3
TOTAL HEATING UNITS FOR THE MONTH..............29   DEPARTURE........-28
TOTAL HEATING UNITS FOR THE SEASON.............29   DEPARTURE........-53
TOTAL HEATING UNITS LAST SEASON TO DATE........60   DIFFERENCE.......-31

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY...............0  DEPARTURE..........-1
TOTAL COOLING UNITS FOR THE MONTH.............102  DEPARTURE.........+50
TOTAL COOLING UNITS FOR THE SEASON............855  DEPARTURE........+266
TOTAL COOLING UNITS LAST SEASON TO DATE.......665  DIFFERENCE.......+190

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY.....................37 SSW AT  9:42 P.M.
                   AERO..........................37 SSW AT 11:23 P.M.
                   ASOS..........................40 SSW AT 11:24 P.M.
                   DAVIS.........................38 SSW AT  9:42 P.M. RMY 41
FASTEST MILE FOR YESTERDAY.......................30 W   AT 11:22 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE....................29 SSW AT 11:10 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE...................29 SSW AT  9:42 P.M.
AVERAGE WIND SPEED AND DIRECTION...............13.9 S
                   ASOS........................13.7
                   DAVIS.......................12.6 SSW [195]   
* Last of several occurrences
**Davis direction malfunctioning 

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.07  DEPARTURE......-0.08
                         ASOS..............0.07
TOTAL PRECIPITATION FOR THE MONTH..........6.46  DEPARTURE......+3.73
                         ASOS..............6.53 
TOTAL PRECIPITATION FOR THE YEAR..........44.41  DEPARTURE......+6.84
                         ASOS.............46.05 

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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

9/01 75/58/67/-1/0.00/521/66        17 NE  AERO 15 NE  RMY 16 
9/02 83/61/72/+4/0.00/684/87        20 SSW AERO 18 SSW RMY N/A 
9/03 92/68/80/+13/0.00/650/83       24 WSW AERO 22 WSW RMY 25
9/04 88/70/79/+12/0.00/695/89       17 W   AERO 16 W   RMY 17 
9/05 89/67/78/+11/0.00/638/82       23 SSW AERO 23 SSW RMY 25 
9/06 92/70/81/+14/0.56/488/63       29 NNW AERO 29 NNW RMY N/A TSTM
9/07 70/63/67/+1/0.01/000/00        24 NE  AERO 22 NE  RMY N/A 
9/08 68/54/61/-5/0.00/031/04        22 NE  AERO 18 NE  RMY 21
9/09 61/53/57/-9/0.00/000/00        23 NE  AERO 21 NE  RMY N/A
9/10 62/56/59/-6/..../.../..        30 E   AERO 28 E   RMY 28
9/11 75/61/68/+3/..../.../..        23 E   AERO 21 E   RMY N/A TSTM 
9/12 69/63/66/+1/..../.../..        21 ENE AERO 21 ENE RMY 21  TSTM 
9/13 68/62/65/+1/..../.../..        21 NE  AERO 21 NE  RMY N/A TSTM 
9/14 75/61/68/+4/..../.../..        13 NE  AERO 12 ENE RMY 12 
9/15 76/62/69/+5/0.01/.../..        14 SW  AERO 13 SW  RMY 13
9/16 84/61/73/+10/..../.../..       15 S   AERO 14 S   RMY N/A
9/17 82/64/73/+10/..../.../..       22 SSW AERO 22 SSW RMY N/A
9/18 74/67/71/+9/..../.../..        31 SSW AERO 30 SSW RMY N/A TSTM
9/19 66/57/62/0/..../.../..         28 NE  AERO 25 NE  RMY 26
9/20 63/55/59/-3/..../.../..        22 NE  AERO 21 NE  RMY 19
9/21 70/55/63/+2/..../.../..        37 SSW AERO 37 SSW RMY 41

9/22 Low temp since midnight is 64F; normal low is now 52F

DAILY RECORDS FOR SEPTEMBER

09/04/18: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F,
          BREAKS PREVIOUS RECORD OF 68F SET IN 1937 AND 1959

09/06/18: DAILY RECORD HIGH MAXIMUM TEMPERATURE OF 92F,
          TIES PREVIOUS RECORD OF 92F SET IN 1900 

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

RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989

RECORDS FOR SEPTEMBER 23
HIGH 93F IN 1895,1914
LOW 33F IN 1904
PRECIP 2.67 INCHES IN 1994
PEAK GUST 62 MPH SSW IN 1989

TODAY'S REPORT PREPARED BY: Mike Iacono / Nate Iannuccillo