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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, APRIL 18, 2017  
ALL TIMES ARE IN EASTERN STANDARD TIME

HIGH PRESSURE GIVES US PARTLY SUNNY SKIES AND NORTHEAST WINDS

Winds shifted out of the northeast shortly before 10:00AM EST
under this region of high pressure.  Despite sunny skies, the
northeast winds brought in cooler air and kept temperatures at
near-normal levels.  The max. at 1:00PM was 52F.  Conditions
remained dry with dew points in the upper 20s and low 30s and
relative humidities in the 40% range.

Clear morning skies became partly cloudy with multiple layers
of cumulus clouds by late morning.  Visibility remained at 70
miles during each observation.  Wind speeds were moderate at
15-20 MPH.


Today's Observations:

7 A.M.
Weather: Few cumulus N-SE, few distant stratocumulus NW-SSE
Temperature: 44F; Dew Point: 25F; Wind: NNW at 11G16 kts
Sea-level pressure: 30.33 ins. Hg, rising, then more quickly
Visibility: 70 miles
6-hr Max temp: 47F
6-hr Min temp: 41F
24-hr precip: 0.00 in.
24-hr snowfall: 0.0 in.
BHO SA 1155 CLR 70 270/44/25/3411G16/033/ FEW CU N-SE FEW DSNT 
SC NW-SSE/ 8/100 53030 10047 20041

10 A.M.
Weather: A layer of scattered cumulus and a layer of broken cumulus 
Temperature: 52F; Dew Point: 29F; Wind: NE at 10G18 kts
Sea-level pressure: 30.38 ins. Hg, rising, then more quickly
Visibility: 70 miles
BHO SA 1455 29 SCT E42 BKN 70 289/52/29/0510G18/038/ 8/100 53019

1 P.M.
Weather: Two layers of scattered cumulus
Temperature: 50F; Dew Point: 31F; Wind: ENE at 11G16 kts
Sea-level pressure: 30.42 ins. Hg, rising, then more slowly
Visibility: 70 miles
6-hr Max temp: 52F
6-hr Min temp: 44F
BHO SA 1755 33 SCT 49 SCT 70 303/50/31/0711G16/042/ 8/100 51014 
10052 20044 


SUMMARY FOR MONDAY, APRIL 17, 2017
 
TEMPERATURE (DEGREES F)
MAX.....75   NORMAL.....56
MIN.....48   NORMAL.....38
MEAN....62   NORMAL.....47

DEPARTURE FROM 30-YEAR NORMAL........................+15
TOTAL DEPARTURE FOR THE MONTH.......................+106 [+6.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY...............3   DEPARTURE.........-15
TOTAL HEATING UNITS FOR THE MONTH.............257   DEPARTURE.........-97
TOTAL HEATING UNITS FOR THE SEASON...........5159   DEPARTURE........-679
TOTAL HEATING UNITS LAST SEASON TO DATE......4814   DIFFERENCE.......+345

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL HEATING UNITS FOR YESTERDAY...............0   DEPARTURE...........0
TOTAL HEATING UNITS FOR THE MONTH...............9   DEPARTURE..........+9
TOTAL HEATING UNITS FOR THE SEASON..............9   DEPARTURE..........+9
TOTAL HEATING UNITS LAST SEASON TO DATE.........0   DIFFERENCE.........+9

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................37  W  AT 1:02 P.M.
                   AERO........................37  W  AT 1:02 P.M.
                   ASOS........................40  W  AT 1:01 P.M.
                   DAVIS.......................36  W  AT 1:00 P.M. RMY 43
FASTEST MILE FOR YESTERDAY.....................27 WNW AT 1:23 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE..................26 WNW AT 1:23 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE.................26  NW AT 1:23 P.M.
AVERAGE WIND SPEED AND DIRECTION.............15.3 W
                   ASOS......................14.2
                   DAVIS.....................13.7 NW [310 deg.]
* LAST OF MULTIPLE OCCURRENCES

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M....0.00  DEPARTURE......-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........4.28  DEPARTURE......+1.48
                         ASOS..............4.29
TOTAL PRECIPITATION FOR THE YEAR..........18.40  DEPARTURE......+1.60
                         ASOS...............N/A ***
*** ASOS annual total not available due to erroneous readings

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE.......-0.1
TOTAL SNOWFALL FOR THE MONTH................2.7  DEPARTURE.......+0.3
TOTAL SNOWFALL FOR THE SEASON..............66.4  DEPARTURE.......+4.3


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

4/1  35/31/33/-8/2.21/2.7/000/00           40 ENE AERO 41 ENE RMY 41
4/2  53/30/42/+1/0.00/0.0/.../..           32 NW  AERO 33 NW  RMY 34
4/3  60/35/48/+6/0.00/0.0/.../..           21 W*  AERO 20 NW  RMY N/A
4/4  42/35/39/-3/0.78/0.0/.../..           41 ESE AERO 43 ESE RMY 42
4/5  41/35/38/-5/0.00/0.0/000/00           21 NNW AERO 20 NNW RMY N/A
4/6  55/35/45/+2/1.27/0.0/000/00           35 SSE AERO 37 S   RMY 37  TSTM
4/7  53/38/46/+3/0.00/0.0/.../..           43 SSW AERO 47 SSW RMY 48
4/8  50/34/42/-2/0.00/0.0/.../..           37 WNW AERO 40 WNW RMY 39
4/9  65/34/50/+6/0.00/0.0/.../..           23 W   AERO 23 W   RMY N/A
4/10 77/45/61/+16/0.00/0.0/.../..          37 S   AERO 37 S   RMY 39
4/11 85/50/68/+23/0.00/0.0/.../..          28 S   AERO 28 S   RMY 30
4/12 68/47/58/+13/0.01/0.0/.../..          26 WNW AERO 28 WNW RMY N/A
4/13 58/40/49/+3/0.00/0.0/.../..           28 WNW AERO 31 NW  RMY 30 
4/14 62/40/51/+5/0.00/0.0/.../..           22 NNW AERO 22 NNW RMY 24
4/15 68/40/54/+7/0.01/0.0/.../..           40 SSW AERO 45 SSW RMY 45
4/16 86/55/71/+24/T/0.0/.../..             38 W*  AERO 39 SW  RMY 42
4/17 75/48/62/+15/0.00/0.0/.../..          37 W   AERO 37 W   RMY 43

4/18 Low temp since midnight is 41F; normal low is now 39F


DAILY RECORDS FOR APRIL 2017

4/11/17: DAILY RECORD MAXIMUM TEMPERATURE OF 85F,
         BREAKS PREVIOUS RECORD OF 78F SET IN 1945

4/11/17: DAILY RECORD HIGH MINIMUM TEMPERATURE OF 50F,
         TIES WITH PREVIOUS RECORD SET IN 1955


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

RECORDS FOR APRIL 18
HIGH 92 IN 1976
LOW 23 1887
PRECIP 1.48 IN 1954
SNOWFALL 3.7 IN. IN 1965
PEAK GUST 59 MPH S IN 1982

RECORDS FOR APRIL 19
HIGH 94 IN 1976 [RECORD FOR MONTH]
LOW 21 IN 1890
PRECIP 1.71 IN 1969
SNOWFALL 6.0 IN. IN 1887
PEAK GUST 66 MPH E IN 1984

TODAY'S REPORT PREPARED BY: Cecilia Borries-Strigle