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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, FEBRUARY 17, 2018  
ALL TIMES ARE IN EASTERN STANDARD TIME

MUCH COLDER WITH ADVANCING CLOUDS TODAY...

After a few rain showers through mid-day on Friday a cold
front crossed the area on gusty winds last evening bringing
a brief return to seasonable cold today. The low temperature
this morning was 23F and the high temperature has reached
only into the middle 30s as of early afternoon. The dew point
dropped into the single digits this morning, and the dry air
has brought very good visibility of 75 to nearly 80 miles. 
Thin scattered cirrus very early this morning have slowly 
advanced to cover most of the sky as mid-level clouds began 
to arrive just after noon. Bright sunshine this morning has
faded this afternoon as the denser clouds are arriving 
ahead of the expected snowfall tonight. With the recent
warm temperatures, Ponkapoag Pond has dropped to one-tenth
ice cover, while Houghton's Pond remains fully ice covered. 

Today's Observations:

7 A.M.
Weather: Thin scattered cirrus, few stratocumulus distant
offshore NE-ESE
Temperature: 23F; Dew Point: 11F; Wind: NW at 12 kts
Sea-level pressure: 30.37 ins. Hg, rising, then more slowly     
Visibility: 75 miles
6-hr Max temp: 29F
6-hr Min temp: 23F
24-hr precip: Trace ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 250 -SCT 75 285/23/11/3212/037/ FEW SC DSNT OFFSHR 
NE-ESE/ 8/501 51037 10029 20023

10 A.M.
Weather: Scattered cirrus
Temperature: 30F; Dew Point: 6F; Wind: NW at 4 kts,
Wind: Light
Sea-level pressure: 30.41 ins. Hg, rising then falling 
Visibility: 75 miles 
3-hr precip: 0.00
3-hr snowfall: 0.0 ins.  
BHO SA 1455 250 SCT 75 298/30/6/3204/041/ WND LGT/ 8/001 
50013 
 
1 P.M.
Weather: Scattered altocumulus, scattered cirrus, thin
broken cirrus, few cumulus distant offshore NE-E 
Temperature: 36F; Dew Point: 7F; Wind: NW at 6 kts 
Wind: Light
Sea-level pressure: 30.36 Hg, falling then more rapidly  
Visibility: 75 miles  
6-hr Max temp: 36F
6-hr Min temp: 23F
6-hr precip: 0.00
6-hr snowfall: 0.0 ins.
Snow depth: 0 in.
BHO SA 1755 180 SCT 220 SCT 250 -BKN 75 280/36/7/1506/036/ 
FEW CU DSNT OFFSHR NE-E WND LGT/ 8/031 58018 10036 20023
 
 
SUMMARY FOR FRIDAY, FEBRUARY 16, 2018

TEMPERATURE (DEGREES F)
MAX.....50   NORMAL.....37
MIN.....31   NORMAL.....19
MEAN....41   NORMAL.....28

DEPARTURE FROM 30-YEAR NORMAL...........................+13
TOTAL DEPARTURE FOR THE MONTH...........................+78 [+4.7 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY.............24   DEPARTURE.........-13
TOTAL HEATING UNITS FOR THE MONTH............532   DEPARTURE.........-79
TOTAL HEATING UNITS FOR THE SEASON..........3853   DEPARTURE........-289
TOTAL HEATING UNITS LAST SEASON TO DATE.....3620   DIFFERENCE.......+233

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY....................45   W AT 4:38 P.M. 
                   AERO.........................44   W AT 4:41 P.M. *
                   ASOS.........................45   W AT 4:42 P.M.
                   DAVIS........................39 M   AT 3:06 P.M.** RMY 42
FASTEST MILE FOR YESTERDAY......................31   W AT 4:41 P.M.   
MAXIMUM 2-MINUTE ASOS AVERAGE...................29   W AT 4:43 P.M.  
MAXIMUM 2-MINUTE DAVIS AVERAGE..................26 M   AT 4:43 P.M.**
AVERAGE WIND SPEED AND DIRECTION..............14.3   W
                   ASOS.......................13.6 
                   DAVIS......................12.6 ** 
* Last of multiple occurrences
** Davis direction malfunctioning

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M...Trace  DEPARTURE......-0.14
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE MONTH..........2.55  DEPARTURE......+0.34
                         ASOS..............2.70  
TOTAL PRECIPITATION FOR THE YEAR...........8.55  DEPARTURE......+1.99
                         ASOS..............9.27

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.0  DEPARTURE........-0.5
TOTAL SNOWFALL FOR THE MONTH................3.6  DEPARTURE........-4.3
TOTAL SNOWFALL FOR THE SEASON..............38.1  DEPARTURE........-3.0

PRELIMINARY CLIMATE SUMMARY FOR FEBRUARY 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

2/1  45/27/36/+10/..../0.0/120/20      36 SSW AERO 35 SSW RMY N/A 
2/2  34/08/21/-5/..../2.5/223/37       43 WNW AERO 46 WNW RMY 46 
2/3  25/04/15/-11/0.00/0.0/557/92      26 S   AERO 24 S   RMY 30 
2/4  45/23/34/+8/.../T/000/00          31 SSE AERO 29 S   RMY 30
2/5  46/19/33/+7/0.00/0.0/464/76       47 WNW AERO 47 WNW RMY 44
2/6  31/17/24/+2/T/T/025/04            26 SSW AERO 23 SSW RMY 23 
2/7  42/21/32/+5/0.62/1.1/000/00       45 SW  AERO 46 SW  RMY 47
2/8  30/20/25/-2/0.00/0.0/501/81       38 WNW AERO 38 WNW RMY N/A
2/9  30/16/23/-4/0.00/0.0/384/62       28 S   AERO 25 S   RMY N/A
2/10 51/28/40/+13/..../0.0/.../..      31 S   AERO 30 S   RMY 31
2/11 46/36/41/+14/..../0.0/000/00      24 SW  AERO 21 SW  RMY N/A
2/12 53/27/40/+13/..../0.0/.../..      33 WNW AERO 33 WNW RMY N/A
2/13 31/21/26/-2/0.00/0.0/.../..       22 S   AERO 18 WNW RMY 21
2/14 46/25/36/+8/0.00/0.0/.../..       30 S   AERO 26 SSW RMY 29 
2/15 47/35/41/+13/..../0.0/000/00      23 SSW AERO 20 SSW RMY N/A
2/16 50/31/41/+13/..../0.0/.../..      45 W   AERO 44 W   RMY 42

2/17 Low temp since midnight is 23F; normal low is now 19F

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

RECORDS FOR FEBRUARY 17
HIGH 61F IN 1981
LOW -16F IN 1896
PRECIP 1.86 INCHES IN 2003
SNOWFALL 20.0 INCHES IN 2003
PEAK GUST 72 MPH NW IN 1968

RECORDS FOR FEBRUARY 18
HIGH 65F IN 1981
LOW -10F IN 1958
PRECIP 1.97 INCHES IN 1887
SNOWFALL 9.2 INCHES IN 1952
PEAK GUST 70 MPH S IN 2008

TODAY'S REPORT PREPARED BY: Mike Iacono