Friday, December 14, 2018

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 14, 2018
ALL TIMES ARE IN EASTERN STANDARD TIME

SOUTHERLY WINDS MARK TRANSITION TO WARMER TEMPERATURES…

Today’s observation period continued to be dominated by
relatively high pressure and mostly clear skies.  This trend has
persisted for most of the week, but today’s weather marks some
notable changes moving forward.  Wind speeds have remained modest
throughout the day, but the most notable change has been the shift
from northerly to southerly winds that occurred throughout the day
yesterday.  Today, warm air moving in from the south has already prompted a
return to warmer than average temperatures, with a high of 45 F already
eclipsing the expected daily maximum of 40 F.  Pressure remained steady for
most of the morning, but the mercury appears to be on its way down, perhaps
marking the beginning of the end of this recent spell of clear skies.
Distant clouds throughout the observation period seem to be in agreement
with this speculation.
Today’s Observations:

7 A.M.
Weather: Few distant altostratus in all directions, few cirrus
Temperature: 29F; Dew Point: 26F; Wind: SSE at 13G16 kts
Sea-level pressure: 30.53 ins. Hg, steady
Visibility: 35 miles
6-hr Max temp: 29F
6-hr Min temp: 28F
24-hr Precip: 0.00 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 CLR 35 339/29/26/1613G16/053/
FEW DSNT AS ALQDS 8/011 53000 10029 20028

10 A.M.
Weather: Few distant altostratus in all directions, few cirrus
Temperature: 39F; Dew Point: 29F; Wind: S at 7G13 kts,
Sea-level pressure: 30.54 ins. Hg, steady
Visibility: 35 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 CLR 35 343/39/29/1707G13/054/ FEW DSNT AS ALQDS/
8/011 50004

1 P.M.
Weather: Few altocumulus, few cirrus
Temperature: 45F; Dew Point: 29F; Wind: S at 7 kts,
Sea-level pressure: 30.44 ins. Hg, falling rapidly
Visibility: 40 miles
6-hr Max temp: 45F
6-hr Min temp: 29F
6-hr Precip: 0.00 ins.
6-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1755 CLR 40 310/45/29/1807/044/ 8/091 58033 10045 20029

SUMMARY FOR THURSDAY, DECEMBER 13, 2018

TEMPERATURE (DEGREES F)
MAX…..31   NORMAL…..40
MIN…..16   NORMAL…..25
MEAN….24   NORMAL…..32

DEPARTURE FROM 30-YEAR NORMAL……………………-8
TOTAL DEPARTURE FOR THE MONTH…………………..-51 [-4.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..41   DEPARTURE………+8
TOTAL HEATING UNITS FOR THE MONTH………….449   DEPARTURE……..+51
TOTAL HEATING UNITS FOR THE SEASON………..1769   DEPARTURE…….+109
TOTAL HEATING UNITS LAST SEASON TO DATE……1342   DIFFERENCE……+427

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..16 NNE AT  6:11 A.M.
AERO…………………….12 SE  AT  9:22 P.M.
ASOS…………………….15 N   AT  1:00 A.M.
DAVIS……………………15 N   AT 12:55 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….11 N   AT  2:04 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….13 SSW AT  6:12 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………12 N   AT  2:10 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..6.8 SE
ASOS…………………..6.8
DAVIS………………….7.3 ENE [68 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE…….-0.16
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….1.04  DEPARTURE…….-1.10
ASOS…………..1.78
TOTAL PRECIPITATION FOR THE YEAR……….64.41  DEPARTURE……+13.93
ASOS………….67.41

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE……..-0.5
TOTAL SNOWFALL FOR THE MONTH…………….0.0  DEPARTURE……..-4.5
TOTAL SNOWFALL FOR THE SEASON……………7.6  DEPARTURE……..+0.5

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 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

12/01 41/28/35/-2/0.00/0.0/391/70          20 NNW AERO 18 NNW RMY N/A
12/02 52/35/44/+8/1.04/0.0/000/00          28 ESE AERO 25 ESE RMY 27
12/03 54/38/46/+10/0.00/0.0/178/32         35 W   AERO 35 W   RMY 38
12/04 38/23/31/-4/0.00/0.0/516/93          30 WNW AERO 31 WNW RMY 33
12/05 33/18/26/-9/0.00/0.0/432/78          16 NNW AERO 15 NNW RMY N/A
12/06 37/24/31/-4/0.00/0.0/354/64          29 W   AERO 28 W   RMY 30
12/07 37/21/29/-5/0.00/0.0/…/..          29 NW  AERO 29 NW  RMY 32
12/08 27/15/21/-13/0.00/0.0/…/..         28 NW  AERO 27 NW  RMY 29
12/09 34/17/26/-8/0.00/0.0/…/..          23 SSW AERO 21 SSW RMY 22
12/10 36/22/29/-4/0.00/0.0/…/..          24 NNW AERO 23 NNW RMY 22
12/11 36/17/27/-6/0.00/0.0/…/..          16 WSW AERO 14 WSW RMY N/A
12/12 35/18/27/-6/0.00/0.0/…/..          30 NW  AERO 29 NW  RMY M
12/13 31/16/24/-8/0.00/0.0/…/..          16 NNE AERO 12 SE  RMY N/A

12/14 Low temp since midnight is 28F; normal low is 24F

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

RECORDS FOR DECEMBER 14
HIGH 62 IN 1901
LOW -6 IN 1893
PRECIP 1.94 INS. IN 2002
SNOWFALL 8.0 INS. IN 1907
PEAK GUST 78e ENE IN 1941

RECORDS FOR DECEMBER 15
HIGH 64 IN 1975
LOW 4 IN 1900, 1905, 1933
PRECIP 1.80 INS. IN 1981
SNOW 7.5 INS. IN 1951
PEAK GUST 65 MPH NW IN 1991

TODAY’S REPORT PREPARED BY: Nate Iannuccillo