Sunday, December 29, 2019

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, DECEMBER 29, 2019
ALL TIMES ARE IN EASTERN STANDARD TIME

DRY WEATHER CONTINUES ANOTHER DAY, BUT CHANGES ON THE WAY….

We have observed our 11th consecutive day without measurable
precipitation, continuing our longest dry stretch of the
year, however that will change come tomorrow as a storm system
moves into the region. High clouds have been on the increase
today ahead of the storm system.

Visibility has been decent today averaging about 70 miles,
however as the wind has gone very light early this afternoon,
a thin smoke layer has developed along the horizon in all
directions. This suggests the development of an inversion
over the region.

Due to the inversion, temperatures today are not quite as mild
as they where yesterday with a high so far today of 42F, which
is 7 degrees above the daily normal maximum of 35F. The low
since midnight is 28F, which is 8 degrees above the normal
minimum of 20F.

Today’s Observations:

7 A.M.
Weather: Thin broken cirrus, few stratocumulus offshore
distant NE-ESE, few altocumulus distant S-SW
Temperature: 29F; Dew Point: 23F; Wind: NW at 10 kts
Sea-level pressure: 30.23 ins. Hg, falling then rising
Visibility: 60 miles
6-hr Max temp: 30F
6-hr Min temp: 28F
24-hr Precip:  0.00 ins.
24-hr Snowfall: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1155 E250 –BKN 60 236/29/23/3210/023/ FEW SC
OFFSHR DSNT NE-ESE FEW AC DSNT S-SW/ 8/571 51012 10030
20028

10 A.M.
Weather: Thin overcast cirrus, few breaks in overcast distant
N-E, few altocumulus distant S
Temperature: 35F; Dew Point: 24F; Wind: NW at 7 kts
Sea-level pressure: 30.24 ins. Hg, rising then steady
Visibility: 70 miles
3-hr Precip:  0.00 ins.
3-hr Snowfall: 0.0 ins.
BHO SA 1455 E250 –OVC 70 242/35/24/3207/024/ FEW BINOVC
DSNT N-E FEW AC DSNT S/ 8/071 50006

1 P.M.
Weather: Thin overcast cirrus, few stratocumulus offshore
distant ENE-ESE
Temperature: 40F; Dew Point: 22F; Wind: WNW at 2 kts
Wind light and variable
Sea-level pressure: 30.18 ins. Hg, falling, then rapidly
Visibility: 70 miles
6-hr Max temp: 42F
6-hr Min temp: 28F
6-hr Precip:  0.00 ins.
6-hr Snowfall: 0.0 ins.
Snow Depth: 0 ins.
BHO SA 1755 E250 –OVC 70 221/40/22/2902/018/ FEW BINOVC
DSNT NE-E FEW SC OFFSHR DSNT ENE-ESE THN K LYR ALNG HRZN
ALQDS WND L/V/ 8/501 58021 10042 20028

SUMMARY FOR SATURDAY, DECEMBER 28, 2019

TEMPERATURE (DEGREES F)
MAX…..47   NORMAL…..36
MIN…..30   NORMAL…..20
MEAN….39   NORMAL…..28

DEPARTURE FROM 30-YEAR NORMAL…………………+11
TOTAL DEPARTURE FOR THE MONTH………………… +3 [-0.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………26  DEPARTURE…….-11
TOTAL HEATING UNITS FOR THE MONTH…………..924  DEPARTURE……..-6
TOTAL HEATING UNITS FOR THE SEASON…………2161  DEPARTURE…….-30
TOTAL HEATING UNITS LAST SEASON TO DATE…….2205  DEPARTURE…….-44

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..23 W   AT  12:15 A.M.
AERO…………………….22 W   AT  12:19 A.M.
ASOS…………………….24 W   AT  12:15 A.M.
DAVIS……………………26 W   AT  12:13 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….20 W   AT  12:13 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….20 W   AT  12:20 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………21 W   AT  12:18 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..12.6 W
ASOS…………………..12.6
DAVIS………………….13.1 WNW [288 deg.]

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……….6.06  DEPARTURE……+1.59
ASOS…………..6.51
TOTAL PRECIPITATION FOR THE YEAR……….55.14  DEPARTURE……+2.13
ASOS………….55.91

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.0  DEPARTURE…….-0.5
TOTAL SNOWFALL FOR THE MONTH……………19.1  DEPARTURE…….+7.2
TOTAL SNOWFALL FOR THE SEASON…………..19.2  DEPARTURE…….+4.7

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  32/16/24/-13/…./5.8/011/02           33 ENE AERO 32 ENE RMY N/A
12/02  37/25/31/-5/…./2.7/000/00            52 NE  AERO 47 NE  RMY 53
12/03  30/23/27/-9/…./4.6/000/00            32 N   AERO 35 N   RMY 36
12/04  34/22/28/-7/…./0.0/000/00            23 WNW AERO 23 NNW RMY N/A
12/05  41/26/34/-1/…./0.0/343/62            33 NW  AERO 35 NW  RMY 37
12/06  33/23/28/-7/0.02/0.1/000/00            25 NW  AERO 23 NW  RMY 29
12/07  31/18/25/-9/0.00/0.0/519/94            25 NW  AERO 23 NW  RMY N/A
12/08  36/15/26/-8/0.00/0.0/…/..            31 SSW AERO 32 SSW RMY N/A
12/09  57/36/47/+13/…./0.0/…/..           53 S   AERO 52 S   RMY 54
12/10  58/37/48/+15/…./0.0/…/..           35 SW  AERO 39 SW  RMY N/A
12/11  36/23/30/-3/…./3.0/…/..            25 NW  AERO 25 NW  RMY N/A
12/12  29/17/23/-10/…./1.8/…/..           29 W   AERO 30 W   RMY 25
12/13  46/22/34/+2/…./0.0/…/..            25 SSE AERO 25 SSE RMY N/A
12/14  58/46/52/+20/…./0.0/…/..           45 S   AERO 41 S   RMY N/A
12/15  48/28/38/+6/0.00/0.0/…/..            53 W   AERO 53 W   RMY 50
12/16  30/25/28/-3/0.00/0.0/…/..            36 W   AERO 36 W   RMY N/A
12/17  35/23/29/-2/…./1.0/…/..            22 NNW AERO 21 NE  RMY 23
12/18  33/18/26/-5/…/0.0/…/..             44 WNW AERO 45 WNW RMY N/A
12/19  20/9/15/-15/…/0.0/…/..             51 W   AERO 47 W   RMY N/A
12/20  29/11/20/-10/0.00/0.0/…./..          32 W   AERO 30 W   RMY 29
12/21  31/16/24/-6/0.00/0.0/…./..           16 SSE AERO 15 SSE RMY N/A
12/22  40/26/33/+4/0.00/0.0/…./..           23 SW  AERO 21 SW  RMY 23
12/23  54/33/44/+15/0.00/0.0/…./..          30 WSW AERO 30 SW  RMY 30
12/24  42/29/36/+7/0.00/0.0/…./..           30 NW  AERO 27 NW  RMY 30
12/25  42/25/34/+6/0.00/0.0/…./..           16 NNE AERO 16 N   RMY N/A
12/26  39/29/34/+6/0.00/0.0/…./..           22 ENE AERO 20 ENE RMY 22
12/27  47/31/39/+11/0.00/0.0/…./..          32 SSW AERO 30 SSW RMY 34
12/28  47/30/39/+11/0.00/0.0/…./..          23 W   AERO 22 W   RMY N/A

12/29 The low since midnight is 28F, daily normal minimum is 20F

DAILY RECORDS FOR DECEMBER

12/01/19: DAILY RECORD SNOWFALL OF 5.8 INS.,
BREAKS PREVIOUS RECORD OF 2.0 INS. SET IN 1902.

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

RECORDS FOR DECEMBER 29
HIGH 72 IN 1984
LOW -19 IN 1933 (RECORD FOR DECEMBER)
PRECIP 1.91 INS. IN 1945
SNOWFALL 18.4 INS. IN 1945
PEAK GUST 95 MPH S IN 1966 (RECORD FOR DECEMBER)

RECORDS FOR DECEMBER 30
HIGH 60 IN 1984
LOW -18 IN 1933
PRECIP 1.48 INS. IN 1891
SNOWFALL 7.5 INS. IN 1956
PEAK GUST 81 MPH WNW IN 1962

TODAY’S REPORT PREPARED BY: Matt Douglas and Greg White