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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, JANUARY 5, 2016
ALL TIMES ARE IN EASTERN STANDARD TIME

ARCTIC AIR IN PLACE- TEMPS DROP TO MINIMUM OF 4F THIS
MORNING, WIND CHILLS NEAR -20F AT TIMES

The streak of 33 consecutive days with above normal warmth
has finally come to an end, with Monday's daily temperature
depart of -6. Snow showers on Monday brought 0.2 inches of
new snow, with just a trace of liquid equivalent. 

Temperatures kept sliding through the night with a low of
4F recorded for several hours this morning. With winds gusting
to 20 kts, wind chills approached -20F. 

Clear skies have dominated this morning under slowly warming
conditions. By the 1:00 PM EST observation skies were still
nearly completely clear with temperatures that had risen
into the lower 20s. 


DECEMBER FINISHES AS THE WARMEST ON RECORD...NEARLY FIVE 
DEGREES WARMER THAN PREVIOUS RECORD FOR THE MONTH...
THIRD RECORD WARM MONTH IN 2015...GREATEST POSITIVE TEMPERATURE
DEPARTURE FOR ANY MONTH...DECEMBER ALSO AMONG CLOUDIEST ON RECORD...

BHO Warmest Decembers (24-hour Mean), deg F (1885-2015)

1) 42.9 in 2015
2) 38.1 in 2006
3) 37.5 in 2011
4) 37.3 in 2001
5) 37.2 in 1891
6) 36.9 in 1998
7) 36.7 in 1990

BHO Largest Monthly 24-Hour Mean Temperature Departure from the Long-Term
Mean, deg F (1885-2015):

1)+13.1 in December 2015
2) +9.9 in January 1913
3) +9.3 in January 1932
4) +9.1 in March 1946
5) +9.0 in March 2012
6) +8.9 in January 1937
7) +8.5 in February 1984

BHO Lowest December Sunshine, hours (1885-2015):

1) 72.9 in 1972  [27%]
2) 81.0 in 1982  [29%]
3) 87.2 in 1933  [32%]
4) 88.2 in 1996  [32%]
5) 89.0 in 1922  [32%]
6) 89.5 in 1981  [33%]
7) 91.1 in 1906  [33%]
8) 92.0 in 2012  [34%]
9) 92.9 in 2013  [34%]
10) 93.3 in 2015 [34%]

PRELIMINARY STATS FOR DECEMBER 2015

TEMPERATURE, Deg. F
Avg. Max. 50.5 [+11.4]
Avg. Min. 36.9 [+13.3]
Mean      43.7 [+12.4]
24-hour Corrected Mean: 42.9 [+13.1]
Max. for month: 67 on 24th
Min. for month: 23 on 29th, 30th

HEATING DEGREE DAYS
Total cooling units: 654 [-389]  
Total for the season: 1656 [-649]
Total for last season: 2060

PRECIPITATION, Inches
Total: 4.27 [-0.49]
Greatest in 24 hrs: N/A
Snowfall: 1.3 [-12.1]
Greatest in 24 hrs: 1.3 ins. on the 29th 
 
WIND, mph
Avg. uncorrected wind speed: 11.3
Avg. corrected wind speed: 11.8
Prevailing wind direction: W @ 12%
Peak gust and direction: 48 W on the 15th

SUNSHINE:
Campbell-Stokes card minutes: 5598 mins. of possible 16470 or 34%
Astronomical total minutes:   5786 mins. of possible 17002 or 34%
Long-term average for December is 46%


Today's Observations:

7 A.M.
Weather: Clear, few stratocumulus distant offshore NNE-S
Temperature: 4F; Dew Point: -5F; Wind: NNW at 13G20 kts
Wind Chill: -18F
Sea-level pressure: 30.48 ins. Hg, rising, then more quickly
Visibility: 70 miles
6-hr Max temp: 9F 
6-hr Min temp: 4F
24-hr precip: Trace
24-hr snowfall: 0.2 ins.
Snow depth: Trace
BHO SA 1155 CLR 70 321/4/-5/3413G20/048/ FEW SC DSNT OFFSHR NNE-S 
WND CHILL -18F NEW SNW PST 24 HRS 0.2 INS/ 8/500 53020 10009 20004

10 A.M.
Weather: Clear, few stratocumulus distant offshore NNE-S
Temperature: 13F; Dew Point: -2F; Wind: NNW at 10 kts
Wind Chill: -1F
Sea-level pressure: 30.54 ins. Hg, rising, then more slowly 
Visibility: 75 miles
BHO SA 1455 CLR 75 343/13/-2/3410/054/ FEW SC DSNT OFFSHR NNE-S 
WND CHILL -1F/ 8/500 51022

1 P.M.
Weather: Clear, few stratocumulus distant offshore NE-SSE
Temperature: 21F; Dew Point: -1F; Wind: NW at 8 kts
Sea-level pressure: 30.52 ins. Hg, steady, then falling 
Visibility: 75 miles
6-hr Max temp: 21F
6-hr Min temp: 4F
BHO SA 1755 CLR 75 335/21/-1/3208/052/ FEW SC DSNT OFFSHR NE-SSE/ 
8/500 58008 10021 20004


SUMMARY FOR MONDAY, JANUARY 4, 2016 
  
TEMPERATURE (DEGREES F)
MAX.....30   NORMAL.....34
MIN.....10   NORMAL.....18 
MEAN....20   NORMAL.....26

DEPARTURE FROM 30-YEAR NORMAL.......................-6
TOTAL DEPARTURE FOR THE MONTH......................+13 [+3.1 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY..............45   DEPARTURE..........+6
TOTAL HEATING UNITS FOR THE MONTH.............141   DEPARTURE.........-13
TOTAL HEATING UNITS FOR THE SEASON...........1797   DEPARTURE........-661
TOTAL HEATING UNITS LAST SEASON TO DATE......2193   DIFFERENCE.......-396

PEAK GUST AND AVERAGE WIND SPEED (MPH) 
PEAK WIND GUST FOR YESTERDAY...................29  NNW AT  9:38 P.M.*
                   ASOS........................32  NNW AT  9:38 P.M.
                   DAVIS.......................28  N   AT  9:20 A.M. RMY 29
FASTEST MILE FOR YESTERDAY.....................22  N   AT  9:21 P.M. 
MAXIMUM 2-MINUTE ASOS AVERAGE..................22  N   AT  9:21 P.M. 
MAXIMUM 2-MINUTE DAVIS AVERAGE.................20  N   AT  9:20 P.M. 
AVERAGE WIND SPEED AND DIRECTION.............12.6 N
                   ASOS......................12.7   
                   DAVIS.....................10.6 N [348 Deg.]

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.........TRACE  DEPARTURE......-0.58
                         ASOS..............0.00
TOTAL PRECIPITATION FOR THE YEAR..........TRACE  DEPARTURE......-0.58  
                         ASOS..............0.00

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M..........0.2  DEPARTURE.......-2.1
TOTAL SNOWFALL FOR THE MONTH................0.2  DEPARTURE.......-2.1
TOTAL SNOWFALL FOR THE SEASON...............1.5  DEPARTURE......-16.8

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER/JANUARY CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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

12/1  42/30/36/-1/0.16/0.0/000/00           19 NNE RMY 19
12/2  53/37/45/+9/0.20/0.0/000/00           25 SSE RMY 25
12/3  53/37/45/+9/0.01/0.0/162/29           43 WNW RMY 42
12/4  47/32/40/+5/0.00/0.0/444/80           32 NW  RMY 32
12/5  50/33/42/+7/0.00/0.0/548/99           21 W   RMY N/A
12/6  57/35/46/+11/0.00/0.0/531/96          22 SW  RMY N/A
12/7  54/37/46/+12/0.00/0.0/353/64          31 NE  RMY N/A
12/8  42/35/39/+5/0.01/0.0/000/00           32 NE  RMY 31
12/9  44/34/39/+5/0.00/0.0/044/08           28 SSE RMY N/A
12/10 57/41/49/+16/T/0.0/209/38             29 SE  RMY N/A
12/11 56/44/50/+17/0.00/0.0/049/09          28 SSW RMY 28
12/12 59/46/53/+20/0.00/0.0/367/67          23 W   RMY N/A 
12/13 54/44/49/+17/0.00/0.0/000/00          18 ESE RMY 19
12/14 60/43/52/+20/..../0.0/000/00          32 S   RMY N/A
12/15 61/45/53/+21/..../0.0/371/68          48 W   RMY 51 
12/16 45/34/40/+9/0.00/0.0/415/76           25 N   RMY N/A
12/17 53/36/45/+14/..../0.0/000/00          29 SE  RMY 28
12/18 50/35/43/+12/..../0.0/000/00          29 NW  RMY 30
12/19 38/30/34/+4/0.00/0.0/480/88           39 W   RMY 40
12/20 40/28/34/+4/0.00/0.0/491/90           24 W   RMY N/A
12/21 51/31/41/+11/T/0.0/000/00             38 SSW RMY 42
12/22 57/49/53/+24/0.28/0.0/000/00          35 SW  RMY 35
12/23 54/47/51/+22/..../0.0/000/00          30 E   RMY 27 
12/24 67/48/58/+29/..../0.0/033/06          37 SSW RMY 39  
12/25 64/52/58/+30/..../0.0/240/44          23 N   RMY N/A
12/26 53/40/47/+19/..../0.0/436/80          26 NNW RMY N/A
12/27 52/35/44/+16/..../0.0/000/00          36 NW  RMY 33
12/28 35/27/31/+3/T/T/355/65                33 NW  RMY 33
12/29 38/23/31/+4/..../1.3/000/00           35 ENE RMY 35
12/30 34/23/29/+2/..../T/000/00             17 SSE RMY N/A
12/31 44/32/38/+11/..../0.0/258/47          25 WNW RMY 25


1/1   37/29/33/+6/0.00/0.0/.../..           29 W   RMY 29
1/2   37/27/32/+5/0.00/0.0/.../..           31 W   RMY N/A         
1/3   41/27/34/+8/0.00/0.0/.../..           28 W   RMY 29
1/4   30/10/20/-6/T/T/.../..                29 NNW RMY 29

1/5 low since midnight is 4F; normal low is now 18F  

DAILY RECORDS FOR DECEMBER 2015

**12/13/2015- NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 44F,
BREAKS PREVIOUS RECORD OF 43F SET IN 1919, TIED 1983
**12/24/2015- NEW DAILY RECORD MAXIMUM TEMPERATURE OF 67F,
BREAKS PREVIOUS RECORD OF 61F SET IN 2014
**12/24/2015- NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 48F,
BREAKS PREVIOUS RECORD OF 46F SET IN 1900
**12/25/2015- NEW DAILY RECORD MAXIMUM TEMPERATURE OF 64F,
BREAKS PREVIOUS RECORD OF 62F SET IN 1889
**12/25/2015- NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 52F,
BREAKS PREVIOUS RECORD OF 46F SET IN 1964

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

RECORDS FOR JANUARY 5
HIGH 61F IN 2007
LOW -9F IN 1981
PRECIP 0.98 INS. IN 1993
SNOW 4.5 INS. IN 1891
PEAK GUST 70 MPH WNW IN 1959

RECORDS FOR JANUARY 6
HIGH 66F IN 2007
LOW -14F IN 1896
PRECIP 3.10 INS. IN 1889 [RECORD FOR MONTH]
SNOWFALL 7.5 INS. IN 1893
PEAK GUST 70 MPH WNW IN 1959

TODAY'S REPORT PREPARED BY: Brian Fitzgerald