Friday, December 20, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
FRIDAY, DECEMBER 20, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

TEMPERATURES REACH 50F EARLY AFTERNOON
WARMING TREND CONTINUES WITH SSW-SW WINDS
SEE RECORD TEMPERATURES BELOW

Temperatures today are the warmest since 55F on December 6.
Bright sunshine prevails today during what has been a cloudy
month. The snow cover is melting down from 9 inches as measured
this morning.

Record maximum temps:
12/20 = 61 in 1957
12/21 = 60 in 1957
12/22 – 62 in 1994
12/23 = 62 in 1990

Today’s Observations:

7 A.M.
Weather: Scattered altocumulus, altostratus, overcast cirrostratus
Temperature: 35F; Dew Point: 28F; Wind: SSE at 13 kts,
Sea-level pressure: 30.11 ins. Hg, falling slightly
Visibility: 12 miles, thin fog, hazy
6-hr. min temp: 34F
Snow on ground: 9 inches
BHO SA 1155 180 SCT E250 OVC 12 196/35/28/1613/011/ THN F HAZY/
8/077 4/009 57008 10039 20034

10 A.M.
Weather: Scattered dense cirrus, overcast cirrostratus,
overcast partly thin, few altocumulus lenticularis distant
to the SE-SSE
Temperature: 42F; Dew Point: 35F; Wind: S at 13 kts,
Sea-level pressure: 30.07 ins. Hg, falling then more rapidly
Visibility: 15 miles, hazy
BHO SA 1455 220 SCT E250 OVC 15 183/42/35/1813/007/ FEW ACSL DSNT
SE-SSE DNS CI WSW-N-NE OVC PTLY THN ALQDS HAZY/ 8/042 58013

1 P.M.
Weather: Scattered cirrocumulus, thin scattered cirrus, few altocumulus
lenticularis SW-N-ESE
Temperature: 51F; Dew Point: 33F; Wind: SSW at 17 kts,
Sea-level pressure: 29.96 ins. Hg, falling then more slowly
Visibility: 30 miles, distant haze
6-hr max. temp. 52F
BHO SA 1755 220 SCT 250 –SCT 30 145/51/33/2017/996/ FEW ACSL SW-N-ESE
CC SE-SW DSNT HZ/ 8/049 56038 10052 20035

WEATHER SUMMARY FOR THURSDAY, DECEMBER 19, 2013

TEMPERATURE (DEGREES F)
MAX…..42    NORMAL…..38
MIN…..22    NORMAL…..23
MEAN….32    NORMAL…..30

DEPARTURE FROM 30-YEAR NORMAL………………….+2
TOTAL DEPARTURE FOR THE MONTH…………………-72 [-4.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..33  DEPARTURE………-2
TOTAL HEATING UNITS FOR THE MONTH………….673  DEPARTURE……..+70
TOTAL HEATING UNITS FOR THE SEASON………..1897  DEPARTURE……..+33
TOTAL HEATING UNITS LAST SEASON TO DATE……1626  DIFFERENCE……+271

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………38 SW  AT 11:37 A.M.
AERO…………………..44 SW  AT 11:37 A.M.
ASOS…………………..42 SW  AT 11:37 A.M.
DAVIS………………….41 SW  AT 11:37 A.N. RMY 42
FASTEST MILE FOR YESTERDAY………………..26 SW  AT 11:26 A,N,
MAXIMUM 2-MINUTE ASOS AVERAGE……………..29 SW  AT 11:38 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….27 SW  AT 11:39 A.M.
AVERAGE WIND SPEED AND DIRECTION…………14.4 WSW
ASOS…………………14.0
DAVIS………………..12.9 WSW [240 degrees]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00  DEPARTURE………….-0.15
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….3.25  DEPARTURE………….+0.17
ASOS…………..3.27
TOTAL PRECIPITATION FOR THE YEAR……….49.85  DEPARTURE………….-1.76
ASOS…………..N/A**
** ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M…….0.0     DEPARTURE………….-0.5
TOTAL SNOWFALL FOR THE MONTH…………15.0*    DEPARTURE………….+7.3
TOTAL SNOWFALL FOR THE SEASON………..15.2     DEPARTURE………….+5.4

The recent storm total of 5.9 now corrected to 6.8 ins.

PRELIMINARY CLIMATE SUMMARY FOR DECEMBER 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SNOW/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY:  RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized

12/1  45/30/38/+1/0.28/T/000/00           22 SSE AERO 23 MPH SSE RMY 23
12/2  38/34/36/0/T/0.0/000/00             15 NW  AERO 15 MPH NW  RMY 16
12/3  45/32/39/+3/0.00/0.0/284/51         18 NNW AERO 18 MPH NNW RMY 20
12/4  43/29/36/+1/0.00/0.0/389/70         21 WNW AERO 21 MPH WNW RMY 21
12/5  53/38/46/+11/0.02/0.0/000/00        36 S   AERO 40 MPH S   RMY 39
12/6  55/33/44/+9/0.38/T/000/00           25 SSW AERO 28 MPH SSW RMY N/A
12/7  40/26/33/-1/0.12/T/287/52           23 NW  AERO 25 MPH NW  RMY N/A
12/8  30/22/26/-8/T/T/039/07              25 NW  AERO 27 MPH NW  RMY N/A
12/9  41/25/33/-1/0.35/0.6/000/00         28 E   AERO 28 MPH E   RMY 24
12/10 33/21/27/-6/0.14/2.1/000/00         28 W   AERO 28 MPH W   RMY 28
12/11 28/19/24/-9/0.00/0.0/345/63         27 SW  AERO 28 MPH SW  RMY 27
12/12 23/14/19/-14/0.00/0.0/…/..        28 WNW AERO 31 MPH NW  RMY 30
12/13 28/14/21/-11/0.00/0.0/…/..        31 W   AERO 32 MPH W   RMY 33
12/14 28/9/19/-13/0.45/4.8/000/00         30 E   AERO 26 MPH E   RMY N/A
12/15 36/21/29/-3/0.98/2.0/…/..         48 NE  AERO 50 MPH NE  RMY 51
12/16 27/14/21/-10/0.00/0.0/…/..        36 W   AERO    MPH W   RMY N/A
12/17 23/7/15/-16/0.53/5.5/…/..         28 N   AERO 30 MPH N   RMY 28
12/18 32/15/24/-7/0.00/0.0/…/..         29 WNW AERO 30 MPH NW  RMY 29
12/19 42/22/32/+2/0.00/0.0/…/..         38 SW  AERO 44 MPH SW  RMY 42

12/20 morning low temp: 34F; the normal low is now 22F

DAILY RECORDS FOR DECEMBER 2013
None so far

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

RECORDS FOR DECEMBER 20
HIGH 61 IN 1957
LOW -16 IN 1942
PRECIP 1.69 INS. IN 1936
SNOWFALL 13.7 INS. IN 2009
PEAK GUST 75 MPH S IN 2002

RECORDS FOR DECEMBER 21
HIGH 60 IN 1957
LOW -10 IN 1942
PRECIP 2.01 INS. IN 1946
SNOWFALL 11.4 INS. IN 1954
PEAK GUST 77 MPH SSE IN 1957

TODAY’S REPORT PREPARED BY: Robert Skilling/Brian Fitzgerald