Thursday, December 12, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, DECEMBER 12, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

SUNSHINE ALONG WITH NEW ARCTIC AIR MASS
WINDS NOT VERY GUSTY THROUGH EARLY AFTERNOON

Sunshine has been ineffective in bringing us much
heating in the new Arctic air mass.
Our temperature struggled up from a morning low
of 16 degrees to an early afternoon high of close
to 23F, well below normal for this date.  At
the same time dew point temperatures have fallen
to the lower single numbers truly a sign of the
newly arriving very cold air ass.

Today’s Observations:

7 A.M.
Weather: Clear, stratocumulus/cumulus layer along and offshore NE-SE.
cirrus distant SE-SSW, distant haze
Temperature: 17F; Dew Point: 11F; Wind: NW at 9 kts.
Sea-level pressure: 30.22 ins. Hg, rising then more slowly
Visibility: 35 miles, distant haze
Total snow on ground at 7 a.m. 1 inch
6-hr. min temp: 16F
BHO SA 1155 CLR 35 234/17/11/3109/022/ CU/SC ALG/OFFSHR NE-SE
CI DSNT SE-SSW LGT DSNT HZ/ 8/801 4/001 53017 10021 20016

10 A.M.
Weather: Clear, few cumulus fractus forming vicinity station E-S,
cumulus/stratocumulus along/offshore NE-SE, cirrus distant ESE-S-SW
Temperature: 20; Dew Point: 4F; Wind: NW at 15G23 kts,
Sea-level pressure: 30.25 ins. Hg, rising then falling
Visibility: 70 miles, light distant haze
BHO SA 1455 CLR 70 245/20/4/3115G23/025/ FEW CUFRA FMRG VC E-S
CU/SC ALG/OFFSHR NE-SE CI DSNT ESE-S-SW WND 28V34/ 8/801 50011

1 P.M.
Weather: Clear, cumulus fractus forming vicinity station mostly
overhead-E-S, stratocumulus, cumulus along and offshore NE-SE,
cirrus distant SE-SW
Temperature: 22F; Dew Point: 2F; Wind: NW at 12 kts.
Sea-level pressure: 30.19 ins. Hg, falling then falling more rapidly
Visibility: 75 miles, light distant haze
6-hr max. temp. 23F
6-hr min. temp: 16F
BHO SA 1755 CLR 75 223/22/2/3112/019/ CUFRA FRMG VC MOSTLY
OVHD-E-S SCCU ALG/OFFSHR NE-SE CI DSNT SE-SW LGT DSNT HZ/
8/801 58022 10023 20016

WEATHER SUMMARY FOR WEDNESDAY, DECEMBER 11, 2013

TEMPERATURE (DEGREES F)
MAX…..28    NORMAL…..41
MIN…..19    NORMAL…..25
MEAN….24    NORMAL…..33

DEPARTURE FROM 30-YEAR NORMAL………………….-9
TOTAL DEPARTURE FOR THE MONTH………………….+0 [-0.2 DEGREE/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..41  DEPARTURE………+9
TOTAL HEATING UNITS FOR THE MONTH………….333  DEPARTURE………-0
TOTAL HEATING UNITS FOR THE SEASON………..1557  DEPARTURE……..-37
TOTAL HEATING UNITS LAST SEASON TO DATE……1407  DIFFERENCE……+150

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………27 SW  AT  9:21 A.M.
AERO…………………..28 W   AT 10:17 P.M.
ASOS…………………..27 W   AT  9:22 A.M.
DAVIS………………….26 W   AT 11:02 P.M. RMY 27
FASTEST MILE FOR YESTERDAY………………..20 WSW AT 10:50 P.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE……………..20 WSW AT 10:49 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….19 W   AT  4:22 A.M.
AVERAGE WIND SPEED AND DIRECTION…………14.0
ASOS…………………13.6
DAVIS………………..12.4 WSW [240 degrees] * last of several occurrences…

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……….1.29  DEPARTURE………….-0.52
ASOS…………..1.26
TOTAL PRECIPITATION FOR THE YEAR……….47.89 DEPARTURE…………..-2.45
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………….-0.4
TOTAL SNOWFALL FOR THE MONTH………….2.7     DEPARTURE………….-0.9
TOTAL SNOWFALL FOR THE SEASON…………2.9     DEPARTURE………….-3.3

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/…/..         27 SW  AERO 28 MPH SW  RMY 27

12/12 morning low temp: 16F; the normal low is now 25F

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 12
HIGH 67 IN 1979
LOW -3 IN 1988
PRECIP 3.94 INS. IN 1992
SNOWFALL 20.3 INS. IN 1960
PEAK GUST 75 MPH SSE IN 2008

RECORDS FOR DECEMBER 13
HIGH 60 IN 1984
LOW 0 IN 1893
PRECIP 1.45 INS. IN 1983
SNOWFALL 9.2 INS. IN 2007
PEAK GUST 81e WNW IN 1976

TODAY’S REPORT PREPARED BY: Robert Skilling