Thursday, December 19, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, DECEMBER 19, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

THE WARMING TREND BEGINS TODAY ON INCREASING SW WINDS
WIND GUSTS TO WELL OVER 30 MPH AND A FEW OVER 40 MPH
TEMPERATURES RISING PAST 40 DEGREES AFTER LONG COLD SPELL

The end of a 12-day stretch of below normal temperatures
came yesterday after beginning December 7.  Today the mean
temperature will average a few degrees above normal for
quite a nice change for those of us who do not like the early
arrival of winter temperatures.  Official astronomical winter
begins with the winter solstice around noon this Saturday.
The 10-inch snow cover here on the summit will be steadily
melting down as this warmer than normal trend is expected
to last through the coming weekend.

Today’s Observations:

7 A.M.
Weather: Overcast altocumulus, breaks in overcast, hazy
Temperature: 27F; Dew Point: 19F; Wind: SW at 12 kts,
Sea-level pressure: 30.08 ins. Hg, about steady
Visibility: 15 miles, hazy
6-hr. min temp: 22F
24-hr precip: none
24-hr snowfall: none
Snow on ground: 10 inches
BHO SA 1155 E95 OVC 15 187/27/19/2312/008/ BINOVC HAZY/
8/07/ 4/010 51001 10027 20022

10 A.M.
Weather: Clear, altocumulus, cirrus NW-E, hazy
Temperature: 32F; Dew Point: 20F; Wind: SW at 15 kts,
Wind: Gust to 24 kts past hour
Sea-level pressure: 30.07 ins. Hg, falling slightly but more rapidly
Visibility: 15 miles, except 20 miles WNW, hazy
BHO SA 1455 CLR 15 182/32/20/2215/007/ AC/CI NW-E VSBY WNW 20
HAZY ALQDS WND GST TO 24 KTS PST HR/ 8/041 58005

1 P.M.
Weather: Clear, few cirrus, hazy
Temperature: 40F; Dew Point: 22F; Wind: SW at 15G19 kts,
Wind: Peak wind 28 kts from SW @ 12:21 P.M.,
Wind: Direction variable SSW-W
Sea-level pressure: 29.98 ins. Hg, falling then more slowly
Visibility: 30 miles, hazy
6-hr max. temp. 41F
BHO SA 1755 CLR 30 153/40/22/2315G19/998/ FEW CI HAZY PK
WND 2328/21 WND 20V27 8/001 56029 10041 20026

WEATHER SUMMARY FOR WEDNESDAY, DECEMBER 18, 2013

TEMPERATURE (DEGREES F)
MAX…..32    NORMAL…..38
MIN…..15    NORMAL…..23
MEAN….24    NORMAL…..31

DEPARTURE FROM 30-YEAR NORMAL………………….-7
TOTAL DEPARTURE FOR THE MONTH…………………-74 [-4.3 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..41  DEPARTURE………+6
TOTAL HEATING UNITS FOR THE MONTH………….640  DEPARTURE……..+72
TOTAL HEATING UNITS FOR THE SEASON………..1864  DEPARTURE……..+34
TOTAL HEATING UNITS LAST SEASON TO DATE……1601  DIFFERENCE……+263

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………29 WNW AT 12:28 P.M. *
AERO…………………..30 NW  AT  8:48 A.M.
ASOS…………………..30 NW  AT  8:49 A.M.
DAVIS………………….28 WNW AT 12:27 P.M. RMY 29
FASTEST MILE FOR YESTERDAY………………..23 WNW AT 12:28 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..22 WNW AT 12:29 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….20 WNW AT 12:27 P.M.
AVERAGE WIND SPEED AND DIRECTION…………14.8 NW
ASOS…………………14.9
DAVIS………………..12.7 WNW [300 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……….3.25  DEPARTURE………….+0.32
ASOS…………..3.27
TOTAL PRECIPITATION FOR THE YEAR……….49.85  DEPARTURE………….-1.61
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…………15.0*    DEPARTURE………….+8.3
TOTAL SNOWFALL FOR THE SEASON………..15.2     DEPARTURE………….+5.9

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  morning low temp: 22F; the normal low is now 23F

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 19
HIGH 59 IN 1899
LOW -1 IN 1919
PRECIP 2.06 INS. IN 1986
SNOWFALL 14.1 INS. IN 1945
PEAK GUST 68 NE IN 1986

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

TODAY’S REPORT PREPARED BY: Robert Skilling