Tuesday, December 18, 2018

| December 18, 2018 | Reply

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

DAILY DISCUSSION AND CLIMATE SUMMARY
TUESDAY, DECEMBER 18, 2018
ALL TIMES ARE IN EASTERN STANDARD TIME

A COOL DECEMBER DAY DOMINATED BY DRY AIR,
STRONG NORTHWESTERLY WINDS, AND INCREASING
PRESSURE….

Today started of almost overcast, but cleared up as pressure
increased almost 7 millibars since this morning. Strong
northwest winds persisted throughout the day, frequently
reaching speeds above 30 mph. The highest gust of 48 mph
occurred around 4 A.M. today. Humidity was at or below 50%
following 9 A.M., allowing 70 miles of visibility at the
10 A.M. and 1 P.M. observations. Snowfall this morning
amounted to a 1/10th of an inch. The high temperature
so far today is 29F, which is 9 degrees below the daily
normal maximum of 38F. The low since midnight is 20F, 3
degrees under the normal minimum of 23F.

Today’s Observations:

7 A.M.
Weather: Broken altostratus and cirrostratus
Temperature: 20F; Dew Point: 10F; Wind: NW at 18G31 kts,
Peak wind: 39 mph (34 kts) NW at 6:05 A.M.
Sea-level pressure: 29.73 ins. Hg, rising rapidly
Visibility: 45 miles
6-hr Max temp: 34F
6-hr Min temp: 20F
24-hr Precip: 0.02 ins.
24-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1155 E90 BKN 250 BKN 45 067/20/10/3118G31/973/
FEW CU ALQDS PK WND 3134/05/ 8/128 70002 53031 10034 20020

10 A.M.
Weather: Broken altocumulus
Temperature: 25F; Dew Point: 11F; Wind: NW at 22G32 kts,
Peak wind: 41 mph (36 kts) NW at 9:33 A.M.
Sea-level pressure: 29.81 ins. Hg, rising rapidly
Visibility: 70 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 E110 BKN 70 096/25/11/3122G36/981/
PK WND 3136/33/ 8/070 51029

1 P.M.
Weather: Clear, few distant cumulus
Temperature: 29F; Dew Point: 12F; Wind: NW at 22G32 kts,
Peak wind: 37 mph (32 kts) NW at 12:55 P.M.
Sea-level pressure: 29.83 ins. Hg, rising steadily
Visibility: 70 miles
6-hr Max temp: 29F
6-hr Min temp: 21F
6-hr Precip: 0.00 ins.
6-hr snowfall: 0.0 ins.
Snow depth: 0 ins.
BHO SA 1755 CLR 70 103/29/12/3122G32/983/ FEW DSNT CU
ALQDS PK WND 3132/55/ 8/100 53007 10029 30021

SUMMARY FOR MONDAY, DECEMBER 17, 2018

TEMPERATURE (DEGREES F)
MAX…..37   NORMAL…..39
MIN…..32   NORMAL…..23
MEAN….35   NORMAL…..31

DEPARTURE FROM 30-YEAR NORMAL……………………+4
TOTAL DEPARTURE FOR THE MONTH…………………..-23 [-1.2 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..30   DEPARTURE………-4
TOTAL HEATING UNITS FOR THE MONTH………….555   DEPARTURE……..+22
TOTAL HEATING UNITS FOR THE SEASON………..1875   DEPARTURE……..+80
TOTAL HEATING UNITS LAST SEASON TO DATE……1517   DIFFERENCE……+358

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………..39 NNE AT 12:05 A.M.
AERO…………………….37 NNE AT 12:05 A.M.
ASOS…………………….41 NE  AT 12:08 A.M.
DAVIS……………………39 ENE AT 12:07 A.M. RMY N/A
FASTEST MILE FOR YESTERDAY………………….26 NNE AT 12:06 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….26 NE  AT 12:08 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………27 NE  AT 12:08 A.M.
AVERAGE WIND SPEED AND DIRECTION…………..15.2 WNW
ASOS…………………..14.6
DAVIS………………….15.2 NW [324 deg.]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.02  DEPARTURE…….-0.13
ASOS…………..0.02
TOTAL PRECIPITATION FOR THE MONTH……….1.95  DEPARTURE…….-0.82
ASOS…………..2.68 *
TOTAL PRECIPITATION FOR THE YEAR……….65.32  DEPARTURE……+14.21
ASOS………….68.31 *
* ASOS MONTHLY AND ANNUAL PRECIPITATION IS SUSPECT

SNOWFALL (INCHES) THROUGH THIS MORNING (EST)
TOTAL SNOWFALL 24 HRS ENDING 7 A.M……….0.1  DEPARTURE……..-0.4
TOTAL SNOWFALL FOR THE MONTH…………….0.1  DEPARTURE……..-6.2
TOTAL SNOWFALL FOR THE SEASON……………7.7  DEPARTURE……..-1.2

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 41/28/35/-2/0.00/0.0/391/70          20 NNW AERO 18 NNW RMY N/A
12/02 52/35/44/+8/1.04/0.0/000/00          28 ESE AERO 25 ESE RMY 27
12/03 54/38/46/+10/0.00/0.0/178/32         35 W   AERO 35 W   RMY 38
12/04 38/23/31/-4/0.00/0.0/516/93          30 WNW AERO 31 WNW RMY 33
12/05 33/18/26/-9/0.00/0.0/432/78          16 NNW AERO 15 NNW RMY N/A
12/06 37/24/31/-4/0.00/0.0/354/64          29 W   AERO 28 W   RMY 30
12/07 37/21/29/-5/0.00/0.0/…/..          29 NW  AERO 29 NW  RMY 32
12/08 27/15/21/-13/0.00/0.0/…/..         28 NW  AERO 27 NW  RMY 29
12/09 34/17/26/-8/0.00/0.0/…/..          23 SSW AERO 21 SSW RMY 22
12/10 36/22/29/-4/0.00/0.0/…/..          24 NNW AERO 23 NNW RMY 22
12/11 36/17/27/-6/0.00/0.0/…/..          16 WSW AERO 14 WSW RMY N/A
12/12 35/18/27/-6/0.00/0.0/…/..          30 NW  AERO 29 NW  RMY M
12/13 31/16/24/-8/0.00/0.0/…/..          16 NNE AERO 12 SE  RMY N/A
12/14 46/28/37/+5/0.00/0.0/…/..          28 SSW AERO 28 SSW RMY 29
12/15 49/33/43/+11/…./…/…/..         28 NE  AERO 27 NE  RMY 30
12/16 40/37/39/+8/…./…/…/..          38 NE  AERO 38 NE  RMY 40
12/17 37/32/35/+4/…./…/…/..          39 NNE AERO 37 NNE RMY N/A

12/18 Low temp since midnight is 20F; normal low is 23F

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

RECORDS FOR DECEMBER 18
HIGH 59 IN 1928
LOW -11 IN 1919
PRECIP 1.44 INS. IN 1915
SNOWFALL 7.0 INS. IN 1904
PEAK GUST 76e W IN 1978

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

TODAY’S REPORT PREPARED BY: Benjamin Turner

 

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