Sunday, November 19, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, NOVEMBER 19, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

COLD FRONT PASSES BRINGING SHIFTS IN WIND, TEMPERATURE
AND PRESSURE

Clouds and rain began the day at the Observatory with
unusually warm temperatures around 56F. Winds gusted
overnight into the mid-30s while winds were out of
the south.  Visibility had been very poor to start the
day.  Just before noon, a cold front came through the
area, shifting the winds from SSW to WNW, dropping the
temperatures by about 10 degrees and creating a low point
to today’s barometric pressure at approximately 29.14 inches.
The pressure began to rise rapidly after the frontal passage
as the skies began to clear.
Today’s Observations:

7 A.M.
Weather: Overcast nimbostratus, few stratus fractus
Temperature: 56F; Dew Point: 56F; Wind: S at 22 kts,
Sea-level pressure: 29.21 ins. Hg, falling then more slowly
Visibility: 20 miles
6-hr Max temp: 58F
6-hr Min temp: 50F
24-hr precip: 0.27 ins.
BHO SA 1155 E25 OVC 20 893/56/56/1922/921/ FEW STFRA
DSNT FG ALQDS/ 8/72// 56028 MANUAL 70027 ASOS 70026 10058 20050

10 A.M.
Weather: Overcast Stratus, Few Stratus Fractus
Temperature: 56F; Dew Point: 56F; Wind: SSW at 16 kts,
Sea-level pressure: 29.14 ins. Hg, falling, then more slowly
Visibility: 30 miles
3-hr precip: 0.12 inches
BHO SA 1455 E25 BKN 55 OVC 30 869/56/56/2016/914/ DSNT FG ALQDS/
8/72/ 56024 MANUAL 60012 ASOS 60013

1 P.M.
Weather: Scattered Cumulus, Few Stratus NE-SE
Temperature: 45F; Dew Point: 34F; Wind: W at 24G40 kts
Sea-level pressure: 29.20 ins. Hg, falling then rising and higher
Visibility: 75 miles
6-hr Max temp: 56F
6-hr Min temp: 45F
6-hr precip: 0.17 inches
BHO SA 1755 60 SCT 75 889/45/34/2724G40/920/ FEW ST DSNT NE-SE
VIRGA E-SE DSNT/ 8/200 MANUAL 60017 ASOS 60015 53020 10056 20045

SUMMARY FOR SATURDAY, NOVEMBER 18, 2017

TEMPERATURE (DEGREES F)
MAX…..49   NORMAL…..50
MIN…..26   NORMAL…..33
MEAN….38   NORMAL…..41

DEPARTURE FROM 30-YEAR NORMAL……………………..-3
TOTAL DEPARTURE FOR THE MONTH…………………….-16 [-1.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..27   DEPARTURE……….+3
TOTAL HEATING UNITS FOR THE MONTH………….399   DEPARTURE………+16
TOTAL HEATING UNITS FOR THE SEASON…………667   DEPARTURE……..-279
TOTAL HEATING UNITS LAST SEASON TO DATE…….727   DIFFERENCE……..-60

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….35 SSW AT 10:54 P.M.
AERO……………………35 SSW AT 10:51 P.M.
ASOS……………………37 SSW AT 10:55 P.M.
DAVIS…………………..37 SSW AT 10:54 P.M. RMY 39
FASTEST MILE FOR YESTERDAY…………………25 SSW AT 10:49 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………25 SSW AT 10:51 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..26 SSW AT 10:50 P.M.
AVERAGE WIND SPEED AND DIRECTION………….12.4 S
ASOS………………….12.4
DAVIS…………………11.5 SSW [213 DEG.] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.27  DEPARTURE……+0.11
ASOS…………..0.26
TOTAL PRECIPITATION FOR THE MONTH……….1.00  DEPARTURE……-1.83
ASOS…………..0.96
TOTAL PRECIPITATION FOR THE YEAR……….48.80  DEPARTURE……+2.20
ASOS……………N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR NOVEMBER CALENDAR DAY DATA
DATE: MAX/MIN/MEAN/DEP/PRECIP/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

11/1  53/39/46/0/0.00/167/27           25 SE  AERO 24 SE  RMY 25
11/2  71/49/60/+14/0.00/000/00         28 SSE AERO 25 SSE RMY 27
11/3  74/47/61/+15/T/350/57            35 WNW AERO 35 WNW RMY 38
11/4  54/39/47/+2/0.00/545/89          31 NW  AERO 31 NW  RMY N/A
11/5  61/46/54/+9/0.01/006/01          26 S   AERO 24 S   RMY N/A
11/6  64/47/56/+11/0.05/000/00         32 S   AERO 28 SSW RMY 35
11/7  46/35/41/-4/0.11/145/24          26 NNW AERO 23 N   RMY 26
11/8  43/34/39/-5/0.08/295/49          26 N   AERO 23 N   RMY 27
11/9  50/31/41/-3/0.01/…/..          25 S   AERO 23 S   RMY N/A
11/10 45/20/33/-11/0.00/…/..         46 WNW AER0 44 WNW RMY 46
11/11 36/18/27/-16/0.00/…/..         28 WNW AERO 26 WNW RMY 28
11/12 44/27/36/-7/0.00/…/..          13 E   AERO  9 S   RMY 14
11/13 40/35/38/-5/…/…/..           20 NNW AERO 17 NNW RMY 20
11/14 40/33/37/-5/…/…/..           18 N   AERO 15 N   RMY 18
11/15 43/31/37/-5/0.00/…/..          20 NE  AERO 15 NE  RMY N/A
11/16 51/37/44/+2/…/…/..           32 SE  AERO 32 SE  RMY N/A TSTM
11/17 42/30/36/-5/0.00/…/..          41 WNW AERO 43 WNW RMY 47
11/18 49/26/38/-3/…./…/..          35 SSW AERO 35 SSW RMY 39

11/19 Low temp since midnight is 45F; normal low is now 33F

DAILY RECORDS FOR NOVEMBER 2017

11/10/17: DAILY RECORD LOW MINIMUM TEMPERATURE OF 20F,
TIES WITH PREVIOUS RECORD SET IN 2004

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

RECORDS FOR NOVEMBER 19
HIGH 72 IN 1941
LOW 10 IN 1936
PRECIP 1.92 INCHES IN 1926
SNOWFALL 11.0 INS IN 1986
PEAK GUST 59e E IN 1945

RECORDS FOR NOVEMBER 20
HIGH 72 IN 1953
LOW 10 IN 1894
PRECIP 2.78 INS IN 1988
SNOWFALL 3.0 INS IN 1897
PEAK GUST 73e S IN 1950

TODAY’S REPORT PREPARED BY: Robert Millette