Saturday, November 18, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
SATURDAY, NOVEMBER 18, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

EARLY MORNING SUNSHINE FADES AS CLOUDS ARRIVE
AHEAD OF APPROACHING STORM…

Under nearly clear skies overnight with very dry air,
the temperature dropped to 26F this morning, which is
well below the normal minimum of 33F for this date.
Middle level and high level clouds began arriving
shortly after 7 AM, and the sky is overcast with
altocumulus and cirrostratus as of 1 PM. The dew point,
which was in the middle teens this morning, has
climbed to the upper 20’s by early afternoon. Although
the wind speed has been relatively light all day, the
wind direction has backed from WNW to S during the day
in advance of the approaching storm that will bring
rain and wind over the next day. Visibility has been
very good today in the 70-75 mile range.
Today’s Observations:

7 A.M.
Weather: Clear, few altocumulus all quadrants, few cirrus
distant SSW-WSW, thin smoke layer along horizon N-NE
Temperature: 29F; Dew Point: 15F; Wind: W at 10 kts,
Sea-level pressure: 29.98 ins. Hg, rising then falling
Visibility: 70 miles
6-hr Max temp: 29F
6-hr Min temp: 26F
24-hr precip: 0.00 ins.
BHO SA 1155 CLR 70 153/29/15/2710/998/ FEW AC ALQDS FEW CI
DSNT SSW-WSW THN K LYR ALG HRZN N-NE/ 8/031 51005 10029 20026

10 A.M.
Weather: Scattered altocumulus, scattered cirrostratus,
thin broken cirrus, smoke layer along horizon NW-E
Temperature: 38F; Dew Point: 15F; Wind: S at 8 kts,
Sea-level pressure: 29.94 ins. Hg, falling, then more quickly
Visibility: 75 miles
BHO SA 1455 75 SCT 200 SCT E250 –BKN 75 139/38/15/1708/994/
K LYR ALG HRZN NW-E/ 8/076 58014

1 P.M.
Weather: Scattered altocumulus, overcast cirrostratus, few
lower altocumulus, thin spots in overcast distant SE
Temperature: 42F; Dew Point: 24F; Wind: S at 10 kts,
Sea-level pressure: 29.83 ins. Hg, falling, then more quickly
Visibility: 75 miles
6-hr Max temp: 42F
6-hr Min temp: 29F
BHO SA 1755 90 SCT E200 OVC 75 102/42/24/1910/983/ FEW LWR AC
THN SPTS IOVC DSNT SE/ 8/076 58037 10042 20029

SUMMARY FOR FRIDAY, NOVEMBER 17, 2017

TEMPERATURE (DEGREES F)
MAX…..42   NORMAL…..50
MIN…..30   NORMAL…..33
MEAN….36   NORMAL…..41

DEPARTURE FROM 30-YEAR NORMAL……………………..-5
TOTAL DEPARTURE FOR THE MONTH…………………….-13 [-1.0 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..29   DEPARTURE……….+5
TOTAL HEATING UNITS FOR THE MONTH………….372   DEPARTURE………+13
TOTAL HEATING UNITS FOR THE SEASON…………640   DEPARTURE……..-282
TOTAL HEATING UNITS LAST SEASON TO DATE…….711   DIFFERENCE……..-71

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….41 WNW AT 10:19 A.M.
AERO……………………43 WNW AT  9:06 A.M.
ASOS……………………45  NW AT 10:20 A.M.
DAVIS…………………..41 WNW AT  9:06 A.M. RMY 47
FASTEST MILE FOR YESTERDAY…………………29 WNW AT 11:36 A.M. *
MAXIMUM 2-MINUTE ASOS AVERAGE………………29  NW AT  9:07 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..30  NW AT 10:20 A.M.
AVERAGE WIND SPEED AND DIRECTION………….17.3 WNW
ASOS………………….15.6
DAVIS…………………16.2 NW [310 DEG.] * 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……….0.73  DEPARTURE……-1.94
ASOS…………..0.70
TOTAL PRECIPITATION FOR THE YEAR……….48.53  DEPARTURE……+2.09
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 Low temp since midnight is 26F; 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 18
HIGH 72 IN 1963
LOW 10 IN 1936
PRECIP 1.80 INS IN 1929
SNOWFALL 6.3 INS IN 1980
PEAK GUST 60 SW IN 1987

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

TODAY’S REPORT PREPARED BY: Mike Iacono / Afshin Pourmokhtarian