Monday, November 20, 2017

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

DAILY DISCUSSION AND CLIMATE SUMMARY
MONDAY, NOVEMBER 20, 2017
ALL TIMES ARE IN EASTERN STANDARD TIME

STRONG WINDS FROM THE NORTHWEST BRING THE
RETURN OF BELOW SEASONABLE TEMPERATURES…

The wind shifted direction yesterday just before noon
from the SSW-WNW. This caused temperatures to drop 10
degrees between 11:00 A.M. EST and 12 P.M. EST.
Temperatures continued to drop until today just before
7:00 A.M. Before the wind shift we reached an unseasonably
warm 58F just after 11:00 A.M. This is 9 degrees above the
normal of 49F. Temperatures today have been much cooler with
a high of 39F by 1:00 P.M. This is 10 degrees below the
normal of 49F for today and 19 degrees lower than our maximum
yesterday of 58F. Wind from the WNW was strong yesterday
with a peak gust of 43 kts (50 MPH) at 1:36 P.M. Today wind
from WNW continues to be strong frequently gusting over
36 kts (41 MPH), and the peak gust so far today is 41 kts
(47 MPH) by 1:00 P.M.

Today’s Observations:

7 A.M.
Weather: Clear, few cumulus in all directions, few
altocumulus SSW-NNE
Temperature: 31F; Dew Point: 16F; Wind: W at 17G28 kts,
Peak Wind: 32 kts (37 MPH) W at 6:58 A.M. EST
Sea-level pressure: 29.83 ins. Hg, rising, then more rapidly
Visibility: 70 miles
6-hr Max temp: 33F
6-hr Min temp: 31F
24-hr precip: 0.17 ins.
BHO SA 1155 CLR 70 103/31/16/2817G28/983/ FEW CU ALQDS
FEW AC SSW-NNE PK WND 2832/58/ 8/160 MANUAL 70017 ASOS 70015
53029 10033 20031

10 A.M.
Weather: Clear, few cumulus in all directions, few cirrus
overhead
Temperature: 36F; Dew Point: 14F; Wind: WNW at 19G32 kts,
Peak Wind: 41 kts (47 MPH) WNW at 9:19 A.M. EST
Sea-level pressure: 29.90 ins. Hg, rising unsteadily
Visibility: 75 miles
3-hr precip: 0.00 ins.
BHO SA 1455 CLR 75 124/36/14/2919G32/990/ FEW CU ALQDS
FEW CI OVHD PK WND 2841/19/ 8/101 51021

1 P.M.
Weather: Scattered Altocumulus
Temperature: 38F; Dew Point: 18F; Wind: W at 15G32 kts,
Peak Wind: 40 kts (46 MPH) W at 12:35 P.M. EST
Sea-level pressure: 29.91 ins. Hg, rising then falling
Visibility: 75 miles
6-hr Max temp: 39F
6-hr Min temp: 31F
6-hr precip: 0.00 ins.
BHO SA 1755 65 SCT 75 127/38/18/2715G32/991/ PK WND 2740/35/
8/060 53003 10039 20031

SUMMARY FOR SUNDAY, NOVEMBER 19, 2017

TEMPERATURE (DEGREES F)
MAX…..58   NORMAL…..50
MIN…..34   NORMAL…..33
MEAN….46   NORMAL…..41

DEPARTURE FROM 30-YEAR NORMAL………………..+5
TOTAL DEPARTURE FOR THE MONTH……………….-11 [-0.8 DEGREES/DAY]

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………19   DEPARTURE……….-5
TOTAL HEATING UNITS FOR THE MONTH………..418   DEPARTURE………+11
TOTAL HEATING UNITS FOR THE SEASON……….686   DEPARTURE……..-284
TOTAL HEATING UNITS LAST SEASON TO DATE…..745   DIFFERENCE……..-59

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….50 W AT 1:43 P.M.
AERO……………………50 W AT 3:37 P.M.
ASOS……………………52 W AT 1:43 P.M.
DAVIS…………………..50 W AT 1:43 P.M. RMY 54
FASTEST MILE FOR YESTERDAY…………………37 W AT 1:43 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………38 W AT 1:43 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..39 W AT 1:43 P.M.
AVERAGE WIND SPEED AND DIRECTION………….22.9 W
ASOS………………….22.0
DAVIS…………………21.7 WSW [249 DEG.] * Last of several occurrences

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.17  DEPARTURE……+0.01
ASOS…………..0.15
TOTAL PRECIPITATION FOR THE MONTH……….1.17  DEPARTURE……-1.82
ASOS…………..1.11
TOTAL PRECIPITATION FOR THE YEAR……….48.97  DEPARTURE……+2.21
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 58/34/46/+5/…./…/..          50 W   AERO 50 W   RMY 54

11/20 Low temp since midnight is 31F; normal low is now 32F

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 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

RECORDS FOR NOVEMBER 21
HIGH 69 IN 1931
LOW 10 IN 1888
PRECIP 2.60 INCHES IN 1950
SNOWFALL 4.0 INS IN 1929
PEAK GUST 69 NW IN 1989

TODAY’S REPORT PREPARED BY: Kaitlin Geagan