Monday, September 21, 2020
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
MONDAY, SEPTEMBER 21, 2020
ALL TIMES ARE IN EASTERN STANDARD TIME
ANOTHER COOL AND BREEZY DAY AT BLUE HILL….
Today marks the 82nd anniversary of the Great New
England Hurricane of 1938. On this day we recorded a
calculated wind gust of 186 mph, which is our station
record. We also measured a 5-minute average wind speed
of 121 mph. Of interest, only 0.13″ of rain fell that
day, as the center of the hurricane passed to the west
of the Observatory, leaving us in a dry slot.
The cool air mass that’s been over the region the last
couple of days remains. Despite plenty of sun, the
temperature has struggled to reach 60 degrees today
peaking briefly at 61F just after the noontime, but has
since settled back into the upper 50s.
Coinciding with the cool temperatures is a gusty NE to
ENE breeze which has gusted 25-30 mph at times.
A thin smoke layer, associated with the wild fires out
west, has returned the region today, albeit not as dense
as it was last week. However models suggest the smoke
may be more dense tomorrow.
Another interesting tidbit today is the high pressure.
While not a record, it is rather high for this time of
year with the barometer peaking at around 1036 millibars
(30.60 in/hg) this morning. This high pressure area is
responsible for the chilly air mass and exceptional
radiational cooling that occurred overnight at some
low lying locations, where readings ranged from the
upper 20s to low 30s!
The visibility has been excellent today averaging 75-80
miles all day!
It has been 10 days since we’ve recorded any measurable
rainfall (0.01″ on the 11th). Only 0.51″ has fallen for
the month to date, which is 2.08 inches below normal.
For the year, our deficit is running 4.29 inches below
normal. The region continues to be generally in a
moderate drought, however severe drought conditions are
being observed across portions of south coastal
Massachusetts and Rhode Island.
The high so far today is 61F, 9 degrees below the daily
normal max of 70F. The low since midnight is 41F, which
is 12 degrees below the normal low of 53F.
Today’s Observations:
7 A.M.
Weather: Clear, few stratocumulus distant ENE-S, thin
smoke layer aloft, thin smoke layer along horizon all
quadrants
Temperature: 44F; Dew Point: 34F; Relative Humidity: 67%
Wind: N at 9 kts
Sea-level pressure: 30.59 ins. Hg: steady, then rising
Visibility: 75 miles
6-hr Max temp: 44F
6-hr Min temp: 41F
24-hr Precip: 0.00 ins.
BHO SA 1155 CLR 75 359/44/34/3609/059/ FEW SC DSNT ENE-S
THN K LYR ALF THN K LYR ALNG HRZN ALQDS/ 8/500 53006
10044 20041
10 A.M.
Weather: Scattered stratocumulus, thin smoke layer aloft
Temperature: 57F; Dew Point: 40F; Relative Humidity: 52%
Wind: NE at 12G24 kts
Sea-level pressure: 30.59 ins. Hg: rising, then falling
Visibility: 75 miles
3-hr Precip: 0.00 ins.
BHO SA 1455 35 SCT 75 360/57/40/0412G24/059/ THN K LYR ALF/
8/500 50001
1 P.M.
Weather: Scattered stratocumulus, thin smoke layer aloft
Temperature: 59F; Dew Point: 35F; Relative Humidity: 40%
Wind: ENE at 12G18 kts
Sea-level pressure: 30.55 ins. Hg: falling, then more rapidly
Visibility: 80 miles
6-hr Max temp: 61F
6-hr Min temp: 44F
6-hr Precip: 0.00 ins.
BHO SA 1755 35 SCT 80 346/59/35/0612G18/055/ THN K LYR ALF/
8/500 58014 10061 20044
SUMMARY FOR SUNDAY, SEPTEMBER 20, 2020
TEMPERATURE (DEGREES F)
MAX…..58 NORMAL…..70
MIN…..40 NORMAL…..53
MEAN….49 NORMAL…..62
DEPARTURE FROM 30-YEAR NORMAL…………….-13
TOTAL DEPARTURE FOR THE MONTH…………….-16 [-1.0 DEGREES/DAY]
HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY………….16 DEPARTURE….. +8
TOTAL HEATING UNITS FOR THE MONTH………….65 DEPARTURE…..+13
TOTAL HEATING UNITS FOR THE SEASON…………68 DEPARTURE….. -9
TOTAL HEATING UNITS LAST SEASON TO DATE…….76 DEPARTURE….. -8
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY………… 0 DEPARTURE……-1
TOTAL COOLING UNITS FOR THE MONTH………… 50 DEPARTURE….. -1
TOTAL COOLING UNITS FOR THE SEASON………..807 DEPARTURE….+219
TOTAL COOLING UNITS LAST SEASON TO DATE……647 DEPARTURE….+160
PEAK WIND GUST FOR YESTERDAY (MPH)
420C/Official…………….25 NE AT 12:03 P.M.
AERO…………………….25 NE AT 12:03 P.M.
ASOS…………………….26 NE AT 12:47 P.M.
DAVIS……………………25 ENE AT 12:03 P.M.
RMY 27 MERLIN 25
FASTEST MILE FOR YESTERDAY………………….19 NE AT 12:04 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………….18 ENE AT 2:18 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE………………19 NE AT 12:03 P.M.
AVERAGE WIND SPEED AND DIRECTION…………..10.5 N (252 total miles)
ASOS…………………..10.6
DAVIS………………….11.0 NE [045 deg.]
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….0.00 DEPARTURE….-0.15
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.51 DEPARTURE….-2.08
ASOS…………..0.51
TOTAL PRECIPITATION FOR THE YEAR……….33.32 DEPARTURE….-4.29
ASOS………….34.09
PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER 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
09/01 76/59/68/0/0.00/698/88 22 SSE AERO 21 SE RMY 20
09/02 69/59/64/-4/0.18/102/13 23 SSE AERO 23 SSE RMY 24
09/03 75/66/71/+4/0.04/000/00 22 SSW AERO 21 SSW RMY N/A
09/04 82/62/72/+5/0.00/763/98 26 WNW AERO 26 WNW RMY 25
09/05 76/55/66/-1/0.00/760/98 25 W AERO 25 W RMY 24
09/06 78/58/68/+1/0.00/356/46 24 W AERO 24 W RMY N/A
09/07 79/61/70/+4/0.00/632/82 27 SSE AERO 30 SSE RMY 28
09/08 82/61/72/+6/0.00/545/71 17 S AERO 16 S RMY 17
09/09 80/62/71/+5/0.00/214/28 16 S AERO 15 S RMY 16
09/10 81/69/75/+10/0.28/015/02 21 SSW AERO 21 SSW RMY N/A
09/11 72/55/64/-1/0.01/152/20 25 N AERO 25 N RMY N/A
09/12 68/51/60/-5/0.00/666/88 21 ENE AERO 21 ENE RMY 21
09/13 74/53/64/0/0.00/611/81 26 SSW AERO 26 SSW RMY 26
09/14 74/50/62/-2/0.00/511/68 29 NNW AERO 33 NNW RMY 30
09/15 64/44/54/-10/0.00/…/.. 18 S AERO 18 S RMY N/A
09/16 72/49/61/-2/0.00/…/.. 31 SSW AERO 31 SSW RMY 31
09/17 76/57/67/+4/0.00/…/.. 26 WSW AERO 28 W RMY N/A
09/18 64/48/56/-6/0.00/…/.. 28 NE AERO 30 NNW RMY N/A
09/19 59/42/51/-11/0.00/…/.. 23 N AERO 23 N RMY N/A
09/20 58/40/49/-13/0.00/…/.. 25 NE AERO 25 NE RMY 27
09/21 The low since midnight is 41F, the daily normal low is 53F
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
RECORDS FOR SEPTEMBER 21
HIGH 91 IN 1895
LOW 35 IN 1929, 1956, 1962
PRECIP 5.58 INS IN 1961 (HURRICANE ESTHER; RETURNED AS TS SEPT 25-26TH)
PEAK GUST 186 MPH S IN 1938 (GREAT NEW ENGLAND HURRICANE; CALCULATED GUST,
STATION RECORD)
RECORDS FOR SEPTEMBER 22
HIGH 90F IN 1895, 1914
LOW 30F IN 1904 (Earliest freeze)
PRECIP 1.16 INCHES IN 2001
PEAK GUST 60 MPH SSW IN 1989
TODAY’S REPORT PREPARED BY: Matt Douglas
