Thursday, October 1, 2015

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, OCTOBER 1, 2015
ALL TIMES ARE IN EASTERN STANDARD TIME

SEPTEMBER 2015 WARMEST SEPTEMBER ON RECORD AT
68.2F- YESTERDAY’S STORM TOTAL OF 2.53 INCHES
UNOFFICIALLY BREAKS DAILY RECORD

Heavy rain associated with the cold front that moved
through our region yesterday dropped an additional 0.37
inches of rain, adding to an overall storm total of 2.53
inches. It is likely, though not yet confirmed, that yesterday’s
rainfall broke the previous daily record of 1.93 inches,
set back in 1946. A brief thunderstorm was also recorded
during the passage of yesterday afternoon’s cold front.

Following the passage of the cold front, winds shifted
to the WNW then NNE, dropping temperatures that peaked
at 75F to 53F by midnight. Overnight, temperatures
dropped to a more seasonable 51F.

With a warmer-than-normal finish to this month that included
the warmest day of the year at 97F and a couple very warm
streaks, September 2015 is now officially the warmest September
on record here at Blue Hill Observatory. The average temperature
of 68.2 F breaks the previous record of 66.9 F set back in 1961.
This is the second time this year we have broken a record for
the warmest month on record (May 2015). Additionally, this September
broke the record for the warmest average maximum temperature
and was the second warmest average minimum temperature. More
monthly statistics and records will become available over the
next several days.

BHO Warmest Septembers (NWS mean), deg F (1885-2015):

1) 68.2 in 2015
2) 66.9 in 1961
3) 66.5 in 1930
4) 66.4 in 1999
5) 66.2 in 2002
66.2 in 2005

BHO Warmest September Average Maximum Temperature, deg F (1885-2015):

1) 77.8 in 2015
2) 76.6 in 1930
3) 75.7 in 2007
4) 75.6 in 1959
5) 75.5 in 1961

BHO Warmest September Average Minimum Temperature, deg F (1885-2015):

1) 58.8 in 1988
2) 58.5 in 2015
3) 58.2 in 1961
58.2 in 1999
5) 57.8 in 2005

BHO Warmest Aug-Sep (24-hour adjusted mean), deg F (1885-2015):

1) 69.8 in 2015
2) 68.9 in 2005
3) 68.6 in 2002
4) 68.2 in 2010
5) 67.8 in 1959

PRELIMINARY STATS FOR SEPTEMBER 2015

TEMPERATURE, Deg. F
Avg. Max. 77.8 [+6.2] Avg. Min. 58.5 [+3.9] Mean      68.2 [+5.1] Corrected mean: 67.3
Max. for month: 97 on 8th
Min. for month: 46 on 27th

COOLING DEGREE DAYS
Total cooling units: 144 [+84] Total for the season: 810 [+213] Total for last season: 587

HEATING DEGREE DAYS
Total heating units: 42 [-75] Total for the season: 43 [-99] Total for last season: 101

PRECIPITATION, Inches
Total: 3.88 [-0.18] Greatest in 24 hrs: N/A

WIND, mph
Avg. uncorrected wind speed: 10.1
Avg. corrected wind speed: 10.3
Prevailing wind direction: SSW @ 13%
Peak gust and direction: 47 S on the 30th

SUNSHINE:
Campbell-Stokes card minutes: N/A
Astronomical total minutes:   N/A

Today’s Observations:

7 A.M.
Weather: Broken stratocumulus
Temperature: 52F; Dew Point: 47F; Wind: NNE at 13G24 kts,
Peak Wind: 26 knots N @ 6:05 AM EST
Sea-level pressure: 30.09 ins. Hg, pressure rising, then more quickly
Visibility: 80 miles, except 40 miles NE-SSW
6-hr Max temp: 52F
6-hr Min temp: 51F
24-hr precip: 1.61 inches
BHO SA 1155 E20 BKN 80 190/52/47/0213G24/009/ VSBY NE-SSW 40 MI
PK WND 3626/05/ 8/500 53021 ASOS 70172 MANUAL 700161 10052 20051

10 A.M.
Weather: Broken stratocumulus, few cumulus distant WNW-N
Temperature: 54F; Dew Point 49F; Wind: NNE at 15G21 kts,
Sea-level pressure: 30.13 ins. Hg, rising, then more slowly
Visibility: 25 miles, except 80 miles WSW-N, thing fog
NNE-SW
BHO SA 1455 E16 BKN 25 204/54/49/0315G21/013/ VSBY WSW-N 80 MI
FEW CU DSNT WNW-N THN FG NNE-SW/ 8/500 51014

1 P.M.
Weather: Broken stratocumulus, overcast altostratus
Temperature: 54F; Dew Point: 49F; Wind: NE at 13G25 kts
Peak Wind: 27 knots NE @ 12:23 PM EST
Sea-level pressure: 30.15 ins. Hg, increasing, then more quickly
Visibility: 35 miles, except 80 miles NE-SW, thin fog NE-SW
6-hr Max: 54F
6-hr Min: 51F
BHO SA 1755 E21 BKN 150 OVC 35 211/54/49/0513G25/015/ VSBY WSW-NNE
80 MI THN FG NE-SW PK WND 0527/23/ 8/51/ 53007 10054 20051
SUMMARY FOR WEDNESDAY, SEPTEMBER 30, 2015

TEMPERATURE (DEGREES F)
MAX…..75   NORMAL…..66
MIN…..53   NORMAL…..49
MEAN….64   NORMAL…..58

DEPARTURE FROM 30-YEAR NORMAL……………………+6
TOTAL DEPARTURE FOR THE MONTH………………….+157  [+5.0 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY……………0   DEPARTURE……….-1
TOTAL COOLING UNITS FOR THE MONTH………….144   DEPARTURE………+84
TOTAL COOLING UNITS FOR THE SEASON…………810   DEPARTURE……..+213
TOTAL COOLING UNITS LAST SEASON TO DATE…….587   DIFFERENCE…….+223

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY……………1   DEPARTURE……….-7
TOTAL HEATING UNITS FOR THE MONTH…………..42   DEPARTURE………-75
TOTAL HEATING UNITS FOR THE SEASON………….43   DEPARTURE………-99
TOTAL HEATING UNITS LAST SEASON TO DATE…….101   DIFFERENCE……..-58

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY……………….47 S   AT 10:34 A.M.
ASOS……………………50 S   AT 10:35 A.M.
DAVIS…………………..49 S   AT 10:34 A.M. RMY 51
FASTEST MILE FOR YESTERDAY……………….. 34 S   AT 10:34 A.M.
MAXIMUM 2-MINUTE ASOS AVERAGE………………36 S   AT 10:35 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE……………..33 S   AT 10:35 A.M.
AVERAGE WIND SPEED AND DIRECTION…………. .17.4 N
ASOS……………………16.8
DAVIS…………………..15.1 S [187 DEG]

PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M…..1.61  DEPARTURE…..+1.46
ASOS……………1.72
TOTAL PRECIPITATION FOR THE MONTH………..3.88  DEPARTURE…..-0.18
ASOS……………3.93
TOTAL PRECIPITATION FOR THE YEAR………..34.13  DEPARTURE…..-4.94
ASOS…………….N/A ***
*** ASOS annual total not available due to erroneous readings

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/RMY 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

9/1  81/65/73/+5/0.00/766/97               20 SSW RMY 20
9/2  89/64/77/+9/0.00/732/93               20 SW  RMY 21
9/3  85/66/76/+9/T/612/78                  17 E   RMY N/A TSTM
9/4  72/58/65/-2/0.00/297/38               31 ENE RMY N/A
9/5  77/55/66/-1/0.00/748/96               14 SW  RMY 18
9/6  87/57/72/+5/0.00/753/97               21 SSW RMY 22
9/7  92/63/78/+12/0.00/727/94              23 WSW RMY 24
9/8  97/70/84/+18/0.00/693/90              22 WSW RMY 24
9/9  92/70/81/+15/0.00/683/89              30 SSW RMY 33
9/10 73/62/68/+3/…./000/00               29 NE  RMY N/A
9/11 70/59/65/0/…./084/11                33 NE  RMY N/A
9/12 75/58/67/2/…./380/50                18 SSE RMY 25
9/13 66/60/63/-1/…./000/00               25 E   RMY N/A
9/14 70/53/62/-2/0.00/550/73               33 W   RMY 35
9/15 82/56/69/+5/0.00/736/98               23 W   RMY N/A
9/16 84/62/73/+10/0.00/711/95              17 NW  RMY N/A
9/17 87/64/76/+13/0.00/723/97              17 SW  RMY 16
9/18 86/64/75/+13/0.00/712/96              21 SSW RMY 21
9/19 80/62/71/+9/0.00/…/..               22 S   RMY N/A
9/20 74/55/65/+3/T/…./…                24 S   RMY N/A
9/21 65/50/58/-3/0.00/…/..               29 ENE RMY 30
9/22 67/55/61/+0/0.00/…/..               21 E   RMY 21
9/23 72/50/61/+1/0.00/…/..               15 E   RMY N/A
9/24 72/56/64/+4/0.00/…/..               22 E   RMY 21
9/25 66/53/60/0/0.00/…/..                21 E   RMY 20
9/26 63/49/56/-3/0.00/…/..               25 ENE RMY 25
9/27 71/46/59/+0/0.00/…/..               17 S   RMY 18
9/28 81/57/69/+11/0.00/…/..              22 SSW RMY 24
9/29 82/65/74/+16/…./…/..              28 S   RMY N/A
9/30 75/53/64/+6/…./…/..               47 S   RMY 51  TSTM

10/1 low since midnight is 51F; normal low is now 49F

DAILY RECORDS FOR SEPTEMBER 2015

**9/7 DAILY RECORD MAXIMUM TEMPERATURE OF 92F
TIES PREVIOUS RECORD SET IN 2007**

**9/8 DAILY RECORD MAXIMUM TEMPERATURE OF 97F
BREAKS PREVIOUS RECORD OF 93F SET IN 2007**

**9/8 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

**9/9 DAILY RECORD MAXIMUM TEMPERATURE OF 92F
BREAKS PREVIOUS RECORD OF 91F SET IN 2002**

**9/9 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 70F
BREAKS PREVIOUS RECORD OF 69F SET IN 1999**

**9/17 DAILY RECORD MAXIMUM TEMPERATURE OF 87F
BREAKS PREVIOUS RECORD OF 86F SET IN 1915, 1941, AND 1991**

**9/18 DAILY RECORD HIGH MINIMUM TEMPERATURE OF 64F
TIES PREVIOUS RECORD SET IN 1992**

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

RECORDS FOR OCTOBER 1
HIGH 85F IN 1927
LOW 30F IN 1992
PRECIP 1.63 INCHES IN 2014
PEAK GUST 68e MPH SSE IN 1977

RECORDS FOR OCTOBER 2
HIGH 85F IN 1968
LOW 29F IN 1899
PRECIP 1.75 INCHES IN 1984
PEAK GUST 52e MPH S IN 1952, 52 NNW IN 1984

TODAY’S REPORT PREPARED BY: Brian Fitzgerald / Mike Iacono