Sunday, August 4, 2013
BLUE HILL METEOROLOGICAL OBSERVATORY
MILTON, MASSACHUSETTS
ELEVATION 635 FEET, 10 MILES SSW OF BOSTON, MA
DAILY DISCUSSION AND CLIMATE SUMMARY
SUNDAY, AUGUST 4, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME
COOL CLEAR MORNING
LIGHT WIND AND SCATTERED CLOUD COVER PREVALENT THROUGHOUT THE DAY
JULY 2013 AVERAGE VAPOR PRESSURE AND DEW POINT HIGHEST ON RECORD…
Today got off to a beautiful start with clear sky, temperatures in the
mid 60s and visibility of 75 miles. Light wind out of the WNW averaged
just under 5 mph and scattered cumulus increased cloud cover throughout
the day.
In addition to having the warmest average minimum temperature on record,
July 2013 also had the highest average vapor pressure on record of 23.5 mb,
and the highest average dew point on record of 68F. Vapor pressure is an
absolute measure of the amount of water vapor in the air, while the dew
point (a related parameter) is a temperature that also reflects the
atmospheric moisture content.
Starting 8/3/2013, these discussions will provide information on the daily,
monthly and seasonal cooling degree day units, which are a measure of the
degree to which the daily mean temperature is warmer than 65 deg F over a
cooling season. A cooling degree day is recorded as the integer difference
between the daily mean temperature and 65 deg F, when the mean temperature
is higher than 65 deg F. The cooling degree day season extends from
January to December.
Additional July statistics can be found below.
JULY 2013 PRELIMINARY STATISTICS:
(departures relative to 1981-2010 average)
TEMPERATURE:
Average Max Temp: 83.2F [+2.4F]
Average Min Temp: 66.9F [+4.0F]
Mean Temp: 75.1F [+3.2F]
24-hr. Corr. Mean Temp: 74.1F [+3.3F]
Max Temp: 95F on 19th
Min Temp: 57F on 25th
Total heating degree day units (month): 6 [-3] *NCDC method
Total heating degree day units (season): 6 [-3] *start July 1 (NCDC)
Total cooling degree day units (month): 327 [+105] *NCDC method
Total cooling degree day units (season): 483 [+132] *start Jan 1 (NCDC)
PRECIPITATION:
Total precipitation: 3.09 inches [-0.93 inch]
Greatest 24-hr precipitation: 1.03 on 25th/26th
WIND:
Avg wind speed: 9.5 MPH
Avg corrected wind speed: 10.1 MPH
Prevailing wind direction: SW [12%]
Peak gust: 38 MPH SSW on 7th
Peak fastest mile: 32 MPH SSW on 7th
SUNSHINE:
Astronomical minutes: 14,428 of a possible 27,729 or 52%
Sun card minutes: 13,884 of a possible 26,682 or 52%
BHO Warmest July’s, deg F (1885-2013)
1) 75.1 in 2010
2) 74.9 in 1952
3) 74.1 in 1994
74.1 in 2013
5) 74.0 in 2011
6) 73.8 in 1999
7) 73.5 in 1949
8) 73.2 in 2012
BHO Warmest July Average Minimum Temperature, deg F (1885-2013)
1) 66.9 in 2013
2) 65.9 in 2010
3) 65.6 in 1994
4) 65.3 in 2006
5) 65.1 in 2008
BHO Greatest Number of 90-Degree Days per Month, (1885-2013)
1) 14 in July 1952
2) 13 in August 2002
3) 10 in August 1944
10 in July 1949
10 in July 1963
10 in July 2010
10 in July 2013
8) 9 in July 1911
9 in August 1928
10) 8 in August 1949
8 in July 1963
8 in July 1988
BHO July Greatest CDD Total, deg F (1885-2013)
1) 355 in 2010
2) 342 in 1952
3) 329 in 1994
4) 327 in 2013
5) 313 in 1949
6) 308 in 1999
7) 303 in 1911
BHO July Highest Vapor Pressure, mb (1932-2013)
1) 23.5 in 2013 (DP: 68F)
2) 22.5 in 1994 (DP: 67F)
3) 21.7 in 2006 (DP: 66F)
4) 21.3 in 1988 (DP: 65F)
5) 21.2 in 1955 (DP: 65F)
21.2 in 1975 (DP: 65F)
7) 21.0 in 1967 (DP: 65F)
BHO Monthly Highest Vapor Pressure, mb (1932-2013)
1) 23.5 in July 2013
2) 22.5 in July 1994
3) 21.7 in July 2006
4) 21.6 in August 1937
5) 21.5 in August 1988
6) 21.3 in July 1988
Today’s Observations:
7 A.M.
Weather: Clear with few thin cirrus all quads, altocumulus distant NNW-E-S
Temperature: 64F; Dew Point: 57F; Wind: NW at 8 kts
Sea-level pressure: 29.84 ins. Hg, decreasing then increasing
Visibility: 75 miles, light distant haze
24-hr precip: Trace
6-hr max. temp: 64
6-hr min. temp: 59F
BHO SA 1155 120 SCT 250 -SCT 75 105/64/57/3108/984/ AC DSNT NNW-E-S FEW CI
ALQDS LGT DSNT HZ/ 8/041 53007 MANUAL 7000/ 10064 20059
10 A.M.
Weather: Clear, few cumulus fractus in the vicinity of the observatory and
distant WSW-N, few cirrus/cirrocumulus in the vicinity of the observatory
and distant W-NNE and ESE-SSE, moderate and towering cumulus distant WSW-NW
Temperature: 74F; Dew Point: 56F; Wind: NW at 6 kts.
Sea-level pressure: 29.83 ins. Hg, decreasing then increasing
Visibility: 75 miles, light distant haze
BHO SA 1455 220 SCT 250 -SCT 75 103/74/63/3206/983/ FEW CUFRA VCTY STN AND
DSNT WSW-N MDT CU AND TCU DSNT WSW-NW FEW CI/CC VCTY STN AND DSNT W-NNE AND
ESE-SSE LGT DSNT HZ/ 8/209 55002
1 P.M.
Weather: Scattered cumulus and cumulus fractus, few cirrus in the vicinity
of the observatory and offshore NE-ESE
Temperature: 76F; Dew Point: 55F; Wind: WNW at 8 kts
Sea-level pressure: 29.80 ins. Hg, increasing then decreasing
Visibility: 75 miles, light distant haze
6-hr max. temp: 76F
6-hr min. temp: 64F
BHO SA 1755 100 SCT 250 –SCT 75 092/76/55/2908/980/ FEW TCU AND MDT CU
ALQDS FEW CI VCTY STN AND DSNT NE-ESE LGT DSNT HZ/ 8/201 58011 10076 20064
WEATHER SUMMARY FOR SATURDAY, AUGUST 3, 2013
TEMPERATURE (DEGREES F)
MAX…..77 NORMAL…..81
MIN…..63 NORMAL…..63
MEAN….70 NORMAL…..72
DEPARTURE FROM 30-YEAR NORMAL……………….-2
TOTAL DEPARTURE FOR THE MONTH……………….-2 [-0.9 DEGREE/DAY]
COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY………….5 DEPARTURE………-3
TOTAL COOLING UNITS FOR THE MONTH…………19 DEPARTURE………-3
TOTAL COOLING UNITS FOR THE SEASON……….502 DEPARTURE…….+129
TOTAL COOLING UNITS LAST SEASON TO DATE…..475 DIFFERENCE…….+27
PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY…………….22 WSW AT 11:35 A.M.
AERO…………………23 WSW AT 11:35 A.M.
ASOS…………………23 SW AT 11:35 A.M.
DAVIS………………..22 W AT 8:14 A.M. RMY 23
FASTEST MILE FOR YESTERDAY………………17 WSW AT 11:40 A.M.*
MAXIMUM 2-MINUTE ASOS AVERAGE……………17 SW AT 11:40 A.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………..17 SW AT 11:40 A.M.
AVERAGE WIND SPEED AND DIRECTION………..11.1 WSW
ASOS………………..10.4
DAVIS………………..9.9 SW [234 deg.]
* Last of multiple occurrences
PRECIPITATION (INCHES) THROUGH THIS MORNING (EST)
TOTAL PRECIPITATION 24 HRS ENDING 7 A.M….TRACE DEPARTURE…………-0.15
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE MONTH……….0.24 DEPARTURE…………-0.21
ASOS…………..0.23
TOTAL PRECIPITATION FOR THE YEAR……….35.53 DEPARTURE…………+4.09
ASOS…………..N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals
PRELIMINARY CLIMATE SUMMARY FOR JULY & AUGUST 2013 CALENDAR DAY DATA
DATA REPORTED:
DATE: MAX/MIN/MEAN/DEP/PRECIP/SUN(MIN.)/SUN(%)/ PEAK GUST/AERO GUST
AERO: Aerovane wind recording system gust
RMY: RMY = R.M. Young wind gust recording system added 8/9/2011
TSTM: Thunderstorm day (thunder heard some time during day)
….: Data not yet available, records not finalized
7/1 82/69/76/+6/0.05/247/27 29 S AERO 31 MPH SSW RMY 32
7/2 82/61/72/+2/T/100/11 23 SSW AERO 23 MPH SSW RMY 25
7/3 87/62/75/+4/T/556/61 28 SW AERO 30 MPH SW RMY 30
7/4 90/71/81/+10/0.00/811/89 25 WSW AERO 26 MPH SW RMY 28
7/5 92/73/83/+12/0.00/874/96 24 W AERO 25 MPH WSW RMY 25
7/6 90/73/82/+11/0.00/836/92 25 WNW AERO 25 MPH WNW RMY 26
7/7 91/72/82/+11/0.21/508/56 38 SSW AERO 43 MPH SSW RMY 44 TSTM
7/8 82/64/73/+1/0.04/617/68 18 NE AERO 20 MPH NE RMY 20 TSTM
7/9 72/63/68/-4/0.01/054/06 14 ENE AERO 14 MPH ENE RMY 14
7/10 84/65/75/+3/T/335/37 32 S AERO 36 MPH S RMY 35
7/11 79/69/74/+2/0.62/009/01 23 W AERO 23 MPH W RMY N/A TSTM
7/12 70/62/66/-6/0.00/162/18 29 NE AERO 29 MPH NE RMY 30
7/13 75/62/69/-3/0.08/009/01 21 ENE AERO 20 MPH ENE RMY N/A
7/14 89/71/80/+8/0.00/477/53 16 W AERO 16 MPH W RMY 16
7/15 91/72/82/+10/0.00/665/74 17 NW AERO 16 MPH NW RMY 18
7/16 91/71/81/+9/0.00/843/94 18 NNW AERO 16 MPH NNW RMY 16
7/17 93/74/84/+12/0.00/841/94 22 SW AERO 23 MPH SW RMY 25
7/18 90/75/83/+11/0.00/724/81 20 S AERO 21 MPH S RMY 22
7/19 95/76/86/+14/0.00/723/81 36 WSW AERO 38 MPH WSW RMY 38
7/20 93/72/83/+11/0.00/570/64 29 W AERO 30 MPH W RMY 31 TSTM
7/21 82/68/75/+3/0.00/568/64 16 NE AERO 16 MPH NE RMY 17
7/22 80/67/74/+2/T/514/58 17 NE AERO 17 MPH NE RMY 19 TSTM
7/23 82/68/75/+3/0.82/159/18 35 WSW AERO 36 MPH WSW RMY 39
7/24 84/64/74/+2/0.00/627/71 23 N AERO 23 MPH N RMY 23
7/25 64/57/61/-11/0.43/000/00 24 NNE AERO 24 MPH NNE RMY 25
7/26 67/59/63/-9/0.70/000/00 23 NNW AERO 23 MPH N RMY 23
7/27 82/60/71/-1/0.00/535/61 22 S AERO 23 MPH S RMY 23
7/28 78/66/72/0/0.03/149/17 16 ENE AERO 16 MPH ENE RMY 15
7/29 81/66/74/+2/0.10/402/46 20 S AERO 18 MPH S RMY 21 TSTM
7/30 81/61/71/-1/0.00/766/88 20 WNW AERO 18 MPH WNW RMY 20
7/31 80/61/71/-1/0.00/747/86 16 S AERO 15 MPH S RMY 16
8/1 81/62/72/0/0.01/…/.. 25 S AERO 26 MPH S RMY 27
8/2 81/62/72/0/0.23/…/.. 26 W AERO 26 MPH W RMY 28
8/3 77/63/70/-2/T/…/.. 22 WSW AERO 23 MPH WSW RMY 23
8/4 morning low temp: 59F; the normal low is now 63F
DAILY RECORDS FOR JULY 2013
7/14 – TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F;
ties previous record of 71F set in 1997
7/15 – NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 72F;
surpasses previous record of 70F set in 1901, 1934, 1995
7/16 – TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 71F;
ties previous record of 71F set in 1901, 1958, 1968
7/17 – TIED DAILY RECORD HIGH MINIMUM TEMPERATURE OF 74F;
ties previous record of 74F set in 1900
7/18 – NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 75F;
surpasses previous record of 73F set in 1900, 1999
7/19 – NEW DAILY RECORD HIGH MINIMUM TEMPERATURE OF 76F;
surpasses previous record of 72F set in 1949, 1991, 2005
DAILY RECORDS FOR AUGUST 2013
None so far.
DAILY EXTREMES
Temperature and precipitation records back to 1885, and
wind records back to 1940 (e = estimated):
RECORDS FOR AUGUST 4
HIGH 95F IN 1928
LOW 48F IN 1900
PRECIP 1.68 INS IN 1983
PEAK GUST 48 MPH SW IN 1974
RECORDS FOR AUGUST 5
HIGH 98F IN 1955
LOW 48F IN 1929,1972
PRECIP 3.03 INCHES IN 1893
PEAK GUST 60e MPH SW 1977
TODAY’S REPORT PREPARED BY: Forrest Iwanik
