Thursday, October 3, 2013

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

DAILY DISCUSSION AND CLIMATE SUMMARY
THURSDAY, OCTOBER 3, 2013
ALL TIMES ARE IN EASTERN STANDARD TIME

CONTINUING A WARM START TO OCTOBER
AIR MASS BECOMES MUCH DRIER TODAY
LIGHT WINDS, TEMPS. REACH 77 DEGREES

Temperatures averaged 10 degrees warmer than normal yesterday,
October 2nd and 6 degrees on the warm side on October 1st.
Again, for a third consecutive day our temperatures are running
well above the seasonal normal for early October. Today’s
high temperature has reached 77 degrees and the air mass
has become much drier with dew points falling from the low
50’s early today to the middle 40’s this afternoon along
with a relative humidity nearing 30%

The streak of dry weather continues. The last measurable rainfall
occurred more than 10 days ago on September 22. From September 3 through
October 2, rainfall has only amounted to 1.16 inches, which is only about
29% of the 30-year normal for this period.

SEPTEMBER FINISHES ON THE COOL SIDE AND SLIGHTLY ON THE DRY SIDE

SEPTEMBER 2013 PRELIMINARY STATISTICS:
(departures relative to 1981-2010 average)

TEMPERATURE:
Average Max Temp: 71.7F [+0.1F] Average Min Temp: 52.5F [-2.1F] Mean Temp: 62.1F [-1.0F] 24-hr. Corr. Mean Temp: 61.9F [-0.2F] Max Temp: 93F on 11th
Min Temp: 40F on 17th and 24th

Total heating degree day units (month): 134 [+17] *NCDC method
Total heating degree day units (season): 146 [+4] *start July 1 (NCDC)
Total cooling degree day units (month): 56 [-4] *NCDC method
Total cooling degree day units (season): 696 [+99] *start Jan 1 (NCDC)

PRECIPITATION:
Total precipitation: 3.91 inches [-0.15 inch] Greatest 24-hr precipitation: 2.44 inches on 1st/2nd

WIND:
Avg wind speed: 10.0 MPH
Avg corrected wind speed: 10.6 MPH
Prevailing wind direction: W [12%] Peak gust: 38 MPH S on 22nd
Peak fastest mile: 30 MPH S on 21st

SUNSHINE:
Total astronomical minutes: 14,488 (241.5 hrs.)
out of possible 22,440 minutes (374.0 hrs) or 65%

Total Campbell Stokes card minutes; 13,944 (232.4 hrs.
out of possible 21,502 (358.4 hrs.) or 65%

Today’s Observations:

7 A.M.
Weather: Thin scattered cirrus, few lower cirrus patches, thin ground
fog ESE-SW below inversion, distant haze
Temperature: 58F; Dew Point: 51F; Wind: WNW at 9 kts.
Sea-level pressure: 30.08 ins. Hg, rising then more rapidly
Visibility: 50 miles, except 30 miles NE-S, 60 miles W-NW,
patches thin ground fog ESE-SW, distant haze W-NW
6-hour min. temp: 56F
BHO SA 1155 300 –SCT 50 185/58/51/3009/008/ FEW LWR CI PTCHS THN GF ESE-SW
BLO INVSN VSBY NE-S 30 W-NW 60 DSNT HZ/ 8/001 53017 10060 20056

10 A.M.
Weather: Scattered dense cirrus, thin broken cirrus, thin overcast cirrus,
large break in overcast, band of clear sky mostly distant NW-E
Temperature: 70F; Dew Point: 52F; Wind: WNW at 5 kts.
Wind: Light
Sea-level pressure: 30.10 ins. Hg, rising then falling slightly,
higher than 3 hours ago
Visibility: 50 miles, except 30 miles NE-S, 60 miles W-NW,
distant haze, thin smoke layer SW-W and NNE-ENE
BHO SA 1455 220 SCT 250 –BKN 300 –OVC 50 192/70/52/3005/010/ PTCHS DNS CI
LG BINOVC/CLR SKY BND XTDNG MSTLY DSNT NW-E THN K LYR NNE-ENE AND SW-W
VSBY NE-S 30 W-NW 60 WND LGT/ 8/002 50007

1 P.M.
Weather: Scattered dense cirrus, thin broken cirrus, (2 levels)
Temperature: 77F; Dew Point: 44F; Wind: WSW at 6 kts,
Wind: Light
Sea-level pressure: 30.05 ins. Hg, decreasing then more rapidly
Visibility: 60 miles, 30 miles NE-E, hazy, 70 NW, light distant haze
6-hour max. temp: 77F
BHO SA 1755 220 SCT 250 –BKN 300 –BKN 60 176/77/44/2406/005/ PTCHS DNS CI
MSTLY CLR SKY BND DSNT NNW-NE THN K LYR ALG HRZN DSNT NE-E VSBY NE-E 30
NE-E HAZY, NW 70 LGT DSNT HZ WND LGT/ 8/002 58016 10077 20058

WEATHER SUMMARY FOR WEDNESDAY, OCTOBER 2, 2013

TEMPERATURE (DEGREES F)
MAX…..78 NORMAL…..65
MIN…..56 NORMAL…..48
MEAN….67 NORMAL…..57

DEPARTURE FROM 30-YEAR NORMAL…………………+10
TOTAL DEPARTURE FOR THE MONTH…………………+16 [+7.8 DEGREES/DAY]

COOLING DEGREE DAYS (SEASON JAN TO DEC)
TOTAL COOLING UNITS FOR YESTERDAY…………..2 DEPARTURE………+2
TOTAL COOLING UNITS FOR THE MONTH…………..2 DEPARTURE………+1
TOTAL COOLING UNITS FOR THE SEASON………..698 DEPARTURE…….+100
TOTAL COOLING UNITS LAST SEASON TO DATE……765 DIFFERENCE…….-67

HEATING DEGREE DAYS (SEASON JUL TO JUN)
TOTAL HEATING UNITS FOR YESTERDAY…………..0 DEPARTURE………-9
TOTAL HEATING UNITS FOR THE MONTH…………..2 DEPARTURE……..-15
TOTAL HEATING UNITS FOR THE SEASON………..148 DEPARTURE……..-11
TOTAL HEATING UNITS LAST SEASON TO DATE……111 DIFFERENCE…….+37

PEAK GUST AND AVERAGE WIND SPEED (MPH)
PEAK WIND GUST FOR YESTERDAY………………29 W AT 3:48 P.M.
AERO…………………..30 W AT 12:17 P.M.
ASOS…………………..30 W AT 3:49 P.M.
DAVIS………………….28 W AT 3:49 P.M. RMY 29
FASTEST MILE FOR YESTERDAY………………..22 W AT 3:50 P.M.
MAXIMUM 2-MINUTE ASOS AVERAGE……………..22 W AT 3:50 P.M.
MAXIMUM 2-MINUTE DAVIS AVERAGE…………….20 W AT 3:50 P.M.
AVERAGE WIND SPEED AND DIRECTION…………14.1 W
ASOS…………………13.7
DAVIS………………..12.3 W [270 degrees]

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……….0.00 DEPARTURE………….-0.31
ASOS…………..0.00
TOTAL PRECIPITATION FOR THE YEAR……….41.92 DEPARTURE………….+2.53
ASOS…………..N/A*
*ASOS malfunctioned during storm on 2/8-9, leading to erroneous totals

PRELIMINARY CLIMATE SUMMARY FOR SEPTEMBER & OCTOBER 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

9/1 76/67/72/+4/2.32/008/01 33 S AERO 39 MPH S RMY 38 TSTM
9/2 79/67/73/+5/0.43/056/07 30 SSE AERO 33 MPH SSE RMY N/A TSTM
9/3 79/61/70/+3/0.00/219/28 28 S AERO 29 MPH S RMY 30 TSTM
9/4 78/57/68/+1/0.00/733/94 24 W AERO 25 MPH W RMY 25
9/5 66/51/59/-8/0.08/179/23 20 NNE AERO 20 MPH NNE RMY 21
9/6 68/46/57/-10/0.00/751/97 18 WSW AERO 17 MPH WSW RMY N/A
9/7 78/51/65/-1/0.00/594/77 20 WSW AERO 21 MPH WSW RMY 21
9/8 74/50/62/-4/0.00/646/84 31 NW AERO 33 MPH NW RMY 32
9/9 69/47/58/-8/T/536/70 23 SW AERO 23 MPH SSW RMY N/A
9/10 73/56/65/0/0.03/008/01 30 S AERO 32 MPH S RMY 33
9/11 93/68/81/+16/0.00/654/86 25 SW AERO 27 MPH SW RMY N/A
9/12 85/66/76/+11/0.47/455/60 32 S AERO 33 MPH S RMY 34 TSTM
9/13 79/58/69/+5/0.17/242/32 24 NNW AERO 25 MPH NNW RMY 23
9/14 67/52/60/-4/0.00/361/48 21 NW AERO 21 MPH NW RMY 21
9/15 70/48/59/-5/0.00/547/73 17 WSW AERO 18 MPH WSW RMY 20
9/16 66/46/56/-7/0.02/179/24 29 NNW AERO 31 MPH NNW RMY 30
9/17 60/40/50/-13/0.00/722/97 27 NNE AERO 27 MPH NNE RMY 26
9/18 73/47/60/-2/0.00/726/98 18 W AERO 18 MPH WSW RMY 20
9/19 78/51/65/+3/0.00/731/99 17 WSW AERO 16 MPH WSW RMY 18
9/20 78/54/66/+4/0.00/706/96 18 SSW AERO 18 MPH SSW RMY 23
9/21 74/57/66/+4/T/512/70 35 S AERO 40 MPH S RMY N/A
9/22 70/49/60/-1/0.39/365/50 38 S AERO 39 MPH S RMY 42
9/23 63/43/53/-7/0.00/711/98 25 NW AERO 26 MPH NW RMY 28
9/24 65/40/53/-7/0.00/702/97 22 ENE AERO 22 MPH ENE RMY 23
9/25 64/45/55/-5/0.00/512/71 18 N AERO 18 MPH N RMY 19
9/26 63/52/58/-1/0.00/503/70 16 ENE AERO 14 MPH ENE RMY 16
9/27 64/53/59/0/0.00/307/43 21 NE AERO 20 MPH NE RMY 20
9/28 70/52/61/+3/0.00/698/98 16 NNE AERO 15 MPH NNE RMY 15
9/29 65/50/58/0/0.00/553/78 15 ESE AERO 15 MPH ESE RMY 15
9/30 64/51/58/0/0.00/573/81 15 NE AERO 14 MPH ENE RMY N/A

10/1 75/50/63/+6/0.00/676/96 16 WNW AERO 16 MPH WNW RMY 18
10/2 78/56/67/+10/0.00/666/95 29 W AERO 30 MPH W RMY 29

10/3 the morning low temp: 56F; the normal low is now 48F

DAILY RECORDS FOR SEPTEMBER 2013
9/1 – NEW DAILY RECORD MAXIMUM PRECIPITATION OF 2.32 INCHES;
surpasses previous record of 1.60 inches set in 1927
9/11 – TIED DAILY RECORD MAXIMUM HIGH TEMPERATURE OF 93F;
ties record of 93F set in 1983

DAILY RECORDS FOR OCTOBER 2013
None so far.

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

RECORDS FOR OCTOBER 3
HIGH 82F IN 1922
LOW 28F IN 1899
PRECIP 1.76 INCHES IN 1979
PEAK GUST 62 MPH WNW IN 1964

RECORDS FOR OCTOBER 4
HIGH 84F IN 2007
LOW 28F IN 1888
PRECIP 1.87 INCHES IN 2011
PEAK GUST 59 MPH SSW IN 1990

TODAY’S REPORT PREPARED BY: Robert Skilling